高效气升循环式短程硝化工艺性能

采用模拟含氨废水和气升循环式好氧反应器研究了短程硝化(partial nitrification,PN)工艺的高效性能。试验结果表明,气升式短程硝化工艺具有很高的容积效率,在30℃、进水氨氮浓度358.5～942.3mg·L-1时,反应器水力停留时间可缩至0.86～2.00h,反应器每天周转次数高达12～28次,平均容积去除速率高达5.5kgN·m-3·d-1,处于文献报道的最高水平范围。该工艺具有超常的运行稳定性,在进水基质浓度、进水流量和pH波动的情况下,氨氮去除率、出水氨氮浓度和亚硝氮积累率的相对标准偏差分别为3.1%～16.8%,4.3%～26.5%和0.4%～5.3%。该工艺的高效稳定性可归因于气升循环式反应器的强污泥持留能力和短程硝化污泥的高反应活力。系统内持留的污泥浓度高达4.0～5.2g VSS·L-1,动力学试验测得的最高比污泥活性达到2.71gN·(g VSS)-1·d-1。

Performance of partial nitrification process with high-rate air-lift circulation reactor

The partial nitrification (PN) process was investigated at 30℃ in an air-lift circulation (ALC) reactor fed with simulated wastewater.The results proved that it was a highly-efficient process for ammonia removal.The turnover of the ALC reactor was 12-28 times per day with hydraulic retention time between 0.86 h and 2.00 h.When influent concentrations of ammonia were increased from 358.5 to 942.3 mg·L~(-1),the average volumetric ammonia removal rate reached as high as 5.5 kg N·m-3·d~(-1),which was at the top level reported in the literature.During the operation,the relative standard deviation of effluent substrate concentration,ammonia removal efficiency and nitrite accumulation was 4.3%-26.5%,3.1%-16.8% and 0.4%-5.3%,respectively,in spite of fluctuation of influent concentration,flow rate or pH.The stability of process performance could be attributed to both the efficient retention of sludge (4.0-5.2 g VSS·L~(-1)) and the high specific activity of biomass (2.71 g N·(gVSS)~(-1)·d~(-1) determined from the kinetic study).