Anaerobic biofiltration of landfill gas

Abstract

This study involved the treatment (via a pilot biofilter) of landfill gas containing volatile organic compounds (including sulphur and chlorinated hydrocarbons) and determining the removal efficiency based on optimum pH, concentrations of volatile organic compounds (VOCs), base gases, pressure drop and inlet biofilter flow rates. Also measured and analysed was the reactor Empty bed residence time, and amount of nutrients added to the biofilter. The biofilter reactor was designed to mimic industrial biofilters with parameters chosen to provide optimum removal efficiencies and consisted of a two biofilters arranged in series. The ultimate focus was to design a biofilter that removes the unwanted volatile organic compounds from the high energy value of methane compound in the biofilter and thereby arriving at treated gas containing methane and oxygen for utilization in internal combustion engines. In this study, hydrogen sulfide was entirely removed, achieving a removal efficiency (RE) of 100%. The other target constituents—vinyl chloride, benzene, toluene, n-octane, and n-decane—also demonstrated significant reductions, with removal efficiencies ranging from 20% to 64%, 64% to 80%, 30% to 60%, 55% to 65%, and 45% to 66%, respectively. Biofiltration was chosen over conventional treatment methods, such as catalytic and thermal oxidation technologies, due to the biofilter's simpler construction and cost-effectiveness. The functional values of the biofilter are an Empty Bed Residence Time (EBRT) exceeding 30 seconds and a biofilter medium pH range of 4 to 11.