Silicone hollow fiber membrane bioreactors for mixed aerobic and anaerobic treatment of gas phase toluene and trichloroethylene

Volatile Organic Compounds (VOCs) are common in effluent waste streams from many sectors of industry and low-cost emission control technologies have the potential to mitigate long-term impacts on the environment. Federal Regulations, such as the Clean Air Act and National Emission Standards for Hazardous Air Pollutants (NESHAPS), as well as state regulations are imposing stricter requirements on point-source emissions, with an emphasis on toxic VOCs. Trichloroethylene (TCE) and tetrachloroethylene (PCE), which are toxic VOCs, have been used since the 1920\u27s for a variety of industrial applications like: degreasing, paint and printing operations, as extraction solvents, and for cleaning and drying cleaning. Microbial degradation of many VOC can be facilitated using hollow fiber membrane bioreactors for a fraction of the cost of traditional control methods. Hollow fiber membrane bioreactors can provide mixed aerobic and anaerobic zones necessary for complete mineralization of alkene chlorinated solvents and allow for greater removal capacity for hydrophobic compounds than typical biological processes. In this work, two silicone hollow fiber membrane bioreactors were operated in parallel to develop loading curves for toluene removal and develop biomass for the subsequent degradation of TCE aerobically and anaerobically. The optimal toluene elimination capacity measured for each reactor varied from 55-60 mg m-2 hr-1 and no biotic TCE removal was observed. --Abstract, page iii