Study of Biological Reactors for Control of Odor, VOC and Toxic Emissions from Wastewater Treatment Plants

An experiment was performed to assess the use of biological reactors to treat off-gases from publicly owned treatment works (POTWs) containing low concentrations of hydrogen sulfide (H 2 S) and volatile organic compounds (VOC). Bench- and pilot-scale biofilters with organic and inorganic media beds were operated under varying pH conditions and retention times. A pilot-scale biotrickling filter was also operated under similar conditions for comparison with the biofilter technology. Results demonstrated that the granular activated carbon (GAC) and yard waste compost (YWC) biofilters performed optimally (removal of >99% H 2 S and >65% VOCs) at 17 and 70 second retention times, respectively. The effects of declining pH on contaminant removal were small. The pilot-scale biotrickling filter, operating at a retention time of 20 seconds, was similar to the GAC biofilter in odor removal (>99% H 2 S), but VOC removal was lower (50% VOCs).