Controlling Volatile Organic Compound Emissions Using Biological Techniques at the Joint Water Pollution Control Plant

Eight pilot-scale biological systems including six biotrickling filter systems and two biofilter systems were tested for volatile organic compound (VOC), volatile sulfur compound (VOSC), and odor removal performances at the Districts' Joint Water Pollution Control Plant in Carson, California. The pilot systems used different media including lava rock, polyurethane foam cubes, spent carbon, polypropylene open cell sheets, wood chips and finished compost, and a proprietary engineered media. The pilot systems were placed downstream of an existing full-scale biotrickling filter system that was designed to remove hydrogen sulfide. The pilot systems were operated under neutral pH conditions to encourage the growth of heterotrophic microorganisms that utilize VOCs as the carbon source. Monitoring activities, which included field VOC measurement by a photoionzation detector (PID) and laboratory analyses of VOCs and VOSCs by GC/MS, were routinely conducted. Odor panel was used to determine odor removal performance of the pilot systems.Results from the study indicated that biotrickling filters using the polyurethane foam media and the two biofilters, one using wood chips and finished compost and the other using a proprietary engineered media, achieved the highest removals of VOC, VOSC, and odor. Removal efficiency in general improved with longer empty bed retention time. VOC, VOSC, and odor removal performances achieved by the biofilter using the proprietary engineered media, at 20 to 30 seconds EBRT, were comparable to those of the existing full-scale activated carbon units.