1株异养硝化-好氧反硝化细菌DK1的分离鉴定及其脱氮特性

从某反应器活性污泥中分离筛选出1株假单胞菌属(Pseudomonas sp.)细菌,命名为DK1,并对该菌进行脱氮特性研究.在以葡萄糖为碳源,C/N量比为5时,分别以NaNO_3和NaNO_2为氮源,二者的好氧反硝化速率为4.09 mg·(L·h)-1和4.43mg·(L·h)~(-1).以二者同时为氮源脱氮率为100%;此外,菌株DK1具有异养硝化性能,NH_4~+-N平均去除速率为2.32mg·(L·h)-1.缺氧时以NO_2~--N为氮源菌株DK1可将一系列梯度浓度NO_2~--N(约100~300 mg·L-1)在36 h内降为0.当NO_3~--N和NO_2~--N同时存在时,菌株DK1会优先利用NO_3~--N进行反硝化.同时该菌株还具有同步硝化反硝化(SND)性能,可同时去除NH_4~+-N、NO_2~--N或NH_4~+-N、NO_3~--N,30 h内脱氮率分别达95.06%和94.69%.相同时间内在NH_4~+-N、NO_2~--N和NO_3~--N三者均存在时,脱氮效果最佳,达100%.菌株DK1的高效SND及反硝化性能表明其在处理含氮废水方面有一定的潜力和应用价值.

Identification and Nitrogen Removal Characteristics of the Heterotrophic Nitrification and Aerobic Denitrification Bacterial Strain DK1

Nitrogen removal by a newly discovered Pseudomons sp. strain, DK1, isolated from activated sludge was investigated. Using glucose as a carbon source and a n(C)/n(N) ratio of five, batch experiments showed that the aerobic denitrification removal rate was 4.09 mg·(L·h)^-1 and 4.43 mg·(L·h)^-1 with NaNO₃ or NaNO₂, respectively. Completely nitrogen removal was achieved when using these two nitrogen sources. DK1 was also found to heterotrophically remove NH₄⁺ -N at a rate of 2.32 mg·(L·h)^-1 and to carry out anoxic denitrification of a range of concentrations of NO₂^- -N (from about 100 to 300 mg·L^-1) within a maximum of 36 hours of inoculation. In the presence of both NO₃^- -N and NO₂^- -N, DK1 was found to preferentially denitrify NO₃^- -N. Simultaneous nitrification and denitrification (SND) capacity of the DK1 strain was observed when using ammonium and nitrate or ammonium and nitrite and the corresponding nitrogen removal rates reached as high as 95.06% and 94.69% within 30 hours of inoculation, respectively. Ammonium with both nitrate and nitrite resulted in a 100% nitrogen removal within the same time frame. The ability to achieve SND and to denitrify both NO₃^- -N and NO₂^- -N makes the DK1 strain potentially useful for future application in nitrogenous wastewater treatment.