Pollutant Removal Efficiency And Economic Evaluation Of Guiyang Xiaohe Sewage Treatment Plant Upgrading

As an important facility of domestic sewage treatment,urban sewage treatment plant is attracting more and more attention.The implementation of the upgrading of the sewage treatment plant can improve the quality of the effluent,reduce the discharge of pollutants and the risk of eutrophication,at the same time,it can be used for reusing of the effluent,and improve the utilization rate of water resources in the arid area.Many sewage treatment plants in Guizhou have been upgraded according to relevant requirements.Guiyang Xiaohe sewage treatment plant had completed and put into operation in December,2003,and modified Sequential Biological Reactors(SBR)is used to treat the sewage.The original designed effluent quality should meet the "urban sewage treatment plant pollutant discharge standard"(GB18918-2002)level B standard,and the sludge moisture content is less than 80%.In accordance with the requirements of Guiyang city,the national environmental protection model city was established.In 2015,the project was upgraded and put into trial operation.The effluent quality should meet the level A standard of pollutant discharge standard of urban sewage treatment plant,and the moisture content of the discharged sludge should be reduced to 60%.Firstly,this paper introduced the background of Guiyang Xiaohe sewage treatment plant(phase I)bid upgrading project,analyzed the existing problems of the project and the specific measures,and made a comparative analysis of the pollutant removal effect before and after upgrading.Through the analysis,it can be seen that the actual inlet concentration of sewage is relatively low,the main pollutant indexes are lower than the design value,and the wastewater is biodegradable.The effluent quality of the deep treatment process was significantly improved compared with the secondary treatment before upgrading,in which the COD removal efficiency was increased by about 50% and up to 62%.The removal efficiency of SS can be increased by more than 50% and the highest is 72%.For TP,it can be increased by 30% on average.The system has a good removal effect on ammonia nitrogen and TN,and the removal efficiency of ammonia nitrogen and TN can be increased by about 40%.By adding the "mixed precipitation + active sand filtration" deep treatment process,the pollutant removal effect can be effectively improved,so that the effluent quality of sewage treatment plant can be stable up to grade A standard.Meanwhile,through the comparison and analysis of the changes in operating costs of sewage treatment plants before and after the upgrading and reconstruction,the total investment in the upgrading project of Guiyang Xiaohe sewage treatment plant is about ?57.8022 million,and the additional direct operating cost is ?0.233 per ton.Through the implementation of the project,fewer pollutants can be discharged into Nanming River every year,which can improve water quality obviously.The project enhances the city's landscape and promotes sustainable economic,social and environmental development.The upgrading and reconstruction of Guiyang Xiaohe sewage treatment plant has important reference value to the similar sewage treatment plants in China.