Strengthening Biotrickling Technology for Deep Treatment of Odor Gas in Large Urban Sewage Treatment Plants

To solve the problem that the odor pollution of urban sewage treatment plants is becoming more and more serious and the conventional deodorization technology is difficult to remove the malodorous gas, an integrated biotrickling filter with a microbial activity promoter was used to treat H₂S from a municipal wastewater treatment plant. The treatment performance was studied, and the influencing factors of the process were also investigated. Based on a large amount of research data, relevant design parameters guidance suggestions were put forward. Results show that when the imported odor air volume is 3 000 m³/h and the imported H₂S concentration is in the range of 152-304 mg/m³, the empty bed residence time (EBRT) is only 8.6 s, the H₂S removal rate of the enhanced biotrickling filter tower can reach 99.9%, and the deodorizationload (as H₂S) can reach up to 62 g/(m³·h) and above. The enhanced biotrickling filter with biological promoters can shorten the acclimation period of microorganisms by about 60% and operate stably for a long time at very low pH (pH≤1.5). Taking an urban sewage treatment plant with an imported H₂S concentration of 180 mg/m³ as an example, the H₂S removal rate of the enhanced biotrickling filter can reach 99.9% when the EBRT is designed only for 17 s. The overall area and volume of the equipment can be also reduced by 30%-50%, which provides a reference value for the practical application of biotrickling technology.