猪场污水异养硝化-好氧反硝化菌筛选及性能研究

Screening and denitrification characteristics of a heterotrophic nitrification aerobic denitrifier bacterium from sewage on a pig farm

高氨氮含量是猪场污水达标处理的一大难点,传统生物脱氮工艺是在不同的工艺条件下分别进行硝化或反硝化作用,设施成本高且占地面积大,因此并不适合应用于猪场污水的处理。异养硝化-好氧反硝化(HN-AD)菌作为一类能同时进行硝化反应和反硝化反应的细菌,能较好解决硝化和反硝化不能同存一池的问题。本研究以猪场污水处理系统兼性塘中长期处于高氨氮状态下污水、污泥为原材料,筛选具有耐高氨氮能力的开塞利节杆菌(Arthrobacter keyseri)。运用控制变量法测出该菌在温度为30℃,pH=7和转速为120 r/min时菌株生长最佳,36 h后培养液氨氮浓度由起始约110.0 mg/L降至约10.0 mg/L,氨氮去除率显著高于对照组(P<0.05)可达90%以上。此外,外源添加该菌猪场污水处理系统出水端污水的COD、NH4^(+)-N、TP、TN各项指标下降率均高于添加前,其中NH4^(+)-N去除率添加菌液组极显著(P<0.01)高于未添加组近10%,其内部菌群变化相比于其他正常运行的污水处理设施并不明显,但从出水的污染物指标以及部分对水质有一定要求的菌群中可以看出,外源添加的开塞利节杆菌在一定程度上增强了系统的反硝化能力,提高了出水的水质和系统运行效果。

The high ammonia-nitrogen content is a major difficulty in the treatment of pig sewage.The traditional biological nitrogen removal process refers to nitrification or denitrification in different areas of the treatment plant.This process requires high facility cost and large floor area,and is therefore not suitable for treating pig farm sewage.Heterotrophic nitrification-aerobic denitrification(HN-AD)bacterium,as a kind of bacteria capable of simultaneous nitrification and denitrification,may better solve the problem that nitrification and denitrification cannot operate in one pool.In this study,the sewage and sludge samples with high-ammonia nitrogen content in the pig farm sewage treatment system were used as raw materials,and then a high ammonia nitrogen tolerance bacterium,Arthrobacter keyseri was chosen for sewage treatment.We found that the optimal growth conditions for the strain were 30℃,p H=7 and 120 r/min using the variable control method.After 36 h of treatment,the ammonia concentration of the culture solution decreased from about 110.0 mg/L to about 10.0 mg/L.The ammonia-nitrogen removal rate was significantly higher than the control groups(P<0.05),by up to 90%.In addition,the decreasing rates of COD,NH4^(+)-N,TP and TN in the outlet water of the pig farm sewage treatment system were higher than those before the addition treatment.The removal rate of NH4^(+)-N was higher than that of the untreated group,by nearly 10%.The internal flora change was not obvious,compared with the other sewage treatment facilities under normal operation.However,the pollutant indexes of the effluent and some bacteria that had requirements for better water quality indicated that external addition of Arthrobacter keyseri enhanced the ability of denitrification of the studied facility,and improved the water quality of the effluent and the operational effect of the facility.