垃圾渗滤液生物处理出水的深度处理组合工艺

Combination process for advanced treatment of biotreatment effluent of landfill leachate

采用'混凝-电解氧化-完全混合式活性污泥法(CSTR)'组合工艺深度处理垃圾渗滤液生物处理出水。探索了工艺的组合及各种工艺操作条件对垃圾渗滤液深度处理效果的影响,并对其影响机理进行了初步探讨。结果表明,以PAC为混凝剂时,在pH和药剂(有效成分)投加量分别为6.0和600 mg/L条件下,渗滤液COD去除率达到50%,有效降低了难溶惰性COD含量,缩短了后续电化学处置时间。混凝工艺后,采用电化学工艺处理,在最优工艺条件下:pH为6.0、电流I为1.2 A(电流密度为18.18 mA/cm2)、Cl-投加量为1 000 mg/L、极板距离为2 cm,电解30 min渗滤液COD去除率达到36%,同时,难降解有毒物含量明显降低,渗滤液可生化性TbOD/COD由10%提升至最大值64%。最后采用CSTR处理渗滤液电解出水,系统出水COD、氨氮和色度分别为100~150 mg/L、7~13 mg/L和25倍,为反渗透(RO)工序提供了良好的水质条件。

A combined process of coagulation-electrolytic oxidation-continuous stirred tank reactor(CSTR) was employed to treat the effluent from biological treatment system of landfill leachate. The effects of combinative state of each process unit and their various operating conditions on the advanced treatment efficiency were investigated,and the influence mechanism was also analyzed. The results indicated that,with the PAC as coagulant, its dosing quantity(effective constituent) and initial pH were 600 mg/L and 6. 0,respectively,the COD removal efficiency of leachate in coagulation process reached 50%,which could reduce the refractory COD effectively and would be conducive to shorten the treatment time in subsequent electrochemical process. Following this, electrochemical process was used to treat the coagulation effluent. Under the optimal electrochemical process conditions: pH of 6. 0,current I of 1. 2 A(current density of 18. 18 mA/cm2),Cl-dosing quantity of 1 000 mg/L,plate distance of 2 cm,electrolytic time of 30 min,COD removal efficiency reached 36% along with the content of refractory toxicants decreased significantly,and leachate biodegradability TbOD/COD increased from 10% to maximum 64%. Finally,the continuous stirred tank reactor(CSTR) was employed to further treat electrolysis effluent,and the effluent COD,ammonia nitrogen and chromaticity were 100 ~ 150 mg/L,7 ~ 13 mg/L and 25 times,respectively,which would supply good quality water to reverse osmosis(RO) process.