污水处理厂三株反硝化菌的优选与性能研究

Research on Denitrification Characteristics of Three Denitrifier Bacteria Isolated from Wastewater Treatment Plants

采集某城市污水处理厂污泥,通过极限稀释法和平板划线法,在优选反硝化菌富集培养基Ⅰ上得到3株反硝化菌LG1、LG2和LG3,经初步鉴定属芽孢杆菌。通过OD600的测定,绘制菌株LG1、LG2和LG3的生长曲线。通过测定模拟污水中投入LG1、LG2和LG3后水中NO3--N和NO2--N的浓度变化,发现LG3更有利于反硝化反应的进行,确定为最优反硝化菌。通过正交试验,研究pH、温度以及DO、反应时间4种不同因素对菌株LG3反硝化速率的影响。结果表明,菌株LG3的最大反硝化速率可达24.46 mg/(L.h);对菌株LG3反硝化速率的影响次序为培养时间>培养温度>pH;对应的最优条件为:培养时间14 h,温度35℃,pH为7.5。

By limiting dilution assay and flat crossed seperation, three denitrifier bacteria named LG1, LG2 and LG3, which isolated from activated sludge drew from city wastewater treatment plants, were cultured in optimum culture medium Ⅰ . It was identifieated that they were all Bacillus. Their growth curves were drawn by OD600. LG1, LG2 and LG3 were used in artificial city wastewater separately and concentration of NO-3- -N and NO2- -N were metered in 28 hours every four hours. The resultion showed that LG3 was the best. Orthogonal experiments were designed to analyze that how pH, temperature, DO and time of denitrification decided on denitrification rate of LG3. The conclusion indicated that the mixmum denitrification rate of LG3 was up to 24.46 mg/（L· h）. For LG3, the most influencing factor on denitrification rate was time, and then was temperature and pH,and it＇s best condition was： time was 14 h ,temperature was 35 ℃ , and pH = 7.5.