Summary

Landfill gas is a mixture of gases generated by the decomposition of organic waste in landfills, former dump sites, and filled land. It poses potential risks to human health, property, and the environment, making assessment and management essential for redevelopment, construction, and compliance.

Definition

Landfill gas (LFG) is a gas mixture—primarily methane, carbon dioxide, and trace volatile compounds—produced by the anaerobic breakdown of organic waste deposited in landfills or historical fill material. It can migrate through soil and structures, accumulate in confined spaces, and present fire, explosion, odour, and health risks if unmanaged.

Why It Matters

Landfill gas presents a significant environmental and safety consideration for brownfield redevelopment, construction projects, and ongoing landfill management.

Understanding LFG behaviour is critical because it can:

migrate horizontally or vertically through soil and preferential pathways

accumulate in buildings, service trenches, or underground voids

create fire and explosion hazards due to methane concentrations

impact indoor air quality and human health

influence vapour intrusion risk assessments

cause odour and community nuisance issues

trigger regulatory and planning constraints

Regulators across Australia require landfill gas assessments for developments on or near former landfills or filled land. LFG can also significantly influence engineering design, environmental approvals, and remediation strategies.

When It’s Required

Landfill gas assessment, monitoring, or mitigation is typically required when works occur on, adjacent to, or down-gradient from former landfills, waste disposal sites, or historical fill areas. Common triggers include:

Development Applications (DAs) on Former Landfills or Fill Sites

Consent authorities often require LFG risk assessments, gas monitoring, and mitigation design before approving redevelopment.

Construction and Excavation Activities

Excavation may create pathways for gas migration or expose organic fill layers, increasing risk during construction.

Contaminated Land Assessment

LFG is assessed during Phase 1 and Phase 2 environmental site assessments where waste materials or historical fill are present.

Landfill Capping, Closure, and Encapsulation Projects

Gas monitoring and extraction systems are essential during closure or long-term containment.

Health and Safety Requirements

Methane and carbon dioxide concentrations are monitored to protect workers in confined spaces or areas with potential gas accumulation.

Regulatory or EPA Conditions

Landfill gas monitoring is often mandated by:

environmental licences

post-closure management plans

conditions of consent

contaminated land and vapour intrusion guidelines

How We Can Help

Nova Group Pacific provides comprehensive landfill gas assessment, monitoring, and mitigation services to support compliant redevelopment, construction, and environmental risk management.

Our capabilities include: