biosolids dryer facility: successfully managing a public...
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Biosolids Dryer Facility: Successfully
Managing a Public-Private Partnership
Luther Blackburn, MSManager – Wastewater Operations
Biosolids Dryer Facility (BDF) P3 Agenda
Great Lakes Water Authority and Biosolids Dryer FacilityBackground
P3 Contractual ElementsContract
Biosolids Thermal Drying ProcessProcess
The 3rd “P” in P3Partnership
Unique Challenges and How P3 Overcame ThemChallenges
Wastewater System
3Main Interceptors
2.9 millionPeople served
9CSOFacities
5Pumpstations
988Square mile service area
181Mile conveyance system with trunk sewers and interceptors
87Member partners serving 77 individual communities
1WRRF
Quick Facts: Great Lakes Water Authority
1,700 MGDTreatment capacity
Largest single-site Water Resource Recovery Facility in North America!
GRAVITY
THICKENING
SLUDGE
STORAGE
INCINERATION & ASH
DISPOSAL
CENTRAL
OFFLOADING
DEWATERING
BFPs
CENTRIFUGE
S
PRIMARY
SLUDGESECONDARY SLUDGE
BIOSOLIDS DRYER FACILITY
WRRF Solids Handling Pre-BDFPost-BDF
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Processing CapacityPermit req’d. 850 dtpd
Sludge Storage Limited capacity
Sludge Offloading Limited capacity
LandfillsLimited nearby space
MACT 129 Compliance Requires MHF upgrades
1940 MHFs At end of useful life
SustainabilityDesire to be eco-friendly
Drivers for the Biosolids Dryer Project
Drivers for a Public Private Partnership
P3
Single Source
D/B and O/M1
Faster Project CompletionsContract measure of performance / profit
Specialized ExpertiseExperience, Knowledge and Skills
Budget CertaintyFixed Fee, Contracted
Quantity
Greater ROIInnovative design and financing approaches
Risk TransferOperational/execution risks fall to the private participant
MAR 2012 MAY 2013 MAY 2014AUG 2012
BIOSOLIDS SYMPOSIUM
Evaluated technologies.
Recommended BDF for its beneficial product re-use.
REQUEST FOR
PROPOSAL
Advertised for Design-Build-Operate-Maintain of biosolids dryer facility.
DESIGN COMPLETE
AUG 2015
CONSTRUCTION
COMPLETE
By contract, NEFCO takes the lead w/ limited GLWA input.
BDF Design/Build Timeline
CONTRACT AWARD
NEFCO leads D/B team.
NEFCO provides 20 yrO/M.
Completion 6 months before contract date.
JUMP JUMP
AUG 2015 FEB 2016 TODAYOCT 2015
SYSTEM TESTING
Trains tested one-by-one
5-DAY DEMONSTRATION
All 4 trains tested together, at capacity, for 5 days, 24 hrs/day
3 YEARS OF SUCCESFUL
OPERATION
In 2018, BDF processed 70% of WRRF sludge
BDF Operating Timeline
COMERCIAL OPERATION
Began operation, typically with 2 to 3 trains in service at a time
Located across the street from the WRRF
Four dryer trains 316 dtpd firm capacity (420 dtpd peak)
Dewatering included in the facility operation
Biosolids Dryer Facility Today
Solids Generation and Disposal
Before BDF
MHF67%
Land App11%Landfill
22%
After BDF
BDF70%
Landfill1%
MHF29%
Average Dry Tons/Year:
135,000
Annual O&M savings:
$14.6 M
20-year O&M savings:
$292 M (in 2013 dollars)
Payback period on
$143 M capital cost:
9.8 years
O&M Savings per Dry Ton Using Dryers
$338 /dry ton
$384 /dry ton
$490/dry ton
COF (Hi)$350
Dewatering $140
COF (Lo) $244 Incineration
$198
Dewatering $140
Dewatering $140
$229 /dry ton
BDF $229
Biosolids Thermal Drying Process
Biosolids Thermal Drying Process
FURNACE
MIXER
DRYER DRUM
COMBUSTION FAN
SEPARATOR
SCREENER
CRUSHERPELLET
COOLER
PNEUMATIC TRANSPORTER
RECYCLE BIN
TRAY SCRUBBER
CAKE BIN
MAIN FAN
RTO FAN
RTO COMBUSTION
FAN
RTO
TO STACK
TO SILO
Proven Technology
No additional need for bulk chemical
addition to stabilize cake
Class A EQ Product with multiple outlets.
Nutrients in biosolids remain after drying
– product suitable for beneficial re-use
Nutrients in biosolids not water soluble –
No runoff
Thermal Drying Product
Bulk land application
Fertilizer blending
Land Reclamation
Alternate Fuel
Cement kilns
Power generation
Renewable fuel
End Uses for Dried Biosolids
Challenges Test the Strength of a Partnership
Startup challenges
Demonstration testing and equipment performance prior to
commercial operations
Dryer drum vendor went out of business amidst design issues
Processing challenges due to variable and low-density sludge
Adjusted design of solids handling equipment
Modifications to ensure process safety
Environmental compliance challenges
Sulfur dioxide treatment retrofit for air emission compliance
Poor Land application BMPs lead to dust and odor concerns
Challenges During Startup & Initial Operations
Testing Challenges and How P3 Overcame
• P3 approach to challenges:
• Testing protocol and “rules of engagement” developed
mutually
• Open communications during testing
• Test reports and expedited review/comment response
Performance Testing Challenges
A range of Primary & Secondary sludge blend ratios needed to be tested, but
abrupt changes impaired BDF operation
A range of ratios were tested, but ratio changes were made gradually and after
mutual agreement
Insufficient sludge was available to support a required 5-day demonstration with 4
dryer trains simultaneously in operation
WRRF sludge inventory management prioritized BDF operations to ensure
adequate sludge available for testing
Mutually agreed upon pause in testing based on sludge inventory and %TSS
Production Challenges
Low density dried product led to:
Plugging in separator discharge
equipment and piping
Piping and divert valve under
separator redesigned
Recycle bin thermal hot spots
Recycle bin discharge
redesigned
Installed inline % solids
instrument in sludge pipe
entering BDF
BEFORE AFTER
Air Emissions Compliance Challenges
SO2 concentrations in the stack exhaust intermittently
peaked above permit limits
Performed diagnostic testing to establish model
Installed continuous emissions monitors (CEMs) on
all 4 dryers
Installed packed tower scrubbers after
regenerative thermal oxidizers (RTOs)
Land Application Challenges
Class A dried biosolids land application is new in Michigan. The inexperienced land
application contractor chose poor sites and used spreading practices that led to
unacceptable offsite dust and odors
Adopted 90% incorporation to reduce odors
MWEA developed Best Management Practices
NEFCO replaced land application contractor
Ongoing Improvements
Main burner tuning
Screener optimization for removal of fibrous material
Chemical suppressant isolation system being installed
Carbon monoxide detectors being piloted
Sludge solids meter being installed for consistent dryer feeding
Pug mill optimization for particle size
Air flow optimization
Partnership – The 3rd “P”
P3
Elements of a Successful P3
Conflict Resolution‘Win, win’ outcomes
CommunicationOpen & collaborative
TrustEarned, mutual, two-way
Work Relationships Developed & Maintained
Risks/BenefitsMutually shared
Contract ExecutionDelivered by both parties
GoalsShared Vision
JUMP
JUMP
Allowed for commercial operations to commence without meeting all
contractual requirements
Lower throughput guarantees due to equipment bottlenecks
Revised liquidated damages mutually developed
NEFCO responsible for alternative disposal as needed
Equipment upgrades proceeded with:
Scheduling and coordination by GLWA
Lower utilization allowed during upgrades
Partnership Exemplified in the Interim Operating Agreement (IOA)
Partnership Exemplified with MI Department of Environmental Quality (MDEQ)
GLWA/NEFCO demonstrated unified approach with MDEQ
Frequent communications between GLWA, NEFCO and MDEQ
Immediate response to all MDEQ requests
NEFCO commitment and diligence, GLWA leadership and flexibility
GLWA/NEFCO leadership commitment
Performance Testing
Testing was to proceed without interruption over the course of the test period.
Challenges Mutually Overcome
BDF operation impacted by abrupt PS:WAS ratio changes
Testing delayed by low sludge inventories
A range of ratios needed to be tested, but abrupt changes impaired BDF operation.
Mutually agreed to revise the sludge blending procedure to insure ratio changes were made gradually.
Revised MHF/sludge management practices to ensure adequate sludge for testing.
Mutually agreed to pause testing as needed.
Processing
Presence of fibrous matter was not anticipated when contract was negotiated.
Production impaired by fibrous material
GLWA IWC determined the characteristics and possible sources.
IWC is working with sources to eliminate.
Dryer exhaust gas had sulfur dioxide levels above the allowable limits.
SO2 levels above permissible limits.
NEFCO installed a new scrubber system as a responsible partner and met permit limits.
Environmental
SO2
Take Away
A public private partnership is a win-win relationship, not a zero-sum
game
Luther BlackburnManager - Wastewater Operations
Great Lakes Water Authority9300 W Jefferson Ave • Detroit, MI 48209
P: 313.297.0300
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