微好氧EBPR系统污泥的同步脱氮及吸磷特性

Simultaneous Nitrogen Removal and Phosphate Uptake Properties of EBPR System with Micro Aeration

反硝化聚磷菌在污水同步脱氮除磷,尤其有限碳源污水的处理,具有广阔的应用前景,而亚硝酸盐型反硝化除磷因仅将硝化进行到亚硝酸盐阶段可进一步降低污水的处理费用.采用一个2L的SBR反应器,通过控制好氧段溶解氧并调整NO_2^-投加时间,在EBPR系统内成功富集了兼具稳定除磷和脱氮性能的污泥,用以考察污泥的缺氧吸磷特性及同步脱氮能力.结果表明:微好氧条件下(DO=0.2mg/L)反应器具有很高的氮、磷去除性能,系统内的NH4^+-N能100%硝化且无NO_X^--N的积累,出水磷浓度低于0.5mg/L.此外,该除磷污泥能利用亚硝酸盐进行缺氧吸磷,NO_2^--N投加浓度为10mg/L和50mg/L时的最大比吸磷速率分别为最大比好氧吸磷速率的44.9%和87.2%.批式试验证明:NH4^+-N通过同步硝化反硝化而非厌氧氨氧化去除,但微好氧条件下氨氧化菌和亚硝酸盐氧化菌活性均较聚磷菌差,因此,低DO条件下,吸磷总是优先于氨氧化进行.

Denitrifying polyphosphate accumulating organisms （DNPAOs） are very promising for simultaneous nitrogen and phosphorus removal, especially for organic carbon limited wastewater treatment. Nitrite type denitrifying phosphorus removal can further lower the operational cost of wastewater treatment because ammonia is only nitrified to nitrite. In this study, a 2-liter sequen-cing batch reactor （SBR） was operated to achieve simultaneous nitrification and denitrification as well as phosphorus removal （SNDPR） performance by controlling dissolved oxygen （DO） during aerobic phase and adjusting the time of nitrite addition in the reactor. The characteristic of anoxic phosphorus uptake coupled with nitrogen removal of the enhanced biological phosphorus removal （EBPR） system was also investigated. The results showed a high phosphorus removal efficiency （phosphate in effluent〈C〇 . 5 mg/L） and complete ammonia oxidation without accumulation of ni-trite and nitrate under low dissolved oxygen （DO） concentration （controlled at 0. 2 mg/L）. Regu-lar operation and batch test demonstrated that the sludge was capable of using nitrite as electron acceptor to take up phosphate, and the maximum specific denitrifying phosphorus uptake rates of adding 10 mg/L and 50 mg/L NO2^--N to maximum specific aerobic phosphorus uptake rate were 44. 9% and 87. 2 % , respectively. Batch tests suggested that ammonia nitrogen was removed by simultaneous nitrification and denitrification rather than anaerobic ammonium oxidation, whereas both ammonia oxidized bacteria （AOB） and nitrite oxidized bacteria （NOB） were observed to be less active than polyphosphate-accumulating organisms （PAOs） in micro aeration environment. As a result, phosphate uptake activity was always prior to ammonia oxidation under low DO con-dition.