Food Waste Anaerobic Digestion
Demonstration Program at theJoint Water Pollution Control Plant
SUSTAINABLE SOLID WASTE MANAGEMENT
FUTURE ROADMAP IMPLEMENTATION
Regional Countywide Subcommittee Meeting
Dave Czerniak

Sanitation Districts of Los Angeles County

April 23, 2015

What we’ll talk about today…
 Policy Drivers in California
 Background & Objectives
 Processing & Receiving
 Results to Date Lessons Learned

Policy Drivers


AB 341 establishes a statewide
solid waste recycling goal of 75%by 2020

CARB AB32 scoping planestablishes approaches to GHGemission reductions

AB1826 established mandatory
commercial organics recycling
starting in 2016

Organic waste estimated at 6-7
million tons per year statewide, 3
million tons in SouthernCalifornia

AB1826 THRESHOLDSWhat this Demonstration is about.
In 2013, the Districts and WM entered into a multi-year
demonstration program Agreement. Operations began inFeb. 2014

WM sources and processes food waste at its Orange County
facility, producing an Engineered BioSlurry (EBSTM)

WM deliveries up to 84 WTPD (~20,000 GPD) of EBSTM toJWPCP for co-digestion in a designated, full scale test digester(#16)

EBSTM is fed into the test digester at a controlled rate.

WM and JWPCP’s Research team monitors the program toevaluate the impacts and performance of the co-digestion
process.

Results will be used to determine the feasibility of a full-scale
food waste AD program at Districts WWTPs

Food Waste AD Options


Two main types of food/organic waste anaerobic digesters:– Dry TS > 15%. Best if feedstock high in green
waste up to 50%, needed to stack in digester.
– Wet TS < 15%. Best if feedstock has no green
waste, can be pumped & mixed in digester.

Dry FW AD digestion generally requires larger
and adjacent composting area, provides lower
biogas yield, and produces more solid digestate.

footprint

Wet FW AD digestion generally provides better mixing anddigestion, higher biogas yields, good odor control, and lower O&M
costs.
– Co-digestion …The digestion of multiple organic wastes in one digester
such as our demonstration program where food waste is mixed withsludge at JWPCP.

Types of Organic Municipal Waste
 Suitable for WWTP co-digestion– Source separated and processedfood waste– Fats oils and grease (FOG) Not suitable for WWTP co-digestion– Green waste– Mixed waste

Why Co-digestion of Food Waste atWWTPs may make sense Advantages:– Digester and associated infrastructure
already exists– Energy recovery equipment
may already exist– Assists WWTPs to become net energy producers

 Concerns and challenges:– Limited capacity statewide – a niche, not a solution– Can accept only relatively clean feedstock– WWTPs have an important public health mission

Project Backdrop
 In 2011, Districts completed a feasibility study on

co-digestion of food waste at Districts WWTPs.
 Conclusion…we had a viable project at JWPCP.
– It is technically feasible (economics still a question)– It is allowed under current regulations– It could assist L.A. County cities/haulers with diversion efforts

 In 2012, performed bench scale testing of co-digestion of FW slurry and JWPCP sludges…
– Characterized FW slurry (developed FW specifications)– Identified no negative impacts on digester operation– Quantified biogas production potential

Adding Food Waste to Bench-scale
Digesters Increases Gas Production

Adding 10-12% (v/v) food waste slurry tosludge could double biogas production
Food Waste Slurry characteristics: Total Solids ~ 14% by wt., Volatile Solids ~ 92% by wt., COD ~ 222,400 mg/L

Joint Water Pollution Control Plant
 24 active digesters each withacapacity of 3.7 million gallons
CNG Fueling Station

 4.4 million gallons of sludge is

20 MW of Electricity

areadded to digesters each day
 Volatile solids breakdown (digest)for 18-19 days before exiting digester
 5,000 scfm (or ~ 20 MW) of biogas is created Remaining biosolids are dewatered and trucked off foruse in composting and for land application

JWPCP Total Energy Facility
Combined Cycle Cogeneration Power Plant– (3) 9 MW Solar Turbine Mars 90’s gas turbine generators– (1) 8.7 MW Shin Nippon Machinery steam turbine-generator– 20 MW used to meet on-site load2012 Grand Prize Winners – Operations Management
AAEE Excellence in Environmental Engineering and ScienceDemonstration Project Objectives
 Assist Districts member cities

and haulers in diversion efforts

 Determine the impacts of full-scale food waste co-digestion
on WWTP operations

 Evaluate the performance and cost-effectiveness offood waste co-digestion at a WWTP

 Use project results to determine feasibility of alarger food waste digestion program at Districts
wastewater treatment facilities
Video up next

MSNBC “LA Scrapping Food Waste”

Click here for video

CzerniakWM’s CORe® Facility in Orange
CORe® (Centralized Organics Recycling equipment)

WM collects food waste from sources such as restaurants, food processing
plants, and grocery stores. Tipped material is inspected prior to processing.

Food waste is processed to remove physical contamination (e.g., utensils,cans, packaging, and heavies) and blended into a consistent EBSTM product

EBSTM is loaded into tanker trucks for delivery to JWPCPEBSTM Receiving at JWPCPEBSTM is pumped from WM tanker trucks into
closed, sealed storage tanks, controlling odors.
Two identical receiving/feed-in stations for redundancy.

ControlSkid

EBSTM Feed-in Station
 EBSTM is recirculated (mixed) in the storage tanks on anintermittent basis to remain “fresh”
 EBSTM is pumped fromstorage tanks into the topof the test digester
 EBSTM is fed to the test

digester at a feed rate set
by the control program WM and Districts remotely monitor feed-in station

operating parameters including storage levels, pumpspeed, mixing times, and feed in rates.

Food Waste Co-Digestion Plan
Test Digester

Control Digesters

WW/Sludge/TWAS Feedgal/day% solids
tons per day solids

Food waste slurry feed

gal/day% Solids
tons per day solids

20,000
14%
11.7

---

liquid basis
solids basis

9%30%

---

gal/day% Solids
HRT, days

225,000
4.2%
16.4

205,000
3.20%
18.0% Food Waste
Digester total

Test Digester

205,000
3.20%
27.3

205,000
3.20%
27.3--------

Control DigesterProject Results – Gas ProductionProjected Digester Gas Production

3ft Digester
Gas/Day
DigesterGas Production,
cfd

700,000
700,000

600,000

600,000
600,000
500,000
500,000
400,000
400,000

455,000
371,000

300,000
300,000
200,000
200,000
100,000
100,000
00

ControlDig.
Digester
Control
Gas
Gas Production
Production

TestDig.
Digester
Test
Gas
Gas Production
Production at 7,000@ 6,500 gpd EBSTM
gpd food waste

Test Dig.
Digester
TestGasGas Production
Production at 20,000@ 20,000 gpd EBSTMgpd food waste

Performance of Digesters
4-Week Average as of March 7, 2015

ParameterUnitsControl

Test% Change

EBSTM Feed Rate

gpd

06,500---Digester Gas

cfd

371,000

455,000

23%Methane

%

62.5

62.50%ppm (v/v)

27

3011%

VSD%

51.9

63.8

23%

Digester Gas/lb VS

cf/lb

8.92

9.112%

Digester Gas H2S

Use of DG from Food Waste Potential usage of digester gas from 84 tpd EBSTM– 200 scfm at 60% methane– 1,500 GGE/day CNG– 750 kW Current usage of digester gas– TEF uses additional digester gas to generate extra
electricity for sale when excess digester gas is not beingflared– If all the gas could be used (non-flaring days), current
digester gas production of 100,000 cfd of digester gas
from EBSTM can produce an additional 270 kW.

Lessons Learned & Takeaways

Early on, EBSTM transport, transfer and control systems at
LACSD had issues. Issures resolved and now work as intended.

The original odor control system (biofilters) could not handle
the high level of H2S generated from EBSTM storage. Switchedto carbon filter canisters. …no further issues



There have been no major impacts to treatment plant
operation or digester operations seen to date. All indicators
look good.

Biogas production levels from EBSTM has met expectations.

Finding suitable sources of Food Waste has been morechallenging than originally envisioned, and has delayed
increased ramp up of EBSTM to the test digester.

New Wet Dry Food Waste
Collection System

Cutting Edge

Neighborhood-Friendly

Low Capital Cost

Thank you. Questions?
Dave Czerniak, P.E.
562-908-4288 2442
dczerniak@lacsd.org“So, this Humpty Dumpty guy falls off the wall andI think, Dang, ain’t lettin’ this go to the food waste bin.”