Application of Anoxic-Aerobic Biological Process for Treatment of Compositive Electroplating Wastewater

In this paper, different physicochemical processes are used to remove heavy metals in electroplating wastewater containing nickel, chromium and fluorine. More, the three items of phosphate, NH4+-N and CODcr are also needed to be decreased to meet discharge standards. Based on the various characteristics of electroplating wastewater, biochemistry technologies are used to improve the effluent quality after pretreatment for actual origin wastewater. Anoxic reactor and biological aerated filter are employed as biological processes (A/O process) to decrease the effluent concentration of CODcr and NH4+-N. The results show that the system effluent meets the national standard of "Emission Standard of Pollutants for Electroplating" (GB 21900-2008), and NH4+-N item reaches the local standard of "Discharge Standard of Main Water Pollutants for Municipal Wastewater Treatment Plant & Key Industries of Taihu Area" (DB 32/1072-2007). The modified A/O process realizes a high denitrification removal of 80%, and the operation cost is only 2.67 Yuan/m(3).