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