Application And Research Of A/O+MBBR Combined Process Of Industrial Sewage Treatment

The comprehensive industrial wastewater of petroleum chemical industrial park has its characteristics of complicated composition,low biochemical degradability,large fluctuation of water quality and quantity,poor biodegradability.Now it has been designed to adopt the combined process of Hydrolytic Acidification & A/O + MBBR after feasibility studies based on its production characteristics of manufactories and combining with operating effects of old industrial wastewater treatment plant.To ensure meeting the quality standards of treated water steadily,the feasibility of the combined process has been verified by tests,and the processing conditions of physicochemical and biochemical treatment stages have been optimized.The COD and NH3-N removal efficiency of the combined process achieved relatively satisfactory result.The tests result supported the design processing parameters,thus the best operating parameters could be confirmed;and it also offered a dependable technical support for the system design.The pilot scale study underwent three stages,namely,equipment commissioning,sludge cultivation,and membrane forming of the packing materials.Then on May 5th in 2016,the device started continuous feeding by design load,and the pretreatment had achieved the desired objective,which the BOD5/COD increased to more than 0.33.Through changing water inflow and air supply and adjusting process parameters such as HRT,DO,etc.,it was proved that when HRT=9h,DO=2~4mg/L,COD and ammonia nitrogen removal efficiency could be up to above 89% and 81% separately,which is the optimum process parameters as same as the design parameters.Thus,it truly met the discharge standard and the running cost would be the lowest.This dissertation showed that effluent quality of the combined treatment process can meet the intended treatment requirements under the optimal running conditions.In order to further analyze the trend of the key influencing factors,the experiment was carried out on the basis of the optimal working conditions,then adjustment of the process parameter was made gradually with operating data combined with theoretical analysis.The effects of different parameters such as dissolved oxygen,hydraulic retention time,pH and temperature on the treatment efficiency were analyzed.At the same time,the sludge quantity of the combined process and the Activated Sludge Process were compared by the tests,and the result showed that the sludge residue of the combined process is lower.Once the project is put into operation,the industrial sewage disposal in the area will realize specialization and large scale,and will achieve economies of scale by centralized treatment of industrial sewage.It was estimated that the emission of the COD and Ammonia Nitrogen would reduce 9636 T/a and 383.3T/a separately,which not only economizes one-time investment and operating cost,but also makes it manageable and easier to realize sewage discharge standard.