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Humboldt Regional Organic Waste Digester
California Integrated
Waste Management Board
July 14, 2009
Purpose:
Divert food waste from landfills
Why Divert Food Waste?
• ~20% of waste stream
• Develop diversion infrastructure:– AB 939 compliance– Population growth– Future legislation (AB 479)
• Reduce greenhouse gas emissions – Landfills emit methane– Waste trucked 190 miles one-way
Diversion Potential
Source: HWMA quarterly reports, waste auditsSource: HWMA quarterly reports, waste audits
Assumes 100% captureAssumes 100% capture
SourceEstimated
Tons / year Diversion
Arcata and Eureka Commercial
5,500 10%
Arcata and Eureka Residential & Commercial
9,000 20%
Food Waste Characteristics
• Wet
• Heavy
• Putrefies quickly
• Contains energy
Food Waste = Energy
75% H2O
25% Total Solids
85% volatile solids (VS)
15% fixed solids (FS)
VS + A.D. = CH4 + CO2
RENEWABLE ENERGY!!!
Renewable Energy Potential
Gas Yields of Various Organic Materials (m3 gas/ton)
25 36
50 55
70 75 80
90 102 110
120 129
170 195 202
220 400
550 660
0 100 200 300 400 500 600 700
Cattle manure Pig manure
Poultry Whey
Fooder beet Beets
Vinasse Suger beet silage
Grass 1. Cut Green waste
Bio waste bio-bin Brewers‘ grain
Corn silage (pasty) Grass silage 1. Cut
Corn silage Food waste
Flotated fats Rape seed cake
Residual fats
Courtesy of M-Con Bio and Farmatic biotech energy ag
Food Waste in Landfills
• Methane (CH4)– ~23 x more powerful than CO2
• Uncontrolled CH4 emissions – Food waste decomposes: 4 months– Collection systems installed: 2-5 years – Variable LFG capture efficiency
Diversion Options:
Food Banks
Pig Farms
Composting
Anaerobic Digestion
Existing Diversion• Food banks
• Pre-consumer waste only
• Pig farms• Pre-consumer or post-consumer + treatment • Limited in local capacity• Produce high-strength waste
Food Waste Composting
• Aerobic decomposition• Produces soil amendment• Green waste used as bulking agent
• Process time 90 – 180 days• Emits some CH4, N2O, VOC• Kills pathogens
Local Compost Challenges
• Competition for green waste
• Food waste prohibited
• Odors
• VOC emissions
• Large footprint
• High rainfall levels
• Aerobic conditions = high energy inputs
Anaerobic Digestion
• Oxygen-free environment• Mature technology
– Wastewater treatment plants– Dairies & pig farms
• Produces biogas (CH4 +CO2)• Reduces VOCs• Positive net energy balance
Benefits:
• Renewable energy – Captures CH4
• Shorter process time• 25 vs. 120 days
• Smaller footprint• 3 vs. 20 acres
• Reduces waste• Soil amendment
Challenges:
• Permitting
• Collection
• Contamination
• Residuals
• Cost efficiencyBottle CapBottle Cap
Food Waste Digestion
• 70 in Europe
• East Bay Municipal Utility District
• Toronto
• UC Davis*
• Inland Empire*
Options:• Dedicated food waste digester + compost
• Co-digest with municipal sludge at WWTP
Hauling
Preprocessing facility
Lifter & Conveyor Belt Screening and
Chopping Buffer tank Plastics
Metals
Digester
Gas
Liquids & Solids
Combined Heat and Power
Heat Electricity
Onsite Grid Digester Landfill Land apply
Collection
Food Slurry
Compost
Food Waste Diversion Flow Diagram
Digester Feed Stocks
Digester Feed Stocks
Digester Feed Stocks
Digester Feed Stocks
Digester Feed Stocks
Scenarios
ScenarioTons waste
per yearDescription
A 4268 FOG + Whey + 50% Arcata & Eureka Commercial
B 7554FOG + Whey + 50% of Arcata & Eureka Commercial +
50% County commercial
C 9919FOG + Whey + 100% of Arcata & Eureka Commercial +
50% County commercial
D 11363FOG + Whey + 50% of Arcata & Eureka Commercial +
50% County commercial + 100% of Del Norte Commercial
Life Cycle Cost
Scenario Digester
(Million $)Business-as-Usual
(Million $)
A $6.5 $3.6
B $8.4 $8.3
C $8.7 $11.7
D $9.6 $13.8
LCC
Renewable Energy
•Assumes 35% generator efficiencyAssumes 35% generator efficiency
•Assumes 25% parasitic loadAssumes 25% parasitic load
Scenario MWh/year # CA house equivalents
A 888 126
B 1,569 223
C 2,059 293
D 2,359 335
$$$Annual savings and Revenues
ScenarioHauling savings
($/year)
Offset Grid Energy at WWTP
($/year)*
Renewable Energy Sold to PG&E ($/year)
A $79,000 $85,000 $0
B $188,000 $105,000 $13,500
C $267,000 $105,000 $48,500
D $316,000 $105,000 $70,000
*Assumes $0.10/ kWh
GHG Reductions
•Assumes 0.7 MT CO2e / MT food waste (CCX)•Assumes 0.524 lbs CO2 / kWh (PG&E)
Carbon Emissions Reductions
Scenario
Avoided long-haul trucking
(lbs CO2/year)
Fossil power replacement (lbs CO2/year)
Avoided landfill gas
(lbs CO2/year)
A 215,000 434,000 17,319,000
B 541,000 767,000 41,392,000
C 729,000 1,007,000 58,711,000
D 861,000 1,153,000 69,288,000
Project Development Plan
• Organic Waste Resource Analysis• Permitting – EPA Region 9• Pilot collection• Phase 1: Demonstration and testing
– Efficient pre-processing– Appropriate technology– Residuals management alternatives
• Phase 2: Expand to regional scale
To conclude…
• Project Benefits include:– Divert waste from landfills– Generate renewable energy– Reduce GHG emissions– Retain $$$ in County – Create jobs– Increase regional sustainability
Acknowledgements• Gary Bird - City of Eureka • Clay Yerby, Gerry Snead - Elk River WWTP• Kurt Gierlich - City of Eureka • Paul Suto, Sophia Scota – East Bay MUD• Charles Chamberlin, Arne Jacobson – HSU• Cara Peck – US EPA Region 9 • Josh Rapport - UC Davis • Mike Leggins, Chris Choate - Recology • Brown and Cauldwell – Eureka WWTP Engineers • Dufferin Organics Processing Facility• BTA Processing – Canada Composting• Cedar Grove & Jepson Prairie composting facilities • Andrew Jolin – HWMA Mad River Composting Facility• Hambro Forest Products• Del Norte Solid Waste Management Authority
Questions?
AB 32: Emissions Reductions Goals
• State-wide: 146.7 MMTCO2e
• Local government: 15% by 2020
• Waste sector goal: 10 MMTCO2e
Annual tons food waste in the California waste stream (CIWMB)
MMTCO2e / year
% of AB 32 emissions
reductions
9,663,405 7.5 3%
Source: Year% Food Waste in Total Disposed Waste Stream
% Food Waste in Commercial Sector
Scale
Humboldt County Source Reduction and Recycling Element 1992 N/A 18.62 County-wideCalifornia Integrated Waste Management Board 1999 N/A 17.2 County-wideCalifornia Integrated Waste Management Board 2004 14.6 18.8 State wideCalifornia Integrated Waste Management Board 2008 14.4 15.2 State-wideUS EPA 2007 18.2 N/A Nation-wideAlameda County Waste Characterization 1995 10.5 14.9 County-wide
Alameda County Waste Characterization 2000 11.9 16.2 County-wideAlameda County Waste Characterization 2008 18.7 26.1 County-wideOregon Statewide Waste Characterization 2005/2006 15.73 N/A State-wideMarion County Waste Characterization 1998 15.34 N/A County-wideMarion County Waste Characterization 2002 17.66 N/A County-wideMarion County Waste Characterization 2005 20.54 N/A County-wideAverage 16 18
Major costs for digestion Cost per unit ($)
Building ($/ft2) w/slab $100
50' Truck weighing scales $32,700
Foundation for scales inclu. Const. $20,000
Print Kiosk (for weight records) $4,000
Software capable of running reports $10,000
PC computer $2,000
Card Scanner $5,000
Odor control system $85,000
Front-end loader $118,000
Pre-processing equipment $450,000
Metering Pumps $40,000
Peristaltic pumps $90,000
Trommel screen $110,000
Buffer tank ($/ft3) $9
Digester ($/ft3) $9
Mixers $40,000
Post digestion tank (for gravity separation) ($/ft3) $9
Gas collection equipment $75,000
H2S Scrubber Tank $5,000
H2S scrubber media (Sulfa Treat) $5,760
Solids drying area ($/ft2) concrete slab $30
Monitoring equipment (SCADA) $100,000
Engineering Planning and Design $250,000
Permitting $100,000
EIR $250,000
New Full Solid Waste Permit $6,300
Geotechnical analysis $17,500
Wetland deliniation $17,500
Land Preparation $30,000
Infrastructure (fencing) ($/linear foot) $35
Infrastructure (roads) ($/ft2) $12
Program Design $100,000
New Water Service $110
Access Gates $10,000
Balance of systems (contingency) 30% of total capital
O&M CostsO&M costs Cost per unit
Labor ($/hour) $22
Supervision and training ($/hour) $30
Insurance ($/year) $15,000
Water ($/750 gallons) $2.84
Iron sponge media replacement ($/year) 4,160
Equipment maintenance 50,000
Solids management ($/ton) 41
New Wastewater disposal permit fee (good for first 3 years) 450
Waste water disposal permit fee (not new) 250
Waste water disposal fee ($/lb BOD) 1
Solid waste permit annual inspection fee 3,788
Funding Options
• Regional partners share funding– Bonds or low-interest loans– Complete ownership– Revenues and “green attributes” allocated to facility owners
• Public/Private partnership– Shared ownership and operation – Shared benefits from “green attributes”– Shared revenues
• Performance contractors– Delayed ownership – option to buy after 6 years– “Green attributes” and revenues allocated to owner– Flat rate electricity at just below utility rate
Feed-in Tariff
• AB 1969 – “requires all electrical corporations to file with the CPUC a standard tariff to provide for payment for every kilowatt hour (kWh) of renewable energy output produced at an eligible electric generation facility”
• CPUC Decision 07-07-027– Tariffs and standard contracts for the
purchase of renewable energy from WWTPs
Feed-in Tariff
• PG&E: 104 MW capacity allocation to WWTPs• PG&E: 104 MW allocation to non-WWTPs• Rates based on:
– # kWh sold– Time of delivery – MPR set by CPUC– 10, 15, 20 year contracts
• Interconnection through FERC SGIP• “Green Attributes”
– To facility for generated RE they use on site– To IOU for RE sold to grid
Analysis Data & Inputs
• HWMA records• CIWMB• EPA region 9• Food waste digestion projects & case studies
– EBMUD– Dufferin Organics– NewMarket– UC Davis
• Eureka WWTP • Brown & Caldwell • Equipment manufacturers• Eureka City Garbage, Nor Cal
Regional Waste Streams
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