Study On Process Design Of Reconstruction And Expansion Of A Traditional Chinese Medicine Hospital Sewage Treatment Station

With the rapid development of medical institutions and the enhancement of people’s awareness of environmental protection,the amount of hospital sewage has increased year by year,and the emission standards have become stricter,in addition,some hospital-supported sewage treatment stations have problems,such as unreasonable process design,aging equipment,outdated facilities and unreasonable selection of actual operating parameters,which make the existing hospital sewage treatment stations unable to meet the requirements of increaseing sewage quantity or meeting standards.Therefore,the research on the process design of reconstruction and expansion project of hospital sewage treatment stations becomes particularly important.The design scale of the sewage treatment station in a Traditional Chinese Medicine Hospital is 1000m³/d,the effluent implements the emission standard of comprehensive medical institutions in“Discharge standard of water pollutants for medica organization”GB18466-2005.As the first phase of hospital’s preparation building has not been opened,the water load rate has been maintained at 20%⁴0%since it was put into operation,which is far from the design scale,according to the measured data,the quality of effluent failed to meet the standard.And the second phase of the hospital project will expand a inpatient building with 550 new beds,the first phase established preparation building will also be put into production,and the hospital sewage will increase sharply,causing the treatment scale of the hospital sewage treatment station increase and the quality of the influent water is different.Therefore,this project carries out study on the design of reconstruction and expansion project of the Traditional Chinese Medicine Hospital sewage treatment station,the main results are as follows:（1）Based on the analysis of the measured water inflow and influent water quality data of the hospital sewage treatment station,combined with the analysis of the increase of water inflow and the characteristics of water quality in the reconstruction and expansion project,the design scale of the reconstruction and expansion project was determined to be 1500m³/d,the design water quality is as follows:COD_Cr=350mg/L,BOD₅=120mg/L,SS=300mg/L,NH₃-N=50mg/L,Coliform-group bacteria=1.6×10⁸MPN/L,Oil and grease=12mg/L,An-ionic sur-factant=15mg/L,TP=3.5mg/L,TN=55mg/L,pH=7.2;the effluent quality implements the emission standard of comprehensive medical institutions in GB18466-2005,TN and TP implement level B standard in the first class of GB18918-2002.（2）By analyzing the measured water quality of the hospital sewage treatment station,it is concluded that NH₃-N,TN,SS and residual chlorine can not meet discharge standards,combined with the analysis of the influent water quality characteristics,the operation status analysis and the calculation of treatment capacity of the existing structures,the study on the process of reconstruction and expansion of the hospital sewage treatment station for the problems existing in the current project.（3）The main results of the reconstruction and expansion project are as follows:Expand the equalization tank in the primary treatment;in the secondary biological treatment,the original A²/O process is transformed into A+A²/O process,and CH₃COONa as carbon source is added in the anoxic tank,adding suspended filler into the aerobic tank,and adding chemical dephosphorization agent PAC to the intake of the secondary settling tank;in the advanced treatment,900m³/d sewage is treated by multi-media filter for emission on standards,600m³/d sewage is processed by the combined process of the multi-media filter and activated carbon adsorption to reuse;the NaClO is used as disinfectant and ClO₂ as standby;the sludge treatment increases sludge disinfection process,and waste gas treatment retains original design process;moreover,in the reconstruction and expansion project a disinfection tank,a dephosphorization dosing room and a sodium acetate dosing room will be newly built,there Multi-media filter,two activated carbon adsorption tanks will be purchased.