还原铁法处理印染废水生化出水及原理

Study on iron reduction method for bio-treated effluents of textile and dyeing wastewater

采用还原铁粉处理印染废水生化出水,以ADMI7.6作为主要测试指标,考察铁粉投加量、反应时间以及进水pH对出水水质的影响,并研究在此过程中铁粉还原作用和混凝絮凝作用对整体效果的贡献比.结果表明,条件1:铁粉投加量=1.0 g.L-1,反应时间150 min,进水pH 2;条件2:铁粉投加量1.0 g.L-1,反应时间150 min,进水pH 3.条件1时,ADMI7.6去除率达到80%,但铁泥量大,酸碱消耗大,在此反应条件下,铁粉还原去除40%,混凝絮凝去除60%;条件2时,ADMI7.6去除率达到50%左右,产铁泥量小,经济合理;在此反应条件下,铁粉还原去除55%—63%左右,混凝絮凝去除37%—45%左右.经XAD8/XAD4树脂联用,分析疏水酸、非酸疏水物质、弱疏水物质及亲水物质4类有机物的去除情况表明,条件1时,能够高效去除非酸疏水物质,去除率为95%,对于疏水酸以及弱疏水物质也有一定的去除效果;条件2时,对4类有机物去除均有一定作用,但对于非酸疏水物质以及疏水酸的去除效果要略差于条件1.

In this paper,reduced iron powder was used for further treatment of bio-treated effluents of textile and dyeing wastewater,and ADMI7.6 was chosen as the main indictor.Iron dosage,reaction time,and initial pH were the factors of the treatment.Iron reduction and coagulation/flocculation were the main reaction of the whole process.Two reaction conditions in the experiment were selected to analyze the mechanism.Condition 1： iron dosage=4 g · L-1,residence time=150 min,pH=2;condition 2： iron dosage=4 g · L-1,residence time=150 min,pH=3.Results shows that the condition 1 could remove 80% ADMI7.6,but that would product large amount of iron sludge and led to acid/base consumption.Under this condition,40% ADMI7.6 was removed by iron reduction,and the rest was removed by coagulation/flocculation.Condition 2 could remove 50% ADMI7.6,which product small amount of iron sludge,and is more economical.Under this condition,about 55%—63% ADMI7.6 was removed by iron reduction,and the rest was removed by coagulation/flocculation.The dissolved organic matters（DOMs） from bio-treated effluents of textile and dyeing wastewater is divided into four different fractions,hydrophobic acids,non-acid hydrophobics,transphilics and hydrophilics,by XAD-8 and XAD-4 resins fractionation.The condition 1 could remove 95% acid hydrophobic substances,and also had a good performance on non-acid hydrophobic and transphilic.The condition 2 had a good performance on the four organics,but for non-acid hydrophobic and hydrophobic acid,removal efficiency was not as well as the condition 1.