嗜盐污泥处理高盐生活污水的短程硝化及其诱因辨析

本研究采集入海口河底泥发展嗜盐活性污泥处理高盐生活污水,在SBR工艺连续运行的120d里取得了稳定的短程硝化.为了确定嗜盐污泥短程硝化的成因,研究基于淡水污泥短程硝化理论系统地分析了pH、游离氨(FA)、温度、溶解氧(DO)和曝气时间等关键工艺参数对嗜盐硝化系统内短程硝化的贡献.试验结果表明,嗜盐硝化系统最适宜盐度范围为10—61g/L,最佳pH范围为7.5—9.尽管盐度、温度对氨氧化菌(AOB)和亚硝酸氧化菌(NOB)的活性有一定的影响,但在测试的温度和盐度范围内AOB的活性始终高于NOB的活性.荧光原位杂交(FISH)技术分析硝化种群结构表明AOB是系统优势生长的主要硝化菌群.嗜盐系统内短程硝化可能和接种的天然环境内的河底泥内NOB数量少而且代谢亚硝酸速率缓慢有关.

Factors Contributing to Short-cut Nitrification in Halophilic Activated Sludge Treating Highly Saline Domestic Wastewater

Halophilic activated sludge was developed by seeding with sediment of the estuary to the sea.During 120d operation,stable short-cut nitrification was achieved in SBRs treating saline domestic wastewater containing 30±2g/L salts.Based on the short-cut nitrification theory of fresh activated sludge,this study evaluated some key process factors possibly contributing to nitrite accumulation such as pH,free ammonium(FA),temperature,dissolved oxygen(DO)and aeration time.The results showed the optimal pH and salinity of halophilic activated sludge was 7.5—9g/L and 10—61g/L,respectively.Aeration time and FA was not the reasons inducing high nitrite accumulation.Salinity and temperature have impact on both the ammonium oxidizing bacteria(AOB)and the nitrite oxidizing bacteria(NOB).However,the activity of halophilic AOB remained higher than halophilic NOB during the experiment.Fluorescence in situ hybridization(FISH)for visualizing nitrification community of the sediments and the halophilic activated sludge showed that AOB was the dominant nitrifiers in the both biological systems.The high nitrite accumulation in halophilic activated sludge may be owed to two reasons,one is that halophilic AOB has higher substrate degrading rate than that of halophilic NOB,the other is that the dominant bacterial population is halophilic AOB other than halophilic NOB.