biosolids dryer facility: successfully managing a public ... ... may 22, 2019  ·...

Biosolids Dryer Facility: Successfully

Managing a Public-Private Partnership

Luther Blackburn, MS Manager – 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

3 Main Interceptors

2.9 million People served

9 CSO Facities

5 Pump stations

988 Square mile service area

181 Mile conveyance system with trunk sewers and interceptors

87 Member partners serving 77 individual communities

1 WRRF

Quick Facts: Great Lakes Water Authority

1,700 MGD Treatment capacity

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Largest single-site Water Resource Recovery Facility in North America!

GRAVITY

THICKENING

SLUDGE

STORAGE

INCINERATION & ASH

DISPOSAL

CENTRAL

OFFLOADING

DEWATERING

BFPs

CENTRIFUGE

S

PRIMARY

SLUDGE SECONDARY SLUDGE

BIOSOLIDS DRYER FACILITY

WRRF Solids Handling Pre-BDFPost-BDF

?

Processing Capacity Permit req’d. 850 dtpd

Sludge Storage Limited capacity

Sludge Offloading Limited capacity

Landfills Limited nearby space

MACT 129 Compliance Requires MHF upgrades

1940 MHFs At end of useful life

Sustainability Desire to be eco-friendly

Drivers for the Biosolids Dryer Project

Drivers for a Public Private Partnership

P3

Single Source

D/B and O/M 1

Faster Project Completions Contract measure of performance / profit

Specialized Expertise Experience, Knowledge and Skills

Budget Certainty Fixed Fee, Contracted

Quantity

Greater ROI Innovative design and financing approaches

Risk Transfer Operational/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 yr O/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

MHF 67%

Land App 11%Landfill

22%

After BDF

BDF 70%

Land fill 1%

MHF 29%

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

CRUSHER PELLET

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

Communication Open & collaborative

Trust Earned, mutual, two-way

Work Relationships Developed & Maintained

Risks/Benefits Mutually shared

Contract Execution Delivered by both parties

Goals Shared 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 upg