Enrichment And Preservation Of Low Temperature Ammonia Oxidizing Bacteria And Its Application In Urban Domestic Sewage

Temperature is one of the key factors in limiting nitrification ability of nitrifying bacteria.Sewage plants generally have low water temperature in winter of north city of china,and biological activity of nitrifying bacteria is limited at such a low temperature( <15℃),especially ammonia oxidizing bacter is more sensitive to temperature.A lot of sewage treatments use traditional activated biological method,ammonia nitrogen can not discharge standards in the actual operation in winter. Adding low temperature ammonia oxidizing bacteria is a kind of better method is an ideal method to solve this problem. This is related to the subject of this study—the low temperature ammonia oxidizing bacteria enrichment culture. Low temperature ammonia oxidizing bacteria are a variety of microorganisms that can maintain high activity and strong ammonia oxidizing ability at low temperature. The technology of ammonia oxidizing bacteria enrichment culture is studied in this paper. Various factors effecting on the nitration of low temperature ammonia oxidizing bacteria are studied. Technology for the enrichment culture of ammonia oxidizing bacteria in low temperature is studied.The practical test and analysis of the application of the enrichment culture of low temperature ammonia oxidizing bacteria in urban domestic sewage in winter is studied. The main results are as follows:1、Using Q ingdao sewage treatment plant aeration tank activated sludge for low temperature inorganic pure culture with high concentration of ammonia nitrogen,and in a certain petiod of time we can get based culture that ammonia oxidizing bacteria is the main bacteria culture.The nitrification intensity of the system was increased from minimum value 2.82NH4~+-N/(L·d)to 154.6 NH4~+-N/(L·d),and the nitrification intensity increase by 54.82 times.2、The influence of ammonia nitrogen concentration, p H value, temper ature and COD on the activity of ammonia oxidizing bacteria in low temperature ammonia oxidizing bacteria are studied. When the ammonia nitrogen concentration increased to 300mg/L, the nitrification intensity reached the maximum of 132 NH4~+-N mg/(L·d). When p H is about 8, ammonia nitrogen removal efficiency of ammonia oxidizing bacteria was the highest. When the temperature reachs 30℃, the ammonia oxidation rate reachs 12 mg N H4+-N/(L·h), which is 2.96 times more than when the temperature is 15 ℃. The enrichment of low temperature ammonia oxidizing bacteria’s nitrification intensity decreased with the increase of COD concentration in a linear manner. When COD concentration increased to 400mg/L, the nitrification intensity is only 30.5 mg NH4~+-N/(L·d), which is 3.59 times lower than that of non COD enrichment.3 、 Continuous subculture is the best method for the enrichment culture of ammonia oxidizing bacteria in low temperature.4、The experiment selected the Dragon K ing River city sewage treatment plant aeration tank of the sewage treatment plant to strengthen the biological effect of ammonia. Used in the test of low temperature nitrifying bacteria a total of four, respectively is the enrichment of low temperature ammonia oxidizing bacteria named for agent A, Beijing agent company’s low temperature nitrifying bacteria D, and from Shanghai two low temperature nitrifying bacteria agents B and C. At the temperature of 0-5℃ strengthening effect of ammonia agent on the Dragon K ing River sewage plant biological removal is not obvious.5、When the temperature control in the working condition(8~10℃), and the enrichment of low temperature nitrifying bacteria A, the Beijing some agents of the company low temperature nitrifying bacteria D, Shanghai a company of nitrification B bacteria and nitrifying bacteria C, nitrification teams are 0.483 mg NH4~+-N/(L·h), 0.567 mg NH4~+-N/(L·h), 0.476 mg NH4~+-N/(L·h), 0.476 mg NH4~+-N/(L·h). The best removal effect of ammonia nitrogen at low temperature D bacteria, nitrification intensity was 0.567 mg NH4~+-N/(L·h). Under the working condition of 12 h, COD removal rate of control group was 91%, nitrifying bacteria group A COD removal rate was 89.5%, nitrifying bacteria group B COD removal rate was 67.7%, nitrifying inoculum C COD removal rate was 72.5%, nitrifying bacteria D COD removal rate was 68%. The enrichment culture of ammonia oxidizing bacteria enriched by low temperature ammonia oxidizing bacteria is more obvious, and has little interference to indigenous bacteria. By further study, the enrichment of low temperature ammonia oxidizing bacteria can be applied to practical applications.