The Study On The Treatment Of Odor Gas Containing H₂S And NH₃ By Biofilter Combined System

Based on the investigation and analysis of odor gas , main origin of odor pollution, ozone fundamental component and harm, and the technique of sewage profession commonly used deodorizes were introduced, we selected hydrogen sulfide and ammonia as the target pollutants. Biofilter combined system(acidic washer- biofilter-alkali washer )for treating these pollutants was investigated, the primary biological law, the absorption of union the chemical and physical law of odor gas containing hydrogen sulfide and ammonia were emphatically studied. The research aimed at the enrichment and training of bacteria ,understanding parameters affecting bioreactor performance and biodegradation mechanism of pollutats. Such system can offer a new technique to purify complex gases containing many components such as the odorous gas , thus there are great market application prospects. Based on the results of these investigations, the major conclusions are shown as following:(1)The microorganism for removing hydrogen sulfide and ammonia can be domesticated from wastewater treatment plants ,the time of training and domesticating needs about two weeks.(2) The method of removing sludge was adopted for the formation of the bio-film in the biofilter which filled with flexible fibre , which has a good enrichement after hanging for one week;Zeolite is an excellent ion exchanger and adsorbent, besides, zeolite is the good biological carrier. The SBR process using zeolite as the bio - carrier in the treatment of wastewater containing nitrogen was studied in this paper ,As the results demonstrated, SBR process had good performance with the shortened time and the sludge has better settling properties. The biofilter and SBR started up quickly, which had good performance running after running for one week,they can romoving 85.7% sulfur and 92% nitrogen respectively.(3) The method of biofilter for treating odor gas containing hydrogen sulfide was investigated. The results suggested that H2S removal efficiency was higher than 98 % when the inlet flow of H2S was 5 L/min, the gas retention time was 60 s, the mass concentration of inlet H2S was below 130 mg/m3, and the maximum volumetric loadings for H2S treatment was below 188.2 g/(m3·d). The remain H2S was absorbed entirely by alkali washer ,the most H2S was removed at the middle and bottom of the biofilter ,sulfate was one of the outcome ,which can decrease the pH, The decrease of pH did not affect the removing efficiency of hydrogen sulfide.(4) The study on the treatment of odor gas containing H2S and NH3 by biofilter combined system(acidic washer- biofilter-alkali washer ):It has a good removing efficiency of H2S and NH3 when the inlet flow of NH3 was 10 L/min, the mass concentration of inlet NH3 was below 100 mg/m3, spray flow of circulating liquid was above 3 L/h, the inlet flow of H2S was below 5 L/min, the mass concentration of inlet H2S was below 80 mg/m3,and the exhaustion of hydrogen sulfide and ammonia could both reach to the primary discharge standard . The SBR process using zeolite as the bio– carrier could remove 112mg/L nitrogen from circulating liquid above 97.7% which could reach to the discharge standard.(5) The reactor could recover quickly in a short time of shock loading. Biofilters restart-up time was 8h,16h,36h,48h after 3 d, 7d,15d,30d of idle phase.