Do “Wet Cell” landfill practices increase greenhouse gas emissions?
The use of leachate recirculation and bioreactor methods incorporate liquid management and pumping systems to maintain higher moisture content in the disposed waste mass. These technologies are similar, with the difference being that bioreactors utilize other liquids, in addition to leachate, in the recirculation and are not considered to be bioreactors until the average waste moisture content reaches 40 percent. The reason for the growth of leachate recirculation and, on a much smaller scale, bioreactors, is for landfill owners to save valuable landfill space. A secondary reason is to economically manage leachate. The implementation of bioreactor technologies does accelerate the generation of methane by a landfill. Therefore, bioreactor landfills are required to install and operate LFG collection and control systems earlier than non-bioreactor landfills. According to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for MSW landfills (40 CFR part 63 subpart AAAA),
