Landfill Gas is the gas produced from the decomposition of Putrescible Waste placed in Landfill. Landfill Gas is a Biogas and is a mixture of Methane and Carbon Dioxide and some trace elements captured in the course of passing through the waste matter.

Landfill Gas is a strongly polluting Greenhouse Gas and when contained in an enclosed space with the correct mixture of Oxygen can be explosive; one of the principal reasons for constructing Landfill with barriers and Landfill Gas extraction systems is to prevent Landfill Gas from escaping from the waste mass in an uncontrolled manner, originally to prevent the build up of Landfill Gas in buildings near Landfill to prevent potential explosion, but more recently to limit release into the atmosphere and reduce environmental impact.

The 'go-to' guidance for many in the landfill sector in the UK is still the waste management papers produced in the mid and late 1990's, and Waste Management Paper 27 (WMP27)[1] describes the process of Landfill Gas generation and management.

Landfill Gas removed from the waste mass needs to be managed in an appropriate fashion. In general this requires, at minimum, the treatment via in a high temperature flare (picture below). However, once collected the Landfill Gas can also be used in a dedicated Landfill Gas Engine (picture below) to generate electricity. In recent years the option to clean the gas for subsequent use in vehicles or for injection into the gas grid have started to be developed in a similar way to other Biogas.

Landfill gas flare - source Hoffsetter
Landfill gas flare - source Hoffsetter
A typical landfill gas engine
A typical landfill gas engine
Landfill Gas Flare Landfill Gas Engine


References

  1. Waste Management Paper 27 (WMP27): Landfill Gas