India’s landfills hold more than just refuse. They could hold the promise of an alternative, renewable fuel source that’s much easier on the environment than conventional fuels such as oil, natural gas and coal.
The Texas Transportation Institute (TTI) is currently leading an effort to evaluate the feasibility of using the gases generated by Maharashtra, India, landfills as a fuel source for their refuse trucks and municipal buses. The U.S. Environmental Protection Agency (EPA), in partnership with the National Environmental Engineering Research Institute (NEERI), Mack Trucks Inc. and the Texas State Energy Conservation Office (SECO), is conducting the study.
The goal is to use landfill gas as a liquefied natural gas (LNG) fuel source for heavy-duty refuse trucks. The process involves converting methane gas, which is naturally produced by landfills, into LNG using a sophisticated chemical process. This process has been used with success in a pilot application in Burlington, New Jersey.
“Landfills in India are very different from the sanitary landfills in the U.S. in that they are open pits without any gas collection systems,” says Joe Zietsman, TTI associate research engineer and director of the Center for Air Quality Studies. “In the sanitary landfills here [in the U.S.], we cover them and are able to recover the trapped landfill gas using underground piping systems.”
The researchers are working on a design to capture the escaping methane by first gathering the refuse into a large pile, covering it with a thin membrane layer and finally collecting the gas using pipes inserted from above, as opposed to the conventional underground systems used in the U.S.
“Methane is a greenhouse gas that remains in the atmosphere for more than 10 years. It is also 20 times more effective as a greenhouse gas than carbon dioxide,” says Zietsman. “To be able to recycle this harmful gas into a clean-burning fuel is a win-win proposition for everyone.”