Landfill Gas 101HALTON REGION

Public Works - Waste Management Services

May 15, 2014 – MWA Spring Workshop, Hockley Valley Resort

Presented by: Art Mercer, Supervisor of Landfill Operations

Today’s Topics• Background on Halton Region

• Sources of Methane

• The How, What & Why of Landfill Gas (LFG) Systems

• Development of Halton’s LFG Collection, Flaring & Utilization System

• Gas Collection Components

• Utilization Facility Components

• Project Costs and Results

• Lessons Learned

The Halton Waste Management Site is located in Milton, OntarioHalton Region

• Population ~ 525,000• On Lake Ontario between Toronto &

Hamilton• 4 Local Municipalities :

Burlington, Halton Hills, Milton & Oakville• Landfill ~ 75,000 tonnes of garbage

per year• Remaining site life is until 2044 at

current fill rates

Major Sources of Methane Emissions…

Environment Canada (2013)

AgricultureGlobally, domestic livestock are the primary source of methane which is produced as part of their normal digestive process

Major Sources of Methane Emissions…

Environment Canada (2013)

Major Sources of Methane Emissions…

Landfills • Anaerobic decomposition of buried

organic waste produces landfill gas• Landfill gas is composed primarily

of methane (CH4 ) and carbon dioxide (CO2) which are greenhouse gases

• CH4 has 21-times the global warming potential of CO2 *

• Canadian landfills account for 20% of national methane emissions *

* Environment Canada (2013)

CH4CO2

O2N2 H2 H20 Trace

Landfill Gas Compo-sition

The How, What & Why of Landfill Gas SystemsHow do you capture Landfill Gas?• Use vacuum pressure within the landfill to collect the LFG

before it escapes to the atmosphere

What can you do with captured Landfill Gas?• Flare it to destroy the methane (good choice)• Use the combustion energy for power generation instead

(better option)

Why collect Landfill Gas at all? • GHG emissions reductions for landfills• Offset use of non-renewable fossil fuels (if utilized for

electricity generation)• Reduce odours and potential for off-site impacts• Regulations now make it mandatory to collect LFG in Ontario

(2010)

Development of the Halton Landfill Gas Collection, Flaring & Utilization System

Phase 1 COLLECTION FACILITY - (Constructed 2006)• Halton Region installed wells within landfill and

constructed a flare station• Landfill gases were then vacuumed from the landfill to

the enclosed flaring system for burning

Phase 2 UTILIZATION FACILITY - (Constructed 2007)• Partnership was struck between Halton Region and

Oakville Hydro in 2004 for development• Oakville Hydro installed two 1-Megawatt engines (GE-

Jenbacher) running exclusively on LFG captured and provided by Halton Region in 2007

• Facility has capacity to generate enough “green power” to provide electricity for up to 1,500 homes (2-MW)

• Electricity is sold to Ontario Power Authority under purchase agreement with Oakville Hydro and distributed by the local utility, Milton Hydro

Gas Collection Components (Phase 1)

1) Vertical Wells – installed in deep waste in closed landfill areas2) Horizontal Collection Trenches – Installed within waste during filling3) Headers & Laterals – Transmit gas from landfill to Blower Building4) Condensate Sumps – Collect moisture along header pathways

Gas Collection Components Vertical Extraction Wells• Wells are drilled into waste

• Consist of perforated vertical piping surrounded by porous granular materials

• Well-head allows volume of gas extracted to be regulated

• Applying vacuum pressure to the well creates a collection “zone-of-influence” of up to 30 metre radius

• Wells are spaced out to achieve full coverage for optimal capture of the landfill gases

Gas Collection Components

Gas Extraction Hardware

Perforated horizontal collection pipe installed in waste

Gas Extraction Hardware

Solid-walled Lateral piping

Gas Extraction Hardware

Solid-walled large diameter perimeter Main Header piping

Gas Extraction Hardware

Condensate sump riser with internal pump and buried discharge

Collection meets Utilization

Utilization Facility Components

Components• Condensate Trap

• Moisture Separator

• Condenser-Chiller Loop

• Blowers

• Main Flare (Enclosed)

• Gas Treatment (Carbon Filter)

• Purge Flare (Candle-stick)

• Generators “Make the Green Power”

Project Costs and Results• Halton’s LFG collection system required initial investment of $3.4-Million in

2006 for 21-Vertical Wells, 5-Horizontal Collection Pipes, Blowers, Flare and peripherals

• Two well-field expansions of $0.25-M (2009) and $0.75-M (2013). System now consists of 80 gas collection points

• Oakville Hydro invested $4.1-Million to construct the power generation facility in 2007, includes two 1-MW gen-sets and peripheral equipment

• Currently collecting 250 – 500 cubic feet per minute of LFG (varies seasonally)

• 99% of LFG collected is utilized for power production on site, generating revenue through OPA standard offer program (2007)

• Halton Region achieved voluntary early-action acknowledgement for compliance with a 2010 Regulation 347 Amendment requiring all landfill’s containing > 1.5-million m3 of waste to have a LFG collection system installed

Lessons Learned

• Differing requirements for Collection and Utilization can create challenges, e.g. volume of gas for environmental controls –vs- power generation/revenue

• Revenue sharing plans (contracts) should be targeted to provide sufficient income to cover operating costs for all partners

• Horizontal collection piping is subject to flooding from perched leachate conditions which “choke off” the gas flow, therefore are not recommended for this climate

• Vertical wells can also partially fill with liquid. Pumping it out improves gas capture, although this does increase costs of collection

Lessons Learned (Cont’d)

• Scrutiny of collection system designs before construction can help reduce operational issues such as unnecessary Confined Spaces and other H&S issues (e.g. in-ground chambers for well heads, chambers for condensate sumps)

• Study of waste composition, density and moisture content can help to maximize gas capture and improve well field design

• Due to the variability of landfill factors, need to ensure that experienced consultants and operators are hired who are familiar with unique design and operation challenges of LFG systems

THANK YOU!

QUESTIONS?

Art Mercer, Supervisor of Landfill Operations

905-825-6000 x 8207, art.mercer@halton.ca

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