Performance and economic analyses of a combined bioreactor for treating odors, volatile organic compounds, and aerosols from a landfill site

Abstract

A full-scale combined bioreactor with a biological aeration zone (BAZ) and a biological filtration zone (BFZ) was adopted to treat odors, volatile organic compounds (VOCs), and aerosols emitted from a landfill site. The BAZ mainly relies on suspended microorganisms that degrade substances with high water solubility, while the BFZ is divided into an acidic biofiltration unit (ABU) and a neutral biofiltration unit (NBU) to further remove remaining contaminants. Average removal efficiencies (REs) of 97.21%, 98.89%, 92.44%, 73.12%, and 81.89% for H2S, NH3, VOCs, culturable bacteria, and fungi, respectively, were achieved during the stable operation period. In particular, the concentrations of water-soluble ions (WSIs), including SO42−, NO2−, NO3−, and Cl− in aerosols, were significantly reduced by the combined bioreactor. The REs and degradation product characteristics for the odors, VOCs, and aerosols in the BAZ and BFZ were different due to different dominant microorganisms. In addition, the economic cost of the combined bioreactor was analyzed considering investment cost, operating cost, and packing material replacement cost, and a sensitivity analysis was performed to determine economically-sensitive parameters. This study clearly demonstrates the low cost and effectiveness of the combined bioreactor to treat exhaust gases containing odors, VOCs, and aerosols from a landfill site.