Enhancing Landfill Gas Collection through Bioreactor Phasing

摘要

In addition to its other benefits, bioreactor landfill operation enhances waste stabilization, resulting in greater gas generation over a shorter time. The traditional method of collecting gas via vertical wells has limitations in bioreactors and is typically not sufficient to collect landfill gas efficiently. Gas recovery can be enhanced, however, by integrating gas collection systems into the landfill design and operations during the active life of the landfill cell. Several strategies for achieving this comprehensive approach are presented to increase gas collection efficiency during the early stages of operation.rnThe leachate collection and removal system and/or gas collection pipes buried in the sand drainage layer below the waste can be used to collect gas as soon as waste is in place. Gas collection can be facilitated by horizontal wells placed within the waste as the landfill is filled. The wells may also be used as components of a bioreactor liquids addition system if phased properly. Using temporary liners on completed slopes allows surface seepage to be intercepted and seals the surface of the landfill, reducing air intrusion into the gas collection system. Another desirable component of a bioreactor is a toe drain to collect surface seepage, which may be tied into the gas collection network. The results of the comprehensive gas collection strategies implemented from the beginning of the landfill filling are higher gas collection efficiency and greater recovery, which will help keep the landfill in regulatory compliance and increase the beneficial use. Earlier and more efficient gas collection also has implications for obtaining carbon and renewable energy credits for the site.