垃圾焚烧发电厂储坑沥滤液是一种高污染、高氯离子和高胶体含量的废水,经过传统生化处理后仍难达标排放.根据生化出水中氯离子浓度较高的特点,面向实际工程应用,设计了板框式电化学反应器,以钛基氧化钌-氧化铱涂层电极(Ti/RuO2-IrO2)作为阳极,304钢板作为阴极,开展了电化学氧化去除废水中难生物降解有机物的研究.重点考察了电流密度、表观流速、氯离子浓度、电极极距等因素对去除废水COD的影响.结果表明:当电流密度为65.35 mA·cm-2,反应器内表观流速为2.72 cm·S-1,初始氯离子浓度为5000 mg·L-1时,废水中COD的去除具有良好的效果.研究了COD去除的动力学过程,提出了反应体系中活性氯的减少可能是第二阶段COD去除速率降低的主要机理.对几种结构电化学反应器的能耗进行了对比分析表明,极距减小50％,去除COD的平均能耗可节约25％以上,紧凑多通道小电极极距结构在设计工业电化学反应器时值得考虑.%Incineration is an effective technology for municipal solid waste (MSW) disposal. However, the MSW leachate after bio-treatment still contains recalcitrant organic compounds, higher concentration of chloride ions and biogenic colloids. Their electrochemical oxidation was conducted in a newly designed filter-press electrochemical reactor. In the electrochemical oxidation process, NH3-N could be easily removed by means of electro-generated chlorine/hypochlorite. The effects of major process parameters on the removal of organic pollutants were investigated systematically. Under experimental conditions, the optimum operation parameters are current density 65.35 mA · cm-2, flow velocity 2.72 cm · s-1 in electrode gap, initial chloride ion concentration 5000 mg · L-1 The COD in the leachate could be reduced below 100 mg · L-1 after 1 h of treatment. The kinetics and mechanism of COD removal were investigated by simultaneously monitoring the COD change and chlorine/hypochlorite production. The kinetics exhibits a two-stage kinetic model and the decrease of electro-generated chlorine/hypochlorite production is the major factor for slowing down of COD removal rate in the second stage. 50% of reduction in electrode gap can result in saving more than 25% of energy consumption. A compact multi-channel bipolar structure should be taken in the design of industrial electrochemical reactors for wastewater treatment.
展开▼
