Study On Engineeirng Technology Of Metal Electroplating Factory Wastewater Treatmented By Chemical And Precipitation Method

Electroplating effluent contains marry varieties pollutant which is harmful tohuman body and environment, corrosivity to building and equipment. Especiallycontains heavy metals、cyanide which is the “three to”contaminants. Therefore,treatment of electroplating effluent always is the conundrum in effluent treatment.Aelectroplating factory in Guangdong is a processors which main productes variousmetal plating products.The wastewater contains contaminants such asnickel,cyanide,hexavalent chromium,zinc,copper,acid and alkali pollutants and soon,and need to Expand operations.According to the requirements of environmentalprotection of “three at the same time” need constrcte a new wastewater treatmentstation. Through designed and constructed process for wastewater treatment stationand study on the key technology, commissioning and operating reached the followingconclusions:It is quite reasonable to treatment this wastewater by once broken cyanidemethod.Compared with the secon broken cyanide method,there is a little differerce incost and operate easily.Concrete operations is:adjust the pH to10.5,then reference themNaClO：mCN-=14.51proportion to add NaClO and react65min, finally controlORP meter at595mV.The mixed wastewater contains more varieties heavy metal ions.Althoughheavy metal ion has different the theoretically best precipitation pH and existenceamphoteric metal in the wastewater,still can select the10.50as the mixed heavymetals best neutralization precipitation pH to achieve the effectively Removetion ofheavy metals.Simultaneous addition of80mg/L PAC and1.25mg/L PAMcombination can promote the hydroxide deposition and reduce the cost.The debugging and running results show that, once broken cyanide method canmeet the requirements in the best conditions of wastewater treatment,the total cyanideconcentration is lower than the standard value after treatment. Chromium containingwastewater can reach six chromium in wastewater into trivalent chromium in underthe action of sodium sulfite, and content is lower than the emission standard;effect of lime milk neutralization and precipitation can greatly remove copper ion in cokephosphor copper wastewater, and can the precipitate nickel ions; After adjust the pHof mixed wastewater to10.50by NaOH and Coagulant,the heavy metal ions all canbe reduced to the emission standard, and can be discharged after callback pH t andfiltering.The design of the wastewater treatment process has the characteristics of simpleand efficient, operate easily,can realize automatic control, low cost and so on.