Integrated Gas Recovery Services Inc.
Constructing the well field
Harnessing landfill energy
Step 1: Planning the system
The size, volume, waste type and age of the landfill are
factors in the decision to install a gas utilization system.
Turning landfill gas into green energy
Landfill gas can be collected from a landfill and
utilized by neighbouring industries as a green
energy source or to generate electricity for the
provincial power grid.
Pump Test
MOE default Lo=125m3/tonne, k=0.04
8,000
11,000
6,500
10,000
6,000
9,000
8,000
8,077 m3/hr (4,754 cfm)
7,000
6,000
5,000
4,000
3,000
2,000
5,000
4,500
4,000
3,500
0
1990
2010
2030
3,000
2,500
2,000
1,500
1,000
T
1,000
1970
5,500
AF
metres per hour
Cubic metres per hour
7,000
R
• A fairly young site just beginning to create gas is ideal. An older site
where gas production is on the decline may not have sufficient gas
for a utilization project.
12,000
D
• A number of extraction gas wells are installed into the landfill to
determine the quality and quantity of the landfill gas.
7,500
2050
Cubic feet per minute
feet per minute
• A gas curve is created for the site that shows the anticipated amount
of gas production over time.
13,000
500
0
2070
Year
Designing the well field
COMCOR
E NV IRO NME NTAL LI MITE D
Consulting Engineers and Landfill Gas Specialists
LFG Production Estimate
East Landfill
Thorold, Ontario
FIGUR
2.3
• Based on the gas curve information and a review of site history, a well field is
designed for the site.
• Extraction wells are placed in locations to ensure gas collection is maximized and
there is sufficient coverage of the site.
• Generally, a well field has a header system that rings the site. Lateral pipes are
then connected from one side of the site to the other so gas can be drawn from
either direction into the header system, and ultimately to the gas plant.
• The entire collection
system must be
approved by the
Ministry of the
Environment prior to
installation.
APPROXIMATE
LOCATION OF
PROPOSED SCALE
Installation of a landfill gas lateral
pipe that will transport gas from the
well field to the gas plant.
NOTES:
CEPTUAL WELLFIELD
1. Received above figure 5.3 (OVERALL CON
tal Limited - 320 Pinebush Road, Suite
INSTALLATION) from Comcor Environmen
) 621-6669, on December 14, 2005.
12 Cambridge Ontario N3C 2V3 - phone (519
FIGURE No.
Proposed Walker South Landfill
Design and Operations Report
NOT TO SCALE
www.walkerind.com
LANDFILL GAS COLLECTION
SYSTEM LAYOUT
24
Integrated Gas Recovery Services Inc.
Constructing the well field
Harnessing landfill energy
Step 2: Construction
Installing and operating the wells
• The gas collection system is installed as areas of the landfill are
closed and ready for gas collection.
• The wells are plastic perforated pipes drilled down into the waste
to about 3-5m above the bottom of the waste fill.
• Screenings (stone) are placed around the outside of the well to
prevent waste from clogging the holes.
Installation of a landfill
gas lateral pipe in the
East Landfill, May 2009.
• A control valve on top of the well is used to adjust the flow of gas
to the gas plant.
• On top of the well are two monitoring ports that measure the
vacuum on the well, the quality and quantity of gas, and the
vacuum from the gas plant.
High density
polyethelene piping for
well field construction.
• The valves are adjusted based
on how much landfill gas is being
produced in the area around the
well.
• In areas of the landfill where less
gas is being generated, the valve is
closed down to limit the flow.
Perforated pipe to be used for
landfill gas extraction well.
• In areas where lots of gas is being
produced, the valves are opened
wide to increase the amout of gas
flow to the gas plant.
Active extraction well in
closed portion of landfill.
Extraction well under
construction: white PVC pipe
is the well, black pipe is the
collection piping.
www.walkerind.com
Integrated Gas Recovery Services Inc.
Constructing the well field
East Landfill, well field site plan
Installing the pipe
• Landfill gas collection piping is typically installed by
trenching in the pipe to a depth of approx. four feet
(1.2 m).
• Trench widths are kept small to minimize odours
and expedite pipe installation.
• Open trench length is also kept to a minimum,
about 20 m.
• Safety measures such
as gas monitoring
and trench safety are
strictly enforced.
• Once installed, the
pipe is backfilled and
the landfill cap is
restored to its original
condition.
• At the end of each
working day the trench
is covered completely
to control odours.
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