Synergies of Composting and Anaerobic Digestion

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Synergies of Composting and Anaerobic Digestion

Synergies of Composting and Anaerobic Digestion:

Odor Control, Marketable Product, and System Selection

May 2011

External View of Digester Building

Jerry Bartlett

Chief Environmental & Sustainability Officer

Cedar Grove Composting


Current Facility


Digester Addition


External View of Digester Building


Commercial Foodwaste in Tipping Building


Phase 1

Tipping / Screening


Screened Material Going Into the High Solids Digester


Receiving Hall

Biofilters

Digesters

M

I

X

I

N

g

Digesters

Percolate

Tank

Office

CHP

Flare


Biofilter

85 ft by 74 ft

Two Sections

Receiving Area

and Screening

250 ft. by 90 ft.

14 Digester Tunnels

99 ft. by 23 ft. by 16 ft.

Mixing Lobby and

Reloading

81 ft. By 200 ft.

Percolate Tanks-2

with Secondary

Containment

Office

Digestate

Mixing/Compost

C

H

P


Material

Movement

Through

the

75,000 SF

Digester

Facility


Phase 3

Fermenter Loading and Unloading


Computer Controlled System


Phase 5

Energy Generation

Piping Above Digesters Routing Gas to Storage Tank


Phase 5

Energy Generation


Gas Production


Equal

Emission

control as

existing

receiving

building

Anaerobic Digestion Emission Points

Digester Receiving

and Screening

Area

Digester Mixing

Area

Biofilter

Flare

Emission

Control

90%

99.9 %

Greater

Emission

control

since

mixing is

performed

in a

building

and then

transported

by tractor

Digester- 14

Tunnels

Digestate and Phase

1 Gore Mixing Area

Transport via covered

trailer vs.

open front end loader

Premixed Gore Phase 1

and Digestate delivered to

Gore Covered Phase 2

Combined Heat and

Power Unit

Emission

Reduction

99.9 %


Everett, Washington

Cedar Grove Composting

Composting and Anaerobic Digestion Facility

Everett Washington Facility


Digester Building

21-28 days

Digestate

Introduction

Screening

Phase I

21-28 days

Phase II

14 days

Phase III

14 days


AD as an Odor Mitigation Strategy

Pre-processing of highly putrescible

feedstock within enclosed air tight

system

Composting of less volatile organic

compounds since digestion has

already occurred reduces potential

compost operation odors


Emission Comparison in Movement of Composted Product

Existing Operation New Management Difference

8 yard Bucket Loader

moves material

average of 200 ft.

8 yard bucket loader

unloads in

uncovered hopper

Material moves 350 feet

at depth of 6 inches

deep on conveyor

Material is dropped 3

times during movement

Material unloaded 8

yd bucket at a time

Material is fluffed up

outside

8 yard bucket loader

loads at the heap no

movement

8 yard bucket

loader unloads

into open truck

Material driven in

close top truck 40

yards at time

No dropping

occurs outside

Material unloaded 40

yards at a time

No material

fluffing outside

Reduction of

200 ft of

movement

No Change

Reduction in

emission due to

reduced surface area

Reduction

Reduction

Reduction


Additional Capital Investments

Not Related to AD

1) Grinding Operation Enclosed in 17,000 SF

building with negative aeration

2) Cover of Gore Cover System Phase 3

3) Cover of finished product piles


Finished Bulk Product Screened to ½”


Cedar Grove Products

Bagged and Bulk

Compost

Topsoil

Potting Soil

Booster Blend

Vegetable Garden Mix

Rooftop Garden Blend

Special Turf Blends


Cedar Grove Composting

Everett Washington Facility

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