Anaerobic Digestion of Agri-food Processing By-Products

Presented By: Keith Wilson, President, EEC Energy Corp.
April 13, 2007

‣ Introduction
‣ Agri-food Processing By-Products in Ontario – an Untapped
Energy Source
‣ The ADvantage System Anaerobic Digester – Overview
‣ EEC Energy Grain Handling By-products Test

According to a study by the Ontario Ministry of Agriculture and Rural
Affairs (OMAFRA), there is almost 2,300,000 tonnes of organic waste
produced by agri-food companies in Ontario annually. The potential energy
value of that organic waste processed by AD translates into:
‣ Over 3.6 Million Megawatts of Electricity Annually
‣ Over 5 Million Megawatts of Thermal Energy Annually (using CHP units)
EEC Energy estimates that today’s energy value of the Biogas from that waste
is almost 100,000 Gigajoules annually.

Types of organic material for AD Systems:
Food Processing:
Fruit & Vegetable Processing
Brewery Waste
Malt Plant Waste
Abattoirs
Sugar Processing
Agricultural:
Dairy
Poultry
Crop & Crop Residuals
Municipal/Industrial:
Sewage Sludge (after treatment)
Organic Landfill Waste
Restaurant Waste (fats/oils)
Grain Elevators
Dairy/Cheese Processing
Corn & Potato Processing
Fish Processing
Beef
Swine
Silage
“Wet” Kitchen Waste
Lagoon Treatment

Unique Features and Benefits:
‣ Modular Design
‣ Easily expandable to handle increased waste volumes
‣ Processes different waste streams in separate digesters
‣ Completely automated – on or off-site control and monitoring
‣ Flexible design – digesters are
standard, complete flexibility to
integrate front & back-end
processing into current operations
‣ Indoor operation – mitigate odours
associated with digestate handling

Unique Features and Benefits:
‣ High Temperature Operation - 55° to 60° Celsius
‣ Shorter Hydraulic Retention Time (HRT) – typically 4-7 days
‣ Complete Pathogen Destruction Rate (99.999%)
‣ 2/3 Less Digester Volume required compared to Mesophilic systems
‣ Increased biogas yields – typically 20-25% higher than Mesophilic
‣ Increased biogas quality at 650-750 BTU’s/ft3

In 2005, EEC Energy
began the R & D
Project to test the
energy potential and
business case for
operating an AD
System on grain dust
from the local grain
handling industry

TEST PURPOSE:
To determine the latent energy potential (in Therms/Ton) through anaerobic digestion
of pelletized barley dust as a sole substrate, as supplied by a local grain-handling
facility
TEST PARAMETERS:
The following tests were performed and recorded:
‣ Temperature, pressure and PH of blend tank, digester and biogas
‣ Quantity, quality and BTU value of biogas production
‣ Solids recovery from digestate
TEST TIMELINE:
The barley substrate was first introduced into the digester on Sept. 11/05. The
digester was gradually weaned off manure and onto the new substrate over the
next few weeks.

OBSERVATIONS:
‣ The digestion of the infeed was immediate and very fast
‣ In the 2 hour period following the batch infeed, excess biogas was generated
‣ Also, during this time, the boiler could not consume all the biogas being
generated and the excess was vented to atmosphere through the safety stack.
‣ During this first 2 hours, the boiler temperature did not rise relative to the extra
gas being consumed and in fact, it occasionally dropped.
‣ There was little recoverable solids from the digester.
‣ Even though there was a large recycled digestate component to the infeed, the
pH of the digester remained stable.

Biogas Production (cu.ft./# Infeed)
(8.66 Avg.)
Cu. Ft. Biogas
14
12
10
8
6
4
2
0
1 3 5 7 9 11 13 15 17 19 21 23
Hours from Infeed

Biogas Production (BTU's/Cu.Ft.)
(692 Avg.)
BTU's/Cu.Ft.
900
800
700
600
500
400
300
200
100
0
1 3 5 7 9 11 13 15 17 19 21 23
Hours from Infeed

Biogas Production (Therms/Ton)
(122 Avg.)
Therms/Ton Infeed
250
200
150
100
50
0
1 3 5 7 9 11 13 15 17 19 21 23
Hours from Infeed

The results of
our research
demonstrate a
strong case for
grain waste as a
feedstock for AD
Systems!