起始pH值对生物产酸处理洗毛废水的影响

采用10 L搅拌釜式生物反应器(STR),研究了化学酸(4.5　mol·L^－1硫酸)预酸化和生物酸化废水预酸化对生物产酸法处理洗毛废水的影响.结果表明,预酸化处理可大大缩短生物产酸法处理洗毛废水的时间. 其中利用生物酸化废水回流代替无机酸调节洗毛废水pH效果更好,当调节起始pH为5.20时,仅需要1.5 d便可以完成处理周期,比不预酸化的对照(需要9 d)缩短7.5 d的处理时间,COD去除率高达91%. 研究进一步表明, 生物酸化废水预酸化能取得很好的处理效果主要是由于预酸化降低了体系pH,有利于硫杆菌的活性大幅度提高,同时大大消减了待处理废水的缓冲容量,更重要的是大量增加了硫杆菌数量所致. 因此采用生物酸化废水回流有利于难处理的洗毛废水生物酸化法处理的连续运行并具有良好的应用前景.

Effect of Initial pH on Bioacidification Treatment of Woolscouring Effluent

To remove biorefractory organic matter from woolscouring effluent, the bioacidification treatments pre-acidified by 4.5 mo x L(-1) sulfuric acid and bioacidified wastewater were performed through a 10 L stirred tank reactor. Hydraulic retention time (HRT) for the treatment was obviously shortened through pre-acidification of woolscouring effluent. Bioacidification treatment efficiency facilitated by pre-acidification with bioacidified wastewater was much higher than that by pre-acidification with sulfuric acid. When initial pH was adjusted to 5.20 with bioacidified wastewater, the bioacidification treatment resulted in more than 91% COD removal and 1.5 days of HRT, which was 7.5 days shorter than that of treatment without pre-acidification. It was found that pre-acidification with bioacidified wastewater played an important role in providing a more satisfactory environment for Acidithiobacillus thiooxidans growth, eliminating the buffer capacity of woolscouring effluent, and also inoculating more A. thiooxidans in the reactor. Therefore, the bioacidification treatment of woolscouring effluent through the recycling of a part of bioacidified wastewater for pre-acidification can be operated steadily and continuously, which exhibits a good prospect for engineering application.