Study On The AMC-PPC/MBBR Process Based On The New Biocarrier For Small Scale Of Domestic Sewage Treatment

With the development of our country's economy and the continuous advancement of urban integration,the discharge of wastewater from urban residents has gradually increased,and the problem of environmental pollution has been serious year by year.The urban sewage treatment has gradually received attention.Therefore,it is urgent to find an urban sewage treatment process with high treatment efficiency,affordable and less residual sludge.Currently,the biological treatment method has the advantages of good treatment effect,simple equipment,low installation and operation cost,and has been widely used in industrial wastewater treatment and urban sewage treatment plants.Due to the advantages of high volumetric load,high efficiency,impact resistance,small footprint,etc.,the MBBR process has great potential application value in the field of process improvement of urban sewage treatment plants in our country.The treatment efficiency and optimal operating parameters of the AMC/PPC-MBBR process for the actual domestic wastewater during the start-up and stable operation stage were explored in this paper.The growth status of the internal microorganisms in two new fillers AMC and PPC was monitored to study the effect of two fillers on the treatment effect of the process and the sludge reduction effect,this study can provide guidance during the actual operation of the process.Through macroscopic and microscopic analysis of AMC and PPC,the mechanisms of efficient treatment of urban domestic sewage and sludge reduction were explored,which provided a theoretical basis for the future engineering application of the process.The main conclusions of this paper are as follows:?1?Under the condition of volume load at 0.5 kgCOD·m^-3·d^-1,the coupled MBBR process with AMC and PPC as filler was started up at room temperature.After 10 days of operation,removal rates of COD,NH₄⁺-N and BOD₅ of the university domestic sewage can reach about 90%,above 99%and about 90%,respectively,which indicated that the process can be successfully started within 10 d.By stepwise lifting the volume load of the process,1.5 kgCOD·m^-3·d^-1 was determined as the optimum operating volume load of the process.?2?Under the condition of volume load 1.5 kgCOD·m^-3·d^-1,the effluent quality of AMC-PPC/MBBR process was determined and calculated after 20 d of continuous operation.The average effluent COD,NH₄⁺-N and BOD₅ concentration were 48 mg·L^-1,0.95 mg·L^-1 and 9.75 mg·L^-1,respectively,which reached the level 1 A-standard of the discharge standard for municipal sewage treatment plant?GB 18918-2002?.?3?In order to obtain the secondary start-up parameters and the conditions of the AMC/PPC-MBBR process,the process was stopped for 3 d and 6 d,respectively,and after the second start-up to stable operation,the removal rate of COD and NH₄⁺-N can reach 85.47%and 99.30%,respectively after stopped for 3 d;after stopped for 6 d,the removal rate of COD reached the maximum value of 86.51%after 4 days of operation,and the removal rate of NH₄⁺-N can reach 97.04%on the 2nd day.Therefore,the secondary start-up time of the process was short and the effect after the second start was better.?4?By macroscopic and microscopic characterization of AMC particles and PPC carrier during operation,it was found that a variety of microbial strains appeared on the surface and inside of AMC particles and PPC carrier,forming a stable biofilm system.On the one hand,the biomass in the process system is increased.At the end of the operation,the carrier biomass reached 220.7 mg·L^-1,which enhanced the sewage treatment effect;on the other hand,the refinement and integrity of the ecosystem prolonged the microbial food chain.The biological predation effect was beneficial to the sludge reduction.The apparent yield of the sludge during the operation of the system was only 0.043 kg MLSS/kg COD.Figure 38,table 11,reference 61.