Research On Renovation Project Of A Sewage Treatment Plant

The first and second phases of the sewage treatment plant studied in this article are worked,and execute the level A in first grade standard of“Discharge standard of pollutants for municipal wastewater treatment plant”?GB18918-2002?.The water has been treated discharged into the main river in the city.However,due to the early design and construction of the first phase,quality of effluent could not be up to standard,upgrading and reconstruction are needed.Firstly,this article studies experiences of the status and the reconstructions of wastewater treatment plants at home and abroad,introduces the process at present used in the wastewater treatment plant studied in this article,and points out some problems of the wastewater treatment plant.For example,water accumulated in the pump room,concentration of the inflow is unreasonable and so on.Secondly,analyzing the water volume and quality data and the operational status of the wastewater treatment plant.And re-determine the concentration of inflow through the analysis of the data of inflow:COD=300mg/L,BOD₅=180mg/L,SS=180mg/L,NH₃-N=30mg/L,TN=40mg/L,TP=6mg/L;And find that the indexes of BOD₅,TN and TP could meet the level A in first grade standard hardly.Finally,for the problems and emphasizes of the sewage treatment plant,analyzing different plans at each treatment unit to put forward two General reform schemes.Then we can obtain the best reconstruction plan After chosen by Procedure quantizing method.In the physicochemical treatment,add PAC into the grit chamber to remove the TP.HRT of Primary settling tanks of the first and second phases is longer than 1.5h,in order to ensure the BOD₅ concentration of inflow of the biological treatment system,transforming the Primary settling tanks to SSH tanks.In the biological treatment,analyzing different plans,the A²/O process was rebuilt to replace the old process,take account of reduce TN and TP.And rearrange aerobic zone heads.A²/O process will be converted to an improved A²/O process in the second phase to weaken the influences of the mix liquid that re-flow into the anaerobic zone.In the advanced treatment,choosing the process of coagulation sedimentation-filtration-UV disinfection.At the coagulation sedimentation unit,selecting the high-efficiency sedimentation tank,saves the floor space,reduces the load of the filtration unit,and adds PAC for chemical phosphorus removal in the unit;At the filtration unit.Because the new process have no Primary settling tanks,SSH tanks can Supply carbon source to the system,so D-type filter will work as it was.At the disinfection unit,through the comparison of chlorination disinfection,ozone disinfection and ultraviolet disinfection,to determine the original UV disinfection process.