wastewater treatment plant annual report pdf

CITY OF EL PASO DE ROBLES WASTEWATER TREATMENT PLANT

2020 ANNUAL REPORT

Submitted to the Central Coast Regional Water Quality Control Board

By Casey Shepherd, Chief Plant Operator January 25, 2021

3200 Sulphur Springs Road Paso Robles, California

805.237.3865

City of Paso Robles Wastewater Treatment Plant

2020 Annual Report

1. Introduction ..............................................................................................................................................................1

2. Summary...................................................................................................................................................................1

Influent Treatment and Quality ............................................................................................................................ 2

Preliminary Treatment ......................................................................................................................................... 3

Primary Treatment ............................................................................................................................................... 3

Waste Activated Sludge Equalization/Dissolved Air Flotation Thickening .............................................................. 3

Biological Nutrient Removal (BNR) /Secondary Treatment .................................................................................... 3

Flow Equalization / Cloth Media Filtration ............................................................................................................ 4

Final Effluent Treatment and Quality .................................................................................................................... 4

Solids Handling ..................................................................................................................................................... 7

Nutrient Harvesting .............................................................................................................................................. 8

3. Wastewater Treatment Plant Maintenance Summary ...............................................................................................8

Plant Maintenance ............................................................................................................................................... 8

Additional Monthly Maintenance & Repairs Other Than Routine Weekly & Monthly Service ........................................ 9

4. CHEMICALS AND UTILITIES ...................................................................................................................................... 12

5. WWTP STAFFING ..................................................................................................................................................... 12

Operations Staffing..............................................................................................................................................12

Staff Training & Development..............................................................................................................................13

Operator Certification .........................................................................................................................................13

6. Wastewater Laboratory Analysis and Instrument Maintenance ............................................................................... 13

7. Pretreatment .......................................................................................................................................................... 15

8. Certification of Report ............................................................................................................................................. 17

Appendix A ..................................................................................................................................................................... 18

Performance Charts ....................................................................................................................................................18

Salinas River Flow Cart ................................................................................................................................................22


List of Tables

Table 1: Influent Parameters ................................................................................................................................. 3

Table 2: Primary Treatment Effluent Parameters Yearly Averages ....................................................................... 3

Table 3: Primary Effluent, BNR* and Secondary Effluent Averages for 2020 ......................................................... 4

Table 4: Key Final Effluent Parameters .................................................................................................................. 5

Table 5: Key Treatment Parameters 2020 ............................................................................................................. 5

Table 6: Monthly Breakdown of Processed Sludge through Belt Press: 2020 ......................................................... 7

Table 7: Monthly Breakdown of Biogas Production from Anaerobic Digestion: 2020 ............................................ 8

Table 8: Plant Maintenance Summary .................................................................................................................. 8

Table 9: Chemicals ...............................................................................................................................................12

Table 10: Utilities .................................................................................................................................................12

Table 11: Plant Staffing ........................................................................................................................................12

Table 12: Wastewater Treatment Operator Certification.....................................................................................13

Table 13: Compliance Record and Corrective Actions ..........................................................................................13


Acronyms

APCD Air Pollution Control District

BNR Biological Nutrient Removal

BOD Biochemical Oxygen Demand

CCB Chlorine Contact Basin

CHP Combined Heat and Power

Cogen Co-Generation of power and heat

DAFT Dissolved Air Flotation Thickener

ELAP Environmental Laboratory Accreditation Program

FOG Fats, Oil, and Grease

HVAC Heating, Ventilation, and Air Conditioning

MG Million Gallons

mg/L Milligrams/Liter

MGD Million Gallons per Day

mJ/cm2 Millijoules per Square Centimeter

MLSS Mixed Liquor Suspended Solids

RAS Return Activated Sludge

RWQCB Central Coast Regional Water Quality Control Board

SCADA Supervisory Control and Data Acquisition

SCF Standard Cubic Feet

THMs Trihalomethanes

TSS Total Suspended Solids

TWAS Thickened Waste Activated Sludge

µg/L Microgram/liter

UV Ultraviolet

WAS Waste Activated Sludge

WWTP Wastewater Treatment Plant

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1. Introduction

The Paso Robles Wastewater Treatment Plant (WWTP) located at 3200 Sulphur Springs Road, Paso Robles, San Luis Obispo County, California, is owned and operated by the City of Paso Robles. It serves a population of approximately 32,000 people. The average dry weather flow was 2.11 Million Gallons per Day (MGD) in 2020. In May of 2019, the City completed construction of the new Tertiary Treatment Project which included the addition of flow equalization, cloth media filtration, and Ultraviolet (UV) light disinfection facilities to the treatment process. The State Water Resources Control Board reclassified the City of Paso Robles WWTP as a Class IV Tertiary Treatment wastewater treatment facility on July 25, 2019. The year 2020 marks the first full calendar year of operation since the implementation of the Tertiary Treatment Facilities at the Paso Robles Wastewater Treatment Plant. The facility currently operates under Order No. R3-2011-0002 issued by the Central Coast Regional Water Quality Control Board (RWQCB).

Treatment plant processes include: preliminary screening and grit removal, primary clarification, three stage Biological Nutrient Removal (BNR) process with internal recycle, secondary clarification with return activated sludge (RAS), tertiary treatment utilizing 10 micron cloth media filtration, and UV light disinfection. Solids handling includes dissolved air flotation sludge thickening (DAFT), anaerobic sludge digestion, combined heat and power (CHP) cogeneration generators, solids dewatering using a belt filter press, and a nutrient harvesting system. Treated effluent is currently discharged via a polishing channel into the Salinas River. Numerous auxiliary systems are required for proper operation of many plant processes including; instrumentation and control system, process water, Heating, Ventilation, and Air Conditioning (HVAC), electrical power distribution, natural gas, biogas management, and chemicals.

This report is a summary of the overall plant operation and performance for the calendar year 2020. The report contains summaries of plant operations and performance, maintenance, laboratory, the City industrial waste control (pretreatment) program, chemicals, utilities, and staffing.

2. Summary

During the year 2020 the Paso Robles Wastewater Treatment plant treated approximately 773 million gallons of influent wastewater. Aside from a few minor equipment malfunctions, the treatment process operated efficiently and effectively to deliver high quality effluent to the Salinas River. The year 2020 was an unprecedented year for everyone in the world and it was an interesting year at the Paso Robles Wastewater Treatment Plant as well. The onset of the COVID 19 pandemic in mid-March caused a significant reduction in flow. Lack of tourism, school closures, shelter in place orders, and shutdowns that affected many different industries caused a reduction of nearly 200,000 gallons per day (GPD) of wastewater flowing to the treatment plant. Given the essential role that wastewater treatment plays to help keep our communities safe, the Paso Robles Wastewater Division staff was fully committed to continuing the day-to-day operations of the collections system and the wastewater treatment facilities. As the pandemic continued, the City of Paso Robles WWTP participated in wastewater epidemiology studies to help track the surging coronavirus.

Despite the impacts of the pandemic, there were many positive things to celebrate at the Wastewater Treatment Plant during 2020. We are honored that the Paso Robles Wastewater Treatment Plant was the recipient of a few prestigious awards throughout the past year. The Tertiary Treatment project was selected by Global Water Intelligence as the winner of the Global Water Awards 2020 Wastewater Project of the Year. The Tertiary Treatment project was also the winner of the 2020 Engineering and Research Achievement Award by the California Water Environment Association. Our Biogas engine generators produced nearly 323,000 Kilowatt-hours of clean renewable energy, that’s enough electricity to power nearly 29 average American homes for an entire year.

As of April 18th, 2019, all effluent flow has been tertiary treated via the new cloth media filtration and UV light disinfection facilities and is currently being discharged into the Salinas River. The new facilities will continue to produce tertiary quality recycled water that, in the future, will be distributed via the recycled water, or “purple pipe”, distribution system that is currently in the design phase and awaiting financing from the State’s Revolving Fund (SRF) loan program. Upon completion, the recycled water distribution system will deliver the recycled water to east side of

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Paso Robles, where it will be used to irrigate golf courses, parks, and vineyards. Surplus tertiary treated water will be discharged to Huerhuero Creek, thus help to passively recharge the Paso Robles Groundwater Basin. Timing for completion of the Recycled Water Distribution System depends on when the City secures SRF financing.

The Paso Robles Wastewater Treatment Facility performed very well during the year 2020. The average influent Biochemical Oxygen Demand (BOD) was 339mg/L while the Final Effluent BOD averaged 3.45 mg/L; this is a yearly average removal rate of 98.9% of influent BOD loadings. The average influent Total Suspended Solids (TSS) was 253 mg/L while the Final effluent Total Suspended Solids (TSS) averaged 3.32 mg/L; this is a yearly average removal rate of 98.70% of influent TSS loadings. This is excellent treatment performance.

Figure 1: Lab Technician Haley Kausen with a beaker of Tertiary Treated Final Effluent from the Paso Robles Wastewater Treatment Plant.

Influent Treatment and Quality The WWTP operated with an average daily influent flow of 2.11 MGD during 2020. The maximum daily influent plant flow was 2.39 MGD in August 2020 which is well below the WWTP design dry weather flow of 4.9 MGD. A summary of annual flow and influent parameter concentrations for BOD and TSS for the past four years is shown in Table 1. During the last four years there has been a reduction in daily and annual plant influent flows due to drought, water conservation, and the disconnection of Templeton Community Services District from the Paso Robles sewer system. The WWTP plant has both influent and effluent flow meters to accurately measure flow in to and out of the plant.

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Table 1: Influent Parameters 2017 2018 2019 2020

Mean Influent flow, MGD

2.35 2.29 2.14 2.11

Total Annual flow. MG

859.5 834.3 781.1 772.5

Mean Influent TSS, mg/L

342 315 266 253

Mean Influent BOD, mg/L

327 343 344 339

Preliminary Treatment The preliminary treatment process includes two climber screens, a washer/compactor, vortex grit removal system, and influent flow measurement. Wastewater enters the plant from two different trunk lines, one from the older west side of town and one from the newer east side of town. The climber screens (one in service at a time) remove the larger pieces of debris and inorganics from the wastewater stream. That debris travels through a washer /compactor and into a screening/grit bin for disposal. The remaining grit is removed in the vortex removal system and is also deposited into the screening/grit bin, which is hauled to the Paso Robles Landfill for disposal on a weekly basis.

Primary Treatment After grit removal, the waste stream flows through a primary splitter box which divides flow to two primary clarifiers where velocity of the flow is reduced, and sedimentation occurs. Utilizing both surface and bottom sludge collectors the settled primary sludge and the surface scum are removed and pumped to Digester #3 where the sludge and scum are broken down through anaerobic digestion. In 2020, the City operated one of the two primary clarifiers at a time, ensuring adequate carbonaceous waste is passed along to properly feed the biological nutrient removal process.

Waste Activated Sludge Equalization/Dissolved Air Flotation Thickening Waste Activated Sludge (WAS) and secondary scum are fed to the WAS equalization basin. Subsequently, solids are fed to a dissolved air flotation thickener (DAFT) where sludge is floated to the surface and thickened so it can be skimmed into a sludge hopper. The thickened sludge is then pumped to anaerobic digesters for further breakdown. Table 2 contains a summary of key primary treatment effluent parameter concentrations over the previous four years.

Table 2: Primary Treatment Effluent Parameters Yearly Averages 2017 2018 2019 2020

Mean Primary Effluent TSS, mg/L

100.4 89.9 88.9 89.2

Mean Primary Eff. TSS% removal

29 66 64 64

Mean Primary Eff. BOD, mg/L

186.7 187 221 207

Mean Primary Eff. BOD, % removal

57 44 35 39

Biological Nutrient Removal (BNR) /Secondary Treatment The secondary treatment process includes two BNR basins for biological treatment of the waste stream and three secondary clarifiers to help with solids separation.

In the activated sludge BNR process, effluent from the primary clarifiers is mixed with return activated sludge (RAS) from secondary clarifiers, routed through anaerobic and anoxic basins, and then aerated in aeration basins. The activated sludge is primarily comprised of micro-organism bacteria, which are a natural part of wastewater and are used to break down the carbonaceous pollutants and nutrients in the wastewater. The consistency of activated sludge

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is measured in mg/L of Mixed Liquor Suspended Solids (MLSS). MLSS concentrations are sampled daily by laboratory staff to help ensure the health of the nutrient removal system. Micro-organisms are monitored microscopically weekly by operations and laboratory staff to confirm the number, type, age, and general health of the biological process. For all of 2020, flows to the plant were low enough that only one BNR basin was in operation; a second basin was kept in a state of readiness.

A mixed liquor recycle return system allows denitrification in the two anoxic zones. This removes nitrate from the waste stream and recovers alkalinity lost during the nitrification process.

The mixed liquor from the aeration basins flows into secondary clarifiers, which allow activated sludge to settle; currently, two of the three clarifiers are online. The number of clarifiers in operation is adjusted to optimize performance during varying flow conditions. A controlled quantity of this sludge is “returned” to the aeration basins as RAS and excess quantities are removed as WAS to the WAS equalization Basin. Table 3 shows key parameters for the secondary treatment process.

Table 3: Primary Effluent, BNR and Secondary Effluent* Averages for 2020

Mean Aeration Loading mg/L & lbs. TSS/day 89.2 mg/L 1688 lbs./day

Mean Aeration Loading BOD (mg/L & lbs./day) 207 mg/L 3919 lbs./ day

Mean Aeration Ammonia Loading (mg/L & lbs/day)

50 mg/L 947 lbs. / day

Mean Mixed Liquor Suspended Solids (mg/L) For Aeration Basins 1 & 2

3681 mg/L

Mean Solids Retention Time (days) 4.4 Days

Mean RAS concentration (mg/L) 9649 mg/L

Mean Secondary Effluent Ammonia, mg/L 1.04 mg/L 19.7 lbs. / day

Mean Secondary Effluent TSS, (mg/L & lbs. /day)

3.09 mg/L 58.5 lbs. / day

*(Loadings are based on a primary effluent pump meter flow of 2.27 MGD average)

Flow Equalization / Cloth Media Filtration Two equalization basins downstream of the secondary clarifiers have a total storage capacity of approximately 694,000 gallons and help buffer the diurnal fluctuations in flow, thus ensuring a more constant and scheduled flow can be delivered to the filtration and UV disinfection process.

Tertiary treatment is achieved via the use of 10 micron opening Aqua-Aerobics AquaDisk cloth media filtration. Three separate filter cells filter the flow from the equalization basins to deliver a constant, filtered flow to the UV disinfection channels. The three filter cells operate in a lead / lag run command so that filtration can still be achieved during high flow conditions. Turbidity is continuously monitored both before and after the filtration process. The daily average turbidity for both the filter influent and effluent was less than 2 nephelometric turbidity units (NTU) every day of the year in 2020.

Final Effluent Treatment and Quality As of April 18th, 2019, all effluent flows are being disinfected with the new TrojanUV Signa 2 Row UV light disinfection system that was installed as part of the Tertiary Treatment Facilities project. The UV disinfection process consists of an influent well, two 40 inch wide, 7 ft deep, and 55 ft long flow channels with automated gates and mixing baffles, a total of 48 1,000 watt UV lamps in each channel, an automated lamp cleaning system, water level control features, and an extensive instrumentation and control system for precise and energy-efficient process control. The entire UV disinfection process is enclosed beneath a metal building to keep out dust and other potential contaminants.

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Disinfection is accomplished by delivering the proper dose of light measured in millijoules per centimeter squared (mJ/cm2). This dose is calculated using an algorithm consisting of three variables: Flow, Ultraviolet Transmittance (UVT), and Ultraviolet Intensity (UVI). Using this calculated dose, the UV banks in each channel operate in a lead / lag run order to achieve an accurate UV light dose and accomplish proper disinfection during varying flow conditions.

The discharge stream from the UV light disinfection system then flows through an effluent polishing channel over rock riffle beds and through shallow pools. This helps maintain adequate Dissolved Oxygen levels in the effluent discharge and reduces the energy of the flowing water before it reaches the Salinas River. A summary of key final effluent parameters for 2020 are shown in Table 4. Details of the final effluent qualities are presented in graphical form in Appendix A. A summary of other key treatment parameters for 2020 is shown in Table 5.

Table 4: Key Final Effluent Parameters 2020

Table 5: Key Treatment Parameters 2020

Influent Flow, MGD

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Max 2.12 2.15 2.29 2.13 2.18 2.38 2.34 2.39 2.33 2.39 2.33 2.21

Mean 1.98 2.0 1.99 1.89 2.0 2.20 2.23 2.22 2.24 2.26 2.21 2.1

Total (MG) 61.5 58.1 61.8 56.8 62.0 65.9 69.0 68.8 67.1 70.0 66.4 65.0

Quarterly Q1 Q2 Q3 Q4

Ammonia (mg/L as N) 0.109 0.706 0.119 ND

Unionized Ammonia (mg/L as N) 0.0018 0.0145 0.003 ND

Nitrate (mg/L as N) 5.39 5.66 6.16 5.50

Copper (g/L) 7.94 11.2 6.92 8.71

Dichlorobromomethane (g/L) ND ND ND ND

Dibromochloromethane (g/L) ND ND ND ND

pH 7.67 7.59 7.69 7.66

Total Nitrogen (mg/L as N) 9.4 8.97 8.39 7.00

Selenium (g/L) 6.50 2.20 1.08 3.61

Bis(2-Ethlhexyl)phthalate (g/L) 1.05 1.03 ND ND

Total Hardness CaCO3 (mg/L) 324 260 206 254

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Influent BOD, mg/L


Max 416 535 414 427 399 360 383 346 364 373 385 399

Mean 375 427 345 352 337 339 323 294 305 327 327 336

Average lbs./day 6,192 7,122 5,726 5,548 5,621 6,220 6,007 5,443 5,698 6,163 6,027 5,885

Influent TSS, mg/L


Max 308 347 337 546 394 299 289 379 442 291 311 430

Mean 264 259 260 273 258 249 225 257 237 240 240 262

Average lbs./day 4,359 4,320 4,315 4,303 4,303 4,569 4,185 4,758 4,428 4,524 4,424 4,589

Effluent Flow, MGD


Max 2.3 2.35 2.53 2.42 2.3 2.38 2.43 2.6 2.5 2.48 2.41 2.37

Mean 2.14 2.15 2.18 2.09 2.15 2.22 2.26 2.25 2.28 2.32 2.3 2.19

Total (MG) 66.3 62.4 67.6 62.7 66.7 66.7 69.9 69.7 68.5 72.0 69.1 68.0

Effluent BOD, mg/L


Max 6.76 5.81 2.98 3.1 7.6 9.78 5.0 3.04 4.90 9.2 9.6 7.8

Mean 3.45 4.32 2.15 1.95 4.0 4.45 2.13 2.18 3.45 4.13 5.14 5.17

Average lbs./day 61.6 77.5 39.1 34.0 71.7 82.4 40.1 40.9 65.6 79.9 98.6 94.4

Effluent TSS, mg/L


Max 6.5 2.9 3.40 3.80 7.40 3.40 5.10 3.00 <2.0 <2.0 2.20 <2.0

Mean 3.32 2.03 2.26 2.29 2.88 2.13 2.20 2.11 <2.0 <2.0 2.01 <2.0

Average lbs./day 59.3 36.4 41.1 39.9 51.6 39.4 41.5 39.6 <38.0 <38.0 38.6 <36.5

Effluent pH


Max 7.79 7.91 7.87 7.97 7.70 7.84 7.93 7.82 7.77 7.80 7.77 7.80

Min 7.58 7.54 7.54 7.50 7.40 7.00 7.62 7.55 7.44 7.50 7.47 7.54

Mean 7.68 7.70 7.68 7.62 7.56 7.63 7.73 7.69 7.59 6.63 7.62 7.63

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Effluent Settleable Solids mL/L


Max <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1

Min <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1

Effluent Chlorine Residual, mg/L (*Caused by maintenance procedure)


Max ND ND ND ND ND ND ND ND 0.05* ND ND ND

Min ND ND ND ND ND ND ND ND ND ND ND ND

Solids Handling

The anaerobic digestion process reduces sludge volume by breaking down the volatile solids; the solids that remain after anaerobic digestion are commonly referred to as bio-solids. During sludge digestion, methane gas, commonly called “biogas", is produced and captured. This biogas is cleaned and used as fuel in the cogeneration engines to produce electrical power and heat. The electrical power is used to offset the plant’s total power consumption and the heat from the engines is used to heat the digesters and offset consumption of natural gas.

In 2020, a daily average of 13,513 gallons of Thickened Waste Activated Sludge (TWAS) and a daily average of 9,567 gallons of Primary Sludge (PS) was pumped to the primary digester. The average TWAS total solids concentration was 3.92 % with a total volatile solids content of 77.0 %. The average PS totals solids concentration was 3.27% with a volatile solids content of 85.4%. The average hydraulic retention time of sludge in the series of three, 366,000-gallon digesters was 48 days. A total of 12,594,296 Standard Cubic Feet (SFC) of biogas was produced by anaerobic digestion during 2020. Of the total biogas produced, 5,663,338 SCF was used as fuel for the biogas engine generators which produced approximately 322,941 Kilowatt Hours of electricity to help offset the WWTP’s energy consumption.

The digested sludge from the digesters is dewatered through a belt filter press. The WWTP processed an average of 30,398 gallons of sludge each day. A total of 11,125,547 gallons of sludge was processed in 2020.

In 2020, approximately 3,148 wet tons of bio-solids were hauled to the City of Paso Robles Landfill; which is a decrease of 456 tons from 2019. At the landfill, biosolids are used for alternative daily cover or mixed and composted with wood chips to produce soil amendment for the landfill. Bio-solids were analyzed seven times throughout the year of 2020, all values were within compliance in order to haul off-site to the landfill.

Table 6: Monthly Breakdown of Processed Sludge through Belt Press: 2020

Total

(gallons) Total

(gallons)

Jan

981,617

Jul

947,517

Feb

899,480 Aug

978,599

Mar

978,288 Sep

900,242

Apr

882,504 Oct

948,922

May

882,005 Nov

957,276

Jun

804,283 Dec

964,814

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Table 7: Monthly Breakdown of Biogas Production from Anaerobic Digestion: 2020

Total

(SCF) Total

(SCF)

Jan

1,156,953

Jul

1,039,124

Feb

1,058,107 Aug

994,651

Mar

1,085,438 Sep

957,788

Apr

1,025,536 Oct

1,028,347

May

1,059,857 Nov

1,045,343

Jun

1,059,865 Dec

1,083,288

Nutrient Harvesting

As an addition to the Tertiary Treatment upgrade, on May 13th, 2019, the WWTP completed installation and began operating a first of its kind in California, Nutrient Harvesting System. The Nutrient Harvesting System is used to remove concentrated ammonia and phosphorus from the liquid (pressate) that is pressed out of the biosolids at the belt filter press after anaerobic digestion. This system reduces the amount of nutrients that are recirculated back into the wastewater treatment process, reducing the discharge of nutrients to the Salinas River. The system also eliminates the formation of nuisance struvite inside pumps, pipes, and other plant equipment, and produces commercial-grade fertilizer. Struvite is formed in the system by the reaction of magnesium, ammonium, and phosphate at a molar ratio of 1:1:1 and pH above 7.8. The up-flow harvester creates this reaction by adding the proper dose of Magnesium Chloride to the filtrate stream as well as Sodium Hydroxide to control the pH of the water. In this controlled environment, the reaction allows the struvite to precipitate out of solution and settle to the bottom of a cone-shaped reactor, where it is harvested and captured in super sack bags. Over the past year, the Paso Robles WWTP has produced approximately 83 tons of struvite material. This material is occasionally sold off to fertilizer manufacturers to be used as a renewable source of phosphorus in agriculture.

3. Wastewater Treatment Plant Maintenance Summary Below is a summary of maintenance activity at the WWTP in 2020:

Plant Maintenance

Table 8: Plant Maintenance Summary

Weekly Monthly

Standby Generator test run +

Bar Screens rotated, cleaned & greased + Fire Extinguishers check + Eye wash stations (9) tested +

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All clarifier drives (5) greased and lubed + DAFT drive greased and lubed + Duty / standby pumps rotated + Co-gen oil sampled, daily recorded run logs Every 250 hours of

run time

Standby Generator oil tested quarterly

Belt press greased and oil added to auger if needed + Primary sludge pump by-pass cleaned +

Primary scum pump basin washed out +

Clean and rotate lead/lag UV Channels +

Clean and rotate lead/lag Cloth Filter Cells +

Primary clarifiers (2), Final clarifiers (3) sprayed down (3) (2)

Primary Effluent pumps and RAS pumps, standby rotated, bumped +

Control Panel maintenance (cleaning, bulb replacement) quarterly

Electrical vaults, water pumped out Wet season

Additional Monthly Maintenance & Repairs Other Than Routine Weekly & Monthly Service

January:

• Siloxane testing on Biogas treatment skid 1/6/2020

• New tube on Ferric pump 7120 1/9/2020

• New tube on Mag pump 1/9/2020

• Chloraminate cloth filter #3 1/20/2020

• Chloraminate cloth filter #1 1/21/2020

• Riverbed Cleanup: 21.8 tons of trash removed from Salinas River 1/22/2020

• Install new engine fan in Cogen 9210 1/24/2020

• Replace hydraulic wiper ram on UV channel 2 bank A 1/29/2020

• Install new tube on Filtrate pump 101 1/31/2020

February:

• Rebuild starter for Digester #3 mixer 2/19/2020

• Reset SCADA server in Ops building 2/20/2020

• Polydyne performed jar testing of different polymers for belt press 2/27/2020

March:

• Chlorinate RAS to combat filament growth 3/2/2020

• Rebuild Chlorine analyzer for 3water monitoring 3/2/2020

• Cogen engine service 3/3/2020

• Drained and cleaned nutrient harvesting reactor 3/3/2020

• Drained and cleaned Blue Filtrate tank 3/4/2020

• Replace hydraulic ram for UV channel 2 bank C 3/13/2020

• Treated Cogen hot water loop with Nitrate solution 3/16/2020

• Sent Ultra-Violet Transmittance probe for Calibration 3/30/2020

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April:

• Chlorinate RAS to combat filament growth 4/6/2020

• Cleared water from Digester #3 flame arrestor 4/6/2020

• Reset Blower PLC 4/8/2020

• Replaced Iron sponge media in Vessel #1 of DGTS 4/13/2020

• Installed new wipers seals on UV bank 1A 4/16/2020

• Install new tube in Ferric pump 7110 4/18/2020

• Tried operation of only 1 final clarifier, not functional for treatment process 4/27/2020

May:

• Install new belts on digester #3 mixer 5/3/2020

• Drain and cleaned both EQ tanks 5/5/2020

• Replaced iron sponge media in vessel #2 5/7/2020

• Installed new tube on Filtrate pump 102 5/8/2020

• Digester #3 upset 5/12/2020

• Drained and cleaned UV channel influent box 5/13/2020

• Suspected dump of hydrocarbons into sewer system 5/14/2020

• Installed new pH probe in nutrient harvester 5/16/2020

• Suspected dump of hydrocarbons into sewer system, working with source control to determine what and where

5/19/2020

• Suspected dump of hydrocarbons into sewer system 5/23/2020

• Installed new level transducer on cloth filter #1 5/27/2020

June:

• Installed new piping on vortex grit separator 6/2/2020

• Installed new piping in Decant Wet well to replace piping damaged with struvite 6/3/2020

• Seismic gas shutoff annual testing 6/4/2020

• Power Outage at WWTP at 7:00 lasted approximately 2 hours 6/6/2020

• New O-rings on boiler heat exchanger for digester #3 6/9/2020

• Installed transducer and meter on magnesium chloride tank 6/9/2020

• Installed Loaner core on blower #2 6/18/2020

• Power fail at WWTP; standby power from 3:12 pm – 7:20pm 6/22/2020

• Replace Hydroranger on chlorine tank 6/24/2020

• Chloraminate cloth filter #3

• Drain and clean EQ basin #1 6/26/2020

July:

• Replaced auger on barscreen conveyor 7/7/2020

• Repair secondary clarifier scum arm 7/9/2020

• Changed magnesium chloride dosing pump tube 7/11/2020

• Started seeding Hycura to digester #3 as pilot test to increase biogas production 7/15/2020

• Install new smaller dosing pump at nutrient harvesting system 7/16/2020

• Repair broken clarifier arm 7/16/2020

• Drained and cleaned combined UV effluent channel 7/28/2020

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August:

• Install new tube on Filtrate pump 101 8/4/2020

• Install new pump tube on sodium hydroxide pump at nutrient harvesting system 8/4/2020

• Power Fail at WWTP at 2:30pm 8/26/2020

September:

• Installed new impeller on RAS pump #3 9/1/2020

• City of San Luis Obispo took 2 truckloads of WAS to seed their process 9/10/2020

• Installed new blower fan on AC unit of blower building 9/10/2020

• Video shoot at WWTP for public outreach program 9/30/2020

October:

• Drained and Cleaned both EQ basins 10/1/2020

• Annual flow meter testing and calibration 10/1/2020

• Annual Backflow preventer testing 10/2/2020

• Chloraminate and cleaned cloth filter cell #1 10/26/2020

• Installed repaired blower core in blower #2 10/27/2020

November:

• Installed new tube on Filtrate pump 102 11/2/2020

• 2G performed tuning on CoGen engines 11/3/2020

• Deep clean of UV channel #2 11/4/2020

• Installed new hose in Filtrate pump 101 11/5/2020

• Fire alarm and fire sprinkler testing at Operations building 11/6/2020

• Annual source testing of Cogen engines for APCD 11/11/2020

• Deep clean of UV channel #1 11/11/2020

• Service batteries in all three generator units 11/12/2020

• DryVac biosolids dewatering demonstration 11/18/2020

• Installed new batteries on ChemScan 11/19/2020

December:

• Repair coupler on DAFT recycle pump 6220 12/3/2020

• Installed new wipers in turbidity meters 12/4/2020

• Calibrate pH probe on nutrient harvesting system 12/8/2020

• Replaced piping at filtrate tank that was damaged with struvite 12/9/2020

• Performed UVI reference check on all banks in channel #1 12/10/2020

• Repair broken water line at final clarifier #1 12/14/2020

• Handled equipment failures around plant due to poor quality power from PGE 12/14/2020 – 12/17/2020

• Installed new check valves on both TWAS pumps 12/18/2020

• Chlorinating RAS to combat filament growth 12/18/2020

• Installed software on ChemScan 12/18/2020

• Repair broken spring on DAFT arm 12/26/2020

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C. 2020 Annual Testing, Inspections & Calibration Record

• UVT sensor calibration 3/30/2020

• Fire Extinguisher service 4/21/2020

• Seismic Natural Gas Valve Testing (AGB) 6/4/2020

• San Luis Obispo County Hazardous Materials inspection (CUPA) 7/1/2020

• Calibration of Influent, Effluent and W3 flow meters (Telstar Instruments) 10/1/2020

• Water Backflow preventer testing (Louis Schmitz Plumbing) 10/2/2020

• Deep Blue Fire Alarm Test 11/6/2020

• Air Pollution Control District Inspection 11/11/2020

• Co-Gen Emission Source Testing (AEROS) 11/11/2020

4. CHEMICALS AND UTILITIES

Table 9: Chemicals YEAR: 2018 2019 2020

Sodium Hypochlorite (Disinfection) $138,759.85 $26,418.94 $5,264.01 Sodium bisulfite (De-chlorination) $97,218.95 $18,407.64 $0 Ammonium sulfate (Chloramination) $65,972.82 $6,139.77 $0 Sodium Hydroxide (Nutrient

Harvesting) $16,385.72 $21,126.60

Magnesium Chloride (Nutrient Harvesting)

$15,801.44 $20,798.48

Ferric chloride (H2S and odor control)

$64,785.51 $69,358.45 $48,014.39

Polymer (Belt press de-watering)

$56,808.88 $46,169.85 $43,091.86

Total Chemical cost $423,546.01 $198,682.21 $138,295.34

Septage Receiving Income $85,632.24 Out of service Out of service

Table 10: Utilities YEAR: 2019 2020

Potable Water City of Paso Robles $ 23,862.05 $33,066.28 Electricity PG&E $ 394,854.01 $445,417.37 Natural Gas So Cal Gas $ 33,722.98 34,506.73 CoGen Power Produced WWTP 322,941 kWh

5. WWTP STAFFING

Operations Staffing Plant staffing as of December 2020 is shown in Table 11.

Table 11: Plant Staffing

Chief Plant Operator 1

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Staff Training & Development Due to the onset of the COVID 19 pandemic, many training and development opportunities were either postponed and or canceled over the past year. WWTP staff has been dedicated to participating in webinars involving safe work practices in the wastewater field, specifically with increased potential exposure to the coronavirus. The Paso Robles WWTP staff has also been adapting to the new online training opportunities offered by the California Water Environment Association, Water Environment Federation, Environmental Protection Agency, and various other industry partners that are continuing to expand their online training platforms.

Operator Certification In 2020, the City employed seven Wastewater Treatment Plant Operators, with the following levels of certification:

Table 12: Wastewater Treatment Operator Certification

Grade V 0

Grade IV 2

Grade III 2

Grade II 2

Grade I 1

OIT 0

6. Wastewater Laboratory Analysis and Instrument Maintenance

The City owns and operates a Water Quality Laboratory certified by the Environmental Laboratory Accreditation Program (ELAP). Operating 7 days a week, the laboratory tests process control parameters as well as numerous certified test procedures for compliance purposes. Tests not covered under ELAP certification were performed by several ELAP-certified contract laboratories, including: Enthalpy Analytical, Fruit Growers Laboratory, and Oilfield Environmental Compliance.

The City had two whole effluent toxicity exceedances in 2020. The City also had one detection of effluent chlorine residual which resulted from a cleaning and maintenance procedure. WWTP staff has discussed the cause of this violation with the Regional Water Quality Control Board. All exceedances were previously self-reported via monthly and quarterly reports. The exceedances are shown in Table 13 below.

Table 13: Compliance Record and Corrective Actions

Parameter Date Permit Limit Violation Corrective Action

Whole effluent Toxicity Chlorine Residual

1st and 4th Quarter, 2020 9/2/2020

Chronic Toxicity of 1 TUc

Non-Detectable

Yes

Yes

Accelerated monitoring and completion of Priority Pollutants scan, no cause found Improved Training and SOP’s

Operator III 1

Operator II 4

Operator I 1

Laboratory Supervisor 1

Laboratory Analyst 2

Maintenance Specialist III 1

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In addition to routine monitoring, WWTP Laboratory staff completed the following analysis and maintenance tasks:

January

● Replaced tubing at primary composite sampler

● Lubricated secondary plunger rod in composite sampler

● Cleaned raw influent sample chamber

● New zero standard for dissolved oxygen probe

● Annual Performance Testing Study

● Thermometer five year and annual calibration

● Changed incubator numbers to get rid of gaps from out of service incubators

● Autoclave timer quarterly

● Micropipette quarterly

February

● New nitrate probe installed

● Clear raw influent sample line

● Replaced final effluent sample tubing

● Quality assurance new lot of bacteriology bottles

● Laboratory technician resigned

March

● Struvite reactor drained

● Method Detection Limit (MDL) check on chlorine

● Bacteriology bottle quality assurance



● MDL study checks quarterly

April

● Bioassay sampling

May

● Annual balance calibration

June

● New chlorine standards

● Final effluent cooler fan broke

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● Autoclave quarterly


July

● Secondary effluent composite sampler air conditioner broke, repaired

● Autoclave quarterly

August

● Influent composite sampler air conditioner broke, repaired

● Start adenosine triphosphate (ATP) testing to better assess health of biological process

● New Lab Tech hired on with the Laboratory

September

● New dissolved oxygen probe tip sensor and battery installed

● Final effluent composite sampler air conditioner broke, repaired

● Change Ammonia probe tip

● Ethics annual training


October

● New Ammonia probe

● Reagent water metals annual testing

November

● New Ammonia probe tip

● Stopwatch check annual

● Quantitray quality assurance

December


● Micropipette volume quarterly

7. Pretreatment

Formal Pretreatment Program The City is currently in the process of revising the pretreatment program to include the updated local limits and revised Sewer Use Ordinance which was approved by City Council on December 1, 2020. The City updated its local limits to reflect the recently completed upgrade to the wastewater treatment plant and disconnection of Templeton Community Services District from the City sewer system in 2019.

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Fats, Oils, and Grease Program The program inspects food facilities for Fats, Oils, and Grease (FOG). Inspections are done to ensure that grease removal devices are being maintained correctly and the fry oil is properly disposed of. The program also coordinates with the Building Department to ensure that grease interceptors are properly sized and installed in new facilities and remodels. The City hired a new Water Quality Specialist in April 2020. 167 Food facilities were inspected. The City revised the FOG program in 2020. A Fats, Oils, and Grease Control Manual was developed to help food facilities properly size new and replacement grease control devices and to properly maintain the devices. The Sewer Use Ordinance revisions included additional requirements for the Fats, Oils, and Grease Control Program, including the use of the manual. Dry Creek Sewer Installation The City installed a sewer main in Dry Creek Road and adjacent streets in the south Airport area in 2020. Commercial and Industrial Users were given until December 31, 2020 to connect to the City sewer. The Industrial Users were sent Industrial Waste Surveys. The City determined by a drive-by and internet search that there were possibly two Significant Industrial Users (SIU) on this road; Santa Cruz Biotechnology and Genesis Bronze. Inspections of both facilities were conducted, and it was determined that Santa Cruz Biotech is not a SIU, but the Genesis Bronze falls under the Federal categorical regulations. (The facility is discussed below.) Industrial Dischargers Genesis Bronze Genesis Bronze is a bronze foundry that makes custom statues for customers. The facility does not discharge any industrial wastewater to the City sewer. The facility falls under 433.17 as a new source metal finisher due to etching of some of the statues. 40 CFR 464, copper forming does not apply since the company does not perform any of the processes in Part 464. The City issued a Zero Discharge Categorical permit to Genesis Bronze. Bella Jule Jewelry Bella Jule Jewelry occasionally dips jewelry in gold or rhodium when requested by customers. The waste liquid from this process not discharged to the sewer. The facility falls under 433.17 as a new source metal finisher. The City issued a Zero Discharge Categorical Permit to Bella Jule Jewelry. Siegel’s Jewelry Siegel’s Jewelry occasionally dips jewelry in rhodium when requested by customers. The waste liquid from this process not discharged to the sewer. The facility falls under 433.17 as a new source metal finisher. The City issued a Zero Discharge Categorical Permit to Siegel’s Jewelry. Sunbank: Sunbank discharges to the City under a two-part Categorical Industrial Permit. Part 1 of the permit is a Zero Discharge Permit for the wastewater from the tumbling operation, which is hauled off site. Part 2 of the permit is for treated wastewater from the plating lines. Sunbank now recycles a majority of their treated wastewater and now only discharges 5,000 - 6,000 gallons once a week. Sunbank did not have any violations in their quarterly or semi-annual monitoring during 2020. The facility falls under both 433.15, existing source and 433.17 new source for the discharge from the plating line.

Lubrizol Advanced Materials, Inc. The City issued a two-part permit to Lubrizol. Part 1 is a Zero Discharge Permit for the categorical regulated Neutar Line. Part 2 is for the wastewater from the non-categorical processes. Lubrizol recycles the treated wastewater by using it as make-up water in the cooling tower as needed. When the treated wastewater is recycled, the only wastewater discharged to the City sewer is the non-contact evaporator condensate. Lubrizol only discharged to the City in January, February, and April. (There was one BOD violation in February due to an upset in their wastewater treatment unit.) Lubrizol did not discharge to the City the rest of 2020.

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Firestone Walker Brewing Company Firestone Walker Brewing is a Significant Industrial User based on the daily flow. The brewery continued to have issues meeting the City’s local limits for Total Dissolved Solids (TDS), Sodium, and Sulfate in 2020. Firestone was issued a compliance schedule in January 2019 to achieve compliance. The brewery had contracted with the City to purchase raw Nacimiento water to use in the chilling towers. This water source is surface water and is not as hard or salty as the rest of the City’s water supply. Firestone anticipated that the raw water would lower the salts levels enough to come into compliance with the discharge limits. However, the raw water caused issues with the chilling towers and had to be treated prior to use. They began using the treated raw water on March 29, 2019 and planned to expand the use to all four towers in September 2019. Unfortunately, the Nacimiento Water line developed a leak and was shut down in September 2019. The water line is expected to be back on-line early 2021. The City will publish a notice in The San Luis Obispo Tribune for Firestone being in Significant Non-Compliance in 2020 for TDS, Sodium, and Sulfate.

Paso Robles Water Treatment Plant The Paso Robles Water Treatment Plant is permitted as Significant Industrial User due to flow. The permit was revised in July to include mass-based limits. The plant is a micro-filtration plant designed to treat raw Nacimiento water for a potable water source for the City. On September 13, 2019, the Nacimiento water supply pipeline was shut down due to a pipe failure and remained down for all of 2020. Therefore, the plant was not fully operational in 2020. The membrane filtration units are flushed daily to keep them wet. In 2020, only the wastewater from flushing the Granular Activated Carbon tanks was sewered. Pass-through and Interference In May 2020, staff detected a hydrocarbon odor in the west side collection system. The discharge occurred three times between May 14th and May 23rd. Staff were able to determine the source was from the northwest part of the City, which is mostly residential. Automatic samplers were set in several manholes and staff responded to each incident. However, the source was never found. The discharge did not cause interference or pass through. There were no incidents of pollutant pass-through or treatment interference caused by industrial discharges in 2020.

8. Certification of Report I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. The information contained in this report is, to the best of my knowledge and belief, true, accurate, and complete. If you have any questions or need additional information, please feel free to contact me at [email protected] or (805) 237-3865.

Sincerely,

Casey Shepherd, WWTPO IV 42805 Chief Plant Operator City of Paso Robles Wastewater Treatment Plant Paso Robles, Ca. 93446

mailto:[email protected]

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Appendix A

Performance Charts

22

Salinas River Flow Cart

wastewater treatment plant annual report pdf

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