低溶解氧污泥微膨胀的发生及脱氮除磷效果优化

采用SBR工艺以缺氧/好氧运行模式处理实际生活污水,在常温条件下通过降低溶解氧诱发活性污泥微膨胀,使污泥的容积指数(SVI)维持在150～220mL/g之间.研究了低溶解氧污泥微膨胀现象的发生和诱因微生物的生长,并对污泥微膨胀状态下系统的脱氮除磷效果进行优化.结果表明,常温条件下诱发污泥微膨胀的丝状菌主要有M.parcicella、0803型和H.hydrossis,其中M.parcicella为优势丝状菌,在丝状菌中所占比例最大.研究还发现,在低氧运行期间SBR出水正磷酸盐明显降低,COD略有升高但影响不大,但氨氮去除率明显下降,由95%以上下降到65%.通过采用厌氧/好氧/缺氧的运行模式:瞬间进水→厌氧搅拌(0.75h)→曝气(5h)→缺氧搅拌(2.25h)→静沉、排水(1h),氨氮和总氮的去除率均达到95%以上,出水总氮5mg/L,同时,PO43--P去除率达到95%以上,实现了低溶解氧污泥微膨胀系统高的脱氮除磷效率.

Induction of Low Dissolved Oxygen Limited Filamentous Bulking and Optimization of Nitrogen and Phosphorus Removal

Actual domestic sewage was treated by SBR process operating in Anoxic/Oxic pattern. Limited filamentous bulking was induced by low dissolved oxygen at normal temperature, and SVI was maintained 150-220 mL/g. Occurrence of limited filamentous bulking and growth of microorganism were researched, as well as optimization of nitrogen and phosphorus removal. Results showed that filamentous bacteria that led to limited filamentous bulking were H. hydrossis, 0803 type, and M. parcicella, which were the dominant filamentous bacteria by the biggest percentage. It was discovered that during phase of low dissolved oxygen, removal rate of NH4(+) -N decreased significantly, from above 95% to 65%, with obviously less PO4(3-) -P and a little higher COD in effluent. Removal rates of NH4(+) -N and TN were greatly improved to above 95% by new operating pattern of Anaerobic/Oxic/Anoxic: transient inlet --> anaerobic stir (0.75 h) --> aeration (5 h) --> anoxic stir (2.25 h) --> settling, drainage (1 h). So efficient, simultaneous removal of nitrogen and phosphorus was realized in system of low dissolved oxygen limited filamentous bulking.