臭氧-BAF组合工艺处理电镀RO浓水

Treatment of electroplating reverse osmosis concentrate by ozone-biological aerated filter combined process

电镀废水反渗透(RO)浓水具有盐度高、难降解有机物浓度高、含重金属等特点,是电镀废水处理工艺提标改造的难点。采用臭氧-曝气生物滤池(BAF)组合工艺,对电镀废水反渗透(RO)浓水中有机物进行处理,使出水COD浓度达到《电镀污染物排放标准》中标准。考察了废水初始p H、臭氧浓度和反应时间等因素对臭氧氧化效果的影响,以及水力停留时间(HRT)和气水比对BAF单元COD去除效果的影响。经优化后的系统运行工况为:臭氧氧化单元中废水初始p H值为10.0,臭氧浓度为31.96 mg·L^(-1),反应时间为40 min;BAF的HRT为3 h,气水比为5∶1。在最佳工况下,当进水COD为180~240 mg·L^(-1)时,经组合工艺处理后COD去除率达78.6%,平均出水COD浓度为47 mg·L^(-1),达到了标准的要求。

The reverse osmosis（ RO） concentrate of electroplating wastewater contains high concentrations of salts,refractory organics,and heavy metals,thus its efficient treatment has become the main obstacle to modification of electroplating wastewater treatment processes. In this research,a combined process of ozonation followed by the use of a biological aerated filter（ BAF） was used to treat the RO concentrate of electroplating wastewater to ensure the effluent met the strict standard of the China＇s Emission Standard of Pollutants for Electroplating. The effects of initial p H,ozone concentration,and reaction time on the degradation performance of the ozone reactor were investigated,and the influences of hydraulic retention time（ HRT） and gas / liquid ratio on the COD removal efficiency of the BAF reactor were evaluated. The operating conditions were optimized as follows： initial p H of 10. 0,ozone concentration of 31. 96 mg·L^（-1）,and reaction time of 40 min for the ozone reactor and a HRT of 3 h and gas / liquid ratio of 5 for the BAF rector. Under these conditions and with an influent COD concentration of 180 to 240 mg · L^（-1）,the COD removal efficiency reached 78. 6% and the effluent COD concentration was reduced to 47 mg·L^（-1）,which meets the emission standard of pollutants for electroplating wastewater.