Fe0/S2O82-异相芬顿与生物组合工艺处理煤化工废水尾水

Depth-treatment of effluent from coal-chemical engineering wastewater treatment by a sequential Fe^0/S_2O_8^(2-) heterogeneous Fenton reaction and biodegradation process

为实现煤化工废水尾水低成本达标排放,采用零价铁/过硫酸盐(Fe^0/S_2O_8^(2-))异相芬顿与气升环流反应器(ALR)组合工艺对其进行深度处理并分析处理成本。结果表明,在pH为6.8、Fe^0和S_2O_8^(2-)投加量分别为2g·L^(-1)和15 mmol·L^(-1)的条件下,Fe^0/S_2O_8^(2-)体系对COD和色度去除率分别为56%和50%。气相色谱-质谱和气相色谱分析显示,尾水中难降解芳香化合物被转化成小分子有机酸,这些小分子有机酸虽然在异相芬顿反应中难以进一步降解,但容易被好氧微生物吸收和利用;出水经ALR处理后,COD和色度进一步从150 mg·L^(-1)和75倍降到48 mg·L^(-1)和25倍,总去除率达到86%和83%。由于异相芬顿反应不需调节pH且出水铁离子浓度小于9mg·L^(-1),该组合工艺在避免大量铁泥产生的同时可低成本地实现煤化工废水尾水达标排放。

A sequential Fe0/S2O82- heterogeneous Fenton reaction and biodegradation process was employed for the depth-treatment of coal-chemical engineering wastewater to meet the discharge standard and its operational cost was discussed. The results showed that COD and color removal efficiency of 56% and 50% was achieved at initial pH of 6.8, Fe0 of 2 g？L-1 and S2O82- of 15 mmol？L-1, respectively in the Fe0/S2O82- Fenton reaction. According to gas chromatography-mass spectrometer （GC-MS） and gas chromatography （GC） analysis, the recalcitrant aromatic compounds were effectively decomposed into low-molecular-weight organic acids. These acids were resistant to the Fe0/S2O82- Fenton reaction, while they were effectively eliminated in the sequential air lift reactor （ALR）, resulting in a further decrease of COD and color concentration from 150 to 48 mg？L-1 and from 75 to 25 times, respectively. A total COD and color removal efficiency of 86% and 83% could be achieved after the above sequential process. Since high performance was achieved at an original pH of 6.8 and ferric ion was below 9 mg？L-1 during the Fe0/S2O82- Fenton reaction, sludge disposal could be avoided after the reaction. It indicated that this combined process is a promising and cost-effective way for the depth-treatment of coal-chemical engineering wastewater to satisfy discharge requirements.