Landfill Gas Utilisation

In 2004, ECO designed and constructed a landfill gas processing plant at the North East New Territories (NENT) landfill. By separating carbon dioxide from landfill gas through Pressure Swing Absorption (PSA), the proportion of methane in the landfill gas can be increased from 50% to 85%. Some organic substances in rubbish decompose and produce significant amount of landfill gas (unconventional gas), which can aggravate the greenhouse effect if emitted directly into the air. On the other hand, treated landfill gas can be converted into clean energy and utilised as fuel for production of town gas. Treated landfill gas, or synthetic natural gas (SNG), is transported to Towngas’ production plant in Tai Po via a pipeline and utilised as fuel for town gas production.

The treatment plant started operation in 2007, with a peak supply of SNG from landfill gas at 8,000 m3 per hour. As a result, the consumption of naphtha at the town gas production plant in Tai Po can be reduced by 40,000 tonnes per annum, reducing carbon dioxide emission up to 135,000 tonnes per annum.