Research On Wastewater Treatment Engineering Of Electroplating Enterprise

The flourishing of the electroplating industry provides strong support for the rapid development of light industry system of China.Nevertheless,with increasingly higher social demand for the industry to be environment-friendly,problems caused by wastewater generated from manufacturing lines of the electroplating industry become more and more prominent to be tackled.This study focused on one electronic component processing factory,and analysis was conducted based on characteristics of its electroplating processes,as well as the discharge requirement of production wastewater.After comparing the pros and cons of different processing techniques based on the actual situation of manufacturing,the concept of“quality-based pretreatment followed by combined treatment”was proposed for treating electroplating production wastewater,concerning traits of individual pollutants.In addition,design and equipment selection was performed for every structure involved in the wastewater treatment work.Results of this study highlight that:1.Different streams of wastewater should be treated by different pretreatment methods:alkaline chlorination approach for cyanide-bearing electroplating wastewater;“Fenton oxidation+coagulation/precipitation”coupling technique for nickel-bearing chemical wastewater;chemical precipitation approach for nickel-bearing electroplating wastewater;“reduction+chemical precipitation”approach for chromium-bearing wastewater;alkaline precipitation approach for zinc-bearing wastewater;“advanced oxidation+precipitation”approach for copper-bearing wastewater.Moreover,pretreatment wastewater was further treated by the“advanced oxidation+precipitation”coupling technique,and the“flocculation precipitation+chemical decoordination”coupling technique was chosen for pretreating cleaning wastewater.These different pretreatment methods applied to various wastewater streams collected separately have achieved effective removal of characteristic pollutants in respective stream,as well as reduced the cost of post-treatment.2.Combined wastewater has met the emission standard after being treated by the“oxidation+precipitation+A~2/O”technique.3.Reverse osmosis(RO)technique was applied to recycle the reclaimed water generated after the precipitation pretreatment of cleaning wastewater.4.After the completion of the project,continuous monitoring of the operation of the wastewater treatment facility was done for 3 months.Results indicated that concentrations of indicator pollutants in the effluent generated had met the standard requirement of“Emission standard of pollutants for electroplating”(GB21900-2008,Table 2).The average removal rates of chemical oxygen demand,suspended solids,ammonia nitrogen,total nitrogen,total phosphorous,total cyanide,total nickel were94.4%,91.0%,85.6%,98.2%,90.8%,93.3%,99.4%,respectively.Total copper,total zinc,and total chromium in the effluent were below the detection limit of the measurement.The wastewater treatment facility is able to produce stable effluent with relatively good impact-resilient loading capacity.5.Operating cost for running the project was estimated:this technique costs11.26 yuan per m~3electroplating wastewater treated,including the operation of reclaimed water recycle system;hence,its economical properties have met the design requirement.