UV/H_2O_2法深度处理焦化废水的研究

Advanced Treatment of Coking Wastewater by UV/H_2O_2 Process

焦化厂生物和混凝处理出水中残留的有机物制约了其安全排放,故有必要研究其深度处理技术.以某焦化废水处理厂尾水为研究对象,用UV/H_2O_2法对其进行处理.采用单因素和正交实验的方法考察了光源距离、H_2O_2浓度、pH值和温度对色度、TOC和UV254去除率的影响.正交实验结果表明,对TOC去除率影响顺序为光源距离>温度>pH>H_2O_2浓度.两种方法确定的最佳条件一致,即距光源距离为4cm、H_2O_2浓度为24mmol/L,温度40℃,pH为5,光照反应时间为2h,TOC、色度和UV_(254)去除率分别为68.76%,97.76%和96.84%.TOC降解符合一级反应动力学.经UV/H_2O_2处理后,焦化废水尾水中一些难以生物降解的有机物得到了部分或完全去除.

Residual organic pollutants in the effluent of biological and chemical treated coking wastewater has limited its safe discharge, so it was necessary to study the feasibility of advanced treatment technolo- gy. Coking tail effluent was investigated by UV/H2O2. The influence of H2O2 concentration, light source distance, pH and temperature on removal rate of chroma, TOC and UV254 were analyzed with method of single factor and orthogonal experiment. Orthogonal experiment results showed that significant influ- ence on TOC removal rate decreased by the order of light source distance, temperature, pH, H2O2 con- centration. The optimum condition determined by two methods were the same. The optimum conditions were that the light source distance was 4 cm, H2O2 concentration was 24 mmol/L, temperature was 40 ℃, pH was 5, and the light reaction time was 2 h. Under this condition, removal reates of TOC, chro- ma and UV254 were 67.86%, 97.76 % 和 96. 84 %respectively. The degradation of TOC could be described by first-order kinetics model. Results of GC/MS analysis also showed that some biologically refractory organic matter in coking tail effluent have been partly or completely removed after UV/H2O2 process.