预酸化下营养剂添加量对生物沥浸处理洗毛废水的影响

Effects of nutrient dosage on treatment of pre-acidifying woolscouring effluent through bioleaching process

洗毛废水是洗毛生产工艺排出的兼具高COD、高悬浮固体浓度、高色度、难固液分离等典型特征,且对环境存在潜在污染的一类工业废水。通过摇瓶实验,研究了预酸化条件下,生物沥浸技术对洗毛废水的处理效果。结果表明,当洗毛废水经预酸化至p H 5.5、营养剂浓度≥4 g/L、回流比例为1∶1的情况下,3个批次实验内复合菌群生物沥浸过程稳定,洗毛废水能够很好地完成生物沥浸过程。反应结束后体系p H稳定在3.0左右,COD去除率高达90%以上,色度由原来的1 875倍降到20倍,沉淀中油脂去除率高于65%,且比阻降低至原来的0.2%~0.3%。而在对照处理中,体系p H值稳定在8.0左右,COD去除率小于10%,油脂去除率不足10%,洗毛废水比阻仅降低20%。因此,采用预酸化及生物沥浸作用有利于洗毛废水酸化处理的连续运行并具有良好的应用前景。

Woolscouring effluent( WSE) is characterized by its high chemical oxygen demand( COD),high suspended solid( SS),high chroma,and poor solid-liquid separation performance. The discharge of WSE improperly results in serious environmental pollution. The effect of bioleaching on the treatment of pre-acidifying woolscouring effluent was studied through flask experiments. The results showed that bacterial consortium of bioleaching was stable during successive three batches of bioleaching experiments,p H in WSE dropped to 3. 0,more than 90% of COD could be removed,and the chroma changed from 1 875 to 20 when initial p H of WSE was adjusted to 5. 5 by pre-acidification,and nutrient dosage was more than 4 g / L. Furthermore,dewaterability of the sediment or dreg was enhanced markedly,as indicating thatsludge resistance to filtration( SRF) declined to 0. 2% ~ 0. 3% of its initial value,and the removal efficiency of wax could reach up to 65%. Throughout the experiment,the control without inoculated with bacterial consortium only led to the removal of less than 10% of COD and wax,its SRF declined less than 20%,and the p H in WSE maintained 8. 0. It seemed that pre-acidification followed by bioleaching approach might be an attractive treatment method for the organic wastewater of high wax content or high suspended solids content.