Renovation Scheme And Efficiency Analysis Of A Sewage Treatment Plant In Zhangjiagang

In China,water resources are insufficient,water pollution and destruction has become a key factor restricting the rapid development of economy and society,and the construction of sewage treatment plant is an important measure to solve water pollution.With the continuous development of the city,the amount of sewage is increasing,and the sewage discharge index is further improved.The index of domestic sewage treatment plant is raised to GB18918-2002 level A standard.This requires the sewage treatment plant to have higher removal capacity for the pollutants such as COD,BOD₅,NH₃-N,TP,TN,SS,etc.which are rich in the sewage,and puts forward higher requirements for the operation and management of the sewage treatment plant.Based on the reconstruction of a sewage treatment plant in Zhangjiagang City,this paper analyzes the problems in the operation of a sewage treatment plant,and specifically analyzes the two main problems of water quantity and water quality.With the main goal of improving the treatment water quantity and treatment water quality,optimize the reconstruction scheme,carry out the standard upgrading of a sewage treatment plant,and compare the index data before and after the transformation.Due to the limitation of potential tapping and capacity expansion,combined with the operation mode and volume margin adjustment of oxidation ditch in the existing plant area,the capacity expansion is 0.5×10⁴m³/d.The original volume margin of the oxidation ditch in phase I is large.After the modification of the operation mode,the treatment capacity can be increased by 0.4×10⁴m³/d to 1.4×10⁴m³/d,while the volume margin of the oxidation ditch in phase II is small.After the modification of the operation mode,the treatment capacity can only be increased by0.1×10⁴m³/d to 2.1×10⁴m³/d.After expansion,the average volume is 3.5×10⁴m³/d and the peak volume is 4×10⁴m³/d,which can meet the water inflow in rainy season and ensure the normal operation of the sewage treatment plant.In order to improve the quality of the effluent,the advanced treatment process should be reformed.Aluminum salt is used for chemical phosphorus removal,and carbon source is added to balance the ratio of C/N/P in sewage,so as to better remove total nitrogen.The tail water disinfection was transformed from chlorination to sodium hypochlorite,and deodorization was carried out by sealing technology.The data of water quantity and quality indicators from 2008 to 2017 are analyzed.The water quality indicators are COD,BOD₅,NH₃-N,TP,TN,SS,etc.After the transformation of the sewage treatment plant,the effluent quality meets the first class a standard,the reduction of total nitrogen and total phosphorus is greatly increased,and it can also meet the treatment of the incoming water in the rainy season.The reasonable operation of the sewage treatment process improves the operation efficiency.