landfill gas collection

To utilize the landfill gas, extraction wells will gather the landfill gas from landfills at first like shown in below. Besides, landfill gas can also be extracted through horizontal trenches instead of vertical wells and both systems are effective at collecting. The figure of the horizontal trenches is attached as Appendix 5. The main collection header may connect to the leachate collection system for condensation collection purpose. And usually, a blower is needed to pull the gas from the collection wells to the collection header and further downstream. Since the landfill gas can increase the global warming greatly, the collection of the landfill gas must be processed carefully. However, 4 to 10 percent of landfill gas will escape the collection system inevitably. Hence, the capture technology still needs improvement to achieve higher capture efficiency.

For further utilization, a treatment system is necessary to remove the impurities, condensate and particulates inside the gas. When the gas is collected for direct use, it can be fuel of boiler, dryer, and process heater as an alternative to natural gas with cheaper price but lower heating value. Or it can go to power infrared heaters to provide power to local greenhouses. As for electricity generation, the landfill gas is usually introduced to a gas turbine or internal combustion engine.

s Flaring. Bristol: Environment Agency. 2002