PRACTICAL EXPERIENCES WITH BIOLOGICAL TREATMENT OF ODOR AND VOCS AT POTWS IN USA

A literature study was conducted to compare the feasibility of biofilters and biotrickling filters for the treatment of complex odorous waste gases containing H2S, organic reduced sulfur compounds, and chlorinated and non-chlorinated volatile organic compounds (VOCs). About 40 pilot-plant studies and full-scale applications at wastewater treatment plants and other facilities were reviewed. Operational and performance parameters were summarized in tables for easy reference and for a perspective on the current state of the literature, and to allow comparison between different projects. The survey indicated that both biofilters and biotrickling filters are capable of combining a high H2S and odor removal efficiency with VOC removal. Apart from odor abatement, biological treatment therefore holds promise for reducing the overall toxicity and potential carcinogenicity of waste gases at wastewater treatment plants. VOC removal efficiencies were in general less than those of H2S and odor, although concentrations of individual VOC species were relatively low. This indicates that for effective treatment of complex odorous gases the design and operation should emphasize VOC removal as the rate-limiting parameter.