采用SBR法处理经缺氧/厌氧UASB预处理的渗滤液,在SBR反硝化过程观察到明显的亚硝态氮积累现象.在此基础上,为深入了解反硝化过程亚硝态氮积累的机制,考察低温条件下5种类型碳源(甲醇、乙醇、乙酸钠、丙酸钠和葡萄糖)对SBR反硝化过程亚硝态氮积累的影响.结果表明,在温度为13.9℃情况下,甲醇、乙醇、乙酸钠、丙酸钠为反硝化碳源时,系统内均发生明显的亚硝态氮积累.此外,4种不同初始NO3^--N浓度(64.9、54.8、49.3、29.5 mg/L)还原过程中,NO2^--N最大积累浓度分别为37.8、21.5、25.2、18.8 mg/L,积累速率(N/VSS.t)分别为0.117、0.136、0.235、0.068 g/(g.d),并且ORP曲线先后出现"nitrateknee"和"nitrite knee"2个拐点,可分别指示NO3^--N、NO2^--N还原反应结束.
Nitrite accumulation during the denitration process with SBR treating pre-treated by anoxic/anaerobic up-flow anaerobic sludge bed (UASB) was observed at low temperatures .The effects of types of carbon sources on nitrite accumulation were investigated for comprehensive understanding the mechanism of nitrite accumulation. Experimental results clearly showed that nitrite accumulated obviously when five carbon sources (methanol, ethanol, sodium acetate, sodium propinoate and glucose), except for glucose, were used as electron donor. Additionally, nitrite accumulations were observed at four different initial nitrate concentrations and lower temperatures. The maximum concentrations of nitrite accumulation were 37.8, 21.5, 25.2 and 18.8 mg/L, respectively, and the corresponding nitrite accumulation rates (N/VSS·t) were 0.117, 0.136, 0. 235 and 0.068 g/( g·d) during the nitrite accumulation period. Two break pionts of "nitrate knee" and "nitrite knee" on oxidation reduction potential (ORP) profile indicated that the reduction reactions of nitrate and nitrite were completed, respectively.