Abstract: 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穋m^-2, flow velocity 2.72 cm穝^-1 in electrode gap, initial chloride ion concentration 5000 mg稬^-1.The COD in the leachate could be reduced below 100 mg稬^-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.

Key words: municipal solid waste leachate, refuse incineration, electrochemical oxidation

摘要： 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。

关键词: 城市固体废弃物沥滤液, 垃圾焚烧, 电化学氧化