INNOVATIVE BIOTRICKLING FILTER TECHNOLOGY FOR TREATING ODOROUS EMISSIONS

Air emissions from manufacturing operations and waste treatment plants often consist of a combination of odors and volatile chemicals. Odors are inorganic or organic compounds, which are present in low concentrations, typically 20 ppmv or less, which have an unpleasant odor. While several U.S. EPA and OSHA regulations govern the emission of hazardous volatile chemicals in the ambient air and in the workplace, odor emissions are often a major nuisance to the plant workers and surrounding communities.Major advantages of biological treatment are ambient temperature and pressure operation, no generation of toxic by-products requiring disposal or further treatment, and favorable economics. Disadvantages associated with biological treatment are upsets due to inactivation of active microbial cultures, and lack of adequate knowledge to operate the process at peak capacity and performance level.In this paper, several issues regarding the use of synthetic support media in biotrickling filters will be addressed: (1) Pretreatment of the gas required to meet the requirements of biotreatment; (2) Effect of the design of the synthetic support media and its characteristics; (3) Impact of liquid flow rate on destruction efficiency; (4) Methodology of introducing nutrients into the biotrickling filter; and (5) Overall investment and operating costs of the biotrickling filter technology.Two case studies will be presented in context of the above issues to illustrate their importance: (1) Treatment of sulfide odors (hydrogen sulfide, mercaptans, etc.) in compost and synthetic media biofilters; and (2) Biotreatment of organic odors from the Zimpro™ sludge conditioning process.Results presented in this paper will allow wastewater treatment plant operators, industrial plant managers and other practitioners to evaluate the applicability of biotrickling filter technology for treating a wide variety of odorous emissions.