wyoming clean water plant biosolids management final · pdf filewyoming clean water plant...
TRANSCRIPT
Wyoming Clean Water Plant
Biosolids Management Final Report
Team 7: Blackwards
Eyosias Ashenafi
Rachel Gaide
Andrew Mitchell
Katherine Vogel
May 2014.
Copyright © 2014 Team 7 and Calvin College.
All rights reserved.
Blackwards
i
Executive Summary
This project focuses on designing a progressive biosolids management system for City of
Wyoming Clean Water Plant (CWP). Landfills contribute 35% of all methane emissions in the US,
and methane gas is 25 times more harmful to the environment than carbon dioxide.
Figure A: Schematic of Proposed Sludge Management Process
The team selected anaerobic digestion for sludge stabilization. The choice was made over
chemical treatment and aerobic digestion on the basis of monetary and non-monetary factors.
The primary design specifications of the client were:
- Class A biosolids product
- Progressive technology
- Nutrient recovery options
Anaerobic digestion is a relatively newer technology that enables treatment plant to
produce Class A product. The team selected temperature-phase operating condition where three
smaller cylindrical tanks operating at thermophillic (65°C) conditions precede two much larger
egg shaped digesters operating at mesophillic conditions (35°C). The tank size for each
thermophillic tank is 60,000 gallons and hydraulic residence time is 22 hours. The mesophilic
tanks have a volume of 1.5 million gallons each and have a hydraulic residence time of 15 days.
Proposed digestion system is shown in Figure B.
Blackwards
ii
Figure B: Two- stage Anaerobic Digestion system (CB&I)
Thickening was then explored in order to decrease sludge volume and therefore decrease
digester costs. Thickening options reviewed include centrifuges, rotary drums and belt presses.
Centrifuges were determined to be the best alternative because there are currently two units in
use that can be utilized in the proposed new process. The new centrifuge can be installed for
$588,800 and will be utilized to get the percent solids in waste activated sludge from 0.7% to 4%.
Once anaerobic digestion was selected as the stabilization option, the need for
dewatering was evaluated. It was decided that for ease of transportation, a dewatering step was
necessary. The methods for dewatering were the same as those for thickening, without the
benefit of having two on site. Despite this, centrifuges still proved to be the best option for the
plant. A building will also need to be put on site for these centrifuges. A 50 x 50 foot steel building
is proposed for this purpose and will cost approximately $40,000.
The team built a bench scale digester in the spring semester. The system was fed with
sludge samples from Wyoming and Grandville CWP. Total and volatile solids test was performed
on samples collected daily. The latter test indicates level of biodegradation that occurs during
digestion. Figure C below shows results from the final run. Experimental period was 18-days long.
Over this period, daily sludge samples were collected, stored at 4 C° and burned weekly. Decrease
of volatile solids can be observed in Figure C which imply volatile solids destruction and methane
production.
Blackwards
iii
Figure C: Bench Scale Results
The team designed a site plan for the proposed biosolids management system which
addresses all of the space constraints for the digesters and additional thickening and dewatering
units. The site plan also provides details on the constraints of operation throughout the year.
Post treatment storage must be able to store all of the biosolids that cannot be land applied due
to seasonal constraint.
Table A: Project Cost Breakdown
Project Cost
Digester System $15 M
Holding Tanks $1 M
Thickening $600 K
Dewatering $1.2 M
Storage Tanks $3.1 M
Cogeneration $1.5 M
Biogas Conditioning $507 K
Gas Storage $300 K
Contingency $2.1 M
Total $22.9 M
Blackwards
iv
Blackwards
v
Table of Contents
Executive Summary .......................................................................................................................... i
Table of Contents ............................................................................................................................. v
Table of Figures ............................................................................................................................. viii
Report Tables .................................................................................................................................. ix
Abbreviations ................................................................................................................................... x
1. Introduction .............................................................................................................................. 11
1.1 Purpose Statement .............................................................................................................. 11
1.2 The Project .......................................................................................................................... 11
1.3 Overview of Wastewater Treatment .................................................................................. 11
1.4 Overview of Biosolids Classification .................................................................................... 13
2. The Client .................................................................................................................................. 14
2.1 City of Wyoming .................................................................................................................. 14
2.2 Wyoming Clean Water Plant ............................................................................................... 14
2.2.1 Overview ....................................................................................................................... 14
2.2.2 Current Wastewater Treatment Practice ..................................................................... 15
2.2.3 Current Biosolids Management .................................................................................... 16
3. Sludge Thickening Design.......................................................................................................... 18
3.1 Introduction ......................................................................................................................... 18
3.2 Evaluation of Thickening Alternatives ................................................................................. 19
3.3 Recommendation ................................................................................................................ 21
3.4 Total Solids Composition for Digestion ............................................................................... 21
3.5 Thickening and Holding Tank Configuration Decision ........................................................ 22
3.6 Cost Information ................................................................................................................. 25
4. Pre-Digestion System: Thermal Hydrolysis ............................................................................... 26
5. Sludge Holding Tank Design ...................................................................................................... 28
5.1 Existing system .................................................................................................................... 28
5.2 Proposed Addition ............................................................................................................... 28
5.3 Mixing Method .................................................................................................................... 29
Blackwards
vi
5.4 Material of Construction ..................................................................................................... 30
5.5 Gas Elimination .................................................................................................................... 30
5.6 Cost Information ................................................................................................................. 31
6.1 Introduction ......................................................................................................................... 32
6.2 Evaluation of Stabilization Alternatives .............................................................................. 32
6.3 Recommendation ................................................................................................................ 34
6.4 Anaerobic Digestion Process Chemistry.............................................................................. 35
6.5 Class A Biosolids Requirement ............................................................................................ 36
6.6 Digestion Temperature ....................................................................................................... 39
6.7 Digester Configuration ........................................................................................................ 41
6.7.1 Tank Design ................................................................................................................... 41
6.7.2 Digester Shape .............................................................................................................. 41
7. Digester Biogas Production ....................................................................................................... 46
7.1 Introduction ......................................................................................................................... 46
7.2 Potential Methane Production at Wyoming CWP .............................................................. 48
7.3 Operation and Maintenance ............................................................................................... 52
7.4 Case Studies......................................................................................................................... 53
8. Cogeneration ............................................................................................................................. 55
8.1 Cogeneration Implementation ............................................................................................ 55
8.2 Cost Savings ......................................................................................................................... 55
8.3 Biogas Conditioning ............................................................................................................. 57
8.4 Cost Information ................................................................................................................. 58
9. Post-Digestion Dewatering ....................................................................................................... 59
9.1 Dewatering Introduction ..................................................................................................... 59
9.2 Proposed Percent Dewatering ............................................................................................ 59
9.3 Method of Dewatering ........................................................................................................ 60
10. Biosolids Storage Tanks........................................................................................................... 61
10.1 Design Considerations ....................................................................................................... 61
10.2 Current Biosolids Storage Facilities ................................................................................... 61
10.3 Required Biosolids Storage Capital ................................................................................... 62
11. Pumping Station Design .......................................................................................................... 64
Blackwards
vii
11.1 Introduction....................................................................................................................... 64
11.2 Pipe Selection .................................................................................................................... 64
11.3 Pipe Diameters .................................................................................................................. 66
11.4 Cleaning Pipes ................................................................................................................... 67
11.5 Cleaning Methods ............................................................................................................. 67
12. Nutrient Removal/Recovery ................................................................................................... 68
13. Site Layout ............................................................................................................................... 69
14. Bench Scale Experiments ........................................................................................................ 70
14.1 Digester Construction........................................................................................................ 70
14.2 Operation and Testing ....................................................................................................... 71
14.3 Results and Discussion ...................................................................................................... 72
14.4 Safety ................................................................................................................................. 73
15. Total Cost of Proposed System ............................................................................................... 74
16. Future Work ............................................................................................................................ 74
Acknowledgements ....................................................................................................................... 75
References .................................................................................................................................... 76
Appendix I: Team Management ................................................................................................... 79
Appendix II: Mathcad Calculations ............................................................................................... 83
Appendix III: Hydraulic Profile .................................................................................................... 105
Appendix IV: Manual of Laboratory Tests .................................................................................. 107
Appendix V: Formatted Selections from Clean Water Act Part 503 ........................................... 113
Appendix VI: Equipment Info ...................................................................................................... 123
Blackwards
viii
Table of Figures
Figure 1: Layout of a Conventional Wastewater Treatment System ........................................... 12
Figure 2: Projected Biosolids Use and Disposal in the United States (EPA, 1999) ....................... 13
Figure 3: Aerial View of Wyoming CWP ........................................................................................ 15
Figure 4: Current Wastewater Treatment at Wyoming CWP ....................................................... 16
Figure 5: Current Biosolids Management at Wyoming CWP ........................................................ 17
Figure 6: Thickening Room with Andritz Bird Centrifuges ............................................................ 18
Figure 7: Schematic of a typical centrifuge system (EPA, 2000) ................................................... 21
Figure 8: Centrifuge Placement Alternatives ................................................................................ 22
Figure 9: Centrisys Model CS26-4 Decanter Centrifuge ............................................................... 25
Figure 10: Sludge Stabilization with CAMBI THP System .............................................................. 27
Figure 11: Sludge Holding Tanks at Wyoming CWP ...................................................................... 28
Figure 12: Jet Mixing System ........................................................................................................ 29
Figure 13: Exponential Cost Curve for Digester Construction ...................................................... 30
Figure 14: Stages of Anaerobic Digestion ..................................................................................... 35
Figure 15: Treatment Processes that achieve Class A Biosolids ................................................... 38
Figure 16: Comparison of Coliform Destruction (Kade, 2004) ..................................................... 40
Figure 17: Two Stage, High-rate Anaerobic Digester .................................................................... 41
Figure 18: Egg Shaped Digester Configuration ............................................................................. 42
Figure 19: Single-stage Cylindrical Digesters ................................................................................ 43
Figure 20: Two- stage Anaerobic Digestion system (CB&I) .......................................................... 45
Figure 21: Effect of Sludge Retention Time (SRT) on VSS Reduction for High-rate System ......... 46
Figure 22: Potential Sources of Biogas for an AD system ............................................................. 48
Figure 23 : Methane Production Prediction for Thermophilic System ......................................... 49
Figure 24 : Methane Production Prediction for TPAD System ..................................................... 50
Figure 25 : Methane Production as a Function of Influent Flow to Plant .................................... 51
Figure 26: Egg-shaped Digester at Grandville CWP ...................................................................... 53
Figure 27: Comparison of Sludge Flow and Associated Gas Production ...................................... 54
Figure 28: Uses for Energy produced from Digestion ................................................................... 56
Figure 29: Hydrogen Sulfide .......................................................................................................... 58
Figure 30: Siloxane Removal System ............................................................................................ 58
Figure 31: Injection Biosolids Land Application Equipment ......................................................... 59
Figure 32: Biosoilds Storage Tanks in the rear .............................................................................. 61
Figure 33: Seasonal Variations in Biosolids Storage in 2013 ........................................................ 62
Figure 34: Pumping Head Needed as a Function of Pipe Diameter ............................................. 66
Figure 35: Suggested Location of Digestion Facility ..................................................................... 69
Figure 36: Bench Scale Anaerobic Digester .................................................................................. 70
Figure 37: Trial Run Spill ............................................................................................................... 71
Figure 38: Results from Trial Run .................................................................................................. 72
Blackwards
ix
Figure 39: Results from Final Digestion Run ................................................................................. 73
Figure 40: Team Photo .................................................................................................................. 79
Figure 41: Spectronic 20D+ equipment ...................................................................................... 109
Report Tables
Table 1: Average Sludge Composition .......................................................................................... 17
Table 2: Thickening Design Matrix ................................................................................................ 20
Table 3 : Comparison of Thickening Placement Alternatives ....................................................... 24
Table 4: Description of Proposed Centrifuge ................................................................................ 25
Table 5: Capital Cost of Holding Tanks.......................................................................................... 31
Table 6: Design Matrix for Sludge Stabilization ............................................................................ 34
Table 7: EPA CWA Pollutant Limits ............................................................................................... 37
Table 8: Digester Operating Temperature Characteristics ........................................................... 40
Table 9: Comparison of cylindrical and egg-shaped digesters ..................................................... 42
Table 10: Configuration of Cylindrical Digesters for Wyoming CWP ............................................ 44
Table 11: Summary of ESD facility plan from CB&I....................................................................... 45
Table 12: Typical Characteristic of Primary and Secondary Solids ............................................... 47
Table 13: Estimated Biogas Production ........................................................................................ 47
Table 14: Information about Wyoming Waste Flow .................................................................... 48
Table 15: VSR Assumption for AD systems ................................................................................... 49
Table 16: Digester Monitoring (WEF, 2007) ................................................................................. 52
Table 17: Digester Gas Composition (by volume)......................................................................... 57
Table 18: Cost Information for Biogas Conditioning .................................................................... 58
Table 19: Comparison of Final Biosolids Percent Solids Composition .......................................... 60
Table 20: Advantages and Disadvantages of Progressive Cavity Pump ....................................... 65
Table 21: Length of New Pipe Needed for Each Section of Route ............................................... 65
Table 22: Comparison of Nutrient Recovery Technologies .......................................................... 68
Table 23: Work Breakdown Structure (Fall 2013) ........................................................................ 80
Table 24: Work Breakdown Structure (Spring 2014) .................................................................... 81
Table 25: Solids Measurement Datasheet .................................................................................. 108
Table 26: COD experiment Datasheet ........................................................................................ 110
Blackwards
x
Abbreviations
AD Anaerobic Digestion BOD Biological Oxygen Demand °C degrees Celsius CHP Combined Heat and Power COD Chemical Oxygen Demand CWA Clean Water Act CWP Clean Water Plant DAF Dissolved Air Floatation EPA Environmental Protection Agency EQ Exceptional Quality
gpm gallons per minute GVRBA Grand Valley Regional Biosolids Authority HRT Hydraulic Residence Time kg kilogram lb/day pounds mass per day m3/day cubic meters per day mg milligram mgd million gallons per day MPN Most Probable Number NPDES National Pollutant Discharge Elimination System ppb Parts per billion ppm Parts per million PS Primary Sludge SCFAs Short-Chained Fatty Acids SRT Sludge Retention Time THP Thermal Hydrolysis Process TPAD Temperature Phase Anaerobic Digestion TS Total Solids TSS Total Suspended Solids tWAS Thickened Waste Activated Sludge UV Ultraviolet VAR Vector Attraction Reduction VS Volatile Solids VSR Volatile Solids Reduction WAS Waste Activated Sludge WW Wastewater WWTP Wastewater Treatment Plant WWTPs Wastewater Treatment Plants
Blackwards
11 | P a g e
1. Introduction
1.1 Purpose Statement
The purpose of this project is to design a modern, efficient and environmentally friendly
biosolids management system for the City of Wyoming Clean Water Plant (CWP). This document
will elaborate on the design process and future work that need to be completed.
1.2 The Project
Calvin College’s Engineering Program includes a year-long senior design project. The
design team formed for this class pursued appropriate project alternatives considering the
previous educational experience of the team members. Dr. David Wunder, the team’s faculty
advisor, suggested that the team approach the City of Wyoming CWP for potential design
projects. The City of Wyoming Clean Water Plant was built to handle waste water from Wyoming,
Byron Center and surrounding cities. The team met with Myron Erickson, superintendent of the
CWP, and with Aaron Vis, Project Manager of GVRBA (Grand Valley Regional Biosolids Authority).
During the meeting, the team was informed that GVRBA was currently collecting bids from
consulting firms for stabilization alternatives to current practice. Upon further consulting with
Myron Erickson, the team decided to design an anaerobic digester for biosolids management for
the City of Wyoming CWP.
1.3 Overview of Wastewater Treatment
In general, municipal wastewater is collected from residential areas, businesses and
industries, and pumped to wastewater treatment plants (WWTPs). Conventional wastewater
treatment consists of four major stages (Figure 1).
Blackwards
12 | P a g e
Figure 1: Layout of a Conventional Wastewater Treatment System
I) Preliminary Treatment is the first step in wastewater treatment. Rags and floatables
present in influent stream are physically removed using bar screens by size. This stage
increases downstream load capacity while preventing damage to pumping
equipment.
II) Primary Treatment is the second stage which removes sediments by a gravity settling
and skimmers. Sludge is allowed to settle inside a primary clarifier. Skimmers remove
suspended solids and grease material on the top surface.
III) Secondary Treatment is a biological treatment with an aeration and settling stage. It
is commonly referred to as activated sludge. During aeration, microbes feed on
organic matter inside a tank fitted with air diffusers. After a certain period of time,
the waste stream is sent to a secondary clarifier. Sludge settles inside the clarifier.
Some portion of the sludge produced is recycled back to the aeration tank to maintain
microbial growth while the remaining is sent for further treatment. Management of
solids produced from primary and secondary clarifiers is the focus of this project.
IV) Tertiary Treatment (Disinfection) is the final step in wastewater treatment before
supernatant or treated effluent is sent to water bodies. Common disinfection schemes
include chlorination, ozonation, and ultraviolet (UV) radiation.
Blackwards
13 | P a g e
Several variables are considered in the design and construction of WWTPs including operating
capacity and regulations. Population growth and industrial expansion is accounted for in
determination of design capacity. Treatment facilities and government agencies assess the
quality of supernatant water and by-product sludge to ensure it meets Environmental Protection
Agency (EPA) and National Pollutant Discharge Elimination System (NPDES) standards.
1.4 Overview of Biosolids Classification
Biosolids are treated residual solids left over after waste water treatment process.
Treated biosolids can be classified as either Class A or Class B. Class A Biosolids can also be
categorized as “exceptional quality” (EQ) if they satisfy pollutant concentration limits. Biosolids
can be applied to land, placed on a surface disposal site, or fired in a sewage sludge incinerator.
Figure 2: Projected Biosolids Use and Disposal in the United States (EPA, 1999) shows current
biosolids disposal methods in the United States. In land application, treated biosolids are used
to moisturize the soil and as fertilizers. “Surface disposal site” is another name for a landfill.
From an environmental perspective, land application is the preferred option for final disposal
place of treated biosolids.
Figure 2: Projected Biosolids Use and Disposal in the United States (EPA, 1999)
0%
10%
20%
30%
40%
50%
60%
1998 2000 2005 2010
Land Application Advanced Treatment Other Benficial Use
Surface Disposal/ Landfill Incineration Other disposal
Blackwards
14 | P a g e
The end location of the biosolids determines what regulations are applicable from Part
503 of the Clean Water Act (CWA). There are three parts to achieving Class A designation for
biosolids. First, the pathogenic content of the sludge must be reduced sufficiently. Second, there
must be sufficient Vector Attraction Reduction (VAR). Third, inorganic pollutants must be below
certain maximum values. These issues are explained in context more in “Section 6.5 Class A
Biosolids Requirement.”
Class A Biosolids, with appropriate pollutant loads, can be land applied to agricultural and
non-agricultural land, public contact sites, a reclamation site, lawns and/or home gardens. Class
A Biosolids can be given away to local farms or it can be sold for its nutrients. Class B Biosolids
are restricted as to where and when land application can occur.
2. The Client
2.1 City of Wyoming
The city of Wyoming lies within the Grand Rapids Metro area in western Michigan. It
occupies an area of 24.9 square miles and serves a population of 73,000 people. The area also
includes several major industries including Gordon Food Services, Michigan Turkey Producers and
Country Fresh.
2.2 Wyoming Clean Water Plant
2.2.1 Overview
Wyoming’s CWP is located on Ivanrest Avenue on the southwestern edge of Wyoming
(see Figure 3: Aerial View of Wyoming CWP). The plant treats wastewater from the City of
Wyoming, the City of Kentwood, Gaines Township, and Byron Township, and has a design
capacity of 24 million gallons per day (mgd). Current average daily flow through the plant is
14.7mgd, 12% of which originates from local industries. Treated water from the plant is
discharged into the Grand River.
Blackwards
15 | P a g e
Figure 3: Aerial View of Wyoming CWP
2.2.2 Current Wastewater Treatment Practice
Raw wastewater from the City of Wyoming, the City of Kentwood, Byron Township, and
Gaines Township is collected at Wyoming CWP. Bar screens remove large sediments and
materials present in incoming wastewater. The flow proceeds to primary clarifiers where large
granular molecules are removed by gravity sedimentation. Currently, there are four primary
clarifiers with removal rate of 10-40% biological oxygen demand (BOD) and 50-60% total
suspended solids (TSS). Clarified effluent from primary treatment proceeds to one of three
aeration basins. The basins are equipped with fine bubble diffusers to aerate and provide a
conducive environment for microbial growth. Mixed liquor is sent to secondary clarifiers.
Flocculated and dense, suspended solids in mixed liquor settle inside the clarifiers. In 2008, a
biological phosphorus removal process (anoxic/anaerobic zone) was incorporated into secondary
treatment. Waste activated sludge (WAS) is recycled to the aeration basins. Clear low-BOD, low-
TSS clarified effluent is chlorinated and de-chlorinated for disinfection before being discharged
to the Grand River. An overview of the treatment process is shown in Figure 4.
Blackwards
16 | P a g e
Figure 4: Current Wastewater Treatment at Wyoming CWP
2.2.3 Current Biosolids Management
Biosolids produced by Wyoming and Grand Rapids WWTPs are currently managed by the
GVRBA. GVRBA was formed in 2003 to address strict regulatory requirements and manage
regionally-produced biosolids efficiently.
Sources of biosolids at Wyoming CWP are primary and secondary clarifiers (Figure 5).
Based on dry ton basis, approximately 55% thickened waste activated sludge (tWAS) and 45%
primary sludge (PS) pumped to sludge holding tanks. Certain volume of WAS from secondary
clarifiers is thickened using centrifuges. Thickened WAS is stored in one of three wet wells before
it is sent to GVRBA pumping station or storage tanks. Characteristics of PS, un-thickened and
thickened WAS are given in Table 1: Average Sludge Composition. To prevent phosphorus
release, WAS is thickened to maximum of 2% total solids (TS), and the wet wells are aerated and
treated with ferric chloride.
Blackwards
17 | P a g e
Table 1: Average Sludge Composition1
Parameter Primary Sludge
Un-thickened WAS
Thickened WAS
Total Solids, %TS 4.26 0.96 3.53
Volatile Solids, %VS 3.72 0.8 2.95
pH 5.52 6.98 6.53
Alkalinity (mg/L) 922 216 444
Approximately 75% of the year biosolids from Wyoming CWP are stored in three tanks
with a combined capacity of 6 million gallons. The biosolids are then lime stabilized and then used
for land application. This process is shown in Figure 5. The remaining 25% is pumped to GVRBA
storage tanks in Grand Rapids WWTP through two 3-miles long pipelines. Incoming flow is
combined with biosolids from the City of Grand Rapids WWTP. The resulting flow is dewatered
by centrifuges and stored in a landfill.
Figure 5: Current Biosolids Management at Wyoming CWP
The team sought out to design a new biosolids management process, focusing on energy
and nutrient capture, environmental concerns and government regulations.
1 Data from 12/11/13 to 02/15/14
Blackwards
18 | P a g e
3. Sludge Thickening Design
3.1 Introduction
Thickening is a mechanical process of altering the solid content of an influent stream. By
removing fluid portion of the entering stream, it is used to increase the concentration of solids in
sludge. Primarily, a thickening step increases tank detention time, reduces operation costs and
lowers tankage capacity downstream in biosolids processing and storage.
Currently, thickening at Wyoming CWP is performed with two Andritz Bird centrifuges
with a unit capacity of 265 gallons per minute (gpm). The existing thickening system is shown in
Figure 6. The centrifuges thicken WAS from 0.5-1%TS on average to 4-5%TS. Mannich and
emulsion polymers are added enhance solids capture. The centrate is the clarified supernatant
produced from the process and is sent to the head works of the plant. Existing centrifuge units
were considered as thickening alternative. Both centrifuges are 24 years old; however one was
rebuilt in 2012, and the other was rebuilt in 2013. The plant expects another 10 years of operation
from both centrifuges. A rehabilitation of the thickening system is under consideration by the
Wyoming CWP.
Figure 6: Thickening Room with Andritz Bird Centrifuges
Blackwards
19 | P a g e
3.2 Evaluation of Thickening Alternatives
Three sludge thickening technologies were considered in the design process. Score of 0%
to 100% was assigned on the basis of performance of each alternative under each category. High
score corresponds to attractive feature or good performance in the respective category. This
leads to values that seem in conflict with categories that describe weaknesses rather than
strengths. Decision matrix of thickening alternatives is presented on Table 2.
Category Considerations:
1. Sustainability: How much energy is required to operate this technology? What form of
energy is used and how is it produced? How much equipment is already owned by the
client and can be reused for this project? Does this technology require nonrenewable
resources in order to function? How efficient is the technology at completing the required
process?
2. Effluent Quality: Does this technology thicken solids adequately? Is it possible to get a
uniform solids concentration in effluent consistently?
3. Progressive Technology: Would the novelty of this technology improve public image of
the facility?
4. Capital Costs: How much does the equipment cost to obtain? How much will it cost to
install? How much time will it take employees to train on using the new equipment?
5. Operating Costs: How much does the technology cost to operate each month?
6. Safety: Is the technology difficult to operate or does the technology utilize conditions that
could cause employee injury during machine malfunction?
7. Expandability: Assuming that the future will require increased production can this
technology be expanded easily?
Blackwards
20 | P a g e
Table 2: Thickening Design Matrix
Category
Weight
Thickening Alternatives
Centrifuge Rotary Drum Gravity Belt
Press
Sustainability 13 1 0.6 0.7
Effluent Quality 16 0.7 0.7 0.7
Progressive Technology 10 0.7 0.7 0.
Capital Costs 19 1 0.7 0.7
Operating Cost 22 0.8 0.8 0.6
Safety 12 0.9 0.9 0.8
Expandability 8 0.7 0.7 0.7
Total Points 100 84.2 73.3 67
Description of Evaluation
I. Centrifuge: The centrifuge yields a higher score in capital costs and sustainability because there
are already two centrifuges on site that could be used for this project. The centrifuge does not
make Class A designation more likely nor does it make it automatically achievable. It does allow
for some expansion as the addition of another centrifuge would be possible with the provided
space, though it does have higher maintenance and energy costs.
II. Rotary Drum: Evaluation of using rotary drums for thickening was very similar to evaluation of
centrifuges with one major difference: there are not rotary drums on site currently. There are no
rotary drums currently on the site and thus this would make the capital cost for the drum much
higher than that of the centrifuge.
III. Gravity Belt Press: The operation prices for the belt press are slightly more than that of the
centrifuge or the rotary drum. Belt presses have been used in industry for over a century, thus
the low score in progressive technology. Other than these slight difference, a belt press also
requires more space than the rotary drum or the centrifuges.
Blackwards
21 | P a g e
3.3 Recommendation
Based on the results from the decision matrix, centrifuges are recommended for
thickening purposes. Centrifuges separate solid and fluid content of a sludge via application of
centrifugal force. Configuration of a conventional centrifuge is shown in Figure 7. Slurry or
influent sludge enters the unit on the right. The bowl drive located at the entrance and bowl
rotation provides centrifugal force that will separate the solids and liquid components of influent
sludge. The scroll drive provides horizontal rotation to the screw conveyor which moves solids
towards the right or the conical section for discharge. Liquid discharge or centrate leaves the unit
on the opposite end. Geometry of system components and drive specification determine the
efficiency and flow range a unit can handle.
Figure 7: Schematic of a typical centrifuge system (EPA, 2000)
3.4 Total Solids Composition for Digestion
To achieve optimal feed composition for digestion, the feed could be thickened to 6%.
This is not ideal for design however because at that level of solids content, the fluid is approaching
a non-Newtonian flow. This would make operation and pumping extremely difficult. To avoid
these issues, the team chose to thicken to only 4%2.
2 http://www.lawpca.org/Anaerobic%20Digestion/Conceptual%20Design%20Report.pdf
Blackwards
22 | P a g e
3.5 Thickening and Holding Tank Configuration Decision
Thickening the solids will decrease the size requirements of system components
downstream. The team decided to thicken secondary solids from 0.7% solids to 4% solids.
Primary solids is composed of 3.5% percent solids, and therefore could be put into the digester
without thickening. However, the team, in acknowledgement that they cannot anticipate all
future operating decisions, chose to build the system such that primary solids could be thickened
prior to digestion. From this point, the team faced a decision of whether to put thickening
upstream or downstream of mixing.
The Wyoming CWP already has two centrifuges on site and the team decided that they
would like to use these centrifuges for thickening rather than replace them. This resulted in a
need to determine the optimal location of thickening within the process between
primary/secondary settling and digestion. The team identified three potential alternatives, which
are pictorially described in Figure 8. In this figure, blue represents structures that already exist,
red represents structures that will need to be built, and green annotations refer to potential
expansions or space constraints that are ambiguous. The number under the label “Centrifuges”
refer to the number of units currently in place or that would need to be installed. The holding
tanks must have mixing mechanisms in order to provide a more consistent feed to the digesters.
Figure 8: Centrifuge Placement Alternatives
Blackwards
23 | P a g e
Alternative 1 involves leaving the current system in place and untouched upstream of the
holding tank. The holding tank must be enlarged and a centrifuge building must be installed
between the holding tank and digestion. Two centrifuges will be needed.
Alternative 2 involves rerouting the flow from secondary settling to the mixing tank and
then rerouting flow from the mixing tank to the thickening building. This alternative requires a
much larger mixing tank and one new centrifuge with a potential future expansion requiring
another new centrifuge.
Alternative 3 involves rerouting flow from primary settling to the thickening building and
increasing the size of the mixing tank. This alternative needs one new centrifuge with a possible
future expansion that would require another new centrifuge.
A cost analysis of each alternative was completed and is shown in Table 3 : Comparison
of Thickening Placement Alternatives. The holding tank expansion was cost estimated using the
assumption that concrete would be the building material and that three days of storage would
be needed (see Section 5 for more information on holding/mixing tanks). Piping distances were
estimated using satellite imagery in reference to the size of a car parking spot.
Blackwards
24 | P a g e
Table 3 : Comparison of Thickening Placement Alternatives
Alternative Major Pipe Rerouting Pumping Changes
Description Cost Description Cost
1 Additional Pipe from Mixing to Second Thickening
Building $ 23,800 2 new pumps from Holding to Centrifuge
Negligible compared to other
costs
2 2 lines from Secondary To Holding Tank
From Holding Tank to Thickening Building $ 114,000
~ Replace 6 pumps from Secondary to Holding? ~ Add pumps to handle extra flow from holding
to centrifuge ~ Move/replace pumps from (thickening to
holding) to (holding to thickening)
Negligible compared to other
costs
3 From Primary to Holding Tank $ 68,900 ~ Add pumps to handle flow from thickening to
holding
Negligible compared to other
costs
Alternative Holding Tank Expansion New Centrifuge Units New Buildings
Total Cost
Description Cost Description Cost Description Cost
1 Yes
$ 314,900 2 $ 1,176,000 New Thickening
Building $ 40,000 $ 1,554,700
2 Yes
Largest Volume Needed $ 1,117,000 1 3 $ 588,000 No New Buildings $ 0 $ 1,819,000
3 Yes
Smallest Volume Needed
$ 284,600 1 4 $ 588,000 No New Buildings $ 0 $ 941,500
3 If the population served by the City of Wyoming Clean Water Plant continues to expand, then an additional unit will be needed. This would require an expansion to the thickening building, as two new units cannot fit into the existing structure 4 Same as 3
Blackwards
25 | P a g e
3.6 Cost Information
One additional centrifuge is required to meet redundancy needs for future WAS flow
condition in the proposed sludge management system. It will be located in Thickening room next
to the existing Bird centrifuges. Primary sludge produced at Wyoming CWP has high %TS and
does not require thickening. Centrisys decanter centrifuge shown in Figure 9: Centrisys Model
CS26-4 Decanter Centrifuge was selected for thickening WAS sludge. The unit’s dimension are
8.25 ft. high by 15.75 ft. wide. Basic technical and cost information of Centrisys decanter
centrifuges used in design are summarized in Table 4: Description of Proposed Centrifuge. G-
force in the table represents the horizontal acceleration that the units imparts on feed slurry in
comparison to gravitational acceleration.
Figure 9: Centrisys Model CS26-4 Decanter Centrifuge5
Table 4: Description of Proposed Centrifuge6
Centrifuge Brand Centrisys
Model CS26-4
Flow Rate (gpm) 200-400
G-force 3000
Motor Horsepower 125
Product Price* $588,000
Number of Units 1 Total Price $588,000
5 http://centrisys.us/products/decanter-centrifuges/CS26-4/ 6 Cost includes centrifuge, hydraulic backdrive, control panel, stand w/out walkway, hoppers (to collect cake and centrate),
piping into plant systems, spare parts kit, service for setup, and shipping.
Blackwards
26 | P a g e
4. Pre-Digestion System: Thermal Hydrolysis
Cambi THP is a thermal hydrolysis process (THP) that solubilizes or disintegrates
extracellular substances present in sludge before digestion at high temperature and pressure.
Feed sludge is heated at 165°C for 20-30 minutes. Solids content of the feed sludge should be 16-
17%TS, and thus a prior dewatering stage is required. Advantages of Cambi THP include low
digester volume requirement, pathogen reduction, high dewater-ability of biosolids and high
biogas generation. Foaming and odor problems are minimized, and the system can enhance
stabilization levels post digestion. High quality biosolids can be produced that can be land
applied. Schematic of sludge management system with Cambi THP is shown in Figure 10.
Cambi THP is an emerging technology from Europe that’s gaining popularity in North
America. East Bay Municipal Utility District WWTP in San Francisco and Blue Plains Advanced
WWTP in Washington D.C. are two treatment plants in the US that have successfully integrated
Cambi THP in their sludge management program. Both plants are designated as Class A solids
processing facilities and use cogeneration system to generate heat and electricity from methane
production. Cambi THP is an expensive technology to implement and maintain at small or
medium scale WWTPs. It requires dewatering equipment. Energy costs associated with
dewatering and heating during THP are relatively higher compared to conventional digestion
systems. The team considered CAMBI as a pretreatment step. It was not selected in the final
design due to high capital and operating cost requirements.
Blackwards
27 | P a g e
Figure 10: Sludge Stabilization with CAMBI THP System
Blackwards
28 | P a g e
5. Sludge Holding Tank Design
5.1 Existing system
Two 150,000 gallons tanks are presently used in Wyoming CWP to store the blend of
primary sludge and thickened WAS (Figure 11). They are located next to the main administration
building. These tanks mix the two streams in order to provide a uniform feed to the digester.
They minimize fluctuations in feed sludge composition and loading rate. They serve as
equalization basins of thickened primary and secondary sludge before stabilization during normal
and higher flow conditions (max month flow). They are also referred to as sludge mixing tanks.
Figure 11: Sludge Holding Tanks at Wyoming CWP
5.2 Proposed Addition
Based on 2025 projected flow, two additional holding tanks with a combined volume of
300,000 gallons will be required. Three day storage at maximum month sludge production rate
was used for determining holding size. More days of storage will lead to sludge quality
deterioration. For emergency situations, it is recommended that the CWP either increase
thickening to no more than 5%TS (to minimize pumping problems) or direct excess flow to Grand
Blackwards
29 | P a g e
Rapids WWTP using existing GVRBA facilities. Both holding tanks will be lined with coal tar epoxy
and will be located adjacent to existing tanks.
5.3 Mixing Method
For the holding tank there were several options of mixing, the most common in industry
being the jet mixing system and the other being mechanical agitation. Mechanical agitation
consists of propellers attached to a shaft driven by a motor. Mechanical agitation has a capital
cost of $15,000 per tank. This system tends to collect rags and other debris on the agitator. The
Jet mixing system, as displayed in Figure 12, consists of a chopper pump, several nozzles, and
piping. The Jet mixer, $25,000 per tank, has two key advantage over the mechanical agitation.
This mixer can be turned on and off as needed which is ideal for the times that the sludge is not
being used.
Figure 12: Jet Mixing System
For a 300,000 to 500,000 gallon tank this system can suspend up to 10% TS in under three
hours. This saves municipal plants 30% of the expected operation energy costs7. Secondly, the jet
mixers can be turned onto the walls and clean the tank when needed and the maintenance for
the jet mixers is minimal. For these reasons the Jet mixer system was implemented.
7 http://www.osti.gov/scitech/servlets/purl/768043
Blackwards
30 | P a g e
5.4 Material of Construction
Cost curves were constructed using cost data found online for determining appropriate
construction material (Figure 13). Steel tank is the cheapest option amongst the different
alternatives. For all materials, construction price decreases with increase in tank volume. In other
words, it is cost effective to construct a single or few large tanks than several small tanks. The
figure also indicates that price difference between the material alternatives narrows down with
increase in tankage. Concrete is a conventional and preferred material for tank construction due
to its durability, low corrosion property, low maintenance cost and high thermal resistance.
Figure 13: Exponential Cost Curve for Digester Construction
5.5 Gas Elimination
In the event that the sludge holding / mixing tanks must be used in an emergency
situation, it is possible that the sludge will naturally produce biogas. A major component of
biogas is methane. As biogas is produced, the pressure inside the tank would build up. Both the
pressure build up and the composition of the biogas contribute to an explosion risk.
y = 0.5*Cost-0.351
y = 0.7*Cost-0.474
y = 0.65*Cost-0.454
$-
$0.20
$0.40
$0.60
$0.80
$1.00
$1.20
$1.40
$1.60
0 0.2 0.4 0.6 0.8 1 1.2
Co
st p
er g
allo
n
Tank Volume (million gallons)
Steel Glass lined steel Concrete
Blackwards
31 | P a g e
For this reason, a flare will be installed that will automatically bleed gas pressure. The
biogas will be burned rather than being simply released because methane is a worse greenhouse
gas than carbon dioxide. The flare will cost $21,000 dollars.8
5.6 Cost Information
Table 5: Capital Cost of Holding Tanks
Item Cost
Holding tanks (2) $33,000
Jet Mixers (2) $25,000
Flare $21,000
Total $1,181,000
8 http://www.epa.gov/gasstar/documents/installflares.pdf
Blackwards
32 | P a g e
6. Sludge Stabilization Design
6.1 Introduction
Waste solid, commonly referred to as sludge in industry is produced from the physical
separation that occurs in primary treatment and biological activity in activated sludge process.
Stabilization is the process of decomposing organics and destroying pathogens present in primary
and secondary sludge. In most treatment systems, sludge stabilization is incorporated in the
treatment scheme to reduce pathogenic content, to control odor problems and to enhance
sludge dewatering.
6.2 Evaluation of Stabilization Alternatives
Conventional stabilization methods considered during the initial stages were alkaline
stabilization, aerobic and anaerobic digestion.
I. Alkaline Stabilization: is a conventional sludge stabilization method which uses alkaline
substance mainly lime for the destruction of pathogens in sludge. Lime is corrosive in nature
which leads to a shorter design compared to other stabilization options. It also presents safety
hazards. It is a caustic chemical with severe health risks when in direct contact of the skin. End
result of the process has a higher volume due to lime addition. Class A product would not be
achieved without operational modifications including increased dosage and contact time. It is
difficult to accurately represent on a cost scale as it cost varies depending on location of lime
suppliers and seasonal availability. At present, lime stabilization is used at Wyoming CWP. The
lime is currently supplied for no cost since it is a byproduct of acetylene production from a local
company.
II. Aerobic Digestion: is the decomposition of biomass using aerobic bacteria in oxygen-rich
environment. About 75% of cell biomass can be oxidized in a series of chemical reactions to
produce carbon dioxide, water and nitrogen. Compared to anaerobic digesters, it requires less
maintenance and control. Project cost is relatively low, except energy cost associated with
oxygen supply. Heating requirements are limited. Satisfactory volatile solids reduction and BOD
removal can be obtained with proper design and operation. Effluent stream has low solids
Blackwards
33 | P a g e
content and consequently higher volume which necessitates frequent trucking and disposal. The
process does not recover methane in sludge for energy generation. Sludge retention time for
Class B product is 40-60 days and depends upon the digester temperature. This process does not
allow for Class A product.
III. Anaerobic Digestion (AD): is the biological degradation of organic materials with
microorganisms in an oxygen-free environment. Volatile solids in sludge are destructed in sealed
tanks, resulting in the production of simple compounds. It is a progressive and proven technology
in the municipal waste management industry. It is sustainable system because methane that
would otherwise get released to the environment from a land fill site is captured on-site resulting
in energy sustainability and reduction of greenhouse gas emissions. Anaerobic digestion can yield
Class A biosolids on a uniform basis with proper design and operation. In comparison to other
stabilization options, the capital cost of anaerobic systems is high due to tank construction,
thickening and dewatering equipment installation and cogeneration system cost. Operational
costs are high due to sludge heating and energy requirements for thickening and dewatering
equipment.
Based on system performance of the different methods, a decision matrix for sludge
stabilization was constructed (Table 6). Three of the stabilization alternatives were weighed on a
scale of 0% to 100%, with 0% corresponding to poor performance and 100% corresponding to
superior performance. Categories in the matrix were given appropriate weight based on client’s
needs, adaptability to existing system and future implications. Description of each category is
presented below.
Category Considerations
1. Capital Costs: How much does the equipment cost to obtain? How much will it cost to
install? How much time will it take employees to train on using the new equipment?
2. Operational Costs: How much does the technology cost to operate each month?
3. Progressive Technology: Would the novelty of this technology improve public image of
the facility?
Blackwards
34 | P a g e
4. Sustainability: How much energy is required to operate this technology? What form of
energy is used and how is it produced? How much equipment is already owned by the
client and can be reused for this project? Does this technology require nonrenewable
energy sources?
5. Reliability: Does this technology depend on operator input for changes in feed flow? Does
this technology produce a product that is consistent over time?
6. Design life: How often will this technology need to be replaced?
7. Biosolids Quality: Does this technology make achieving Class A easier or possible?
8. Effect on Plant: If the effluent water is recycled into the plant, will the composition of the
stream cause the water treatment process to be less effective?
9. Potential Energy Production: Will this technology result in methane production
Table 6: Design Matrix for Sludge Stabilization
Category Weight Alkaline
Stabilization Anaerobic Digestion
Aerobic Digestion
Capital Cost 14 0.9 0.8 0.7
Operational Cost 1 0.7 0.3 0.7
Progressive Technology 9 0.2 0.8 0.6
Sustainability 9 0.2 1 0.7
Reliability 9 0.7 0.8 0.8
Design Life 11 0.6 0.8 0.8
Biosolids Quality 18 0 1 0.2
Effect on Plant 3 1 0.4 1
Potential Energy Production 16 0 1 0
Total Points 100 36.8 60.5 48.8
6.3 Recommendation
Based on the design matrix above, anaerobic digestion is the ideal stabilization alternative
at Wyoming CWP. The process meets design objectives and regulations. Design objectives of this
project include attainment of Class A product and energy recovery. High rate reactors with mixing
and uniform loading are recommended.
Blackwards
35 | P a g e
6.4 Anaerobic Digestion Process Chemistry
Different microorganisms are involved in the decomposition of organic material in
anaerobic digestion process. Cellulose, proteins and other organic compounds in sludge are
solubilized into fatty acids, alcohol and carbon dioxide by extracellular enzymes. The soluble
compounds are further broken down to short-chained fatty acids (SCFAs) such as acetic acid and
hydrogen by acidogenic bacteria. The final stage is the formation of biogas from acetate
decarboxylation and conversion of carbon dioxide and hydrogen by methanogenic bacteria. The
final product, biogas consists of 60% methane and 40% carbon dioxide. Byproducts include
hydrogen sulfide, siloxane and ammonia.
The activation of different microorganisms depends on the operating temperature of
digester, pH and sludge retention time (SRT). Methanogenic bacteria are important
microorganisms in the digestion process that regulate the rate of methane formation. Stages of
anaerobic digestion are presented in Figure 14.
Figure 14: Stages of Anaerobic Digestion
Blackwards
36 | P a g e
6.5 Class A Biosolids Requirement
In order to obtain Class A designation for the end product of the anaerobic digester, three
requirements must be met. First, the biosolids must have satisfactory pathogen content
reduction. There are six alternatives for reducing the pathogenic content to below detectable
levels. The proposed anaerobic digestion system for Wyoming CWP meets Alternative 1
(Thermally Treated Biosolids).
Two basic requirements must be met to achieve Class A status. First, either the biosolids
must have a fecal coliform level less than 1000 Most Probable Number (MPN) per gram of total
solids or the biosolids must have a salmonella level less than three MPN per four grams of total
solids. Research has shown that this level can be achieved using a thermophilic anaerobic
digester. Second, the time and temperature of the stabilization must meet one of four options.
Influent total solids levels of 4% means that this design will meet option D. The Clean Water Act
classifies the sludge by percent solid, temperature, and residence time. The equation shown
below describes the relationship between temperature and minimum residence time according
to Part 503 of EPA regulation.
D =50,070,000
100.14∗T
In this equation, T stands for temperature in degrees Celsius (C) and D is residence time
in days. Since a thermophilic digester operates at a temperature of 55°C, this equation shows
that our residence time must be at least one day. The residence time chosen was 10 days;
therefore this constraint will be met.
The second requirement for Class A designation is Vector Attraction Reduction (VAR). In
layman’s terms, this means that the biosolids must not have enough energy to support large
populations of new microbes. There are 8 alternatives for meeting vector attraction reduction.
This design meets option 1, which reads as follows:
The mass of volatile solids in the sewage sludge shall be reduced by a minimum of 38
percent. (see calculation procedures in “Environmental Regulations and Technology—
Blackwards
37 | P a g e
Control of Pathogens and Vector Attraction in Sewage Sludge”, EPA–625/R–92/013, 1992,
U.S. Environmental Protection Agency, Cincinnati, Ohio 45268).
Research has shown that actual VSS reduction for thermophilic anaerobic digesters is
usually between 40 and 60% which meets this requirement.
The third requirement for Class A designation is meeting pollutant restrictions. For this
requirement, the end location of the biosolids determines what regulation applies. All land
applied biosolids must be at or below the values shown in column 1 of Table 7. In addition, any
biosolids applied to agricultural land, forest, public contact sites, or reclamation sites must either
have a cumulative pollutant loading rate less than column 2 or must have a point concentration
less than column 3. Any biosolids sold or given away in a bag or another container for land
application must either have concentrations less than the third column or must have a total
annual loading rate less than column 4. The four most common treatment configurations that
produce Class A biosolids are presented on Figure 15. In this project, option 2 and 4 were
investigated.
Table 7: EPA CWA Pollutant Limits
Pollutant Ceiling
Concentration (mg/kg)
Cumulative Pollutant
Loading Rate (kg / hectare)
Monthly Average Concentration
(mg/kg)
Annual Pollutant Loading Rate
(kg / hectare / 365 day)
Arsenic 75 41 41 2
Cadmium 85 39 39 1.9
Copper 4300 1500 1500 75
Lead 840 300 300 15
Mercury 57 17 173 0.85
Molybdenum 75 - - -
Nickel 420 420 420 21
Selenium 100 100 100 5
Zinc 7500 2800 2800 140
Blackwards
38 | P a g e
Figure 15: Treatment Processes that achieve Class A Biosolids9
9 Willis and Schafer, 2006
Blackwards
39 | P a g e
6.6 Digestion Temperature
Anaerobic digestion can occur at different temperatures. Mesophilic and thermophilic
operation correspond to digestion at 35°C and 55°C respectively. Both processes have their own
strengths and weaknesses. Important benefits of mesophilic operation include operational
simplicity and good pathogen reduction. The mesophilic range does not require nearly as much
attention to operating details as the thermophilic range. As a result, most WWTP digestion
systems in the US operate at mesophilic temperature. However, volume requirement of
mesophilic digesters is almost twice than volume required in thermophilic digesters since average
mesophilic HRT is 20 days, approximately twice that of thermophilic HRT. The hydraulic retention
time is longer because it takes a long time for the microbes to mature and digest substrate in
sludge. The heating costs for mesophilic is not as high as thermophilic due to lower heating
temperatures but construction costs are much higher. It is practically not possible to reach Class
A pathogen level at mesophilic temperature without additional treatment.
The second mode of anaerobic digestion is operation at thermophilic or 55°C. The high
temperature requirement is associated with high heating costs. However, the tank volume is
nearly half of that required for mesophilic digestion which lowers construction costs
considerably. Reaching the thermophilic temperature range also allows the biosolids to reach
Class A pathogen level with pre-digestion pasteurization or thermal hydrolysis system. Semi-
batch operation at thermophilic temperature can achieve Class A status if short-circuiting is
avoided. Thermophilic digesters are commonly buried to minimize heat loss from digester walls
to the atmosphere.
Temperature-phased anaerobic digestion (TPAD) is the thermophilic and mesophilic
anaerobic digestion in sequence. Solid residence times (SRT) are varied across two tanks to find
appropriate loading rate. TPAD systems have been proven to have better performance in volatile
solids (VS) reduction and gas production than single-stage mesophilic or thermophilic digestion
(Bolzonella et al). Other benefits include good odor control and no short-circuiting or reinfection
which makes Class A designation possible. Previous research work has shown that TPAD system
produces fecal coliform less than the regulatory level of 1000MPN or 3-log per gram of total solids
Blackwards
40 | P a g e
(Figure 16: Comparison of Coliform Destruction (Kade, 2004). A summary of the different
digestion temperatures is presented on Table 8.
Figure 16: Comparison of Coliform Destruction (Kade, 2004)
Table 8: Digester Operating Temperature Characteristics
Category Mesophilic Thermophilic TPAD
Operating Temperature 35°C 55°C Both
Energy Costs Lowest Highest Middle
Residence Time Highest Lowest Middle
Class B A or B A
Blackwards
41 | P a g e
6.7 Digester Configuration
6.7.1 Tank Design
The team considered thermophilic digestion and TPAD. First, anaerobic digestion system
operating at thermophilic temperature was studied. In particular, sizing requirements and
potential gas production were determined for a high rate, single stage thermophilic digesters.
Since there is no recycle stream, the solids retention time (SRT) is equal to the hydraulic retention
time (HRT). Second, temperature-phased anaerobic digestion (TPAD) system for Wyoming CWP
was investigated. Schematic of a two-stage digestion system is shown Figure 17.
Figure 17: Two Stage, High-rate Anaerobic Digester10
6.7.2 Digester Shape
Commonly used digestion tanks are cylindrical and egg-shaped. Advantages and
disadvantages of both configurations are outlined in Table 9. Cylindrical shaped digesters are
conventionally used in many WWTP digestion facilities and farming communities for treating
animal manure. Common construction material for cylindrical digesters is concrete. A
modification of cylindrical tanks, German digesters have cylindrical shape with truncated, conical
top and bottom surfaces for efficient mixing and hydraulics. Cylindrical digesters were chosen for
the design of thermophilic digestion system.
10 Source: http://water.me.vccs.edu/courses/env108/anaerobic.htm
Blackwards
42 | P a g e
Table 9: Comparison of cylindrical and egg-shaped digesters11
Cylindrical Digesters
Advantage Disadvantage
High gas storage Poor mixing
Possible use of floating covers
Grit and scum accumulation
Conventional construction methods
Egg-shaped Digesters
Advantage Disadvantage
Better mixing (hydraulic efficiency)
Complex design (digester, foundation and seismic)
Low grit accumulation and foaming
High construction cost
Smaller footprint Limited gas storage capacity
Low O&M costs
Egg-shaped digesters are gaining popularity in the United States due to their high
hydraulic performance. Major benefits include simple operation control, smaller footprint and
good mixing. Common construction material is steel due to ease of construction. A local waste
water (WW) treatment facility, Grandville Clean Water Plant has an egg-shaped digester.
Minimum foaming occurs due to the narrowing near the top. Proposed TPAD system for
Wyoming CWP has egg-shaped, mesophilic digesters. Enough land space is available for
construction with capacity for future expansion.
Figure 18: Egg Shaped Digester Configuration12
11 Adapted from Metcalf and Eddy, 2003 12 Source: http://www.gec.jp/jsim_data/water/water_4/html/doc_282_1.html
Blackwards
43 | P a g e
6.7.2.1 Cylindrical, Thermophilic Digesters
The anaerobic digestion tank design integrated two key parameters volume and
redundancy. After researching common practice, it was decided that the projected 2025 average-
annual sludge flow should be shared between two digesters of equal size. There will be a total
of three digester of equal size including a redundant digester for max month loads (Figure 19).
Figure 19: Single-stage Cylindrical Digesters
For peak days, the storage tanks preceding the digesters will contain the exceeding flows
so the digesters will not have to continually turn on and off. Also, when the digesters are running
at relatively constant volumetric flow rates, the digester offline can be maintained if required. In
order to find volume of digestion tanks, appropriate design loads for average month condition as
well as hydraulic residence time was designated. The radius and height are equal due to ideal
heating conditions as well as ease of burial. All calculations can be found in Appendix II: Mathcad
Calculations. Table 10: Configuration of Cylindrical Digesters for Wyoming CWP provides a
summary of the results.
Blackwards
44 | P a g e
Table 10: Configuration of Cylindrical Digesters for Wyoming CWP
Parameter Value
Digester volume (per unit) 1,000,000 gallons13
Number of units 3
Material of construction Reinforced concrete
Diameter and height above ground
35ft.
Mixing mechanism Typically mechanical agitation or
recirculation
Burial Fully above ground (water table located 12-15 ft. below ground)
Batch or semi batch operation of single- stage thermophilic digestion is required to meet
Class A requirements. Continuously fed systems re-infect the digested sludge. Other operational
issues include volatile solids (VS) fluctuation, foaming and odor problems. Methane production
and cost analysis of this option were performed for comparison with TPAD system and presented
in this report. Foam and odor control for this configuration were not investigated.
6.7.2.2 TPAD system with Egg-Shaped Digestion (ESDTM)
Temperature-phase anaerobic digestion (TPAD) system is a digestion alternative
developed by Richard Dague and co-workers at Iowa State University. The US patent number of
the process is 5,746,919 and was given on May 5, 1998. It consists of a short thermophilic
digestion followed by a long mesophilic digestion system (Figure 20). Major benefits include good
hydrolysis, high volatile solids destruction, significant gas production, odor control and ability to
meet Class A requirements. Significant pathogen destruction occurs in the acid/thermophilic
stage while high volume of methane is produced from the mesophilic stage. Limited number of
WWTPs use TPAD system for sludge stabilization.
13 Grit accumulation, mixing equipment space requirement and gas storage volume included in calculation.
Blackwards
45 | P a g e
Figure 20: Two- stage Anaerobic Digestion system (CB&I)
TPAD system for Wyoming CWP will consist of three thermophilic (acid) reactors followed
by two egg-shaped mesophilic digesters. Cleaning of the egg-shaped digesters is minimal since
there is only minor scum accumulation in egg-shaped digesters. Summary of proposed system
based on 2025 design conditions is presented on Table 11.
Table 11: Summary of ESD facility plan from CB&I
Parameters Thermophilic
(Acid) Reactors Mesophilic
Unit volume 60,000 gallons 1,500,000 gallons
Number of units Three Two Tank shape Cylindrical Sphere- egg shaped
Height above ground 76ft. 96ft. Major diameter 12ft. 72ft.
Digestion time 22hr 15 days
Mixing system External recirculation pump
and integral foam Suppression
Jet mix draft tube and integral foam Suppression
Blackwards
46 | P a g e
7. Digester Biogas Production
7.1 Introduction
The anaerobic biodegradation of organic waste produces biogas and other gaseous
compounds such as hydrogen sulfide and siloxane. In particular, biogas production is associated
with volatile solids (VS) destruction. Several relationships exist that describe the effect of
different parameters on VS reduction. Based on Equation 14-14 from Metcalf & Eddy, VS
reduction rate (in percent) as a function of sludge retention time (SRT) is graphed and presented
on Figure 21. Higher destruction occurs at long retention times, high temperatures and neutral
pH conditions.
Figure 21: Effect of Sludge Retention Time (SRT) on VSS Reduction for High-rate System
The biological and chemical property of the influent sludge as well as loading rate are
important variables that determine the maximum level of gas production possible. Table 12
summarizes the properties of the primary and secondary sludge from wastewater treatment
process. Primary and thickened WAS will be digested in proposed system. Pre-digestion storage
provides a uniform, homogenous feed to the digester tanks and potentially a stable operation.
Parameters such as phosphorous and nitrogen levels in secondary sludge are largely determined
by the efficiency of biological treatment. Typically, primary sludge removed from primary
y = 0.137ln(x) + 0.189
20%
25%
30%
35%
40%
45%
50%
55%
60%
65%
70%
0 5 10 15 20 25 30 35
VSS
Red
uct
ion
%
SRT (in days)
Blackwards
47 | P a g e
clarifiers contains high percentage of substrate (BOD) and TSS and has high energy production
potential via digestion. Furthermore, the configuration of digester and efficiency of mixing
mechanism affect the conversion of volatile solids to biogas.
Table 12: Typical Characteristic of Primary and Secondary Solids14
Parameters Concentration (dry-weight basis)
Primary Sludge Secondary Sludge
Total Solids 2-8 0.4-1.2
Volatile Solids (% of TS) 60-80 60-85
Grease (% of TS) 5-8 5-12
Phosphorus (% of TS) 0.8-2.8 1.5-3
Nitrogen (% of TS) 1.5-4 2.4-7
pH 5-8 6.5-8
Based on past research and actual operation of AD systems, different mathematical
models have been formulated on methane yield. Two widely-used approaches to estimate
volume of biogas production are volatile solids reduction and conversion of soluble BOD in
sludge. Observed values of biogas volume per mass for both approaches is tabulated in
Table 13. Biogas can be produced at different parts of an AD system and can be used to
generate heat and electricity (see Figure 22: Potential Sources of Biogas for an AD system). The
majority of biogas is produced in the digesters, and biogas from the other sources is normally
flared due to its limited amount.
Table 13: Estimated Biogas Production15
Parameter Value Unit
Volatile solids reduction 0.8-1.1 m3/kg
13-18 ft3/lb.
Soluble BOD conversion 0.35 m3/kg
5.61 ft3/lb.
14 WEF Task Force, 2010 15 WEF Task Force, 2010
Blackwards
48 | P a g e
Figure 22: Potential Sources of Biogas for an AD system
7.2 Potential Methane Production at Wyoming CWP
Volatile solids reduction (VSR) approach was used to calculate methane production under
different flow conditions. The loads of the influent stream were found and documented on Table
14: Information about Wyoming. Potential VSR using the two AD configurations was computed
based on SRT (Table 15). These loads were used in an anaerobic biomass equation to find the
pounds of biomass (in terms of TSS and VSS) produced per day. Based on 15 ft3 volume biogas
production per lb. VSS destroyed, estimated biogas generation during average annual and
maximum month flow conditions were determined. Finally, methane generation was found with
the assumption that 60% of biogas by volume is methane. Detailed calculations can be found in
the Appendix II: Mathcad Calculations.
Table 14: Information about Wyoming Waste Flow
Parameter 2014 2025
Annual average flow (mgd) 14.7 2416
TSS loading- annual average (lb./day)
29056 47438
TSS loading- maximum month (lb./day)
31630 51641
VS Loading rate (lb./ft3/day)
0.084-0.09 0.137-0.149
16 Represents the plant’s design capacity and expected flow
Biogas
Sludge Holding
Tank
Digesters
CHP
Biosolids Storage Tanks
Blackwards
49 | P a g e
Table 15: VSR Assumption for AD systems
AD Configuration VSR (%)
Single-stage, thermophilic 51%
Two-stage, TPAD system 57%
Methane production is dependent on TSS loading which is proportional to wastewater
flow into the plant. It can vary with changes in the number of residential homes and industries
that are served by the treatment plant. Furthermore, higher gas generation than theoretical
findings may occur with operation of CB&I’s TPAD system due to its high mixing efficiency.
Theoretical methane production with thermophilic and TPAD system at Wyoming CWP is
presented below in Figure 23 : Methane Production Prediction for Thermophilic System and
Figure 24 : Methane Production Prediction for TPAD System respectively.
Figure 23 : Methane Production Prediction for Thermophilic System
Average annual
Max. month
0
50000
100000
150000
200000
2014 2025
102000
166,000
111000
181000
Me
tha
ne
Pro
du
ctio
n (
ft3/
da
y)
Thermo
Blackwards
50 | P a g e
Figure 24 : Methane Production Prediction for TPAD System
Average annual
Max. month
0
50000
100000
150000
200000
250000
2014 2025
115000
187,000
125000
204000
Me
tha
ne
Pro
du
ctio
n (
ft3/
da
y)
TPAD
Blackwards
51 | P a g e
Figure 25 : Methane Production as a Function of Influent Flow to Plant
y = 11535x0.8963
R² = 0.8812
y = 10669x1.0545
R² = 0.8628
1
10
100
1,000
10,000
100,000
1,000,000
0.1 1 10 100
Met
han
e P
rod
uct
ion
(ft
3/d
ay)
Current Flow to WWTPs in WI (mgd)
Methane Generation Vs. Flow
Wyoming CWP
(2025)
Wyoming CWP
(2014)
14.7 24
Blackwards
52 | P a g e
7.3 Operation and Maintenance
Several physical and chemical properties of sludge in digester tanks should be monitored
frequently for process control. Products of acidogenesis process lower digester pH while
methanogenesis products raise pH. Neutral pH is considered the ideal digester pH to support the
different stages of digestion process. Fluctuations in pH can have detrimental effect on volatile
solids reduction and gas production. Digester parameters that should be monitored daily are
presented in Table 16. Alkalinity and volatile acids determine the health of an AD system. Higher
alkalinity values are associated with system stability in terms of ability to sustain increased
organic loading. Ratio of Volatile acids (VA) and alkalinity give an early indication of pH changes.
Table 16: Digester Monitoring (WEF, 2007)
Parameter Units Target Test Method
Temperature °C 65- Thermo.
35- Meso. Meter
pH - 6.8-7.2 Meter
Alkalinity (mg/L) mg/L 2000-5000 AWWA 2320
VA/Alkalinity ratio mg/L 0.1-0.2 Ratio calculation
Total Solids (TS) % (record) 2540B
Volatile Solids (VS) % (record) 2540E
Flow gal/day (record) Meter
Gas Production ft3/ lb. VS destroyed
12-16 Meter
Gas Composition % Low CO2, H2S
and NH3 Gas Analyzer/
chromatography
Blackwards
53 | P a g e
7.4 Case Studies
Digestion systems at three WWTPs were evaluated in light of assessing methane
production and benefits from its utilization. A comparison of the plants’ design capacity and gas
production is presented on Error! Reference source not found.. Expected gas production at
Wyoming CWP is also included.
I. Grandville CWP (Grandville, MI)
In fall 2012, construction of an egg-shaped anaerobic digester was completed at
Grandville CWP (Figure 26). It was the first of its kind in Michigan. The digester has one million
gallon volume and operates at mesophilic temperature. Primary sludge is the only feed stream
of the system since WAS is co-settled in primary clarifiers. Biosolids produced from the plant has
Class B quality and is land applied locally. The plant utilizes methane produced from digestion
process using a cogeneration system to meet 90% of its heating and electricity demands.
Estimated energy savings is $142,000 per year, and the expected payback period for the digestion
system is 8 years.
Figure 26: Egg-shaped Digester at Grandville CWP
II. Blue Plains Advanced WWTP (Washington D.C.)
Blue Plains is one of the largest WW treatment facilities in the world. The plant is located
in Washington D.C., and it serves more than 2 million people. Lime stabilization is currently being
used to treat waste sludge. A new digestion process train will be completed in 2015 at a cost of
Blackwards
54 | P a g e
$400 million. A CAMBI THP system, four cylindrical digesters (3.8 million gallon units) and a
cogeneration system will be installed. The biosolids from the plant will have Class A quality and
can be land applied without space and time limitations. The plants will meet about 30% of its
energy needs from methane generated.
III. Western Lake Superior Sanitary District (Duluth, MN)
The treatment facility serves City of Duluth, Hermantown and neighboring townships in
Minnesota. The solids management consists of a dissolved air floatation and two-stage,
temperature phased anaerobic digestion (TPAD) system. It was the first, full-scale TPAD system
in North America. Prior to 2001, sludge co-incineration with solid waste was used. Sludge is
treated in a sealed, cylindrical tank at thermophilic temperature for 5 days in the first stage,
followed by mesophilic treatment in three separate, 1.05 million gallon tanks for 15 additional
days. Treated biosolids is land applied after dewatering with centrifuges.
Figure 27: Comparison of Sludge Flow and Associated Gas Production
0
50,000
100,000
150,000
200,000
250,000
300,000
350,000
400,000
450,000
500,000
0
100,000
200,000
300,000
400,000
500,000
600,000
Grandville CWP Wyoming CWP(Current Capacity)
Wyoming CWP(Design Capacity)
Western LakeSuperior
Gas
Pro
du
ctio
n (
ft3/d
ay)
Slu
dge
Fo
w (
gal.
/day
)
Sludge Flow Gas Production
Blackwards
55 | P a g e
8. Cogeneration
Digester gas is typically composed of 60% methane and 40% carbon dioxide. Unlike
natural gas, digester gas does not contain ethane, propane, butane or other combustible gases,
which results in its relatively low heating value. A combined Heat and Power (CHP) system is
required to capture the energy in digester gas. Heating sludge pre-digestion will be the primary
use of energy from methane production.
8.1 Cogeneration Implementation
The cogeneration system that the team recommends for implementation is a CHP system.
This system generates energy in the form of both stem for the sludge and the remaining portion
as electricity for the rest of the plant. The CHP system uses combustion and steam turbines that
use the biogas and create mechanical energy which powers a generator that produces electricity
for use. This system will cost $1.5 million dollars according to HESCO.
8.2 Cost Savings
Gas production increases with the increase in flow, and thus there is more potential
energy produced in 2025 than for the current flow conditions. It was determined the cost to heat
the sludge prior to digestion in 2025 will be 10.9MMBTU/year and that the energy produced from
digestion will be 15MMBTU/year. The energy used for heating will account for approximately
80% of the energy produced as seen in Figure 28. The remaining energy will be used on site as a
subsidiary electricity source. Annual cost savings from this additional energy is estimated at
$95,000.
Blackwards
56 | P a g e
Figure 28: Uses for Energy produced from Digestion
0%
20%
40%
60%
80%
100%
Energy Produced 2014 Energy Produced 2025
Energy for Sludge Heating Remaining
Blackwards
57 | P a g e
8.3 Biogas Conditioning
Digester gas contains trace amounts (<5%) of hydrogen sulfide, siloxane and other gases
which cause problems in gas piping and cogeneration system. Several technologies are available
in the market to remove these harmful gases. Hydrogen sulfide can be removed or controlled by
application of activated carbon, ferric chloride or scrubbing with liquid media. High pH in the
digester tanks reduces the rate of hydrogen sulfide formation. Piloting of TPAD system and gas
chromatographic tests provide valuable information regarding concentration of this contaminant
gases based on system changes such as loading rate and mixing rate.
The system provider is Unison Solutions, Inc. A special media, SulfaTreat media is used to
remove hydrogen sulfide, inside a vertical vessel. Typical and design maximum concentration for
hydrogen sulfide and siloxane are presented on Table 17: Digester Gas Composition (by volume).
Rated removal efficiency for particulates above 3 microns is 99%. Recommended removal
systems for both gases are shown in Error! Reference source not found. and Error! Reference
source not found..The two systems are pivotal for smooth operation and maintaining the design
life of cogeneration units.
Table 17: Digester Gas Composition (by volume)
Parameter Typical Range in Digester Gas17
Max. Discharge Conc. (Unison)
Hydrogen Sulfide 200-3500ppm 10ppm
Siloxane 100-4000ppb 100ppb
17 WEF Task Force, 2010
Blackwards
58 | P a g e
Figure 29: Hydrogen Sulfide Removal System
Figure 30: Siloxane Removal System
8.4 Cost Information
The cost of the biogas conditioning systems is outlined in Table 18: Cost Information for
Biogas Conditioning. The values are before tax and installation. Cost information was found from
Unison Solutions, Inc.
Table 18: Cost Information for Biogas Conditioning
Removal System Capital Cost
Hydrogen Sulfide $135,000
Siloxane $85,000
Gas Compression/ Moisture
$270,000
Shipping $8500
Commissioning $8500
Total $507,000
Blackwards
59 | P a g e
9. Post-Digestion Dewatering
9.1 Dewatering Introduction
Dewatering is an optional mechanical process in biosolids management that increases
total solids (TS) concentration in post treatment flow. Major benefits of dewatering include:
Reduction in biosolids volume for disposal.
No seasonal dependence on disposal method.
Wide range of applications for Class A product.
Because digestion causes the biodegradation of solids, the post digestion percent solids is
expected to be reduced to 2.5%. The calculations used to produce this value can be found in
Appendix II: Mathcad Calculations.
9.2 Proposed Percent Dewatering
The team considered two potential final biosolids levels: 4% solids and 18-20% solids.
Currently, the Wyoming CWP has equipment on site for injection of 3-8% biosolids and an
example can be seen in Figure 31. The equipment is managed by a separate company but stored
and maintained on site. Currently the Wyoming CWP land applies biosolids at approximately 6%
solids.
Figure 31: Injection Biosolids Land Application Equipment
Blackwards
60 | P a g e
The ideal percent solids for pumping is 4% solids because flow is reduced while flow
characteristics remain similar to water. A composition at 4% solids would not require the
purchase of any additional land application equipment.
If total solids of post dewatered sludge is between 18-20%, then the effluent of the
process is termed as cake solids. Cake solids do not behave like a fluid and cannot be pumped or
injected. An example of cake solids is Milorganite, a commercial fertilizer manufactured by the
Milwaukee Metropolitan Sewage District. There is currently little to no market demand for
bagged cake biosolids in the Grand Rapids metropolitan area. A comparison of the two options
for thickening is summarized in Table 19. After consulting Wyoming CWP, the team decided only
to dewater to 4% solids with the option to dewater to a higher percentage during atypical
operation.
Table 19: Comparison of Final Biosolids Percent Solids Composition
Dewatering Final Percent
Solids
Can be Bagged for Residential Application
Capital Needed for Land Application
Already Exists on Site
Hydraulic Properties of
Water
Volume to be Stored in Winter
4% No Yes Yes Large
18-20% Yes No No Small
9.3 Method of Dewatering
Because dewatering is the same mechanical process as thickening, the options for
dewatering are similar. The team looked into three methods for dewatering including
centrifuges, rotary drums and gravity thickening equipment. Each of these options could
concentrate the solids to 4%. The team selected centrifuged because it was the most effective
and versatile method. With centrifuges, the option to increase the amount of dewatering to up
to 10% can be done with no additional equipment. This condition provides the CWP with
flexibility in the future and also allows for conserving storage during unusual long winters.
Blackwards
61 | P a g e
10. Biosolids Storage Tanks
10.1 Design Considerations
For the purpose of this project, the system was designed for typical use without GVRBA
facilities. For this reason, the Wyoming CWP must be able to store biosolids for approximately 3
months during the year when biosolids cannot be land applied via injection due to frozen ground.
10.2 Current Biosolids Storage Facilities
Currently, the Wyoming CWP has two 1.9-million gallon tanks and one 2.1 million gallon
tank on site. These tanks handle current biosolids treatment operations such as an equalization
basin during upsurges, system shutdown and other emergency situations. These tanks are shown
in the distance in Figure 32.
Figure 32: Biosoilds Storage Tanks in the rear
Based on 2013 GVRBA sludge data, a graph of biosolids entering, leaving and remaining
in the storage tanks was created (Figure 33: Seasonal Variations in Biosolids Storage in 2013). The
remaining biosolids volume at end-of-month (EOM) is the differential of the flow in and out of
the tank plus initial volume in tank from previous month. The dark line represents the total
capacity of the existing biosolids storage tanks. According to the graph, approximately half of the
tank volume is unused. Also, the values for land application show that the majority of biosolids
are stored during summer months.
Blackwards
62 | P a g e
Figure 33: Seasonal Variations in Biosolids Storage in 2013
10.3 Required Biosolids Storage Capital
Calculations of the volume of biosolids produced during the winter were completed and
can be found in Appendix II: Mathcad Calculations. An additional two cylindrical tanks with
volumes of 2 million gallons will be needed for holding typical biosolids production in the winter
of 2025. A cost estimate for each was calculated based on an assumed cost per volume for a
concrete tank construction. Each tank costs approximately $1.5 million. In the event of a longer
winter period than typical, several contingencies for operation exist. First, the biosolids can be
dewatered to higher than 4% total solids. Second, biosolids storage at GVRBA could be utilized.
However, since the volumetric flow rates used in this calculation are from the year 2025, neither
of these options should be needed for some time.
While being stored over the winter, the biosolids are at risk of gravity thickening which
would make removing the biosolids for land application difficult. For this reason, the tanks need
an agitation or mixing system to keep solids suspended. The jet pump mixing system described
for the holding tanks was again utilized here. This system is used mainly because the system can
be shut off when not needed which is ideal for when the sludge is not needed, but when restarted
0
1,000,000
2,000,000
3,000,000
4,000,000
5,000,000
6,000,000
7,000,000B
ioso
lids
Vo
lum
e(g
al.)
Storage Capacity Sludge in tanks @EOM Addition to storage tanks Land Applied
Blackwards
63 | P a g e
can agitate the contents of the tank in under 3 hours. This mixing system will cost $25,000 per
tank.
During atypical operation, biogas could build up in the biosolids storage tanks. Increasing
pressure and gas composition causes a risk for explosion. For this reason a flare will be installed
into the facility to relieve pressures. This flare will cost $21,000 to purchase and install.18
Biosolids quantity (dry metric tons) = Sludge Volume (gal. ) ∗ %TS ∗ 8.34lb
gal∗
1 ton
2000lb
(1)
18 http://www.epa.gov/gasstar/documents/installflares.pdf
Blackwards
64 | P a g e
11. Pumping Station Design
11.1 Introduction
Pumping sludge, a non-Newtonian fluid, presents a unique challenge. The complexity
arises from variations in physical and chemical quality of sludge on a seasonal basis. Some factors
affecting sludge pumping include viscosity, temperature and flow velocity. Frictional head loss
varies with changes in viscosity of sludge at different %TS and temperature. This phenomenon
should be considered in sizing pumps and pipes. Worst case operation and maximum viscosity of
wastewater strength material should be researched and used as a basis for design. In addition,
empirical findings in sludge pumping from previous work should be studied.
11.2 Pipe Selection
Redundancy is required in piping and pumps. On the other hand, system components
must be regularly cleaned and maintained for extended use (at or above design life) and for good
hydraulic performance. As a result, flanges or couplings must be placed at appropriate locations
(at bends, before and after a pump etc…) for easy maintenance. In addition, pipe bends should
be minimized.
In regards to pump selection, information regarding suitable sludge pumps is presented
in Table 20: Advantages and Disadvantages of Progressive Cavity Pump. Progressive cavity pumps
can be used to transport primary, secondary, thickened and digester sludge. It is a positive
displacement pump. Darcy-Weisbach equation was used to calculate head loss in sludge
transport. Each component of the system was drawn into the site plan shown in Section 13. Site
Layout. Then pipes were drawn into the site plant between each component and the lengths of
each section of pipe were combined for each route. Assumed cost of 8 inch inner diameter steel
pipe is $4.7 per linear foot.
Blackwards
65 | P a g e
Table 20: Advantages and Disadvantages of Progressive Cavity Pump
Pump Type Description Advantages Disadvantages
Progressive Cavity
Positive
Displacement pump
Accuracy of flow Fixed flow rate
Small turbulence Regular stator replacement
Ideal for fluid with varying viscosity
Large footprint
Lower suction head Chopper/
grinder Centrifugal
pump Minimum clogging Higher energy cost
Reliable at large TS conc.
Rotary Lobe
Positive Displacement
pump
Compact Not precise
Higher flow rate and efficiency
No particulates
Table 21: Length of New Pipe Needed for Each Section of Route
Pipe Route Pipe Length
(feet) Cost
Primary Settling to Thickening Building
420 $2000
Secondary Settling to Thickening Building
0 $0
Thickening Building to Sludge Holding Tanks
280 $1350
Sludge Holding Tanks to Top of Thermophilic Digesters
770 $3600
Bottom of Mesophilic Digesters to Dewatering Building
640 $3000
Dewatering Building to Biosolids Storage
370 $1750
Total $11,700
Blackwards
66 | P a g e
11.3 Pipe Diameters
For each flow route, the head needed from a pump was calculated (See Appendix II:
Mathcad Calculations). This included minor frictional losses, major frictional losses, and elevation
change. Then all variables were kept constant except pipe diameter and the results graphed in
Figure 34: Pumping Head Needed as a Function of Pipe Diameter.
In Figure 34: Pumping Head Needed as a Function of Pipe Diameter, Pump 1 Head refers
to the head needed from a pump to convey flow from the bottom of the holding/mixing tanks to
the top of the thermophilic digesters. Pump 2 Head refers to the head needed from a pump to
convey flow from the bottom of the mesophilic digesters to the dewatering building. Pump 3
Head refers to the head needed from a pump to convey flow from the dewatering building to the
top of a biosolids storage facility.
Figure 34: Pumping Head Needed as a Function of Pipe Diameter
0
10
20
30
40
50
60
70
80
0 5 10 15
Pu
mp
Hea
d N
eed
ed (
ft.)
Pipe Diameter (in.)
Pump 1 Head
Pump 3 Head
Pump 2 Head
Blackwards
67 | P a g e
11.4 Cleaning Pipes
Transport of solids from primary settling and secondary settling have a few associated
problems. These materials are high in grease and tend to adhere to surfaces. As sludge is
pumped through pipes, a film coating forms on the inner surface of the pipe. This film increases
frictional losses which means the pumps must operate at a higher head in order to send the
sludge through the pipe. One method of reducing the work needed from the pump is to
periodically clean off this film.
11.5 Cleaning Methods
In today’s water and sewage management pigging is a type of plug that is pumped
through a water or sewer main to clean out the sludge, slime, or corrosion. The more commonly
used type of pigging today is foam pigging which is very effective but has its limitations. The first
limitation is the possibility of getting stuck in the pipe which then leads to digging out the main
which is highly energy intensive. This system also would need to include pig docking stations
where the pig can be added and removed from the piping system. The overall process is quite
slow and labor intensive. Another option for pigging is a new and much easier system called ice
pigging. This system involves a truck with a slurry of salty ice that will act as a semi-solid mixture
that will clean the sides of the pipe as it is passed down. The major perks of a system like this are
efficiency, ease of operation, and effectiveness. The efficiency is much better with this system
because instead of pigging docks used with the foam pigs, the ice just needs a standard valve that
can pass ice through. Another benefit of choosing the ice method is there is no possibility of the
ice getting stuck. If the ice ever does get bound up it will quickly melt. Additionally the ice is far
more effective in the removal of biofilm and sediment. The current practice is to increase the
pressure which is not cleaning the piping system very well. If the ice system is implemented in
the pipes it could raise pumping efficiency considerably. The icing option is very clear and it is
our recommendation to the city of Wyoming CWP because of many factors but mainly the cost,
ease of use, and effectiveness.
Blackwards
68 | P a g e
12. Nutrient Removal/Recovery
Nutrient removal from wastewater discharges is an increasing challenge for water
authorities, as regulatory authorities tighten discharge standards to avoid eutrophication
problems in receiving waters. Significant costs are associated with the extra treatment processes
required to meet these new discharge standards. The most widely used technologies for nutrient
removal include biological nitrification/denitrification for nitrogen removal and polymer
flocculation for phosphorus removal. Both approaches result in the nutrient being made
unrecoverable for possible use as a fertilizer. An alternative to these conventional technologies
which can provide for recovery of the nutrient as a commercial fertilizer could be the production
of struvite. Below are listed all of the options currently available for nutrient recovery with the
associated benefits and detriments for the overall system.
Table 22: Comparison of Nutrient Recovery Technologies
Method Phosphorus
Recovery Nitrogen Recovery
Throughput Dewatering Chemical Addition
Multiple Screens Poor None High Poor None
Decanting Centrifuge High None High Good None
Polymer Flocculation High None High Good High
Nitrification / De-nitrification
None High Low Poor none
Traditional Ammonia Stripping
None High Low Poor High
DVO Approach Some Some High Poor Some
Struvite High High High Average High
From the preliminary research into these options, the team would suggest the
implementation of the Struvite system in a few years. The system was successful on the pilot
plant scale and is starting to be implemented in different waste water treatment plants in
conjunction with an anaerobic digester. For the plant that would be similar to CWP with a two
stage digestion and 25mgd was estimated at 13 million dollars. In addition to the removal and
recovery of Phosphorus and Nitrogen, ammonia is also removed from the system. The team
Blackwards
69 | P a g e
would suggest waiting until the digester is fully operational and nutrient potential can be
analyzed in detail before proceeding with any of the above options19.
13. Site Layout
Figure 35: Suggested Location of Digestion Facility
19 http://www.epa.gov/agstar/documents/conf12/10b_Dvorak-Frear.pdf
Blackwards
70 | P a g e
14. Bench Scale Experiments
14.1 Digester Construction
The team constructed a bench scale anaerobic digester for experimental purposes. The
batch process was used for modeling since the proposed continuous flow method would be too
difficult to maintain due to high cost, time, and space requirements. The digester was modeled
using a 4.5-gal pressure cooker. The digester was fitted with a motor and two radial impellers
that rotate at 5 rpm. To simulate thermophilic conditions, the digester was placed in a water bath
at 50°C. A plastic tube directs biogas produced from digestion to an inverted, graduated cylinder.
Seed for the digester was obtained from egg-shaped anaerobic digester at Grandville CWP. Raw
and thickened WAS were collected from Wyoming CWP.
Figure 36: Bench Scale Anaerobic Digester
Blackwards
71 | P a g e
14.2 Operation and Testing
Once the digester was fed with seed and feed sludge samples, the first test run was
commenced on Thursday, February 25, 2014. The team discovered on the second day that almost
all of the water has evaporated, and the sludge was cooked inside the digester and eventually
spilled. The gas tube was plugged with sludge (see Figure 37: Trial Run Spill). To solve the
problem, about two gallons of sludge was removed, and the gas tube was connected near the
cover. The team performed COD, total solids and volatile solids experiments to measure system
performance based on changes in organic content. COD experiment was not successful because
the digester has high solids content. Result of the first experimental run is shown on Error!
Reference source not found.. No general trend of TS and VS was observed over the test period.
Figure 37: Trial Run Spill
Blackwards
72 | P a g e
Figure 38: Results from Trial Run
For future experiments, the team decided on taking small samples every day, storing in
refrigerator and performing solids test weekly. High-range COD vials were purchased for COD
tests. The head motor was replaced with a 6rpm motor to solve mixing problems. To standardize
sampling method, one team member was assigned to take all remaining daily samples. For the
final run, the digester was operated for a total of 18 days. Over this period of time, a daily sample
was collected, stored at 4 C° and burned weekly.
14.3 Results and Discussion
For the final run, the digester was in operation for a total of 18 days. Over this period of
time, sludge samples were collected daily, stored at 4°C and burned weekly. In Figure 39: Results
from Final Digestion Run, it is clear that the volatile solids show a general downward progression
which imply that solids degradation occurred and methane was produced. The total solids show
a similar trend overall but the trend is not as apparent. The team believes that this is the result
of the testing method. By burning weekly, the sample had time to degrade slightly in the
refrigerator, thus the trend is increasing for some sampling periods, but there is an observable
overall decreasing trend.
0%
5%
10%
15%
20%
25%
30%
35%
0%
1%
2%
3%
4%
5%
6%
24-Feb 25-Feb 26-Feb 27-Feb 28-Feb 1-Mar 2-Mar 3-Mar 4-Mar
% V
ola
tile
So
lids
(avg
.)
% T
ota
l So
lids
(avg
.)
Sampling Dates
Total Solids
Total Volatile Solids
Blackwards
73 | P a g e
Figure 39: Results from Final Digestion Run
14.4 Safety
To ensure safety of the team and other students working in the lab room, all experiments
(except solids testing) were conducted inside a fume hood. Upon entering the lab, safety glasses
and goggles were worn. Furthermore, all items in contact with test sludge and in the vicinity were
thoroughly washed and disinfected.
Blackwards
74 | P a g e
15. Total Cost of Proposed System
Project Cost
Digester System $15 M
Holding Tanks $1 M
Thickening $600 K
Dewatering $1.2 M
Storage Tanks $3.1 M
Cogeneration $1.5 M
Biogas Conditioning $507 K
Gas Storage $300 K
Contingency $2.1 M
Total $22.9 M
16. Future Work
Final design of a full-scale digestion system would include further analysis. The team
proposes the following items should be researched:
- Piloting (gas production, pollutant concentration in biosolids)
- Instrumentation (SCADA system)
- HVAC and Plumbing
- Architectural and Structural Design
- Geotechnical Analysis
- Effective Nutrient Recovery
Blackwards
75 | P a g e
Acknowledgements
The team would like to thank Dr. David B. Wunder (Ph.D., P.E.) for serving as the team’s
advisor and providing valuable information throughout the semester. Myron Erickson (P.E.),
superintendent at City of Wyoming CWP and Aaron Vis, Project Manager of GRVBA have been
active participants in our work. The team appreciates their timely response to team requests and
showing guidance. Phil Jasperse, manager of Calvin’s metal shop was instrumental in the
construction and operation of our bench scale digester. Brain Vu from Grandville CWP has
supplemented our bench scale efforts by supplying feed samples from the plant’s egg-shaped
digester, and the team appreciates his assistance. Finally, the team is grateful for Jim Flamming
(P.E.) and David Filipiak (CHMM) from Fishbeck, Thomson, Carr and Huber, Inc. (FTC&H) for
serving us our industrial consultants in the design process and evaluating the team’s decisions.
Blackwards
76 | P a g e
References
"Opportunities for Combined Heat and Power at Wastewater Treatment Facilities: Market Analysis and Lessons from the Field." U.S. Environmental Protection Agency: Combined Heat and Power Partnership (2011). Web. 14 Dec. 2013. <http://www.epa.gov/chp/documents/wwtf_opportunities.pdf>.
Abbasi, Tasneem, and Tauseef Abbasi. "Anaerobic Digestion for Global Warming Control and Energy Generation—An Overview." Centre for Pollution Control and Environmental Engineering 16 (2012): 3228-242. Elsevier. Web.
Arnett, Clifford, Joseph Farrell, Daniel Hull, Steven Krugel, Billy Turner, Warren Uhte, and John Willis. Biosolids Flow-Through Thermiphilic Treatment Process. Columbus Water Works, assignee. Patent US 2004/0011718 A1. 22 Jan. 2004. Print.
Asada, Lucia, Gilberto Sundefeld, Carlos Alvarez, and Sidney Seckler. "Water Treatment Plant Sludge Discharge to Wastewater Treatment Works." Water Environment Research 82.5 (2010): 392-400. Print.
Badger Laboratories and Engineering. 2008. Quality Assurance Manual. Bolzonella, David, Francesco Fatone, Silvia Di Fabio, and Franco Cecchi. "Mesophilic, Thermophilic
and Temperature Phased Anaerobic Digestion Of Waste Activated Sludge." The Italian Association of Chemical Engineering. Web. 4 May 2014.
Camp Dresser & McKee Inc. Charting the Future of Biosolids Management: Final Report. Rep. N.p.: Water Environment Research, 2011. Print.
Clean Water Act, Part 503, section (a)(3)(ii)(D), page 20 D, Parry, and Loomis P. "DC Water Biosolids and Energy Process: Blue Plains Advanced
Wastewater Treatment Plant." 18th European Biosolids & Organic Resources Conference and Exhibition. Web. 13 Apr. 2014.
Day, Doug. "A Good Egg" TPO- Treatment Plant Operator Dec. 2013: 28-33. Web. 13 Apr. 2014. Digestion Systems for Livestock Manures. USDA.
Eastern Research Group, Inc. Protocol for Quantifying and Reporting the Performance of Anaerobic Digestion Systems for Livestock Manures. Rep. Lexington: n.p., 2011. U.S. Environmental Protection Agency, 2011. Web.
Environmental Research Information Center. Technology Transfer. Sludge Treatment and Disposal. Cincinnati, OH: Environmental Protection Agency, Environmental Research Information Center, Technology Transfer, 1978. Print.
EPA "Opportunities for Combined Heat and Power at Wastewater Treatment Facilities: Market Analysis and Lessons from the Field." U.S. Environmental Protection Agency: Combined Heat and Power Partnership (2011). Web. 14 Dec. 2013. <http://www.epa.gov/chp/documents/wwtf_opportunities.pdf>.
EPA “Biosolids Generation, Use, and Disposal in the United States.” N.p.: United States Environmental Protection Agency, 1999. Web. 2 Mar. 2014. <http://www.epa.gov/compost/pubs/biosolid.pdf >.
Erickson, Ryan J. "Concrete Water Storage Tanks." Sunrise Engineering, n.d. Web. 1 Apr. 2014. <http://deq.state.wy.us/wqd/
Blackwards
77 | P a g e
Goldstein, Jerome. "Around the World with Anaerobic Digestion." Biocycle Energy 44.4 (2003): 78-81. Print.
Greer, Diane. "Funding Anaerobic Digestion Facilities." BioCycle Energy 52.3 (2011): 70-73. Print. Greer, Diane. "Vermont Builds Anaerobic Digestion Capacity." BioCycle Energy 52.10 (2011): 38-
41. Print. Informa Economics. National Market Value of Anaerobic Digestor Products. Rep. Innovation
Center for US Dairy, Feb. 2013. Web. Kade, Farid. "Enhancing Solids Destruction from Anaerobic Municipal Digesters." M.S. thesis,
Marquette University (2004). Web. Khalid, Azeem, Muhammad Arshad, Muzammil Anjum, Tariq Mahmood, and Lorna Dawson. "The
Anaerobic Digestion of Solid Organic Waste." Waste Management 31.8 (2011): 1737-744. Print.
Kleiven, Harald. Cambi; Recycling Energy. Norway: n.p., 2010. Print. Kopp, Ewert. "New Processes for the Improvement of Sludge Digestion and Sludge
Dewatering." Influence of Surface Charge and Exopolysaccharides on the Conditioning Characteristics of Sewage Sludges. Ed. Hamburg Lengede. Vol. 5. N.p.: Springer, 1998. N. pag. Print.
Mancl, Karen. Wastewater Treatment Principles and Regulations. Ohio State University, n.d. Web. 13 Nov. 2013. <http://ohioline.osu.edu/aex-fact/0768.html>
Martin, J. 2007. A Protocol for Quantifying and Reporting the Performance of Anaerobic Meringa, Joshua. "Grandville's Clean Water Plant: First of its Kind in Michigan." the review Jan.
2013: 27-30. Web. 14 Dec. 2013. <http://www.mml.org/thereview/review-janfeb2013/offline/download.pdf>.
Metcalf & Eddy., George Tchobanoglous, Franklin L. 1927- Burton, and H. David Stensel. Wastewater Engineering: Treatment and Reuse. 4th ed. Boston: McGraw-Hill, 2003.
Panter, Keith, and David Auty. "Thermal Hydrolysis, Anaerobic Digestion and Dewatering of Sewage Sludge as a Best First Step in Sludge Strategy: Full Scale Examples in Large Projects in the UK and Strategic Study including Cost and Carbon Footprint." (n.d.): n. pag. Print.
Pauley, Keith. Mid-Atlantic Technology, Research and Innovation Center. Rep. MARTIC Research, 23 Mar. 2010. Web. <http://depts.washington.edu/cpac/Activities/Meetings/Satellite/2010/Thursday/Pauley%20Biomass%20Gasification%20presentation.pdf>.
United States. Environmental Monitoring Systems Laboratory. Office of Research and Development. Chemical Oxygen Demand: [test] Method 410.4. By James O'Dell. Cincinnati, OH: U.S. Environmental Protection Agency, 2001. Web. <http://water.epa.gov/scitech/methods/cwa/bioindicators/upload/2007_07_10_methods_method_410_4.pdf>.
United States. Environmental Protection Agency. Office of Water. U.S. Environmental Protection Agency. By Engineering and Analysis Division. N.p., 2001. Web. <http://water.epa.gov/scitech/methods/cwa/bioindicators/upload/2008_11_25_methods_method_biological_1684-bio.pdf>.
United States. Massachusetts Department of Environmental Protection. Tapping the Energy Potential of Municipal Wastewater Treatment: Anaerobic Digestion and Combined Heat and Power in Massachusetts. By Shutsu Wong. Massachusetts: n.p., 2011. Print.
Blackwards
78 | P a g e
United States. Water Environment Federation. Laboratory Evaluation of Thermophilic-Anaerobic Digestion to Produce Class A Biosolids. By Michael Aitken, Glenn Walters, Phillip Crunk, John Willis, Joseph Farrell, Perry Schafer, Cliff Arnett, and Billy Turner. 7th ed. Vol. 77. Stockholm: Water Environment Research, 2005. Print.
United States. Water Environment Federation. Laboratory Evaluation of Thermophilic-Anaerobic Digestion to Produce Class A Biosolids. By Michael Aitken, Glenn Walters, Phillip Crunk, John Willis, Joseph Farrell, Perry Schafer, Cliff Arnett, and Billy Turner. 7th ed. Vol. 77. Stockholm: Water Environment Research, 2005. Print.
US EPA "Alkaline Stabilization of Biosolids." Biosolids Technology Fact Sheet (2000).http://www.epa.gov/owm/septic/pubs/alkaline_stabilization.pdf. Web. 10 Apr. 2014.
US EPA "Centrifuge Thickening and Dewatering." Biosolids Technology Fact Sheet (2000).http://water.epa.gov/scitech/wastetech/upload/2002_06_28_mtb_centrifuge_thickening.pdf. Web. 10 Apr. 2014.
Water Environment Federation, Design of Municipal Wastewater Treatment Plants Task Force. Design of municipal wastewater treatment plants. Volume 3: Solids Processing and Management. 5th ed. Alexandria, VA: Water Environment Federation Press, 2010. Print.
WEF Manual of Practice No. 11, Operation of Municipal Wastewater Treatment Plants. Alexandria, VA: Water Environment Federation, 2007. Web. 2 May 2014.
Wilkinson, Kevin. "Development of On-Farm Anaerobic Digestion." BioCycle Global Jan. 2011: 49-50. BioCycle Global. Web.
Willis, John, and Perry Schafer. Advances in Thermophilic Anaerobic Digestion. Rep. no. 1114. Rancho Cordova: Brown and Caldwell, n.d. Print.
Blackwards
79 | P a g e
Appendix I: Team Management
Eyosias Ashenafi
Eyosias is a senior civil and environmental
engineering student from Addis Ababa, Ethiopia.
He enjoys playing soccer and studying maps in
his free time. He also volunteers regularly with
local organizations including Comprenew. He
has worked on an environmental research
project at Calvin. Two summers ago, he worked
with middle school students in Detroit, teaching
math and science. His roles in the project
included project management and
communication.
Rachel Gaide
Rachel is a senior chemical engineering student
from Pueblo, CO. She enjoys baking, playing
volleyball and softball, and reading historical
fiction in her free time. She has interned at Xcel
Energy for a summer and been an engineering
research assist for a summer. She volunteers as
a Sunday school teacher and librarian for Trinity Lutheran Church and school. She is currently
seeking full time employment following graduation in May 2014.
Andrew Mitchell
Andrew is senior civil and environmental engineering student from Iron Mountain, MI. He likes
skiing or snowboarding, kayaking, and multiple motorsports. Andrew is captain of the Calvin
men’s swim team and enjoys the athletic competition. He spent the last summer in Kenya Africa
working with Bridging the Gap Africa building suspended bridges.
Katherine Vogel
Katherine Vogel grew up in Littleton, CO and is receiving a BSE with a concentration in Civil and
Environmental engineering. She volunteers at Madison Square Church as a Sunday school small
group leader and as a student representative for two governance committees at Calvin College.
Katherine enjoys yoga, watching educational YouTube, reading science fiction, and baking in her
free time. She has completed two summers of internship at Knight Piésold Consulting and is
currently looking for full time employment in the Denver Metro Area.
Figure 40: Team Photo
Blackwards
80 | P a g e
Table 23: Work Breakdown Structure (Fall 2013)
Task Start Finish Actual Finish Responsible
Person
Define Scope and Objectives Thu 9/26/13 Thu 10/3/13 Thu 10/3/13 Team
Background of Project (Introduction) Thu 9/26/13 Thu 10/17/13 Thu 10/17/13 AM
Flows and Loads Tech Memo Thu 10/10/13 Fri 11/8/13 Fri 11/8/13 KV
Determine Operating Capacity Mon
10/14/13 Thu 11/7/13 Thu 11/7/13 KV
Analytical Methods Tech Memo Fri 10/11/13 Fri 11/29/13 Fri 11/29/13 RG
Solids Management Alternatives Tech Memo
Thu 9/26/13 Mon 12/2/13 Thu 12/19/13 EA
Stabilization Thu 10/3/13 Mon 12/2/13 Thu 12/19/13 AM
Chemical Thu 10/3/13 Fri 10/11/13 Thu 12/19/13
Wet Chemical Thu 10/3/13 Thu 12/19/13 Thu 12/19/13 KV
Lime Stabilization Thu 10/3/13 Thu 12/19/13 Thu 12/19/13 RG
Time and Temp Thu 10/3/13 Thu 10/17/13 Thu 10/17/13 AM
Biological Thu 10/3/13 Thu 10/24/13 Thu 10/24/13 Team
Aerobic Digestion Thu 10/3/13 Fri 10/11/13 Fri 10/11/13 Team
Anaerobic Thu 10/3/13 Thu 10/24/13 Thu 10/24/13 AM
TPAD Thu 10/3/13 Wed 10/16/13 Wed
10/16/13 EA, AM
Thermophilic Thu 10/3/13 Wed 10/16/13 Wed
10/16/13 EA, AM
Mesophilic Thu 10/3/13 Wed 10/16/13 Wed
10/16/13 EA, AM
Dewatering Thu 9/26/13 Thu 10/17/13 Thu 10/17/13 RG
Thickening Thu 10/3/13 Thu 10/31/13 Thu 10/31/13 EA
Government Regulations Mon 11/4/13 Mon 12/9/13 Mon 12/9/13 KV
Major Components of Digester Thu 10/17/13 Thu 11/14/13 Thu 11/14/13 Team
Mixing method Thu 10/17/13 Wed 10/23/13 Wed
10/23/13 Team
Reactor Type Thu 10/17/13 Thu 11/7/13 Thu 11/7/13 Team
Heating Method Thu 10/24/13 Thu 10/31/13 Thu 10/31/13 Team
Complete Process Flow Diagram Thu 10/10/13 Fri 11/29/13 Fri 11/29/13 EA
Optimization of Biodigester Design Fri 11/1/13 Tue 12/3/13 Tue 12/3/13 RG
PPFS 1st Draft Thu 9/26/13 Thu 11/28/13 Thu 11/28/13 Team
PPFS Editing Fri 11/22/13 Sat 12/14/13 Sat 12/14/13 Team
Blackwards
81 | P a g e
Table 24: Work Breakdown Structure (Spring 2014)
Task
Due Date
Week of
10-Mar
17-Mar
24-Mar
31-Mar
7-Apr
14-Apr
21-Apr
28-Apr
5-May
12-May
Bench Scale Experiments
Sampling ALL-daily
Testing Every Sat.
EA, AM
KV, RG
EA, AM
KV, RG EA, AM
KV, RG
EA, AM
KV, RG
EA, AM
KV, RG
Data Input & Analysis Every Sat.
EA, AM
KV, RG
EA, AM
KV, RG EA, AM
KV, RG
EA, AM
KV, RG
EA, AM
KV, RG
Final Design
Mathcad calculations EA
Final Report UPDATE ALL
-2015 &2025 Comparison
EA
- Cost analysis EA, KV
- Thickening edit on PPFS
EA
-Dewatering edit on PPFS
RG
Regulations edit KV
Edit PPFS AM
Research TS coming out of a digester
AM
Digester shape and material
EA
Mixing for Digester RG
Heat Exchanger RG
Pumping Design EA, KV
Nutrient Recovery RG
P&ID KV
Site Layout EA
Review Project Brief EA
Odor Control KV,AM
Instrumentation KV,RG
Effects to Head Stream RG
Cogeneration EA
Excavation/digester design
AM
Team Photo
Assigned Tasks
Blackwards
82 | P a g e
Engineering Fridays at Calvin
14-Mar
ALL
Industrial Consultant Meeting
ALL
Website Update 2-Apr
AM/RG
Executive Summary for CEAC
11-Apr
ALL
Senior Banquet & Projects Night
10-May
ALL
Draft Design Report 25-Apr
Final Design Report 15-May
ALL
Blackwards
83 | P a g e
Appendix II: Mathcad Calculations
Part A: Sizing of System Components
Anaerobic Digestion Calculation for Wyoming CWP
WWTP Location Wyoming, MI
Design Information
- Projected 2025 values for biosolids parameters were used for sizing digester, determining heating requirements and evaluating gas production.
Annual Average Flow Maximum Month Flow
Primary Sludge (PS)
%Total Solids PS
Waste Activated Sludge (WAS)
%Total Solids WAS
Combined Sludge Production
Average Annual Flow
Maximum Month Flow
Thickening with Centrifuges
Existing System
Currently, there are two Andritz Bird centrifuges in the Sludge Thickening Building.
Centrifuge capacity per unit
Number of units
Proposed Addition (for thickening primary sludge)
Number of centrifuge unit
Capacity of added centrifuge
%Thickening
QPS.ave 104516gal
day QPS.max 124218
gal
day
%TSPS.ave 3.5% %TSPS.max 3.5%
QWAS.ave 422902gal
day QWAS.max 498356
gal
day
%TSWAS.ave 0.7% %TSWAS.max 0.7%
QPS.ave 72.581gal
min QPS.max 86.263
gal
min
QWAS.ave 293.682gal
min QWAS.max 346.081
gal
min
Qcombined.ave QPS.ave QWAS.ave 366.263gal
min
Qcombined.max QPS.max QWAS.max 432.343gal
min
Birdcapacity 265gal
min3.816 10
5
gal
day
Birdnumber 2
Centrifugeadd 1
Centrifugecap 265gpm
%TScentri 4%
Blackwards
84 | P a g e
Addition of a third centrifuge and a rehab of existing centrifuges is planned to occur in the next 10 years.
Combined Flow to Sludge Holding Tanks
- Based on Annual Average flow condition (2025 projected)
- Based on maximum month condition (2025 projected)
Sludge Storage at Holding Tanks
There are two sludge holding tanks at Wyoming CWP with mixing.
Sludge holding tank volume per unit
Number of sludge holding tanks at present
Calculation for required storage
Difference between required tankage and current capacity
Proposed addition(s)
Sludge holding tank volume per unit
Number of sludge holding to be added
During emergency flow conditions, GVRBA facilities i.e. flow routing to Grand Rapids WWTP can be utilized.
Qthick.PSave
QPS.ave %TSPS.ave
%TScentri
63.508gal
min
Qthick.WAS.ave
QWAS.ave %TSWAS.ave
%TScentri
51.394gal
min
Qthick.PS.maxmonth
QPS.max%TSPS.max
%TScentri
75.48gal
min
Qthick.WAS.maxmonth
QWAS.max%TSWAS.max
%TScentri
60.564gal
min
Qholding.ave
QPS.ave %TSPS.ave
%TScentri
QWAS.ave %TSWAS.ave
%TScentri
0.165mgd
Qholding.max
QPS.max%TSPS.max
%TScentri
QWAS.max%TSWAS.max
%TScentri
0.2mgd
Volhold.present 150000gal
Numberhold.present 2
Storagereq 3day Qholding.max
Storagereq 5.877 105
gal
Vdiff Storagereq Volhold.present Numberhold.present
Vdiff 3 105
gal
Volhold.new 1.5 105
gal
Numberhold.new 2
Blackwards
85 | P a g e
Design I: Sizing of Cylindrical Digesters
Thermophilic Design (55 degrees Celsius)
Digestion System Properties
-Thermophilic operation (high VS and pathogen destruction) - No recycle stream (HRT=MCRT) - Single-stage, high-rate digester (short HRT) - Steady state operation - Complete mix reactors
Operational Temperature
Hydraulic Retention Time
Feed to digester
Total digester volume required
Allowance for grit accumulation on top, mixing equipment, gas collection etc...
There will be a total of three digester tanks including a redundant tank of equal size.
Number of operational digesters
Digester volume per tank
Designed digester is cylindrical with equal radius and height.
Radius/height
Boundary Area of Digester
Lateral Surface Area
Top/bottom Area of Digester
The digesters will be constructed entirely above ground since the water table is located 12-15ft below ground surface.
Tthermo 55°C
HRT 10day
Qfeed Qholding.ave
Voldigesters.max Qholding.ave HRT 1.65 106
gal
FinalVoldigesters 1.2Voldigesters.max 2 106
gal
Numberdigester 2
UnitVolumedigester
FinalVoldigesters
Numberdigester
UnitVolumedigester 992756.10gal
rdigester
UnitVolumedigester
1
3
34.8ft
Alateral 2 rdigester2
7.62 103
ft2
Atop rdigester2
3.81 103
ft2
Blackwards
86 | P a g e
Part B: Methane Production
Volatile Solids Reduction (VSR) Approach
Design Information
Design VSS/TSS ratio of treatment plant is 0.8
Influent TSS concentration
Average annual
Maximum month
TSS removal rate
Primary Clarifiers
Secondary Clarifiers (assumed)
I. Present Condition (2014)
Average annual wastewater flow
TSS loading (lb./day)
Average annual
Maximum month
Volatile Solids entering digesters
Average annual condition
Maximum month condition
Loading rate
Normal loading range= 0.05-0.2
TSScave.annual 237mg
L
TSScmax.month 258mg
L
%TSSremo.pri 49%
%TSSremo.sec 93%
Qann.2014 14.7mgd
TSSave.2014 Qann.2014TSScave.annual 2.907 104
lb
day
TSSmax.2014 Qann.2014TSScmax.month 3.165 104
lb
day
VSstart.ave.2014 0.8TSSave.2014%TSSremo.pri 1 %TSSremo.pri TSSave.2014%TSSremo.sec
VSstart.ave.2014 2.243 104
lb
day
VSstart.max.2014 0.8TSSmax.2014%TSSremo.pri 1 %TSSremo.pri TSSmax.2014%TSSremo.sec
VSstart.max.2014 2.442 104
lb
day
loadingave
VSstart.ave.2014
2000000gal0.084
lb
ft3
day
loadingmax
VSstart.max.2014
2000000gal0.091
lb
ft3
day
lb
ft3
day
Blackwards
87 | P a g e
% Volatile solids destruction (Empirical formula from Metcalf and Eddy, Page 1513)
Design I: Thermophilic digestion (cylindrical)
Sludge retention time
% Volatile solids destruction
Higher destruction requires longer SRT and subsequently bigger digester tanks. Since there is enough capacity in sludge holding, the SRT can be varied to increase volatile solids destruction. Based on diminishing returns, a 10-day digestion period gives an optimum VSS reduction.
Design II: TPAD digestion (egg shaped mesophilic reactor)
Sludge retention time
% Volatile solids destruction
Density of digester gas
Biogas production
Design I: Thermophilic digestion (cylindrical)
Design I: TPAD digestion (egg shaped mesophilic reactor)
Biogas production (ft3/lb VSS destroyed)
Methane Production
Assume 60% of biogas (digester gas) is methane.
Design I: Thermophilic digestion (cylindrical)
Design II: TPAD digestion (egg shaped mesophilic reactor)
SRTI 10
%VSdes.I 13.7ln SRTI 18.9 % 50.45%
SRTII 16
%VSdes.II 13.7ln SRTII 18.9 % 56.88%
biogas 0.062lbm
ft3
Massbiogas.ave.I.2014 %VSdes.I VSstart.ave.2014 1.131 104
lb
day
Massbiogas.max.I.2014 %VSdes.I VSstart.max.2014 1.232 104
lb
day
Massbiogas.ave.II.2014 %VSdes.II VSstart.ave.2014 1.276 104
lb
day
Massbiogas.max.II.2014 %VSdes.II VSstart.max.2014 1.389 104
lb
day
volbiogas.ave.14
Mass biogas.ave.II.2014
biogas
2.058 105
ft
3
day
biogasVSS 15ft
3
lb
VCH4.ave.I.2014 0.6Mass biogas.ave.I.2014biogasVSS 1.02 105
ft
3
day
VCH4.max.I.2014 0.6Mass biogas.max.I.2014biogasVSS 1.11 105
ft
3
day
VCH4.ave.II.2014 0.6Mass biogas.ave.II.2014biogasVSS 1.15 105
ft
3
day
VCH4.max.II.2014 0.6Mass biogas.max.II.2014biogasVSS 1.25 105
ft
3
day
Blackwards
88 | P a g e
II. 2025 Design Condition
Average annual wastewater flow
TSS loading (lb/day)
Average annual
Maximum month
Volatile Solids entering digesters
Average annual condition
Maximum month condition
Loading rate
Normal range= 0.05-0.2
Biogas production
Design I: Thermophilic digestion (cylindrical)
Design II: TPAD digestion (egg shaped mesophilic reactor)
Qann.2025 24mgd
TSSave.2025 Qann.2025TSScave.annual 4.747 104
lb
day
TSSmax.2025 Qann.2025TSScmax.month 5.167 104
lb
day
VSstart.ave.2025 0.8TSSave.2025%TSSremo.pri 1 %TSSremo.pri TSSave.2025%TSSremo.sec
VSstart.ave.2025 3.662 104
lb
day
VSstart.max.2025 0.8TSSmax.2025%TSSremo.pri 1 %TSSremo.pri TSSmax.2025%TSSremo.sec
VSstart.max.2025 3.986 104
lb
day
loadingave.2025
VSstart.ave.2025
2000000gal0.137
lb
ft3
day
loadingmax.2025
VSstart.max.2025
2000000gal0.149
lb
ft3
day
lb
ft3
day
Massbiogas.ave.I.2025 %VSdes.I VSstart.ave.2025 1.847 104
lb
day
Massbiogas.max.I.2025 %VSdes.I VSstart.max.2025 2.011 104
lb
day
Massbiogas.ave.II.2025 %VSdes.II VSstart.ave.2025 2.083 104
lb
day
Massbiogas.max.II.2025 %VSdes.II VSstart.max.2025 2.268 104
lb
day
volbiogas.ave.25
Mass biogas.ave.II.2025
biogas
3.36 105
ft
3
day
Blackwards
89 | P a g e
Methane Production
Assume 60% of biogas (digester gas) is methane.
Design I: Thermophilic digestion (cylindrical)
Design II: TPAD digestion (egg shaped mesophilic reactor)
Energy Production from Methane
Energy content of methane gas
Electric efficiency
Availability in a year
*Since it costs more to buy natural gas than sell on a volume basis, it is imperative to utilize
biogas produce on-site for heating purposes.
Power Generation
2014 Average Flow conditions
Design I: Thermophilic digestion (cylindrical)
Average annual
Design II: TPAD system
Average annual
VCH4.ave.I.2025 0.6Mass biogas.ave.I.2025biogasVSS 1.66 105
ft
3
day
VCH4.max.I.2025 0.6Mass biogas.max.I.2025biogasVSS 1.81 105
ft
3
day
VCH4.ave.II.2025 0.6Mass biogas.ave.II.2025biogasVSS 1.87 105
ft
3
day
VCH4.max.II.2025 0.6Mass biogas.max.II.2025biogasVSS 2.04 105
ft
3
day
EnergyCH4 650BT U
ft3
%effec 38.92%
avail 98%
Powerave.I.2014 %effec EnergyCH4 VCH4.ave.I.2014 avail
Powerave.I.2014 2.52 107
BTU
day
Powerave.II.2014 %effec EnergyCH4 VCH4.ave.II.2014 avail
Powerave.II.2014 2.85 107
BTU
day
Blackwards
90 | P a g e
There will be a total of two G8-380 model Tech 3
Solutions Turbo Charged
cogeneration systems with a
rated
electrical
power of 380kW per unit.
2025 Average Flow conditions
Design I: Thermophilic digestion (cylindrical)
Average annual
Design II: TPAD system
Average annual
Cogeneration System Capacity
TPAD system was selected for design after comparing biosolids quality and energy generation potential. The team used maximum methane gas production rate to size cogeneration system.
Powerave.I.2025 %effec EnergyCH4 VCH4.ave.I.2025 avail
Powerave.I.2025 4.12 107
BTU
day
Powerave.II.2025 %effec EnergyCH4 VCH4.ave.II.2025 avail
Powerave.II.2025 4.65 107
BTU
day
Cogen %effec EnergyCH4 VCH4.max.II.2025
Cogen 6.305 105
W
Blackwards
91 | P a g e
Calculation of Storage Space Needed
Assuming a month is 31 days
Assuming that we need 3 and a half months storage to get through winter
Flow Rate of sludge leaving the holding/mixing tank for average conditions
Percent Total Solids leaving the holding tank Mass fraction
Flow Rate of Solids entering digester Assume that density of solids = density of water
Percent Total Volatile Solids of Total Solids for flow entering Digester
Flow Rate of Volatile Solids entering digester Assume that density of volatile solids = density of solids
Flow Rate of Fixed Solids Entering digester
Flow Rate of Water Entering Digester
Reduction in Volatile Solids within Digester
Flow Rate of Volatile Solids leaving Digester and Entering Dewatering
Flow Rate of Total Solids Percentage leaving digester and entering dewatering
Flow Rate of Sludge Poste Digestion
month 31day
StorageNeeded 3month 93day
Qholding 0.16546mgd
TSholding 0.04
Solidsholding Qholding TSholding 6.618 103
gal
day
TVS 0.80
VolatileSolidsholding Qholding TSholding TVS 5.295 103
gal
day
FixedSolidsholding Qholding TSholding 1 TVS( ) 1.324 103
gal
day
Waterholding Qholding 1 TSholding 1.588 105
gal
day
Reduction 0.5
VolatileSolidspostDigestion Reduction VolatileSolidsholding 2.647 103
gal
day
SolidspostDigestion VolatileSolidspostDigestion FixedSolidsholding 3.971 103
gal
day
QpostDigestion Waterholding SolidspostDigestion 1.628 105
gal
day
Blackwards
92 | P a g e
Percent Total Solids leaving digester and entering dewatering
Percent Total Solids leaving dewatering
Flow Rate of Sludge leaving
Current Storage on Site
How Long Current Storage can handle normal flow
Storage Needed for Winter in No Dewatering Scenario
Storage Needed for Winter in Dewatering Scenario
Cost of Tanks
TSpostDigestion
SolidspostDigestion
QpostDigestion
0.024
TSpostDewatering 0.04
QpostDewatering
QpostDigestion TSpostDigestion TSpostDewatering
9.928 104
gal
day
Storagecurrent 6000000gal
TimeCurrentStorage
Storagecurrent
QpostDewatering
60.438day
Storagenodewatering QpostDigestion StorageNeeded 1.514 107
gal
NtanksnewNoDewatering
Storagenodewatering Storagecurrent 2000000gal
4.571
Storagedewatering QpostDewatering StorageNeeded 9.233 106
gal
NewtanksDewatering
Storagedewatering Storagecurrent 2000000gal
1.616
VolumeoneTank 2000000gal
UnitCost0.65
gal
CostoneTank VolumeoneTank UnitCost 1.3 106
Costtotal 2 CostoneTank 2.6 106
Blackwards
93 | P a g e
Pumping Station Design
Head Needed for Pump that Takes Sludge from Mixing/Holding Tanks to Digestion Tanks
Average Flow Rate
Diameter of Pipe
Length of Pipe Actual distance between buildings is 660 ft.
Assume an extra 25 ft of pipe inside each
building to handle flow between units Cross Sectional Area of Pipe
Flow Velocity
Major Headloss Due to Friction with Pipe Use Figure 19-4 from Chapter 19 of System Design for Sludge Pumping by Carl N. Anderson
and David J. Hanna This figure can be used to get frictional losses within a pipe flowing with sludge from
the frictional losses within a pipe flowing with water, the TS percentage, and the
velocity within the pipe
Q1 115gpm
D1 8in
Lpipe1 770ft
Across1
D12
40.349ft
2
v1
Q1
Across1
0.734ft
s
Blackwards
94 | P a g e
Factor relates headloss for water to headloss for sludge
Use Darcy Weisbach formula for head calculation of water flowing within pipe
Kinematic Viscosity
Use coldest temperature for viscosity (10 deg Celsius) which will be worst case
Viscosity Value taken from engineeringtoolbox.com
Calculating Reynold's Number
Assume laminar flow Calculating friction factor
Calculating Frictional head loss
Relate headloss for water to headloss for sludge
Friction Losses due to bends in pipe
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-6, pg. 898 for a branch flow through a cross fitting or
Tee fitting
Friction Losses due to in line valves
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-7, pg. 899 for a Rubber flapper check valve with a
flow velocity less than 6ft/s
Frictional losses due to transition from tank to pipe
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-6, pg. 898 for a rounded entrance flush with side of
tank
factor 1 80
H20 1.307106
m
2
s
ReH201
v1 D1
H20
3.478 104
f164
ReH201
1.84 103
hLfH201 f1
Lpipe1 v12
D1 2 g 0.018ft
hLf1 hLfH201factor 1 1.424ft
nbend1 11
Kbend 0.75
KbendTot1 nbend1 Kbend 8.25
nvalve1 22
Kvalve 2
KvalveTot1 nvalve1 Kvalve 44
nentrance1 1
Kentrance 0.25
KentranceTot1 nentrance1 Kentrance 0.25
Blackwards
95 | P a g e
Frictional losses due to transition from pipe to tank
K value taken from Pumping Station Design edited by Robert L. Sanks
Table B-6, pg. 898
Total Energy Loss Coefficients
Total Minor Headloos
Use energy equation
Relating surface of fluid in mixing/holding tanks to surface of fluid in digester
System Description
Assume constant pipe diameter (Ai=Af) therefore vi=vf because Qi = Qf
Althought system is not explosed to atmosphere, the system is not pressured relative to
outside system. Therefore pressure at surface level is 1 atmosphere.
Z i refers to the water surface heght within the mixing / holding tank. Conseratively this
number was chosen for a tank half full.
Z f refers to the sludge surface height inside digester above sea level.
Fluid Properties
Specific Gravity of water
nexit1 1
Kexit 1
KexitTot1 nexit1Kexit 1
KSum1 KbendTot1 KvalveTot1 KentranceTot1 KexitTot1 53.5
hLminor1
KSum1v12
2g0.448ft
vi1 v1 vf1 v1
Pi1 1atm Pf1 1atm
zi1 640ft
zf1 685ft
999.7kg
m3
hp1
vf12
2g
vi12
2g
Pf1
g
Pi1
g
zf1 zi1 hLf1 hLminor1 46.871ft
Blackwards
96 | P a g e
Head Needed for Pump that Takes Sludge from Digestion to Dewatering
Average Flow Rate
Diameter of Pipe
Length of Pipe Actual distance between buildings is 660 ft.
Assume an extra 25 ft of pipe inside each
building to handle flow between units Cross Sectional Area of Pipe
Flow Velocity
Major Headloss Due to Friction with Pipe
Use Figure 19-4 from Chapter 19 of System Design for Sludge Pumping by Carl N. Anderson
and David J. Hanna This figure can be used to get frictional losses within a pipe flowing with sludge from
the frictional losses within a pipe flowing with water, the TS percentage, and the
velocity within the pipe
Q2 115gpm
D2 8in
Lpipe2 640ft
Across2
D22
40.349ft
2
v2
Q2
Across2
0.734ft
s
Blackwards
97 | P a g e
Factor relates headloss for water to headloss for sludge
Use Darcy Weisbach formula for head calculation of water flowing within pipe
Kinematic Viscosity
Use coldest temperature for viscosity (10 deg Celsius) which will be worst case
Viscosity Value taken from engineeringtoolbox.com
Calculating Reynold's Number
Assume laminar flow Calculating friction factor
Calculating Frictional head loss
Relate headloss for water to headloss for sludge
Friction Losses due to bends in pipe
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-6, pg. 898 for a branch flow through a cross fitting or
Tee fitting
Friction Losses due to in line valves
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-7, pg. 899 for a Rubber flapper check valve with a
flow velocity less than 6ft/s
Frictional losses due to transition from tank to pipe
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-6, pg. 898 for a rounded entrance flush with side of
tank
factor 2 80
H20 1.307106
m
2
s
ReH202
v2 D2
H20
3.478 104
f264
ReH202
1.84 103
hLfH202 f2
Lpipe2 v22
D2 2 g 0.015ft
hLf2 hLfH202factor 2 1.183ft
nbend2 6
Kbend 0.75
KbendTot2 nbend2 Kbend 4.5
nvalve2 12
Kvalve 2
KvalveTot2 nvalve2 Kvalve 24
nentrance2 1
Kentrance 0.25
KentranceTot2 nentrance2 Kentrance 0.25
Blackwards
98 | P a g e
Frictional losses due to transition from pipe to tank
K value taken from Pumping Station Design edited by Robert L. Sanks
Table B-6, pg. 898
Total Energy Loss Coefficients
Total Minor Headloos
Use energy equation
Relating surface of fluid in mixing/holding tanks to surface of fluid in digester
System Description
Assume constant pipe diameter (A1=A2) therefore v1=v2 because Q1 = Q2
Althought system is not explosed to atmosphere, the system is not pressured relative to
outside system. Therefore pressure at surface level is 1 atmosphere.
Z 1 refers to the sludge surface heght in the digesters. Conseratively this number was
chosen for a tank half full.
Z 2 refers to the height of the dewatering centrifuges above sea level.
Fluid Properties
Specific Gravity of water
nexit2 0
Kexit 1
KexitTot2 nexit2Kexit 0
KSum2 KbendTot2 KvalveTot2 KentranceTot2 KexitTot2 28.75
hLminor2
KSum2v22
2g0.241ft
vi2 v2 vf2 v2
Pi2 1atm Pf2 1atm
zi2 590ft
zf2 600ft
999.7kg
m3
hp2
vf22
2g
vi22
2g
Pf2
g
Pi2
g
zf2 zi2 hLf2 hLminor2 11.424ft
Blackwards
99 | P a g e
Head Needed for Pump that Takes Sludge from Dewatering to Storage Tanks
Average Flow Rate
Diameter of Pipe
Length of Pipe Actual distance between buildings is 660 ft.
Assume an extra 25 ft of pipe inside each
building to handle flow between units Cross Sectional Area of Pipe
Flow Velocity
Major Headloss Due to Friction with Pipe
Use Figure 19-4 from Chapter 19 of System Design for Sludge Pumping by Carl N. Anderson
and David J. Hanna This figure can be used to get frictional losses within a pipe flowing with sludge from
the frictional losses within a pipe flowing with water, the TS percentage, and the
velocity within the pipe
Q3 115gpm
D3 8in
Lpipe3 370ft
Across3
D32
40.349ft
2
v3
Q3
Across3
0.734ft
s
Blackwards
100 | P a g e
Factor relates headloss for water to headloss for sludge
Use Darcy Weisbach formula for head calculation of water flowing within pipe
Kinematic Viscosity
Use coldest temperature for viscosity (10 deg Celsius) which will be worst case
Viscosity Value taken from engineeringtoolbox.com
Calculating Reynold's Number
Assume laminar flow Calculating friction factor
Calculating Frictional head loss
Relate headloss for water to headloss for sludge
Friction Losses due to bends in pipe
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-6, pg. 898 for a branch flow through a cross fitting
or Tee fitting
Friction Losses due to in line valves
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-7, pg. 899 for a Rubber flapper check valve with a
flow velocity less than 6ft/s
Frictional losses due to transition from tank to pipe
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-6, pg. 898 for a rounded entrance flush with side of
tank
factor 3 80
H20 1.307106
m
2
s
ReH203
v3 D3
H20
3.478 104
f364
ReH203
1.84 103
hLfH203 f3
Lpipe3 v32
D3 2 g 8.55 10
3 ft
hLf3 hLfH203factor 3 0.684ft
nbend3 2
Kbend 0.75
KbendTot3 nbend3 Kbend 1.5
nvalve3 9
Kvalve 2
KvalveTot3 nvalve3 Kvalve 18
nentrance3 0
Kentrance 0.25
KentranceTot3 nentrance3 Kentrance 0
Blackwards
101 | P a g e
Frictional losses due to transition from pipe to tank
K value taken from Pumping Station Design edited by Robert L. Sanks
Table B-6, pg. 898
Total Energy Loss Coefficients
Total Minor Headloos
Use energy equation
Relating surface of fluid in mixing/holding tanks to surface of fluid in digester
System Description
Assume constant pipe diameter (A1=A2) therefore v1=v2 because Q1 = Q2
Althought system is not explosed to atmosphere, the system is not pressured relative to
outside system. Therefore pressure at surface level is 1 atmosphere.
Z 1 refers to the sludge surface heght in the digesters. Conseratively this number was
chosen for a tank half full.
Z 2 refers to the height of the dewatering centrifuges above sea level.
Fluid Properties
Specific Gravity of water
nexit3 1
Kexit 1
KexitTot3 nexit3Kexit 1
KSum3 KbendTot3 KvalveTot3 KentranceTot3 KexitTot3 20.5
hLminor3
KSum3v32
2g0.172ft
vf3 v3 vi3 v3
Pf3 1atm Pi3 1atm
zi3 600ft
zf3 640ft
999.7kg
m3
hp
vf32
2g
vi32
2g
Pf3
g
Pi3
g
zf3 zi3 hLf3 hLminor3 40.856ft
Blackwards
102 | P a g e
Cost Analysis of Holding Tank / Centrifuge Configuration
Assume Concrete as Tank Material
Taken from page 6 of "Concrete Water Storage Tanks" by Ryan J. Erickson
Assume 3 days of storage (Hydralic Residence Time [HRT]) needed in holding tank
Assume max month flow conditions
Assume centrifuge thicken to 4%
Volume of holding tanks on site
Calculate New Flow Rates
Calculate Flow into Holding Tank for Each Alternative
Calculate Volume of Holding Tank Necessary for Each Alternative
Costtank 0.651
gal
HRT 3day
QOriginalPrimary 86.3gal
min TSOriginalPrimary 0.035
TSOriginalSecondary 0.007QOriginalSecondary 346.1
gal
min
TSThick 0.04
Volexisting 150000gal
QThickPrimary QOriginalPrimary
TSOriginalPrimary
TSThick
75.513gal
min
QThickSecondary QOriginalSecondary
TSOriginalSecondary
TSThick
60.568gal
min
Qalt1 QOriginalPrimary QThickSecondary 146.868gal
min
Qalt2 QOriginalPrimary QOriginalSecondary 432.4gal
min
Qalt3 QThickPrimary QThickSecondary 136.08gal
min
Volalt1 HRT Qalt1 6.345 105
gal
Volalt2 HRT Qalt2 1.868 106
gal
Volalt3 HRT Qalt3 5.879 105
gal
Blackwards
103 | P a g e
Calculate Volume Still Needed for Each Holding Tank for Each Alternative
Calculate Cost of New tanks
Piping
Piping distances have been estimated using a satellite photo and using a car parking spot
as a reference point. Typical Car Spot is 7.5 ft to 9 ft wide by 16 ft to 20 ft long
We'll say a spot is 18 ft long
Cost of piping
Assume cast iron, 6" diameter. Number taken from RSMeans Building
Construction Cost Data,2009
Parking lengths between primary settling and thickening
Parking lengths between secondary settling and thickening
Parking lengths between primary settling and mixing
Parking lengths between secondary settling and mixing
VolneededAlt1 Volalt1 Volexisting 4.845 105
gal
VolneededAlt2 Volalt2 Volexisting 1.718 106
gal
VolneededAlt3 Volalt3 Volexisting 4.379 105
gal
Costalt1 VolneededAlt1 Costtank 3.149 105
Costalt2 VolneededAlt2 Costtank 1.117 106
Costalt3 VolneededAlt3 Costtank 2.846 105
Lengthcar 18ft
Costpipe44
ft
PrimaryToThickening 35 LPrimaryToThickening Lengthcar PrimaryToThickening 630ft
SecondaryToThickening 34 LSecondaryToThickening Lengthcar SecondaryToThickening 612ft
PrimaryToMixing 27 LPrimaryToMixing Lengthcar PrimaryToMixing 486ft
SecondaryToMixing 55 LSecondaryToMixing Lengthcar SecondaryToMixing 990ft
Blackwards
104 | P a g e
Parking lengths between mixing and second thickening building
Parking lengths between mixing and second thickening building
Length of Pipe Needed for Each Alternative
Cost of Pipe Needed for Each Alternative
MixingToThickening2 15
ThickeningToMixing 17 LThickeningToMixing Lengthcar ThickeningToMixing 306ft
Pipealt1 Lengthcar 2 MixingToThickening2( ) 540ft
Pipealt2 Lengthcar 2SecondaryToMixing 2ThickeningT oMixing( ) 2.592 103
ft
Pipealt3 Lengthcar 2PrimaryToThickening ThickeningT oMixing( ) 1.566 103
ft
CostpipeAlt1 Costpipe Pipealt1 2.376 104
CostpipeAlt2 Costpipe Pipealt2 1.14 105
CostpipeAlt3 Costpipe Pipealt3 6.89 104
MixingToDigestion 37
LMixingToDigestion Lengthcar MixingToDigestion 666ft
DigestionToDewatering 37
LDigestionToDewatering Lengthcar DigestionToDewatering 666ft
DewateringToStorage 20
LDewateringToStorage Lengthcar DewateringToStorage 360ft
DigestionToCogen 11
LDigestionToCogen Lengthcar DigestionToCogen 198ft
HoldingToCogen 51
LHoldingToCogen Lengthcar HoldingToCogen 918ft
StorageToCogen 44
LStorageToCogen Lengthcar StorageToCogen 792ft
Blackwards
105 | P a g e
Appendix III: Hydraulic Profile
A Hydraulic Profile was created of the proposed system from information given by the
Wyoming CWP. Where information was not available, a conservative estimate was chosen. In
the drawing, the Primary and Secondary settling tanks are not shown to scale. Pipe lengths were
chosen using the drawing of the site layout in AutoCAD 2012.
Blackwards
106 | P a g e
Blackwards
107 | P a g e
Appendix IV: Manual of Laboratory Tests
Solid Concentration Test Purpose
The purpose of this experiment is determine the solid concentration present in a sludge sample.
Physical and thermal treatment methods are applied to measure suspended and dissolved solids
(TSS and TDS) in addition to volatile and fixed solids present in each grouping. Treatment facilities
perform solids test for quality control. Since we will not use filters to determine TDS and TSS,
total solids can be found by following equation:
%𝐓𝐨𝐭𝐚𝐥 𝐒𝐨𝐥𝐢𝐝𝐬 = %𝐅𝐢𝐱𝐞𝐝 𝐒𝐨𝐥𝐢𝐝𝐬 (𝐅𝐒) + %𝐕𝐨𝐥𝐚𝐭𝐢𝐥𝐞 𝐒𝐨𝐥𝐢𝐝𝐬 (𝐕𝐒)
TS and VS can be determined by exposing sludge sample to different temperatures for a duration
of time. For our purposes, we are interested in TS and VSS levels of sludge samples pre- and post-
digestion. VSS is a measure of the organic matter and microbial population of a waste stream and
thus serves as an indicator of the methane production potential. In this experiment, three dishes
with sludge samples will be tested for repeatability and calculating averages in each test run.
Equipment Used
100mL aluminum dishes, muffle furnace (Lucifer), drying oven, analytical balance and
thermometer
Procedure
(Adapted from Method 2540B and 2540E of Standard Methods book, 19th Edition)
1. Label three clean empty dishes with date.
2. Place the dishes in Lucifer furnace for 1 hour at 550°C (1022°F).
3. Put dishes in the decanter until ready for use.
4. Take out of decanter and weigh the dishes. This is the weight of empty dish.
Use table below for recording.
5. Obtain approximately 30mL of slurry sludge (V).
6. Pulverize thoroughly with mortar and pestle.
7. Weigh the dish with sludge. This is the weight of the wet dish.
8. Place samples in furnace for overnight at 103°C (217°F). Only small amount of organic
matter is lost at this temperature.
9. Remove from furnace and place in desiccator to cool.
10. Weigh this sample. This is the weight of the dry sample at 103°C.
11. Heat the furnace to 550°C (1022°F), place samples and heat for one hour.
12. Let the samples cool down inside the furnace for 20 minutes with doors open.
13. At the end of the hour, remove samples and let them cool in desiccator.
14. Weigh this sample. This is the weight of the burned sample at 550°C.
15. Perform TS and TVS calculations.
Blackwards
108 | P a g e
Table 25: Solids Measurement Datasheet
Parameter Dish 1 Dish 2 Dish 3
Weight of empty dish, Wdish (mg)
Weight of wet dish, Wwet (mg)
Weight of dry sample at 103°C, W103 (mg)
Weight of burned sample at 550°C, W550c (mg) Calculations
%𝑻𝑺 = (𝑾𝟏𝟎𝟑−𝑾𝒅𝒊𝒔𝒉
𝑾𝒘𝒆𝒕−𝑾𝒅𝒊𝒔𝒉) ∗ 𝟏𝟎𝟎
%𝑽𝑺 = (𝑾𝟏𝟎𝟑−𝑾𝟓𝟓𝟎
𝑾𝟏𝟎𝟑−𝑾𝒅𝒊𝒔𝒉) ∗ 𝟏𝟎𝟎
*Duplicate measurements should agree within 5% of the average (AWWA’s Standard book)
Blackwards
109 | P a g e
Chemical Oxygen Demand (COD) Test Purpose
The purpose of this experiment is to determine the amount of organic matter present in a sample
that could be oxidized by a strong reducing agent such as sulfuric acid. It is normally reported in
units of mg/L. Previous research has shown that correlation between COD and 5-day BOD could
be derived. Standard potassium hydrogen phthalate (KHP) solutions will be used to create
calibration curve for COD. A 425 mg/L KHP solution has a theoretical COD value of 500mg/L.
Safety Precaution
COD vials contain high concentration of sulfuric acid and some mercury sulfate which may cause
skin burn and cancer. Thus the experiment should be performed in fume hood. MSDS for the
COD vials can be found in the lab binder and team’s folder.
Equipment/materials Used
Pierce Reacti-Therm digester block, CHEMetrics COD vials, plastic vial rack, Spectronic 20D+
spectrophotometer analytical balance, micropipette, standard KHP solutions, amber bottles and
thermometer
Procedure
(Adapted from CHEMetrics Test Procedure Manual)
1. Obtain 20mL sludge sample using amber bottles and thoroughly
mix.
2. Label vials using masking tape and organize on white rack.
3. Heat the digester block to 150°C (7.6 on the scale) inside fume
hood. To measure T°, insert thermometer at the small slot on the
block.
4. Carefully remove cap from vials avoiding physical contact and gas
inhale.
5. Using micropipette, place 2mL of sample into vials.
6. Close cap tightly and invert vials five times for mixing holding the
cap. Heat is produced from the mixture of strong acid and sample
(mostly water).
7. Use a damp towel to wipe the surface of the vial carefully.
8. Place samples in the heated digester block for 2hrs and record
start time.
9. Prepare vials for another sludge sample, deionized water (reagent blank) and standard
KHP solutions as described above, place in digester block and record time.
10. At the end of the 2hr. digestion period, turn off the block. Leave it for the next 15
minutes to cool down.
Figure 41: Spectronic 20D+ equipment
Blackwards
110 | P a g e
11. With care, remove the vials holding the cap and let them cool for at least 30mins in a
dark place.
12. Follow instructions on the left to start the spectrophotometer. Select the 600-950nm
filter position.
13. Set the absorbance of the device to zero using reagent blank. Clean the outer surface of
the vial.
14. Make sure to clean and swipe.
15. Place used COD vials in fume hood. DO NOT drain down the sink. The contents should
be transferred to the bottle with labels “Hazardous Waste: COD……” Rinse vials with DI
water.
16. Bottles with KHP solutions should be refrigerated for future experiments.
17. Prepare a calibration curve using KHP standard solutions.
Experiment Time:
1. Preparation (~ 30min) - Requires supervision
2. Digestion (2hrs) - Does NOT require supervision
3. Cooling (45- 50mins) - Does NOT require supervision
4. Measurement & Data analysis (~15mins) - Requires supervision
Table 26: COD experiment Datasheet
DI water KHP (mg/L)
KHP (mg/L)
KHP (mg/L)
Sample 1
Sample 2
Start time (hr: min)* End of digestion Absorbance
COD** *Start time is the actual time that the vial containing specified liquid is placed in digester block.
**Based on calibration curve.
References
1. Idris, Azni, and W.A.W.A.K.G Ghani. "Preliminary Study on Biogas Production of Biogas
from Municipal Solid Waste (MSW) Leachate." Journal of Engineering Science and
Technology 4.4 (2009): 374-80. Web. 23 Feb. 2014.
2. Standard Methods for the Examination of Water and Wastewater. 19th ed. Washington,
DC: American Public Health Association, 1995. Print.
Blackwards
111 | P a g e
DayLabel on
Dish
Weight of
dish (gm)
Wet
sample
(gm)
Dry sample
weight (gm)
Residue
Weight (gm)
[Post Burn]
%TS %TVSAVG. of
TS
AVG. of
TVS
1.1 1.3353 3.7936 1.4727 1.3537 5.59% 13.39%
1.2 1.337 12.9505 1.9476 1.4225 5.26% 14.00%
1.3 1.327 24.7171 2.5211 1.5074 5.11% 15.11%
2.1 1.3284 6.0106 1.4429 1.3537 2.45% 22.10%
2.2 1.3218 9.9672 1.5305 1.3679 2.41% 22.09%
2.3 1.3251 7.9889 1.4867 1.3608 2.43% 22.09%
3.1 1.331 21.867 1.6831 1.4072 1.71% 21.64%
3.2 1.324 21.837 1.6672 1.4005 1.67% 22.29%
3.3 1.329 25.178 1.7277 1.4152 1.67% 21.62%
7.1 1.322 13.1531 1.4641 1.3729 1.20% 35.82%
7.2 1.3213 23.0265 1.6306 1.4142 1.43% 30.04%
4.1 1.3215 8.4604 1.5256 1.3555 2.86% 16.66%
4.2 1.3235 9.0242 1.4995 1.3595 2.29% 20.45%
5.1 1.319 6.3348 1.4562 1.3495 2.74% 22.23%
5.2 1.3248 8.8766 1.4683 1.3595 1.90% 24.18%
6.1 1.32 13.2671 1.4093 1.3344 0.75% 16.13%
6.2 1.35 13.065 1.4362 1.3661 0.74% 18.68%
13 1.3378 16.5658 1.5402 1.4034 1.33% 32.41%
14 1.32 11.044 1.5246 1.3882 2.10% 33.33%
19 1.3257 21.5065 2.0201 1.4128 3.44% 12.54%
20 1.3367 24.5058 2.3271 1.455 4.27% 11.94%
1 1 1.3292 16.7377 1.5968 1.3836 1.7% 79.7% 1.70% 79.67%
27 1.3157 9.4627 1.3593 1.3267 0.54% 74.8%
2 1.3277 9.0305 1.37 1.338 0.5% 75.7%
3 1.329 4.801 1.3532 1.334 0.7% 79.3%
4 1.3275 3.992 1.4051 1.3443 2.9% 78.4%
21 1.3338 8.4327 1.3681 1.352 0.5%
22 1.3406 6.1142 1.3689 1.3472 0.6% 76.7%
6 1.3285 5.575 1.3941 1.3432 1.5% 77.6%
7 1.333 9.4711 1.3838 1.345 0.6% 76.4%
11 1.337 11.1815 1.4063 1.3541 0.7% 75.3%
12 1.3315 6.2485 1.4028 1.342 1.5% 85.3%
5 1.353 7.378 1.3868 1.3599 0.6% 79.6%
28 1.3291 7.7371 1.3669 1.3384 0.6% 75.4%
24 1.3499 6.2136 1.3719 1.355 0.5% 76.8%
26 1.3275 7.6083 1.4326 1.3559 1.7% 73.0%
10 1.3252 3.2745 1.3382 1.3285 0.67% 74.6%
9 1.3275 10.539 1.3502 1.3329 0.25% 76.2%
25 1.3329 8.1502 1.3562 1.3562 0.34% 0.0%
34 1.3212 7.5372 1.3412 1.3412 0.32% 0.0%
32 1.323 10.4089 1.3534 1.3534 0.33% 0.0%
33 1.3308 10.5184 1.3599 1.3599 0.32% 0.0%
30 1.3199 5.5514 1.3536 1.3536 0.80% 0.0%
31 1.3224 2.7 1.3308 1.3308 0.61% 0.0%
18 1.3299 14.7538 1.3952 1.3952 0.49% 0.0%
17 1.3427 18.7488 1.4112 1.4112 0.39% 0.0%
8
7
13
10
9
11
Lab Data For Team 7 Batch Reactor
ALL Weights in GRAMS
6
7
2
3
4
5
6
12
78.84%
80.30%
1.1%
0.46%
0.54%
0.33%
0.33%
0.70%
0.44%
75.21%
3
1
2
1.70%
17.40%
0.00%
0.00%
0.00%
0.00%
Start
Date
2.43%
1.69%
5.32% 14.17%
22.09%
21.85%
32.93%
18.56%
23.21%
1.80%
32.87%
12.24%
0.74%
77.49%
75.41%
76.68%
76.98%
74.90%
0.58%
1.08%
1.08%
5
4 1.31%
2.57%
2.32%
1.72%
3.86%
Blackwards
112 | P a g e
DayLabel on
Dish
Weight of
dish (gm)
Wet
sample
(gm)
Dry sample
weight (gm)
Residue
Weight (gm)
[Post Burn]
%TS %TVSAVG. of
TS
AVG. of
TVS
Start
Date
29 1.3172 10.7777 1.3594 1.3286 0.4% 73.0%
23 1.3258 11.8108 1.4091 1.3437 0.8% 78.5%
16 1.3244 13.3099 1.5057 1.3654 1.5% 77.4%
15 1.3216 6.7823 1.3789 1.336 1.0% 74.9%
1 1.3241 5.476 1.3688 1.3337 1.1% 78.5%
2 1.3244 10.9002 1.4392 1.3515 1.2% 76.4%
1 1.3275 9.284 1.4283 1.3513 1.3% 76.4%
2 1.3254 11.3384 1.4397 1.3534 1.1% 75.5%
3 1.3212 12.9161 1.4485 1.3539 1.1% 74.3%
4 1.3296 10.0404 1.4633 1.3607 1.5% 76.7%
5 1.3247 10.2969 1.442 1.3489 1.3% 79.4%
6 1.3283 7.4655 1.3958 1.3448 1.1% 75.6%
7 1.3309 11.0218 1.4379 1.3575 1.1% 75.1%
8 1.326 10.6328 1.4255 1.3512 1.1% 74.7%
9 1.3136 14.8563 1.4476 1.0%
10 1.3319 13.2135 1.4528 1.3626 1.0% 74.6%
14 1.3285 10.9875 1.4122 1.3507 0.9% 73.5%
15 1.3318 8.7546 1.3926 1.3478 0.8% 73.7%
16 1.3249 11.1817 1.3734 1.3379 73.2%
17 1.3229 12.9692 1.4021 1.3438 0.7% 73.6%
18 1.3299 10.2797 1.4024 1.3504 0.8% 71.7%
19 1.3257 10.8992 1.4051 1.3491 0.8% 70.5%
21 1.3152 11.1329 1.3999 1.3391 0.9% 71.8%
22 1.3258 9.1113 1.4073 1.3473 1.0% 73.6%
23 1.3247 12.2669 1.4217 1.3512 0.9% 72.7%
24 1.3154 13.3836 1.4194 1.3439 0.9% 72.6%
25 1.3209 10.0873 1.3965 1.342 0.9% 72.1%
26 1.3163 8.3964 1.3785 1.333 0.9% 73.2%
16 20 1.3235 10.5313 1.3861 1.3414 0.7% 71.4% 0.68% 71.41%
17 27 1.3157 15.147 1.4421 1.3677 0.9% 58.9% 0.65% 69.00%
28 1.3304 10.4603 1.3758 1.3376 0.5% 84.1%
29 1.3245 15.3836 1.4349 1.3788 0.8% 50.8%
30 1.3179 8.8661 1.3474 1.3316 0.4% 53.6%
18
8 1.3396 9.6512 1.4258 1.3597
0.95% 72.70%
0.68%
0.87% 72.62%15
0.64% 67.48%
14 0.87% 72.64%
13
12 0.82% 71.13%
11 73.40%
10 0.84% 73.58%
9 1.00% 74.61%
8 1.09% 74.91%
7 1.20% 77.46%
6 1.32% 75.53%
5 1.20% 75.95%
3
2
1.14% 77.46%
1.0% 76.7%
0.62% 75.75%
1.28% 76.13%
1.04% 76.68%
4
1
Blackwards
113 | P a g e
Appendix V: Formatted Selections from Clean Water
Act Part 503
503.13 Pollutant limits. a) Sewage sludge.
1) Bulk sewage sludge or sewage sludge sold or given away in a bag or other container shall not be applied to the land if the concentration of any pollutant in the sewage sludge exceeds the ceiling concentration for the pollutant in Table 1 of 503.13.
2) If bulk sewage sludge is applied to agricultural land, forest, a public contact site, or a reclamation site, either:
i. The cumulative loading rate for each pollutant shall not exceed the cumulative pollutant loading rate for the pollutant in Table 2 of 503.13; or
ii. The concentration of each pollutant in the sewage sludge shall not exceed the concentration for the pollutant in Table 3 of 503.13.
3) If bulk sewage sludge is applied to a lawn or a home garden, the concentration of each pollutant in the sewage sludge shall not exceed the concentration for the pollutant in Table 3 of 503.13.
4) If sewage sludge is sold or given away in a bag or other container for application to the land, either:
i. The concentration of each pollutant in the sewage sludge shall not exceed the concentration for the pollutant in Table 3 of 503.13; or
ii. The product of the concentration of each pollutant in the sewage sludge and the annual whole sludge application rate for the sewage sludge shall not cause the annual pollutant loading rate for the pollutant in Table 4 of 503.13 to be exceeded. The procedure used to determine the annual whole sludge application rate is presented in appendix A of this part.
Blackwards
114 | P a g e
b) Pollutant concentrations and loading rates—sewage sludge. 1) Ceiling concentrations.
Table 1 of §503.13 – Ceiling Concentrations
Pollutant
Ceiling Concentration
(mg/kg)1
Arsenic 75
Cadmium 85
Copper 4300
Lead 840
Mercury 57
Molybdenum 75
Nickel 420
Selenium 100
Zinc 7500 1 Dry weight basis
2) Cumulative pollutant loading rates Table 2 of §503.13 – Cumulative Pollutant Loading Rates
Pollutant
Cumulative pollutant loading rate
(kg / hectare)
Arsenic 41
Cadmium 39
Copper 1500
Lead 300
Mercury 17
Nickel 420
Selenium 100
Zinc 2800
3) Pollutant concentrations Table 3 of §503.13 – Pollutant Concentrations
Pollutant
Monthly average concentration
(mg/kg)1
Arsenic 41
Cadmium 39
Copper 1500
Lead 300
Mercury 173
Nickel 420
Blackwards
115 | P a g e
Selenium 100
Zinc 2800 1 Dry weight basis
4) Annual pollutant loading rates
Table 4 of §503.13 – Annual Pollutant Loading Rates
Pollutant
Annual pollutant loading rate (kg / hectare / 365 day
period)
Arsenic 2
Cadmium 1.9
Copper 75
Lead 15
Mercury 0.85
Nickel 21
Selenium 5
Zinc 140
c) Domestic septage. The annual application rate for domestic septage applied to
agricultural land, forest, or a reclamation site shall not exceed the annual application rate calculated using equation (1).
𝐀𝐀𝐑 =𝐍
𝟎.𝟎𝟎𝟐𝟔 Eq. (1)
Where: AAR = Annual Application rate in gallons per acre per 365 day period. N = amount of nitrogen in pounds per acre per 365 day period needed by the crop or vegetation grown on the land.
[58 FR 9387, Feb. 19, 1993, as amended at 58 FR 9099, Feb. 25, 1994; 60 FR 54769, Oct. 25, 1995] 503.32 Pathogens.
a) Sewage sludge—Class A. 1) The requirement in 503.32(a)(2) and the requirements in either 503.32(a)(3), (a)(4),
(a)(5), (a)(6), (a)(7), or (a)(8) shall be met for a sewage sludge to be classified Class A with respect to pathogens.
2) The Class A pathogen requirements in 503.32 (a)(3) through (a)(8) shall be met either prior to meeting or at the same time the vector attraction reduction requirements in 503.33, except the vector attraction reduction requirements in 503.33 (b)(6) through (b)(8), are met.
3) Class A—Alternative 1. i. Either the density of fecal coliform in the sewage sludge shall be less than 1000
Most Probable Number per gram of total solids (dry weight basis), or the density
Blackwards
116 | P a g e
of Salmonella sp. bacteria in the sewage sludge shall be less than three Most Probable Number per four grams of total solids (dry weight basis) at the time the sewage sludge is used or disposed; at the time the sewage sludge is prepared for sale or give away in a bag or other container for application to the land; or at the time the sewage sludge or material derived from sewage sludge is prepared to meet the requirements in 503.10 (b), (c), (e), or (f).
ii. The temperature of the sewage sludge that is used or disposed shall be maintained at a specific value for a period of time. A. When the percent solids of the sewage sludge is seven percent or higher, the
temperature of the sewage sludge shall be 50 degrees Celsius or higher; the time period shall be 20 minutes or longer; and the temperature and time period shall be determined using equation (2), except when small particles of sewage sludge are heated by either warmed gases or an immiscible liquid.
𝐃 =𝟏𝟑𝟏,𝟕𝟎𝟎,𝟎𝟎𝟎
𝟏𝟎𝟎.𝟏𝟒𝟎𝟎𝐭 Eq. (2)
Where, D=time in days. t=temperature in degrees Celsius.
B. When the percent solids of the sewage sludge is seven percent or higher and small particles of sewage sludge are heated by either warmed gases or an immiscible liquid, the temperature of the sewage sludge shall be 50 degrees Celsius or higher; the time period shall be 15 seconds or longer; and the temperature and time period shall be determined using equation (2).
C. When the percent solids of the sewage sludge is less than seven percent and the time period is at least 15 seconds, but less than 30 minutes, the temperature and time period shall be determined using equation (2).
D. When the percent solids of the sewage sludge is less than seven percent; the temperature of the sewage sludge is 50 degrees Celsius or higher; and the time period is 30 minutes or longer, the temperature and time period shall be determined using equation (3).
𝐃 =𝟓𝟎,𝟎𝟕𝟎,𝟎𝟎𝟎
𝟏𝟎𝟎.𝟏𝟒𝟎𝟎𝐭 Eq. (3)
Where, D=time in days. t=temperature in degrees Celsius.
4) Class A—Alternative 2. i. Either the density of fecal coliform in the sewage sludge shall be less than 1000
Most Probable Number per gram of total solids (dry weight basis), or the density of Salmonella sp. bacteria in the sewage sludge shall be less than three Most Probable Number per four grams of total solids (dry weight basis) at the time the sewage sludge is used or disposed; at the time the sewage sludge is prepared for
Blackwards
117 | P a g e
sale or give away in a bag or other container for application to the land; or at the time the sewage sludge or material derived from sewage sludge is prepared to meet the requirements in 503.10 (b), (c), (e), or (f).
ii. A. The pH of the sewage sludge that is used or disposed shall be raised to above
12 and shall remain above 12 for 72 hours. B. The temperature of the sewage sludge shall be above 52 degrees Celsius for
12 hours or longer during the period that the pH of the sewage sludge is above 12.
C. At the end of the 72 hour period during which the pH of the sewage sludge is above 12, the sewage sludge shall be air dried to achieve a percent solids in the sewage sludge greater than 50 percent.
5) Class A—Alternative 3. i. Either the density of fecal coliform in the sewage sludge shall be less than 1000
Most Probable Number per gram of total solids (dry weight basis), or the density of Salmonella sp. bacteria in sewage sludge shall be less than three Most Probable Number per four grams of total solids (dry weight basis) at the time the sewage sludge is used or disposed; at the time the sewage sludge is prepared for sale or give away in a bag or other container for application to the land; or at the time the sewage sludge or material derived from sewage sludge is prepared to meet the requirements in 503.10 (b), (c), (e), or (f).
ii. A. The sewage sludge shall be analyzed prior to pathogen treatment to
determine whether the sewage sludge contains enteric viruses. B. When the density of enteric viruses in the sewage sludge prior to pathogen
treatment is less than one Plaque-forming Unit per four grams of total solids (dry weight basis), the sewage sludge is Class A with respect to enteric viruses until the next monitoring episode for the sewage sludge.
C. When the density of enteric viruses in the sewage sludge prior to pathogen treatment is equal to or greater than one Plaque-forming Unit per four grams of total solids (dry weight basis), the sewage sludge is Class A with respect to enteric viruses when the density of enteric viruses in the sewage sludge after pathogen treatment is less than one Plaque-forming Unit per four grams of total solids (dry weight basis) and when the values or ranges of values for the operating parameters for the pathogen treatment process that produces the sewage sludge that meets the enteric virus density requirement are documented.
D. After the enteric virus reduction in paragraph (a)(5)(ii)(C) of this section is demonstrated for the pathogen treatment process, the sewage sludge continues to be Class A with respect to enteric viruses when the values for the pathogen treatment process operating parameters are consistent with the values or ranges of values documented in paragraph (a)(5)(ii)(C) of this section.
iii.
Blackwards
118 | P a g e
A. The sewage sludge shall be analyzed prior to pathogen treatment to determine whether the sewage sludge contains viable helminth ova.
B. When the density of viable helminth ova in the sewage sludge prior to pathogen treatment is less than one per four grams of total solids (dry weight basis), the sewage sludge is Class A with respect to viable helminth ova until the next monitoring episode for the sewage sludge.
C. When the density of viable helminth ova in the sewage sludge prior to pathogen treatment is equal to or greater than one per four grams of total solids (dry weight basis), the sewage sludge is Class A with respect to viable helminth ova when the density of viable helminth ova in the sewage sludge after pathogen treatment is less than one per four grams of total solids (dry weight basis) and when the values or ranges of values for the operating parameters for the pathogen treatment process that produces the sewage sludge that meets the viable helminth ova density requirement are documented
D. After the viable helminth ova reduction in paragraph (a)(5)(iii)(C) of this section is demonstrated for the pathogen treatment process, the sewage sludge continues to be Class A with respect to viable helminth ova when the values for the pathogen treatment process operating parameters are consistent with the values or ranges of values documented in paragraph (a)(5)(iii)(C) of this section.
6) Class A—Alternative 4. i. Either the density of fecal coliform in the sewage sludge shall be less than 1000
Most Probable Number per gram of total solids (dry weight basis), or the density of Salmonella sp. bacteria in the sewage sludge shall be less than three Most Probable Number per four grams of total solids (dry weight basis) at the time the sewage sludge is used or disposed; at the time the sewage sludge is prepared for sale or give away in a bag or other container for application to the land; or at the time the sewage sludge or material derived from sewage sludge is prepared to meet the requirements in 503.10 (b), (c), (e), or (f).
ii. The density of enteric viruses in the sewage sludge shall be less than one Plaque-forming Unit per four grams of total solids (dry weight basis) at the time the sewage sludge is used or disposed; at the time the sewage sludge is prepared for sale or give away in a bag or other container for application to the land; or at the time the sewage sludge or material derived from sewage sludge is prepared to meet the requirements in 503.10 (b), (c), (e), or (f), unless otherwise specified by the permitting authority.
iii. The density of viable helminth ova in the sewage sludge shall be less than one per four grams of total solids (dry weight basis) at the time the sewage sludge is used or disposed; at the time the sewage sludge is prepared for sale or give away in a bag or other container for application to the land; or at the time the sewage sludge or material derived from sewage sludge is prepared to meet the requirements in 503.10 (b), (c), (e), or (f), unless otherwise specified by the permitting authority.
7) Class A—Alternative 5.
Blackwards
119 | P a g e
i. Either the density of fecal coliform in the sewage sludge shall be less than 1000 Most Probable Number per gram of total solids (dry weight basis), or the density of Salmonella, sp. bacteria in the sewage sludge shall be less than three Most Probable Number per four grams of total solids (dry weight basis) at the time the sewage sludge is used or disposed; at the time the sewage sludge is prepared for sale or given away in a bag or other container for application to the land; or at the time the sewage sludge or material derived from sewage sludge is prepared to meet the requirements in 503.10(b), (c), (e), or (f).
ii. Sewage sludge that is used or disposed shall be treated in one of the Processes to Further Reduce Pathogens described in appendix B of this part.
8) Class A—Alternative 6. i. Either the density of fecal coliform in the sewage sludge shall be less than 1000
Most Probable Number per gram of total solids (dry weight basis), or the density of Salmonella, sp. bacteria in the sewage sludge shall be less than three Most Probable Number per four grams of total solids (dry weight basis) at the time the sewage sludge is used or disposed; at the time the sewage sludge is prepared for sale or given away in a bag or other container for application to the land; or at the time the sewage sludge or material derived from sewage sludge is prepared to meet the requirements in 503.10(b), (c), (e), or (f).
ii. Sewage sludge that is used or disposed shall be treated in a process that is equivalent to a Process to Further Reduce Pathogens, as determined by the permitting authority.
b) Sewage sludge—Class B. 1)
i. The requirements in either 503.32(b)(2), (b)(3), or (b)(4) shall be met for a sewage sludge to be classified Class B with respect to pathogens.
ii. The site restrictions in 503.32(b)(5) shall be met when sewage sludge that meets the Class B pathogen requirements in 503.32(b)(2), (b)(3), or (b)(4) is applied to the land.
2) Class B—Alternative 1. i. Seven representative samples of the sewage sludge that is used or disposed shall
be collected. ii. The geometric mean of the density of fecal coliform in the samples collected in
paragraph (b)(2)(i) of this section shall be less than either 2,000,000 Most Probable Number per gram of total solids (dry weight basis) or 2,000,000 Colony Forming Units per gram of total solids (dry weight basis).
3) Class B—Alternative 2. Sewage sludge that is used or disposed shall be treated in one of the Processes to Significantly Reduce Pathogens described in appendix B of this part.
4) Class B—Alternative 3. Sewage sludge that is used or disposed shall be treated in a process that is equivalent to a Process to Significantly Reduce Pathogens, as determined by the permitting authority.
5) Site restrictions.
Blackwards
120 | P a g e
i. Food crops with harvested parts that touch the sewage sludge/soil mixture and are totally above the land surface shall not be harvested for 14 months after application of sewage sludge.
ii. Food crops with harvested parts below the surface of the land shall not be harvested for 20 months after application of sewage sludge when the sewage sludge remains on the land surface for four months or longer prior to incorporation into the soil.
iii. Food crops with harvested parts below the surface of the land shall not be harvested for 38 months after application of sewage sludge when the sewage sludge remains on the land surface for less than four months prior to incorporation into the soil.
iv. Food crops, feed crops, and fiber crops shall not be harvested for 30 days after application of sewage sludge
v. Animals shall not be grazed on the land for 30 days after application of sewage sludge.
vi. Turf grown on land where sewage sludge is applied shall not be harvested for one year after application of the sewage sludge when the harvested turf is placed on either land with a high potential for public exposure or a lawn, unless otherwise specified by the permitting authority.
vii. Public access to land with a high potential for public exposure shall be restricted for one year after application of sewage sludge.
viii. Public access to land with a low potential for public exposure shall be restricted for 30 days after application of sewage sludge.
c) Domestic septage. 1) The site restrictions in 503.32(b)(5) shall be met when domestic septage is applied to
agricultural land, forest, or a reclamation site; or 2) The pH of domestic septage applied to agricultural land, forest, or a reclamation site
shall be raised to 12 or higher by alkali addition and, without the addition of more alkali, shall remain at 12 or higher for 30 minutes and the site restrictions in 503.32 (b)(5)(i) through (b)(5)(iv) shall be met. [58 FR 9387, Feb. 19, 1993, as amended at 64 FR 42571, Aug. 4, 1999] 503.33 Vector attraction reduction.
503.33 Vector attraction reduction
a) 1) One of the vector attraction reduction requirements in 503.33 (b)(1) through (b)(10)
shall be met when bulk sewage sludge is applied to agricultural land, forest, a public contact site, or a reclamation site.
2) One of the vector attraction reduction requirements in 503.33 (b)(1) through (b)(8) shall be met when bulk sewage sludge is applied to a lawn or a home garden.
3) One of the vector attraction reduction requirements in 503.33 (b)(1) through (b)(8) shall be met when sewage sludge is sold or given away in a bag or other container for application to the land.
Blackwards
121 | P a g e
4) One of the vector attraction reduction requirements in 503.33 (b)(1) through (b)(11) shall be met when sewage sludge (other than domestic septage) is placed on an active sewage sludge unit.
5) One of the vector attraction reduction requirements in 503.33 (b)(9), (b)(10), or (b)(12) shall be met when domestic septage is applied to agricultural land, forest, or a reclamation site and one of the vector attraction reduction requirements in 503.33 (b)(9) through (b)(12) shall be met when domestic septage is placed on an active sewage sludge unit.
b) 1) The mass of volatile solids in the sewage sludge shall be reduced by a minimum of 38
percent (see calculation procedures in “Environmental Regulations and Technology—Control of Pathogens and Vector Attraction in Sewage Sludge”, EPA–625/R–92/013, 1992, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268).
2) When the 38 percent volatile solids reduction requirement in 503.33(b)(1) cannot be met for an anaerobically digested sewage sludge, vector attraction reduction can be demonstrated by digesting a portion of the previously digested sewage sludge anaerobically in the laboratory in a bench-scale unit for 40 additional days at a temperature between 30 and 37 degrees Celsius. When at the end of the 40 days, the volatile solids in the sewage sludge at the beginning of that period is reduced by less than 17 percent, vector attraction reduction is achieved.
3) When the 38 percent volatile solids reduction requirement in 503.33(b)(1) cannot be met for an aerobically digested sewage sludge, vector attraction reduction can be demonstrated by digesting a portion of the previously digested sewage sludge that has a percent solids of two percent or less aerobically in the laboratory in a bench-scale unit for 30 additional days at 20 degrees Celsius. When at the end of the 30 days, the volatile solids in the sewage sludge at the beginning of that period is reduced by less than 15 percent, vector attraction reduction is achieved.
4) The specific oxygen uptake rate (SOUR) for sewage sludge treated in an aerobic process shall be equal to or less than 1.5 milligrams of oxygen per hour per gram of total solids (dry weight basis) at a temperature of20 degrees Celsius.
5) Sewage sludge shall be treated in an aerobic process for 14 days or longer. During that time, the temperature of the sewage sludge shall be higher than 40 degrees Celsius and the average temperature of the sewage sludge shall be higher than 45 degrees Celsius.
6) The pH of sewage sludge shall be raised to 12 or higher by alkali addition and, without the addition of more alkali, shall remain at 12 or higher for two hours and then at 11.5 or higher for an additional 22 hours.
7) The percent solids of sewage sludge that does not contain unstabilized solids generated in a primary wastewater treatment process shall be equal to or greater than 75 percent based on the moisture content and total solids prior to mixing with other materials.
8) The percent solids of sewage sludge that contains unstabilized solids generated in a primary wastewater treatment process shall be equal to or greater than 90 percent based on the moisture content and total solids prior to mixing with other materials.
Blackwards
122 | P a g e
9) i. Sewage sludge shall be injected below the surface of the land.
ii. No significant amount of the sewage sludge shall be present on the land surface within one hour after thesewage sludge is injected.
iii. When the sewage sludge that is injected below the surface of the land is Class A with respect to pathogens, the sewage sludge shall be injected below the land surface within eight hours after being discharged from the pathogen treatment process.
10) i. Sewage sludge applied to the land surface or placed on an active sewage sludge
unit shall be incorporated into the soil within six hours after application to or placement on the land, unless otherwise specified by the permitting authority.
ii. When sewage sludge that is incorporated into the soil is Class A with respect to pathogens, the sewage sludge shall be applied to or placed on the land within eight hours after being discharged from the pathogen treatment process.
11) Sewage sludge placed on an active sewage sludge unit shall be covered with soil or other material at the end of each operating day.
12) The pH of domestic septage shall be raised to 12 or higher by alkali addition and, without the addition of more alkali, shall remain at 12 or higher for 30 minutes.
[58 FR 9387, Feb. 19, 1993, as amended at 64 FR 42571, Aug. 4, 1999]
Blackwards
123 | P a g e
Appendix VI: Equipment Info
I Biosolids Treatment Wastewater System Solutions
A World of Solutions Visit www.CBI.com
Egg-shaped digestion systems CB&I's Egg-Shaped Digesters (ESD'M) combine the opt imum shape for anaerobic digestion with patented and proprietary design improvements to maximize reliabi li ty and minimize operat ing and maintenance costs. CB&l is the leading suppl ier of ESD systems in the Western Hemisphere with a proven track record, having supplied more than 80 stee l ESD vessels and related systems since 1989.
Thermophilic pretreatment systems CB&I's ATP'M 2-stage digestion system reduces pathogens to meet U.S. EPA req uirements fo r Class A biosolids and improves the stabi lization process while reducing tota l retention within the digestion process.
Gas storage Gasholders and spheres round out CB&I's product offering with economica l storage of the methane gas generated from anaerobic digestion.
ATP 2-STAGE DIGESTION SYSTEM
....•... : t- Air Aspiration .. Heat ~anger
Heat Recovery Exchanger
Pretreated Sludge
Egg-Shaped Digester Facilities CB&I focuses on delivering advanced anaerobic digestion solutions safely, on time and with the highest quality standards. Our advanced EPC approach includes designing and bu ilding projects turnkey, self performing the work from concept to commissioning and providing a lump-sum price for the project. For any project, we can provide:
Vent air
.. ··•· .. : j. Air Aspiration
• Concept definition • Design and detai l engineering • Specifications and procurement • Fabrication • Project management • Field construction • Inspection and testing • Startup and training
~ Digested Biosolids
Egg-Shaped Digester (ESD™) Systems Egg-shaped anaerobic digesters have been used throughout North America and Europe for many yea rs. Their optimum shape eliminates dead zones with in the vessel to maxim ize solids stabilization and minimize so lids accumulation. CB&I's techn ica l experti se and process improvements enhance the benefits of ESDrM techno logy.
The key to the ESD system is the blending of t he optimum egg shape w ith effective and effic ient liquid mixing to enhance digester performance. The double cu rvature shape, reduced operating liquid level surface area and effective mixing eliminate scum and grit bu ild-ups, dead zones and the need to take the egg-shaped digesters out of service for clean ing. Th is contrasts with conventional digesters, wh ich, even with the use of more complex and energy intensive mixing systems, must be periodically clea ned.
High reliability and superior performance • Employs leak-tight, all welded steel construction for long
life and durability • Maintains full working volu me and consistent residence time • Accepts high solids concentrations and reduces
digester volume
• Features outstanding capabil ity to t reat fats, oil and grease • Applies integrated foam suppress ion system
to control foaming • Uses no internal moving parts w ith in the digester • App lies redundant mechanical systems for reliability • Enhances process control fl exibility and minimizes
operator attention with automated contro l system
Low operating and maintenance costs • Cleaning expenses and downtime are virtually el iminated • Simple, easy-to-operate, automated control system
permits stand-alone operation • Durable, monolith ic Automatic Foamed-In-Place (AFIPTM)
insu lation system minimizes heat loss and reduces energy input
• AFIP insulation protects vessel from atmospheric moisture • Patented internal discharge system limits maintenance • Patented jet pump mixing system
- Eliminates all internal moving parts - Decreases foam generation and attendant foam
control problems - Minimizes energy use and maintenance costs
Low install ion costs • Small footprint minimizes land requirements and costs
High reliablity can eliminate the cost of back-up digesters Large space underneath vessel eliminates the need for a sepa rate equ ipment building
• Internal mixing system is simple and inexpensive • Steel composition allows economica l, fast,
all-weather const ruct ion • Economical AFIP insulation is appl ied on site
Good neighbor • Leak-t ight, al l-welded steel containment
significantly reduces odor em issions Compact plant w ith sma ll footprint minimizes community impact
• AFIP insu lation provides attractive appea rance
Superior safety and security • Includes patented internal d ischarge system • Removes risk of routine gas relea ses • Eliminates confined space work areas
JET PUMP DUAL ZONE MIXING SYSTEM
HEAT-X SYSTEM
UPPER DRAFT TUBE
UPPER ZONE MIXING SYSTEM
ATP Class A System The ATP thermophi lic pret reatment system operates under nearly anoxic conditions resulting in acidified, hydrolyzed and homogenized sludge. This thermal conditioning, when combined w ith anaerobic digestion, provides U.S. EPA certified Class A-pathogen reduct ion.
ATP's nominal Hydraulic Residence Time (HRT) is one day, fol lowed by 12 to 15 days of mesophilic anaerobic digestion. The ATP system has been used for more than 100 insta llations throughout North America and Europe. Representative pathogen reduction performance data is provided below.
U.S. 40 CFR PART 503 ATP
Salmonella <3 MPN/4 grams
Helminth Eggs <1/4grams
Enterovirus < 1 PFU/4 grams
Superior performance • Certifi ed U.S. EPA Class A process • Greater so lids destruction • Increased digester ca pacity • En hanced gas production • Improved dewaterabi lity • Minimized odor • Demonstrated Nocardia destruction
Low operating costs • Heat recovery reduces heating requirements • Digester heating system is eliminated • Automated control system supports stand
alone operation
High reliability • Minimal moving parts in vessel • Fu lly redunda nt mixing systems • Asp irated ai r injection • Atmospheric operat ion
Flexible application • New or existing insta llations • Upgrades for both convent iona l and
egg-shaped digeste r facilities • Batch or continuous feed options avai lable • Single vesse l design for small facili ties • Multiple vesse l design for larger fac ili t ies
<1 MPBN/4 grams
<1/4 grams
<1 PFU/4 grams
L•nd•n Wcuttwcrt•r Trf'llltmf'nt Plont
~C:===:JI~-~ .. ~-;;:· IJz l ~~' ~o lliiiiiii Tuu61y, Wotd'I10, 3X8 2 C3
I WIUCW. I lcOUIIIc- w!--. :: 4 h! I ..
ll-1 01 21.on
II*IER CtWoleEA
"""""'~
Class A Sludge System
l--"""""'-'1 1""'"'""""""1
Gas Storage Whether the need is for high-pressure or low-pressure storage, CB&I provides a variety of gasholder so lutions to meet any requirement.
High-pressure gas storage Hortonsphere® pressure vessels provide large volumes of product gas storage in a sma ll area. These vessels:
• Holds more gas in a smaller footprint compared with low-pressure storage
• Al lows for variable discharge pressure for downstream usage • Provides lower capita l cost than large-volume, low-pres
sure gas storage
Low-pressure gas storage Two types of low-pressure gas storage are ava ilable, dry seal and wet sea l. Compared with high-pressure storage, these systems provide consistent gas pressure to meet the needs of downstream usage and operate with minimal mechanical operating equipment.
LOW POSITION
HIGH POSITION
DRY SEAL GAS HOLDER
····· Tank Shell
Dry seal gas storage • Increases gas storage
volume compared with a wet seal design for a given tank volume
• Reduces odor emissions
• Provides weatherprotected piston and seal
Wet seal gas storage • Accepts multiple
liquids for the wet seal • Allows for sludge and gas storage within a single vessel • Operates on either constant or variable liquid level • Reduces capital expend iture due to size and
output requirements
LOW POSITION
HIGH POS ITION
WET SEAL GASHOLDER
. ... ....... Open Top
•·· ·········Tank Shell
········· Liquid Level
• .. .. Piston
•- ······Open Top
•- - Tank Shell
...... Piston
Liquid Level
A World of Solutions Visit www.CBI.com
Only employees, agents or representatives authorized under and pursuant to written agreement with CB&I are authorized to distribute t his brochure to an actual or potential client of CB&I. ©Copyright 2013 by Chicago Bridge & Iron Company. All rights reserved. Printed in USA. 08M082013H 2-7 09.27.2013
2980.0117.32
150.05.91
446.317.573280.0
Main Cover Length
129.13
150.05.91
1008.739.71
R45.01.77
125.0Feed Pipe Offset from
Bracket
4.92
984.2Approx.
38.75
1450.0Clearance needed for
Feed Pipe Removal
57.09
850.033.46
962.837.91
150.05.91
Note:Cover Hooks to be used formain Cover Remoaval ONLY.Do NOT use to lift entire unit.
Main Cover & Integrated Housing
Main Cover Lifting Lugs
2-1/2" NPT Feed PipeConnection
PulleySafety Cover
Name Plate
Lifting LugsTypical 4 Corners
of Main Frame
RotodiffSafety Cover
Solids End ChamberInspection Hatch
1561.261.46
1840.0Min. HeightRequired for
RotatingAssemblyRemoval
72.44
Liquid End ChamberInspection & Weir PlateAccess Hatch
Rotodiff & JunctionBox ChamberAccess Plate
Strap Down Slots
177.87.00
4178.3164.50
177.87.00
99.43.91
622.324.50
302.011.89
364.914.36
2884.0113.54
929.536.59
277.210.91
603.323.75
1206.547.50
40.01.57
149.85.90 Centrate Discharge
See Flange DetailSolids Discharge
See Flange DetailA
A B
B C
CMain MotorElectrical
Connection
Vibration IsolatorsTypical 10 Places
4734.9Main Frame Length
186.41
965.838.02
822.7Motor Mount
Length
32.39
5700.7Overall Length
224.44
109.54.31
4500.0177.17
125.44.94
672.226.46
690.027.17
1380.0Motor Mount Width
54.33
1203.2Lifting Lugs Width
47.37
1406.4Main Frame Width
55.37
2750.0108.27
Vibration Sensor(Optional)
Main Rotating Assembly Components areCentrifugally Cast Stainless Steel Duplex
Shown with Covers RemovedBearing TemperatureSensors, Typical 2 places(Optional)
125 H.P. Main Drive Motor
Strap Down Slots
ElectricalJunction
Box
Rotodiff
132.5 Typ. Spacing5.22
530.020.87
1060.041.73
115.0 Typ.Spacing
4.53
230.09.06
460.018.11
250.09.84
500.019.69
550.021.65
1100.043.31
Discharge Flange DimensionsTypical Centrate & Solids End
M10x1.5Tapped HoleTyp. 24 Places
Weights:
Rotating Assembly 8,054 lbs.Bowl Filling w/S.G. 1.0 1,328 lbs.Complete Centrifuge 18,100 lbs.(with filling)
Static Load Below each point ofcomplete Centrifuge:A = 3,840 lbs.B = 4,060 lbs.C = 1,150 lbs.
Dynamic Load Below each point ofcomplete Centrifuge:(additional 25% of static load)A = 4,800 lbs.B = 5,075 lbs.C = 1,438 lbs.
Frequency of mounting isolators:0.83Hz @ max loading of 6,500 lbs.
Sht: Scale:1 OF 1
D.S.
General Arrangement
M-C1471518100
REVISE O
N C
AD O
NLY
Estimated weight (lbs):
NAMaterial(s):3rd Angle
Projection
1:20
THIS PRINT IS PROVIDED ON A RESTRICTED BASIS AND IS NOT TO BEUSED IN ANY WAY DETRIMENTAL TO THE INTERESTS OF CENTRISYS CORP.
02/22/08
Date:
Date:
Date:
Approved by:
Chk'd by:
Drawn by:
Tel:Fax:
REV14715 Drawing #:Part #:
Cs26-4.01 2-Phase Centrifuge
Project:
Title:9586 58th PlaceKenosha, WI 53144
(262) 654-6006(262) 654-6063
Date:Designed by:
CENTRIFUGE SYSTEMS
Page 1 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Leaders in Biogas Technology
BUDGET PROPOSAL
GAS CONDITIONING SYSTEM Date: 4/25/14 Expires: 7/25/14 Glenn Hummel HESCO Proposal Number: PX-214-1742.1 Project Name: GVRBA (Grand Valley Regional Biosolids Authority) Unison Solutions, Inc. is pleased to provide this BUDGET proposal for a Gas Conditioning System for the GVRBA (Grand Valley Regional Biosolids Authority) Project. This BUDGET proposal includes all of the system engineering, CAD design services, technician labor, fabrication and materials to construct a Gas Conditioning System. Thank you for giving Unison Solutions the opportunity to provide you with the enclosed proposal. If you have questions or require additional information, please contact me at your convenience. Sincerely, Tony Schilling Unison Solutions, Inc. Phone: 563-585-0967 Cell: 563-543-6069
Page 2 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
EQUIPMENT/SUB-SYSTEMS HYDROGEN SULFIDE REMOVAL SYSTEM
- Hydrogen Sulfide Inlet Moisture/Particulate Filter - Hydrogen Sulfide Removal Media Vessel - Work Platform and Ladder - Initial Charge of SulfaTreat Media
GAS COMPRESSION/MOISTURE REMOVAL SYSTEM
- Gas Blower Inlet Moisture/Particulate Filter - Gas Blower - Forced Air to Gas Heat Exchanger - Dual Core Heat Exchanger - Gas Recirculation - Skid Base
GLYCOL CHILLER
- Glycol Chiller - Initial fill of Propylene Glycol/Water Mixture
SILOXANE REMOVAL SYSTEM
- Siloxane Removal Media Vessels - Work Platform and Ladder - Initial charge of Siloxane Removal Media - Siloxane Removal Final Particulate Filter
CONTROL SYSTEM
- Gas Conditioning System Control Panel - Transformer
DESIGN CONDITIONS
SITE INFORMATION
- Minimum Ambient Temperature 5°F - Maximum Ambient Temperature 86°F - Site Elevation 800’ AMSL
SYSTEM REQUIREMENTS
- Gas Flow 285 scfm
Page 3 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
ASSUMED INLET GAS CONDITIONS
- Inlet Gas Pressure 10”WC - Inlet Gas Temperature 100°F - Relative Humidity 100% - Methane (CH4) 60% - Carbon Dioxide (CO2) 40% - Nitrogen (N2) <1% - Oxygen (O2) <1% - Hydrogen Sulfide (H2S) 500 ppmv - Siloxanes (L2, L3, L4, L5, D3, D4, D5, D6) 1,500 ppbv
DISCHARGE GAS CONDITIONS
- Discharge Gas Pressure 3 psig - Discharge Gas Temperature 80°F - Dew Point Temperature 40°F - Maximum Hydrogen Sulfide <10 ppmv - Maximum Siloxane <100 ppbv - Particulate Removal 99% removal of >3 micron
SITE REQUIREMENTS
ELECTRICAL CLASSIFICATION
- NEC Class I, Division 1 Group D Areas - Hydrogen Sulfide Removal System - Gas Compression/Moisture Removal System - Siloxane Removal System
- Unclassified Electrical Areas - Glycol Chiller - Gas Conditioning System Control Panel
EQUIPMENT MOUNTING
- Skid Mounted
- Gas Compression/Moisture Removal System
- Standalone
- Hydrogen Sulfide Removal System - Glycol Chiller - Siloxane Removal System - Gas Conditioning System Control Panel
Page 4 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
EQUIPMENT/SUB-SYSTEM DETAILS
HYDROGEN SULFIDE REMOVAL SYSTEM
- Hydrogen Sulfide Inlet Moisture/Particulate Filter
- Mounted upstream of the Hydrogen Sulfide Removal Media Vessel - 99% removal of 3micron and larger particulates and liquid droplets - Materials of construction shall be 304L stainless steel - 150# ANSI B16.5 side inlet and outlet connections - Cleanable polypropylene structured mesh element - Differential pressure gauge across the filter element - Sight glass for liquid level indication - Level switch above the condensate drain to warn of failure - Bottom drain with strainer, float drain, manual bypass and piping
- (1) Hydrogen Sulfide Removal Media Vessel
- 12’Ø x 10’ straight side - Rated for 5psig pressure and 1psig vacuum - Materials of construction shall be 304L stainless steel - 150# ANSI B16.5 side inlet and outlet connections - Flanged and dished top and bottom heads - Vessel shall be free-standing on four 304L stainless steel legs - Vessel equipped with a top manway - Vessel equipped with a side manway - Internal supports and grating for media - Pressure relief valves included - Two top vents with stainless steel ball valves - Bottom manual condensate drain with stainless steel ball valves
- Work Platform and Ladder
- Work platform shall be welded carbon steel construction with satin black powder coat finish
- Ladder shall be galvanized steel construction - Initial Charge of SulfaTreat Media
- The initial charge of SulfaTreat media for each Hydrogen Sulfide Removal Media Vessel will be provided.
- SulfaTreat to be loaded into Hydrogen Sulfide Removal Vessel by INSTALLATION CONTRACTOR
GAS COMPRESSION/MOISTURE REMOVAL SYSTEM
- Gas Blower Inlet Moisture/Particulate Filter
Page 5 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
- Mounted upstream of the Gas Blower - 99% removal of 3micron and larger particulates and liquid droplets - Materials of construction shall be 304L stainless steel - 150# ANSI B16.5 side inlet and outlet connections - Cleanable polypropylene structured mesh element - Differential pressure gauge across the filter element - Sight glass for liquid level indication - Level switches above the condensate drains to warn of failure - Bottom drain with strainer, condensate pump, check valve, manual bypass and piping
- Gas Blower
- One Rotary Lobe Positive Displacement Blower rated for 285scfm - Belt driven 15Hp, 480V/3Ph/60Hz EXP electric motor - Motor speed will be controlled by a VFD - Cast iron casing - Inlet and discharge flex connectors - Discharge silencer - Discharge check valve - Discharge pressure safety valve - Belt guard
- Forced Air to Gas Heat Exchanger
- Air to Gas plate/fin core - Materials of construction shall be aluminum plate and fins - 480V/3Ph/60Hz EXP electric motor - Motor speed will be controlled by a VFD
- Dual Core Heat Exchanger
- Stage 1 - Gas to gas plate/fin core - Materials of constructions shall be aluminum plate and fins - Stage 2 - Gas to glycol fin/tube core - Materials of construction shall be aluminum fins on 304L stainless steel tubes - Mounted in single 304 stainless steel housing - 150# ANSI B16.5 inlet and outlet connections - All condensation generated during cooling will be removed inside the heat exchanger housing
- Level switch mounted on the housing to warn of drain failure - RTD mounted on the housing to verify the coldest temperature that the gas reaches
- Bottom drain with strainer, float drain, manual bypass and piping
Page 6 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
- Gas Recirculation
- Modulating V-port Ball Valve shall be provided to allow excess gas to flow from the discharge of the system back to the inlet. This valve shall be controlled by monitoring the delivery pressure of the system.
- V-port Ball Valve - Type 7 explosion proof actuator - 120V weatherproof
- Skid Base
- Welded carbon steel construction with satin black powder coat finish - All components mounted, piped and wired on skid base - 24V and 120V electrical components wired to one of two junction boxes on edge of skid
- INSTALLATION CONTRACTOR to provide conduit and wiring to 480V components
- Conduit shall be rigid aluminum - Condensate drains piped to edge of the skid base. Drains to be routed to floor drain by INSTALLATION CONTRACTOR.
GLYCOL CHILLER
- Glycol Chiller
- Sized for the process heat load - Suitable for outdoor installation - Refrigeration System
- One refrigeration circuit - One compressor sized for 100% capacity - Chiller capacity: 25% to 100% of rated capacity - EC motor driven condenser fans - Aluminum micro-channel air cooled condensers - 316L stainless steel evaporator - R410a refrigerant. R-410a is an HFC refrigerant with 0 ODP - Refrigeration circuit has sealed core filter drier, liquid line solenoid valve, liquid line shut-off valve, and sight glass/moisture indicator
- Electronic expansion valve - Glycol Chiller shall be factory tested and shipped with complete refrigerant charge
- Glycol Circulation - One glycol circulation pump sized for 100% capacity - Pump is stainless steel end suction centrifugal - Pump motor is TEFC - Pump isolation valves on inlet and outlet - Pump discharge check valve - Glycol reservoir is a 304 stainless steel closed tank - Glycol piping is copper with anti-corrosion coating
Page 7 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
- Armaflex insulation - Glycol Chiller to utilize propylene glycol/water mix - Initial fill of Propylene glycol will be provided
- Support Structure - G90 galvanized steel member frame - Powder-coated aluminum cover panels - All components mounted, piped and wired on skid
- Glycol Chiller Control Panel - UL Type 4 - UL 508A Listed Industrial Control Panel - Painted carbon steel - 480V/3Ph/60Hz feed will be required - 480V disconnect - Microprocessor based controller with full text LCD display - 480VAC to 24VAC transformer
SILOXANE REMOVAL SYSTEM
- (2) Siloxane Removal Media Vessels
- 4’Ø x 8’ straight side - Materials of construction shall be 304L stainless steel - 150# ANSI B16.5 inlet and outlet connections - Flanged and dished top and bottom heads - Vessels shall be free-standing on four 304L stainless steel legs - Elliptical access nozzle on top of each nozzle - Internal septas for even gas distribution through media - Pressure relief valves included - Bottom manual condensate drain with stainless steel ball valves - Test/purge ports with ball valves on the inlet and outlet of each Siloxane Removal Media Vessel
- Lead/Lag piping and valves between Siloxane Removal Media Vessels will be provided
- Work Platform and Ladder
- Work Platform shall be welded carbon steel construction with satin black powder coat finish
- Ladder shall be galvanized steel construction - Initial charge of Siloxane Removal Media
- The initial charge of siloxane removal media for each Siloxane Removal Media Vessel will be provided.
- The media shall be specifically engineered for removal of siloxanes and similar contaminants from landfill and digester gas sources.
- Siloxane media to be loaded into the Siloxane Removal Media Vessels by the INSTALLATION CONTRACTOR.
Page 8 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
- Siloxane Removal Final Particulate Filter
- Mounted downstream of the Siloxane Removal Vessels - 99% removal of 3micron and larger particulates and liquid droplets - Materials of construction shall be 304L stainless steel - 150# ANSI B16.5 side inlet and outlet connections - Cleanable polypropylene structured mesh element - Differential pressure gauge across the filter element - Sight glass for liquid level indication - Level switch above the condensate drain to warn of failure - Bottom drain on vessel with manual ball valve
CONTROL SYSTEM
- Gas Conditioning System Control Panel
- Enclosure
- UL Type 12 - UL 508A Listed Industrial Control Panel - Painted carbon steel - Indoor location
- Thermal Management (as necessary) - Rated for installation in ambient temperatures from 40°F to 104°F
- Power Distribution - Fused Disconnect - 480V/3Ph/60Hz feed required - 35kA Short Circuit Current Rating - Over current and branch circuit protection via fuses - 480VAC field wiring to terminate at the component or terminal strips inside control panel
- Surge Suppression - 480VAC Transient Voltage Surge Suppressor - 120VAC Surge Filter
- Motor Control - (1) 15Hp rated VFD for Gas Blower Motor - (1) 1-1/2Hp rated VFD for Forced Air to Gas Heat Exchanger Motor - (1) 1/2Hp rated Motor Starter Overload for Condensate Pump
- Programmable Logic Controller - Allen Bradley - Compact Logix PLC and I/O - Native Allen Bradley Ethernet IP data network
- Human Machine Interface - Proface PFXGP4601TAF - TFT Color LCD Display - 12” diagonal - 800 x 600 pixels
- Instrument wiring to terminate at terminal strips inside Control Panel - Transformer
Page 9 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
- 5kVA - 480VAC to 120VAC - NEMA 3R; Painted carbon steel
INSTRUMENTATION
- All instrumentation provided will be designed for gas service and rated for use in a NEC Class I, Division 1 Group D area.
- Hydrogen Sulfide Removal System Instrumentation - Inlet Pressure Transmitter - Inlet Resistive Temperature Detector (RTD) 3 Wire-100Ω
- Gas Compression/Moisture Removal System Instrumentation - Level Switches at each Condensate Drain - Level Indicators at each Condensate Drain - RTD’s (3 Wire-100Ω) at each Temperature Change Point - RTD (3 Wire-100Ω) to Monitor Glycol Temperature - Bi-metal Thermometers at each Temperature Change Point - Gas Blower Discharge Pressure Transmitter
- Siloxane Removal System Instrumentation - Delivery Pressure Transmitter
PIPING
- Pipe will be SA-312 TP304/304L Weld Pipe, minimum Schedule 10S. Threaded pipe shall be minimum Schedule 40S.
- Flange connections will be ANSI B16.5, SA-182 F304/304L Class 150. - Pipe welding will follow ASME B31.3 Process Piping. Welded pipe will be visually inspected and pressure tested.
VALVES
- Inlet Electric Actuated Butterfly Valve
- Butterfly valve will be lug style, iron body with stainless steel disc and stem and FKM seat.
- Type 7 explosion proof actuator - Spring return closed upon power loss - 120V weatherproof
- Ball Valves - Stainless steel with PTFE or RTFE seat. - Valves will be full port.
- Butterfly Valves - Lug style iron body with stainless steel disc and stem and FKM seat.
- Check Valves - Will be one of 2 styles; ball or dual-door.
- Ball check valves shall be stainless steel with RTFE ball. - Dual-door check valves shall be wafer style body, material shall be aluminum and/or stainless steel with an FKM seat.
- Globe Valves
Page 10 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
- Stainless steel with PTFE packing FASTENERS
- Fasteners shall be F593 304 stainless steel
TEMPERATURE CONTROLLED ENCLOSURE (OPTIONAL)
- All electrical inside the enclosure is rated Class I Division 1 - Mounted to THE Gas Compression/Moisture Removal Skid
- Steel exterior with multiple color options for site esthetics - 3/4” fire rated plywood construction over steel studs - Insulated walls and ceiling
- Interior 5/8” green board (mildew resistant drywall) - Lighted interior with two EXP incandescent light fixtures - Thermostatically controlled heater to prevent freezing - LEL inside enclosure for gas detection and warning - Ventilation fan and intake louver to prevent over heating inside enclosure - Double steel entry doors
Note: Customer will be required to power the heater, ventilation fan and lights SUBMITTALS
- Quantity: (3) copies of 3 ring binders and (1) electronic CD copy - Shop Drawings and Product Data will be provided in sufficient detail to confirm compliance with the requirements for the project. Shop Drawings and Product Data will be provided in a complete submittal package.
- Shop Drawings - Installation drawings and specifically prepared technical data, including design capacities will be provided.
- Specifically prepared wiring diagrams unless standard wiring diagrams are submitted with product data will be provided.
- Written description of operation will be provided. - Product Data - Catalog cuts and product specifications for each product specified will be provided.
- Standard wiring diagrams unless wiring diagrams are specifically prepared and submitted with Shop Drawings will be provided.
FACTORY TESTING
- The System will be tested on ambient air at Unison’s facility prior to shipment. - The CUSTOMER is allowed to witness the testing and Unison will inform the customer (2) weeks prior to anticipated testing date so customer can make travel arrangements.
OPERATION & MAINTENANCE MANUALS
- Quantity: (6) copies of 3 ring binders and (1) electronic CD copy
Page 11 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
- After shipment the Gas Conditioning System will be provided with a specifically prepared Operation & Maintenance Manuals. The information provided includes a system overview, operator interface, start-up/shut down procedures, communications, alarms procedures, maintenance overview, mechanical component spec sheets and electrical component spec sheets.
OPERATION & MAINTENANCE
- Hydrogen Sulfide Removal System - Clean Hydrogen Sulfide Inlet Moisture/Particulate Filter - Replace Hydrogen Sulfide Media - Estimated Cost = $31,460.00 every 205 days** *Labor for change out, disposal and shipping of media not included **No Gas Test data provided at time of proposal. Assumed 500ppmv
- Gas Compression/Moisture Removal System
- Clean Gas Compressor Inlet Moisture/Particulate Filter - Change Blower Oil - Clean Glycol Chiller Condenser - Test Glycol for Freeze Point - Estimated Cost = $1,500.00 every 365 days
- Siloxane Removal System
- Replace Siloxane Media - Estimated Cost = $16,830.00 per change out** *Labor for change out, disposal and shipping of media not included **No Gas Test data provided at time of proposal
ELECTRICAL PARASITIC
- Electrical Parasitic - Condensate Pump = 1 kW
- Gas Blower Motor = 12 kW - Forced Air to Gas Heat Exchanger = 1 kW - Glycol Chiller = 18 kW - Controls & Auxiliary Equipment = 4 kW Total = 36 kW (Full Load) Total = 25 kW (Average Run Load) Optional - If Temperature Controlled Enclosure is Included - Enclosure Lighting = 2 kW - Enclosure Heater = 17 kW - Enclosure Ventilation Fan = 2 kW
DELIVERY SCHEDULE
- Submittals delivered 3 to 4 weeks after order acceptance - Equipment delivery 16 to 18 weeks after submittal approval
Page 12 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
- Delivery is subject to confirmation at the time of order placement and/or submittal approval PRICING SUMMARY
- Price includes all labor and expenses associated with the fabrication of the system. - Prices do not reflect any taxes that may be applicable and are valid for 90 days. - Price is FCA; Factory, Dubuque, IA 52002, per Incoterms 2010. Shipping costs not included, see
estimate below
- Price does not include Start-up and Commissioning. Costs are shown below
BUDGET Hydrogen Sulfide Removal System ...................................................................... $135,000.00 BUDGET Gas Compression/Moisture Removal System ...................................................... $270,000.00 BUDGET Siloxane Removal System ....................................................................................... $85,000.00 Shipping ESTIMATE to Grand Rapids, MI ................................................................................ $7,000.00
Cost is an estimate and is subject to change without notice. It does not include any special packaging or permitting that may be required and is dependent on the final equipment dimensions and weights.
Start-up and Commissioning Services ESTIMATE ................................................................... $8,500.00 Price includes Four (4) consecutive, 8 hour days, for one Unison Technician onsite with travel and expenses included. Additional days may be necessary to complete start-up and commissioning, they will be billed to the Buyer/Owner/End User at the cost of $1,200 per day, per technician, plus travel & expenses.
Temperature Controlled Enclosure (OPTIONAL) .................................................................. $70,000.00 PAYMENT SCHEDULE
- 30% upon order acceptance - 30% at midpoint of construction - 30% upon equipment delivery - 10% upon site acceptance not to exceed 180 days from shipment - Net 30 days on all payments
PROVIDED BY OTHERS
- VPN connection for remote access to Unison supplied equipment for troubleshooting and remote assistance.
PRICE DOES NOT INCLUDE
- Shipping of equipment to jobsite - Start-up and commissioning services - Wind or seismic calculations for all equipment - Any maintenance work after start-up
Page 13 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
- Siloxane or H2S removal media after initial fill - Performance guarantee or service/maintenance contract - Any gas testing or analyses - Permitting for the installation of the equipment or air permits - Freeze protection; including insulation and/or heat trace and heat trace power - Pipe stands for field piping
ASSUMPTIONS
VESSELS & MEDIA
- H2S and VOC’s present in the gas will foul Siloxane media, additional gas testing will be necessary to finalize all vessel and media requirements, budget pricing is dependent on gas data given at the time of the proposal.
- No assumption of media life has been given; additional gas testing will be required at the Buyer/Owner/End Users expense.
- Any assumption of media life that has been given is an estimate; additional gas testing will be required at the Buyer/Owner/End Users expense.
- Vessel sizes are estimates only, gas testing will be necessary to finalize all vessel sizing. MECHANICAL
- Flare is supplied by OTHERS - If an existing flare is being used, it is assumed this flare is in good working order, with all safety and control equipment.
- Foundations and/or maintenance pads are designed by OTHERS to properly support the equipment.
ELECTRICAL
- 480V/3Ph/60Hz is available - The following Equipment/Sub-systems will be located in an NEC Class I, Division 1 Group D Area
- Hydrogen Sulfide Removal System - Gas Compression/Moisture Removal System - Siloxane Removal System
- The following Equipment/Sub-systems will be located in an Unclassified Area - Glycol Chiller - Gas Conditioning System Control Panel
INSTALLATION CONTRACTOR RESPONSIBILITIES
- Installation responsibilities are broken out below into three categories to outline the work; these responsibilities by no means fall on any single contractor or individual. It is the responsibility of the Buyer/Owner/End User to ensure all these conditions are adhered to, as necessary. It is responsibility of the Buyer/Owner/End User to install all equipment in compliance with local and national codes applicable to the installation site.
Page 14 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
BUYER/OWNER/END USER RESPONSIBILITIES
- All foundations and/or maintenance pads as necessary for equipment - Provide and seal all roof and building penetrations as necessary - Provide all anchor bolts, temporary lift equipment, power, labor, and all other
incidentals required for proper installation of the equipment shown on the drawings that will be provided by Unison Solutions, Inc.
- All rigging and setting of equipment at job site - Proper storage of the equipment and media prior to installation - Provide installation of Equipment/Sub-systems per the Unison Solutions Installation Guide
- Load initial charge of Hydrogen Sulfide Media and Siloxane Media into the vessels
MECHANICAL CONTRACTOR RESPONSIBILITIES
- Provide all field piping between the Equipment/Sub-systems, including but not limited to:
- Hydrogen Sulfide Removal System - Gas Compression/Moisture Removal System - Glycol Chiller - Siloxane Removal System
- Provide pipe supports as necessary. Piping shall be self-supporting, and not supported off of the Unison supplied equipment.
- Install all field located or shipped loose devices - Provide all Heat Trace and/or Insulation as necessary to provide proper freeze
protection as defined by Unison Solutions.
ELECTRICAL CONTRACTOR RESPONSIBILITIES
- Provide 480V/3Ph/60Hz feed to the Gas Conditioning System Control Panel - Provide all field wiring and conduits between the Equipment/Sub-systems to the Gas Conditioning Control Panel and associated equipment. This includes but not limited to:
- Hydrogen Sulfide Removal System - Gas Compression/Moisture Removal System - Glycol Chiller - Siloxane Removal System - Gas Conditioning System Control Panel
- Provide local disconnects as necessary - Provide all Hazardous location conduits & wiring systems per Article 500 of the NEC - Provide conduit seals entering and/or leaving the Class I, Division 1 Electrical Area. Conduit seals will need to be filled during Start-up and Commissioning after verification of field wiring by Unison’s Start-up Technician. Conduit seals are to be filled prior to the introduction of gas to the equipment.
- Provide heat trace power from local lighting panel, as necessary.
Page 15 of 15
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 www.unisonsolutions.com Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
WARRANTY
- Unison Solutions, Inc. will warrant all workmanship and materials in conformance with the attached Warranty Statement. Warranty is valid for 18 months from the time the equipment is shipped from Unison’s factory or 12 months from the date of startup, whichever occurs first.
- This proposal is for equipment only and does not include any system engineering and design services expressed or implied.
- Unison Solutions, Inc. will not release the PLC program for this system. This is considered proprietary and the intellectual property of Unison Solutions, Inc.
WARRANTY STATEMENT
Unison Solutions, Inc. (Unison) is committed to providing quality products and services to its customers. As a demonstration of this commitment, Unison offers the following warranty on its products.
Grant of Warranty: Unison provides this warranty for its equipment under the terms and conditions which are detailed herein. This warranty is granted to the person, corporation, organization, or legal entity (Owner), which owns the equipment on date of start‐up. This warranty applies to the owner during the warranty period, and is not transferable.
Warranty Coverage: Equipment that is determined by Unison to have malfunctioned during the warranty period under normal use solely as a result of defects in manufacturing workmanship or materials shall be repaired or replaced at Unison’s option. Unison’s liability under this warranty to the Owner shall be limited to Unison’s decision to repair or replace, at its factory or in the field, items deemed defective after inspection at the factory or in the field.
Warranty Exclusions: All equipment, parts and work not manufactured or performed by Unison carry their own manufacturer’s warranty and are not covered by this warranty. Unison’s warranty does not override, extend, displace or limit those warranties. Unison’s only obligation regarding equipment, parts and work manufactured or performed by others shall be to assign to the Owner whatever warranty Unison receives from the original manufacturer. Unison does not warrant its products from malfunction or failure due to shipping or storage damage, deterioration due to exposure to the elements, vandalism, accidents, power disturbances, or acts of nature or God. This warranty does not cover damage due to misapplication, abuse, neglect, misuse, improper installation, or lack of proper service and/or maintenance, nor does it cover normal wear and tear. This warranty does not apply to modifications not specifically authorized in writing by Unison or to parts and labor for repairs not made by Unison or an authorized warranty service provider. This warranty does not cover incidental or consequential damages or expenses incurred by the Owner or any other party resulting from the order, and/or use of its equipment, whether arising from breach of warranty, non‐conformity to order specifications, delay in delivery, or any loss sustained by the Owner. No agent or employee of Unison has any authority to make verbal representations or warranties of any goods manufactured and sold by Unison without the written authorization signed by an authorized officer of Unison. Unison warrants the equipment designed and fabricated to perform in accordance with the specifications as stated in the proposal for the equipment and while the equipment is properly operated within the site specific design limits for that equipment. Any alterations or repair of Unison’s equipment by personnel other than those directly employed by, or authorized by Unison shall void the warranty unless otherwise stated under specific written guidelines issued by Unison to the Owner. This warranty does not cover corrosion or premature wear or failure of components resulting from the effects caused by siloxanes, hydrogen sulfide or volatile organic compounds in excess of the design limits. All media must be purchased through Unison Solutions or approved in writing by Unison Solutions dur‐ing warranty period. Media purchased though alternate sources and not approved in writing by Unison shall void the war‐ranty. The design limit is based on site specific gas data provided by the Owner prior to the proposal for the equipment. Owner shall be responsible for all maintenance service, including, but not limited to, lubricating and cleaning the equipment, replacing expendable parts, media, making minor adjustments and performing operating checks, all in accordance with the procedures outlined in Unison’s maintenance literature. Unison does not warrant the future availabil‐ity of expendable maintenance items.
Warranty Period: This Unison warranty is valid for 18 months from the time the equipment is shipped from Unison’s factory or 12 months from the date of startup, whichever occurs first.
Repairs During Warranty Period: All warranty claim requests must be initiated with a Return Material Authorization (RMA) number for processing and tracking purposes. The RMA number shall be issued to the Owner upon claim approval and/or field inspection. When field service is deemed necessary in order to determine a warranty claim, the costs associated with travel, lodging, etc. shall be the responsibility of the Owner except under prior agreement for a field inspection. This warranty does not include reimbursement of any costs for shipping the equipment or parts to Unison or an authorized service establishment, or for labor and/or materials required for removal or reinstallation of equipment or parts in connection with a warranty repair. This warranty covers only those repairs that have been conducted by Unison or by a Unison authorized warranty service provider, or by someone specifically authorized by Unison to perform a particular repair or service activity. All component parts replaced under the terms of this warranty shall become the property of Unison. UNISON ASSUMES NO OTHER WARRANTY FOR ITS EQUIPMENT, EITHER EXPRESS OR IMPLIED, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR ANY PARTICULAR PURPOSE, OR NONINFRINGEMENT, OR LIABILITY FOR ANY INCIDENTAL OR CONSEQUENTIAL DAMAGE.
5451 Chavenelle Road, Dubuque, Iowa 52002 [O] 563.585.0967 [F] 563.585.0970 www.unisonsolutions.com
WARRANTY STATEMENT 2013 Unison Solutions, Inc.