A landfill gas collection system is designed to capture gas as it forms within the waste mass and transport it safely to a central point for treatment or energy recovery. The system creates a gentle vacuum in the landfill so that gas flows into extraction points instead of escaping through the surface or migrating underground.
At a high level, the system has three main parts:
- Gas collection points inside the waste (wells and horizontal collectors).
- A network of pipes that move the gas around the site.
- A central station where the gas is dried, measured, and then flared or used for energy.
Collection wells and horizontal collectors
Most modern landfills use a combination of vertical wells and horizontal collectors.
- Vertical wells are drilled down into the waste, usually after a cell has reached its final or interim height. A perforated section of pipe is installed in the gas‑producing zone and surrounded by a gravel or aggregate backfill that allows gas to flow into the well. The upper part of the well is sealed to stop air being drawn into the waste.
- Horizontal collectors are slotted pipes laid in trenches within the waste, often installed during filling. They are then covered by gravel and further waste. These are particularly useful in newer areas of the landfill or where vertical drilling is difficult.
At the top of each well there is a wellhead assembly. This typically includes:
- A valve to adjust the vacuum and gas flow.
- Sampling and monitoring ports to measure gas composition, pressure and temperature.
- Connections to the lateral pipes that carry gas away from the well.
Pipework, condensate and vacuum
The individual wells and collectors are linked together by a network of pipes:
- Lateral pipes connect groups of wells to larger header pipes.
- Header pipes carry the combined gas flow to the central gas compound.
Because landfill gas is warm and saturated with moisture when it leaves the waste, water condenses inside the pipework as it cools. The system therefore needs:
- Adequate pipe slopes so condensate can drain.
- Low points, traps or sumps where condensate can be collected and removed.
- Materials and joints that can tolerate both gas and liquids over many years.
A set of blowers at the central compound provides the vacuum that “pulls” gas from the wellfield. By adjusting valves at the wells and the blower settings, operators balance the system so that:
- Sufficient gas is captured to minimise emissions and odour.
- Excessive air is not drawn into the landfill, which can cause fires or reduce methane content.
Central gas compound
The gas compound is the hub of the landfill gas system. Here, the collected gas typically passes through:
- Moisture‑separation equipment to remove condensate.
- Filters or basic treatment stages to protect downstream plant.
- Flow‑measurement devices and gas analysers for operational control and reporting.
From this point, the gas is either directed to:
- An enclosed flare, where it is combusted under controlled conditions.
- Energy‑recovery equipment such as gas engines, turbines, boilers or upgrading plant.
Control panels and automation systems at the compound allow the operator to monitor key parameters, respond to alarms and log data for compliance and performance tracking.
Operation, monitoring and optimisation
A gas collection system is not “fit and forget”. The waste mass settles, gas production changes over time, and new cells are added. To keep the system effective, operators routinely:
- Inspect wells and pipework for damage, blockages or signs of air ingress.
- Measure gas flows, pressures and composition at wells, headers and the compound.
- Adjust valve settings and blower vacuum to optimise capture and maintain stable operation.
- Add, relocate or deepen wells and collectors as the landfill evolves.
Good monitoring and balancing help to:
- Reduce odours and visible emissions from the landfill.
- Maximise gas recovery for energy projects.
- Minimise safety risks such as landfill fires or gas migration.
Design considerations for UK and UAE sites
For UK landfills, gas‑collection system design is closely tied to permitting requirements and best‑practice guidance. Systems are expected to cover the full gas‑generating area, provide sufficient redundancy, and be adaptable to future changes in waste composition, regulation and energy markets.
In the UAE, many of the same design principles apply, but there are additional practical considerations such as:
Integration with large waste‑to‑energy plants, where landfill gas may become a secondary energy source rather than the main focus.
Hotter ambient temperatures and higher evaporation rates, which influence condensate management and materials selection.
Different power and gas‑tariff structures, which affect whether flaring or energy‑recovery projects are viable.