响应曲面法优化电化学耦合体系预处理焦化废水

针对焦化废水有机负荷高、生物抑制性强等特点，采用电化学耦合体系进行预处理研究。以原厂污泥制备污泥活性炭（AC）粒子电极，并表征其表面含有羟基、醚基、羰基、羧基等多种含氧官能团，有利于催化反应。考察阴极曝气对预处理的影响及降解机理分析，结果表明曝气有利于开环反应。基于Central-Composite响应曲面法考察外加电压、初始pH、曝气量、AC填充比等因素对预处理的单独影响及交互作用，并以COD去除率为评价指标。结果表明：各因子的影响显著性顺序为AC填充比 > 初始pH > 曝气量 > 外加电压，其中初始pH和曝气量的交互作用较显著。最佳运行条件为外加电压15 V，初始pH 5.8，曝气量12.4 ml·min^-1，AC填充比50%，反应时间45 min，此时COD去除率达46.8%。废水COD由4700 mg·L^-1降至2500 mg·L^-1，色度去除率为50%，B/C由0.05增至0.37，可生化性明显提高，且能耗较低为0.971 kW·h·（kg COD）^-1。研究表明，采用电化学技术能有效预处理焦化废水，并提高可生化性。

Optimization of electrochemical coupling system process for coking waste water pretreatment by response surface method

The electrochemical coupling system was used on the pretreatment of coking waste water with high organic loading and biological inhibition. The sludge-derived activated carbon(AC) particle electrodes were prepared from in-site sludge and characterized, indicating that surface oxygen groups contained hydroxyl, ether, carbonyl, carboxyl, etc., which could accelerate catalytic reaction. The effects of cathode aeration were investigated and degradation mechanism of organic contaminants was analyzed. The results showed that aeration was beneficial to open-loop reaction. Based on the Central-Composite response surface method, the separate action and interaction effects of impressed voltage, initial pH, aeration rate, and AC filling ratio were evaluated, and COD removal rate was used as the evaluation index. The significance of influencing factors followed the order:AC filling ratio > initial pH > aeration rate > impressed voltage, and the most significant interaction occurred between initial pH and aeration rate. The optimal conditions were determined to be impressed voltage 15 V, pH 5.8, aeration rate 12.4 ml·min^-1, AC filling ratio 50%, and reaction time 45 min. Then COD removal rate reached 46.8%. Under optimal conditions, COD of the treated waste water decreased from 4700 mg·L^-1 to 2500 mg·L^-1, and chroma removal rate was 50% with low energy consumption of 0.971 kW·h·(kg COD)^-1. And B/C increased from 0.05 to 0.37, indicating the biochemical properties were improved. Therefore, the electrochemical technique can efficiently pretreat the coking waste water and improve its biodegradability.