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REMOVAL OF ODOROUS COMPOUNDS IN WASTEWATER BY USING ACTIVATED CARBON, OZONATION AND AERATED BIOFILTER Yonwoo Hwang, Tomonori Matsuo, Keisuke Hanaki and Noriyuki Suzuki Department of Urban Engineering, University of Tokyo 7-3-I Hongo, Bunkyo-ku. Tokyo 113, Japan
AbstractActivated carbon, ozonation and aerated biofilters were applied to eliminate odor-causing compounds that occur in wastewater and effluents from the activated sludge process. Odorous organics used in this experiment were sulfur containing odorous compounds which include carbon disulfide, methyl mercaptan, dimethyl sulfide and dimethyl disulfide, and nitrogen containing compounds such 45 ammonia, trimethylamine, dimethylamine and n-propylamine. The removal of sulfur containing odorous compounds by activated carbon, was very effective compared to nitrogen containing compounds under the same experimental conditions. Sulfur containing substances were oxidized with ozone rapidly, while the reaction of low aliphatic amines with ozone occurred slowly. Methane sulfonic acid was converted from methyl mercaptan through dimethyl disulfide by ozonation. Ammonia and trimethylamine was converted to nitrate and nitromethane by ozonation, respectively. More than 50% of the sulfur and nitrogen containing malodorants were removed by acclimated microorganisms in an aerated biofilter at about 30 mm of hydraulic retention time. Neither carbon disulfide nor dimethyl disulfide were removed at all in the biofilter without aeration. Conclusively, the aerated biofilter was the most acceptable process for eliminating sulfur and nitrogen containing odorous compounds in wastewater as it produced none of the oxidized organics noticed with ozonation, and it had an equally high removal efficiency for both sulfur and nitrogen containing odorous compounds.
ConclusionActivated carbon adsorption, ozonation and aerated biofilter were applied for removal of odor-causing compounds that occur in wastewater and the treated effluents from the activated sludge process. The removal of sulfur containing odorous compounds by activated carbon was very effective compared with nitrogen containing compounds under the same experimental conditions. Sulfur containing substances were oxidized with ozone rapidly, but the reaction of the low aliphatic amines with ozone occurred slowly under similar conditions. Ozonation produced methane sulfonic acid from methyl mercaptan through dimethyl disulfide. Ammonia and trimethylamine were each converted by ozonation to the oxidized products, nitrate and nitromethane, respectively. More than 80% of sulfur or nitrogen containing malodorants were removed by acclimated rnicroorganisms in an aerated biofilter. Under anaerobic conditions in the same reactor, however, carbon disulfide and dimethyl disulfide were not removed at all. dimethyl sulfide and amines were removed in both aerobic and anaerobic conditions. Additionally, the aerated biofilter was the most acceptable process for the removal of the representative dissolved malodorous compounds containing nitrogen or sulfur in wastewater, because it produced no oxidized organics, unlike ozonation, and it was effective in removing both sulfur and nitrogen containing odorous compounds. Contact Ozone Solutions for more information on this application. | |||||
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