低温对中试AAO-BAF双污泥脱氮除磷系统的影响

Effect of low temperature on pilot-scale AAO-BAF two-sludge system

以实际城市污水为对象,研究了低温（11~15℃）对处理量约为45m3/d的AAO-曝气生物滤池（BAF）典型双污泥脱氮除磷系统的影响.研究发现,本系统的硝化在受到低温抑制后会在短时间内恢复,而同样环境条件下运行的某水厂AAO系统的硝化却一直受低温抑制.AAO-BAF系统硝化受抑制期间,其缺氧段反硝化吸磷的总量减少,缺氧末段TP浓度从1上升至4mg/L左右,但系统的好氧段可继续完成这部分剩余P的去除.批次试验发现,硝化菌停留时间的长短差异是本系统与AAO系统硝化产生差距的主要原因.在11、16、21、27和32℃下,本系统中活性污泥的厌氧释磷速率分别为6.745、8.378、13.218、11.513、9.726mg TP/（h·g MLSS）;缺氧反应过程中P去除速率分别为1.668、1.892、2.496、2.835、2.976mg TP/（h·g MLSS）,NO3--N的去除速率分别为0.786、1.112、1.761、2.614、3.464mg NO3--N/（h·g MLSS）.

The influence of low temperature（11~15℃） on a two-sludge denitrifying and phosphorus removal system was studied in this experiment, the system is named AAO-biological aerated filter（BAF）, which treats about 45m3 urban wastewater per day. The nitrification of this system recovered from the inhabitation of low temperature in a short time, however, the nitrification of AAO system which is running in the same condition with the AAO-BAF system was inhibited by the low temperature for a long time. The inhibition of low temperature on nitrification leads to the decline of phosphorus uptaking in the anoxic phase of this system, TP concentration in the effluent of anoxic phase rise from 1to 4mg/L, however, its aerobic phase can uptake the surplus phosphorus. The retention time of nitrifying bacteria is the main reason that leads to the difference of nitrification between the AAO and AAO-BAF according to the batch experiments. At 11, 16, 21, 27, 32℃, anaerobic phosphorus release rate of the sludge in the AAO-BAF system was 6.745, 8.378, 13.218, 11.513, 9.726 mg TP/（h·g MLSS） respectively; The phosphorus removal rates during the anoxic reaction was 1.668, 1.892, 2.496, 2.835, 2.976 mg TP/（h·g MLSS） respectively, the NO3--N removal rate was 0.786, 1.112, 1.761, 2.614, 3.464 mg NO3--N/（h·g MLSS） respectively.