Study On Process Design And Commissioning Of Improved A~2/O+MBR

With the development of the society and gradual growth of the population,the domestic sewage caused by improved living standards increase continuously,thus resulting in the gradually saturated water environmental capacity.Therefore,it is urgent to control the total amount and concentration of pollutants discharged into the water environment.The effluent standard of urban domestic sewage treatment plant is further improved.The three main pollutant indexes of chemical oxygen demand,ammonia nitrogen and total phosphorus reach the standard V in the environmental quality standard for surface water(GB3838-2002),and other pollutant indexes reach a discharge standard of grade A.Membrane bioreactor(MBR)as a wastewater recycling technology developed in the late20 th century is very effective for wastewater treatment.The combination of improved A~2/O+MBR process is conducive to the design,construction and operation of urban domestic sewage treatment plant.Taking a municipal sewage treatment plant with a daily treatment capacity of 150000 m3/h in Shanxi Province as an example,after determining the inflow water quality,sewage discharge standard,determining the engineering properties(new construction or reconstruction),and comparing various processes,the improved A~2/O+MBR process is finally selected as the core treatment process of the project.During the process design of the sewage treatment plant,the design parameters shall be selected according tothe specification requirements,combined with the local actual situation and the experience of similar projects,so as to reduce the investment of civil engineering equipment and carry out the design transformation for the corresponding process when the effluent reaches the standard.The improved A~2/O+MBR process is debugged and run to optimize the operation parameters in order to reduce the operation cost.The results show that during the commissioning of the sewage treatment plant,the on-site operators should pay more attention to the carbon source dosage and the operation of the equipment.After the chemicals are added,the C/N of the biochemical tank is better at 4-6.When the water volume is 7000 tons / day,the carbon source dosage is easy to be 2000 kg/d.The fluctuation of water quantity has an effect on the quality of effluent water,and the fluctuation of TN affected by water quantity is obvious.In aerobic area,the amount of aeration is insufficient,nitrification is inhibited,and denitrification basically has no obvious change.When the single biochemical tank is under full load operation(i.e.the treatment water volume is 7500 tons / day),the frequency of the blower in the biochemical tank shall not be lower than 35 Hz,and the design parameters of the primary,secondary and tertiary reflux shall remain unchanged.