异养硝化-好氧反硝化菌YZ-12的脱氮性能及其对养殖废水的处理效果

Denitrification performance and aquaculture wastewater treating effects of heterotrophic nitrifying aerobic denitrifying bacteria YZ-12

为获得高效脱氮菌,从南昌县一中型养猪厂曝气池筛选出一株异养硝化-好氧反硝化菌株YZ-12,经过16S r RNA基因序列分析,鉴定其为Klebsiella oxytoca;随后检测了该菌株的硝化和反硝化能力。结果表明,在NH_(4)^(+)-N质量浓度为100 mg·L^(-1)的硝化培养基和NO_(3)^(-)-N质量浓度为400 mg·L^(-1)的反硝化培养基中,NH_(4)^(+)-N去除率在96%以上,NO_(3)^(-)-N去除率在99%以上,无NO_(3)^(-)-N、NO_(2)--N积累。同时,还考察了碳源、氮浓度、C/N、p H、盐度5种单因素对菌株脱氮效果的影响。结果表明,菌株最佳脱氮条件为C/N=10、p H=7、盐度≤10 mg·L^(-1)、NH_(4)^(+)-N质量浓度≤150 mg·L^(-1)、NO_(3)^(-)-N质量浓度≤450 mg·L^(-1)、碳源为蔗糖;用蔗糖将养殖废水C/N调节为10,加入5%菌株进行脱氮处理,灭菌后的养殖废水NH_(4)^(+)-N和NO_(3)^(-)-N的去除率分别为95.15%和99.69%。

To obtain highly efficient denitrification bacteria,a bacterium YZ-12 with heterotrophic nitrification-aerobic denitrification was isolated from an aeration tank of a medium-sized pig factory in Nanchang County.The strain YZ-12 was identified as Klebsiella oxytoca by 16 S rRNA gene sequence analysis.And its nitrification and denitrification abilities were tested.The results showed that the ammonia nitrogen removal efficiency reached above 96%in the nitrification medium with the initial ammonia nitrogen concentration of 100 mg·L^(-1),and the nitrate nitrogen removal efficiency reached above 99%in the denitrification medium with the initial nitrate nitrogen concentration of 400 mg·L^(-1).Meanwhile,the accumulation of ammonia nitrogen and nitrate nitrogen did not occur.In addition,the effects of five factors(including carbon source,nitrogen concentration,carbon to nitrogen ratio,pH,and salinity)on denitrification efficiency of the strain YZ-12 were investigated,respectively.The optimum denitrification conditions were as follows:C/N ratio of 10,pH 7,salinity less than or equal to 10 g·L^(-1),ammonia nitrogen concentration less than or equal to 150 mg·L^(-1),nitrate nitrogen concentration less than or equal to 450 mg·L^(-1),sucrose as the optimal carbon resource.The carbon nitrogen ratio of aquaculture wastewater was adjusted to 10 with sucrose,and 5%strains was added for denitrification,the removal rates of ammonia nitrogen and nitrate nitrogen for sterilized aquaculture wastewater were 95.15%and 99.69%,respectively.