Study On FGD Wastewater Treatment Using Biological Aerated Filter With Pre-denitrification

The water quality of desulfurization wastewater from coal-fired power plants makes it the most difficult effluent to be treated in the discharge wastewater of coal-fired power plants,explore the processing technology of efficient economy is the focus of current power plant research.This paper use the high salt and high ammonia nitrogen actual power plant desulfurization wastewater as test water quality,focuses on experimental study the feasibility and denitrification efficiency on the Biological Aerated Filter pre-denitrification process for biological membrane method processing special complicated water quality.In this paper,the changes of ammonia nitrogen,COD,nitrate and nitrogenous nitrogen in the process of suspension and domestication and the effects of reflux ratio,C/N,hydraulic load,pH value and other operating parameters and the effect of backwashing on the efficiency of the system were studied,in order to make sure the optimal operation parameters and test environment.The results of this study have improved the experience and reference for the treatment of desulfurization wastewater with high salt and high ammonia nitrogen.The main conclusions of this experiment are as follows:⑴The system can be used to deal with the membrane and domestication of the complex water quality of high salt and high ammonia nitrogen.After the domestication,the removal rate of NO₃^--N was greater than 87.09%,and the removal rate of COD was greater than 85%in the anaerobic reactor.At the same time,the removal rate of ammonia nitrogen was over95%in the aerobic reactor.In addition,a layer of black biofilm was attached to the surface of the packing surface in the anaerobic reactor,and the surface of the aerobic reactor was covered with brown yellow biofilm in the aerobic reactor,which indicated that the system hanging film and domestication effect were ideal.⑵The Biological Aerated Filter pre-denitrification process has obvious effect on the removal of nitrogen and organic compounds from the desulfurization wastewater of high salt and high ammonia nitrogen.The influent ammonium concentration was 260³00mg/L,the average concentration of ammonia nitrogen in the system was 45.23mg/L,and the average removal rate of ammonia nitrogen was 83.62%.The average removal rate of COD can reach88.87%.⑶Reflux ratio,C/N and hydraulic load have significant effect on the removal of nitrogen and COD to the Biological Aerated Filter pre-denitrification process.The optimal operating parameters of the test are:100%reflux,C/N=3:1,hydraulic load was 0.06m/h.Under this parameter,the removal rate of COD was 88.87%,and the removal rate of ammonia nitrogen was 83.62%,and the discharge nitrate nitrogen 8.44mg/L and nitrogen-nitrogen concentration was 15.99mg/L,which was relatively small.⑷The combination of air and water has good backwashing effect,and backwash has little effect on nitrification.In addtion,the aerobic reactor was slightly faster than the anaerobic reaction column of COD removal.