Technical Scheme And Commissioningooperation Of Biological Product Wastewater Treatment Expansion Project

With the country’s increasingly strict sewage discharge requirements,the original sewage treatment system of Anhui Hefei Huashengsheng Products Company’s water quality can not meet the new discharge standards.At the same time,the company is also faced with the expansion of production requirements,the original sewage treatment system treatment water can not meet the demand for drainage after the expansion.Therefore,it is urgent to transform the original sewage treatment system.And the company hopes to make full use of the original structure on the basis of transformation,so that the treatment capacity of the transformed sewage treatment system can meet the drainage requirements of the workshop,and at the same time,the operation is stable and meet the new discharge standards.In view of the problems faced by the enterprise in sewage treatment,the following three aspects of work have been done in this transformation:First of all,through the analysis of the original sewage treatment process,proposed the existing problems of the original sewage treatment process,and according to the reference of domestic and foreign literature and data,combined with the actual limited conditions in the case of the overall transformation of the technical scheme.By increasing air mixing in the regulating pool;The inlet way of workshop drainage into the regulating pool is changed to multi-point inlet;The fluctuation of water quality in the regulating tank can be reduced by off-line regulation of high concentration wastewater.And the mother liquor produced in the workshop is recycled after evaporation through the MVR evaporator,which reduces the water quality of the wastewater and generates income for the enterprise.The transformation technical scheme retains the original high-efficiency anaerobic+nitrification and denitrification process,changes the original IC-secondary AO process to IC-UASB-secondary AO process,changes the series operation mode of the original two IC reactors to parallel operation,and changes the concurrent oxygen pool to UASB reactor by changing the structure and equipment inside the pool.The organic matter removal ability of the sewage treatment system is improved.The original AO longitudinal volume of the tank was expanded,and nylon filler was hung in the whole tank,so as to realize the contact oxidation process.This scheme aims to increase the capacity of the sewage treatment system from 100m³/d to 300m³/d without increasing the floor area.Secondly,after the transformation plan is put forward,the technical plan is implemented in full combination with the production requirements of the workshop,and the reformed system is debugged according to the actual transformation situation.In the commissioning process according to the water quality concentration of the regulating pool to determine the amount of water intake to ensure the stability of the system load.As for the anaerobic system,the parameters such as influent p H,alkalinity,temperature and rising velocity of the anaerobic reactor are strictly controlled to ensure the stable operation of the reactor.In the actual operation,the carbon removal capacity of the anaerobic reactor reaches the design standard and can meet the carbon removal requirements of the workshop drainage.In terms of denitrification system,by controlling the temperature,C/N,nitrification liquid return flow,mixing effect in the denitrification tank;The parameters of aerobic tank,such as DO,MLSS,FA,temperature and sludge return flow,can realize the effective nitrogen removal in the system.The short-cut nitrification and denitrification process is realized in the first stage AO,which reduces the energy consumption for the system operation.In addition,by gradually reducing the sludge return flow,the contact oxidation process is realized in the denitrification system,which reduces the sludge discharge volume of the system.After debugging,the nitrogen removal capacity of the denitrification system can reach the expected standard,and the system can realize stable operation while the effluent meets the new discharge requirements.Finally,in the actual debugging process,the problems still exist in the reformed system are found,and measures are taken for further optimization.The problem of uneven water distribution in UASB reactor was solved by changing the inflow mode.By changing the internal pipeline of the IC reactor,the problem of excessive load leading to mud running was solved.Through the use of coagulation and sedimentation process,the problems of high chroma and high COD of the system effluent are solved,and compared with the treatment capacity of the same type of wastewater and the same type of treatment process.After the transformation,the sewage system treatment capacity can meet the demand of the discharge after the expansion of production,and the system runs stably,and the treated water volume increases from the original 100m3/d to 250-300m³/d.The removal rates of TN,COD and NH₄⁺-N of effluent are about 95%,96%and 99%respectively,all meeting the new discharge standards,and the energy consumption and drug consumption per ton of water are reduced from 7.46 yuan to 6.67 yuan.Through the actual debugging of the system,the control conclusions of the parameters of the structure are as follows:（1）Through the control of the influent p H and the control of the rising velocity in the reactor,the rapid start of the IC reactor can be realized.When the influent p H is controlled between 6.5-7.5 and the ascending flow rate of the IC reactor is controlled within 3m/h,the IC reactor can be started within 20 days.After the start-up,the maximum removal load of the IC reactor can reach 7kg/（m³·d）,and the removal rate is about 85%.（2）The problem of uneven water distribution in the UASB reactor can be solved by changing the intake of the UASB reactor to three and uniformly distributed at the bottom.The inlet mode adopts the intermittent inlet mode,and the local rising velocity of a single inlet is controlled at 1m/h.After the transformation,the maximum removal load of the UASB reactor is increased to 4kg/（m³·d）,and the removal rate is about 80%.（3）When C/N in the denitrification tank is controlled at 5,the reflux ratio of primary AO nitrification liquid is controlled at 300%,and the reflux ratio of secondary nitrification liquid is controlled at 100%,stable operation of AO system combined anaerobic reactor can be realized within 20 days.During normal operation,the maximum total nitrogen removal load of denitrification system is 0.35kg/（m³·d）.Short-cut nitrification and denitrification process can be realized when the influent total nitrogen load is higher than0.2kg/（m³·d）,FA is greater than 1,and DO value is controlled within 0.8-1mg/L.（4）The use of coagulation and sedimentation process for advanced treatment of the effluent from the sedimentation tank can effectively solve the problems of high chroma of effluent and high COD value that is difficult to degrade.When the dosage of PAC is about0.03kg/m³and the dosage of PAM is about 6g/m³,the effluent COD removal rate is43.67%,and it is expected to increase the water treatment cost by 0.5 yuan per ton.