Application Research On Nitrogen Removal Treatment For Electroplating Tail Wastewater With Reverse A~2/O Process

Along with the national promotion of the centralized rectification on heavy pollution andhigh energy consumption industry, organics and nitrogen pollution in electroplatingwastewater is increasingly attracted by electroplating industry and environmental concerns.Pollutants of heavy metals and pH in electroplating wastewater can be effectively removedby chemical method etc. but the removal of organics and nitrogen can be dissatisfied.Because of the heavy metals such as Ni+、Cu2+etc. and high nitrogen content,electroplating wastewater is hardly treated by microbial method. The electroplating tailwastewater after pretreatment was setted as the target wastewater, which was treatedcombining with domestic sewage. According to the comparison of different processes, theelectroplating tail wastewater was treated by the improved reverse A2/O process withadding some fillers. The performance of the removal of nitrogen by the improved reverseA2/O process was researched. At the same time, the advantage of the improved reverseA2/O process and the improved effect for the removal of nitrogen of the fillers wereinvestigated. Results show that combined treatment of domestic sewage can improve thebiodegradable ability of electroplating tail wastewater, and when the volume percentage ofelectroplating tail wastewater is30%, the biodegradable ability of the wastewater（B/Cvalue） is improved to0.30from0.12. Compared with the hydrolytic acidification+A/Oprocess and O1AO2process, the improved reverse A2/O process runned much moreefficiently. When volume percentage of electroplating tail wastewater was30%, with theconditions of the DO was1.90~2.10mg/L and the ratio of internal recycle was about150%,the efficiencies of NH4+-N, CODcr, TN were97%,80%,85%. The efficiencies of TN couldbe84%, when there were degradable organic carbon source enough, which could improvethe CODcr/TN of the wastewater. Besides, the volcanic rock and combined packingcontribute to form the system of suspended sludge and attached activated sludge, holdback the dominant bacteria,and improve the removal of reverse A2/O process. Combinedpacking in aerator tank contribute to form simultaneous nitrification denitrification, whichcan improve the efficiency of denitrogenation.