Tsuneda Satoshi, Nagano Tatsuo, Hoshino Tatsuhiko, Ejiri Yoshihiro, Noda Naohiro, Hirata Akira
Department of Chemical Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku-ku, Tokyo 169-8555, Japan.
Water Res. 2003 Dec;37(20):4965-73. doi: 10.1016/j.watres.2003.08.017.
Since nitrification is the rate-determining step in the biological nitrogen removal from wastewater, many research studies have been conducted on the immobilization of nitrifying bacteria. In this research, granulation of nitrifying bacteria in an aerobic upflow fluidized bed (AUFB) reactor in a nitrification process for inorganic wastewater containing 500 g/m(3) of NH(4)(+)-N was investigated. It was observed that spherical, pseudocubic and elliptical granules with a diameter of 346 microm were produced at the bottom of the reactor after 300 days. Denaturing gradient gel electrophoresis analysis revealed that Nitrosomonas-like bacteria were the dominant ammonia-oxidizing species in the granules. Many colonies of Nitrosomonas-like bacteria were found in the outer part of the granules based on the spatial distribution analysis by fluorescence in situ hybridization. By stepwise reduction of the hydraulic retention time, the ammonia removal rate of the AUFB reactor containing these nitrifying granules finally reached 1.5 kg-N/m(3)/day. Results suggested that the use of granules realizes the retention of a large amount of nitrifying bacteria in the reactor, which guarantees a highly efficient nitrification.
由于硝化作用是废水中生物脱氮的限速步骤，因此已经开展了许多关于硝化细菌固定化的研究。本研究考察了在含有500 g/m(3) NH(4)(+)-N的无机废水硝化过程中，好氧上流流化床（AUFB）反应器中硝化细菌的颗粒化情况。观察到300天后在反应器底部产生了直径为346微米的球形、准立方体形和椭圆形颗粒。变性梯度凝胶电泳分析表明，颗粒中类似亚硝化单胞菌的细菌是主要的氨氧化菌。基于荧光原位杂交的空间分布分析，在颗粒外部发现了许多类似亚硝化单胞菌的菌落。通过逐步缩短水力停留时间，含有这些硝化颗粒的AUFB反应器的氨去除率最终达到1.5 kg-N/m(3)/天。结果表明，颗粒的使用实现了大量硝化细菌在反应器中的保留，从而保证了高效硝化作用。
