SNAD工艺在不同间歇曝气工况下的脱氮性能

Nitrogen removal performance of the SNAD process under different intermittent aerobic conditions

探讨了城市污水SNAD生物膜反应器在高溶解氧工况下的脱氮性能.SBR反应器以城市生活污水为进水,反应器内放置鲍尔环生物膜载体,控制温度为30℃,采用间歇曝气方式,曝气阶段曝气量为500L/h,溶解氧浓度达5mg/L.阶段1控制曝气和非曝气时间都为20min,生物膜的NOB活性较低,反应器具有良好的脱氮性能.反应器的总氮平均去除率和出水总氮浓度平均值分别为89%和llmg/L.阶段2、阶段3和阶段4研究了曝气时间对反应器脱氮性能的影响.曝气时间对生物膜的厌氧氨氧化活性影响较小,对生物膜的NOB活性影响较大.阶段3控制曝气时间为60min,生物膜的NOB活性较低,反应器的总氮平均去除率和出水总氮浓度平均值分别为83%和14mg/L.阶段4控制曝气时间为160min,生物膜的NOB活性较高,反应器的总氮平均去除率降低至50%,出水总氮浓度平均值为35mg/L.

The simultaneous partial nitrification,anammox and denitrification(SNAD)process for treating domesticwastewater was investigated under high dissolved oxygen(DO)concentration.Intermittent aerobic condition wasoperated in a sequencing batch reactor(SBR)with the air flow rate of500L/h at30℃.The DO concentration was up to5mg/L.Domestic wastewater was used as influent and Kaldnes rings were used as biomass carriers.In phase1,the reactorwas operated with the aerobic time and non-aerobic time of both20min.As a result,the biofilm performed low nitriteoxidizing bacteria(NOB)activity and the reactor achieved high nitrogen removal performance.The average totalinorganic nitrogen(TIN)removal efficiency reached89%with the average effluent TIN concentration of11mg/L.Besides,the effect of the aerobic time on the SNAD biofilm reactor performance was evaluated during phase2,phase3and phase4.The results showed that the length of aerobic time played a little effect on the anammox activity of the SNAD biofilm,while the NOB activity was largely affected by the length of aerobic time.In phase3,the aerobic time was controlled at60min.As a result,the biofilm performed low NOB activity and the reactor achieved high nitrogen removal performance.The average TIN removal efficiency reached83%with the average effluent TIN concentration of14mg/L.The aerobictime of phase4was controlled at160min.On the contrary,the biofilm performed high NOB activity and the reactorperformed poor nitrogen removal performance.The average TIN removal efficiency decreased to50%with the averageeffluent TIN concentration of35mg/L.