Abstract: Biological treatment of high concentration NO₂^--N in passivation washing wastewater is difficult. In this paper nitrite oxidizing bacteria (NOB) was enriched by feeding NO₂^--N wastewater, NOB-rich activated sludge was used in an SBR system to treat simulated passivation washing wastewater, and a process control strategy was put forward. The results showed that using the process passivation washing wastewater with NO₂^--N concentration 2000 mg·L^-1 could be totally oxidized within 300 min. The nitrite oxidation process was not inhibited by the high NO₂^--N concentration. Furthermore, this process had a correlation with the variation of DO concentration during reaction. DO-MSC, a parameter of the process control strategy, indicated the end of the reaction when it was more than 0.02. The results of batch tests showed that the DO-MSC could indicate the end of the nitrite oxidation process both in different aeration rates(0.02-0.125 m³·h^-1) and different temperature(15-30℃).

Key words: wastewater, nitrite, SBR, DO-MSC, process control, aeration, temperature

摘要： 钝化清洗废水含有高浓度亚硝态氮，采用普通活性污泥难以进行生物处理。采用亚硝态氮废水富集亚硝态氮氧化菌（NOB），以富含NOB污泥的SBR装置处理模拟化学清洗钝化废水，并提出了该处理工艺的过程控制策略。结果表明：该工艺可以在300 min内完全氧化亚硝态氮浓度高达2000 mg·L^-1的钝化废水，高浓度亚硝态氮没有对生物降解过程产生明显抑制；反应过程中DO浓度的变化与亚硝态氮氧化过程存在相关性，溶解氧浓度的移动斜率变化（DO-MSC）可作为亚硝态氮氧化过程控制参数；当DO-MSC >0.02时，亚硝态氮氧化过程结束，此时可停止曝气。批次试验结果显示在不同曝气量（0.02～0.125 m³·h^-1）和不同温度条件（15～30℃）下，DO-MSC指数均可有效指示亚硝态氮氧化终点。

关键词: 废水, 亚硝态氮, SBR, DO-MSC, 过程控制, 曝气, 温度