Biofiltration - Acrylonitrile Removal Success Story

Biofiltration is being used to treat more and more waste streams but there is little information available on the ability of biofilters to treat individual volatile organic compounds (VOC). This paper provides data showing the effectiveness of biofiltration on treatment of acrylonitrile and hydrogen sulfide.The INEOS ABS plastics manufacturing facility is near Cincinnati, Ohio. Wastewater from the acrylonitrile-butadiene-styrene (ABS) manufacturing process is collected and treated in an on-site 157 m3/hr (1 MGD) activated sludge wastewater treatment plant (WWTP) prior to discharge to the Ohio River.INEOS wished to reduce odor and acrylonitrile emissions from the facility and contracted an investigation into odor and acrylonitrile emission sources from the WWTP. This investigation was followed by a pilot project to test the effectiveness of biofiltration on this air stream and subsequent phased construction projects.The initial source testing showed process emissions contained hydrogen sulfide (H2S), acrylonitrile (AN), butadiene, styrene, ethyl benzene, methyl ethyl ketone (MEK), and many other compounds in lower concentrations. INEOS' main focus was on AN and H2S removal. The pilot test results showed biofiltration would provide excellent removal efficiencies for H2S, and AN, and achieve marginal removal efficiencies for several other compounds. The pilot test results led to a full-scale biofilter design and construction of a 10,500 cfm full-scale biofilter with a coarse blend of carefully screened organic media, designed for long life and low pressure drop, was ultimately constructedPerformance testing was conducted on the full-scale biofilter and the results indicate essentially 100% removal of AN and H2S.This paper provides real-world test results and mass removal efficiencies that will be beneficial to owners and engineers who are evaluating the appropriateness of using biofiltration to treat specific volatile organic compounds.