碱性工业废水对Orbal氧化沟的冲击影响及其调控

Impact of Alkaline Industrial Wastewater on Orbal Oxidation Ditch and Its Solutions

活性污泥在污水处理中起着决定性的作用,但在受到强碱性工业废水冲击时极易发生污泥中毒现象。为了探明不同p H值的碱性工业废水对Orbal氧化沟的影响,找到最佳的调控方案,采用中试Orbal氧化沟模型模拟受不同碱性p H值的废水冲击,分析了对活性污泥及处理效果的影响,并通过控制进水流量、污泥回流比和回流二沉池上清液,对比了三种调控方案的效果。结果表明:活性污泥的比耗氧速率(SOUR)和DO的变化呈现负相关性,反映了污泥微生物的代谢活性。当碱性废水p H值≤9.5时,污泥未发生中毒现象,当p H值升至12时,冲击5.1 h后污泥开始中毒,SOUR<8 mg O2/(g MLVSS·h);冲击8 h后污泥严重中毒(SOUR≈0),对COD、NH3-N、TN、TP的去除率分别为70.2%、82.9%、45.0%、7.0%,去除率严重下降。当p H值≤11.5时,仅用方案一调控8 h后就能恢复污泥活性,提高出水水质;当p H值为12时,经三种方案调控8 h后,污泥仍处于中毒状态,出水TN、TP含量较高,表明p H值≥12会导致系统运行受阻,调控难以使系统恢复到冲击前的状态;但方案三的调控效果最好,SOUR相对最高,出水水质相对最好。

Activated sludge plays a decisive role in wastewater treatment. However, it can get toxic easily when impacted by strong alkaline industrial wastewater. In order to investigate the impact of different alkaline industrial wastewater on Orbal oxidation ditch and find out the best solution, a pilot-scale model was established to simulate such impact. Meanwhile, the influence on treatment system and effluent quality was analyzed, and then three solutions were put forward and compared by using the methods of adjusting influent flow, controlling sludge return ratio and returning the supernatant from secondary claritier. The results showed that the changes of specific oxygen uptake rate （SOUR） and dissolved oxygen （DO） presented negative correlation which could reflect the metabolic activity of sludge microorganisms. When the pH of the alkaline wastewater was equal to or less than 9.5, the sludge had no sign of poisoning. When the pH reached to 12, the sludge became poisoned, and SOUR was less than 8 mgO2/（ gMLVSS · h） after being impacted for 5.1 h. And 8 h later, the sludge became seriously poisoned （ SOUR ≈0）, and the removal rates of COD, NH3 - N, TN and TP were 70.2% , 82.9% , 45.0% and 7.0% respectively, all of which sharply declined. When the pH of the alkaline wastewater was equal to or less than 11.5, sludge activity could be almost recovered totally and the effluent quality could be improved rapidly after being adjusted for 8 h by using the solution one. When the pH of the alkaline wastewater was 12, although adjusting for 8 h by the three design solutions, the effluent TN and TP were still in high level and sludge poisoning still happened. It showed that the operation of the system was hindered, and the sludge activity could hardly be recovered by any adjustment and control. But compared with the other two solutions, the third solution was the best, with the highest SOUR and the best effluent quality.