Research On The Engineering Application Of High Concentration Activated Sludge Process Treating Wastewater

With the development of urbanization of china and with the perfection of theenvironmental protection policy of the state and with the improvement of our livingstandard and the treatment of sewage of our country，Nowadays, our economic is ina rapid development, so we will need more water resource. But our country is lackof water, so in our country projects of sewage for recycled water gradually increase.General secondary sewage treatment process could not meet the recycled waterrequirements as for ammonia nitrogen.This paper is mainly designed to study the debugging process of the sewagetreatment project and deeply analyses the processing efficiency of aeration tank ofhigh concentration, determined the operation parameters, after the analysis of theproject, the reliable recommended parameter will be found out to make thedesigning, constructing and operating of such project more and more efficient.The sewage treatment plant is designed to have a Capacity of50000m3/d. Thetreated water was used for regenerated plant, and the regenerated plant provides thelocal power plant for recirculated cooling water. To reduce the difficulty of therenewable water treatment, the effluent Pollutant index was designed in this way:COD≤30mg/L,BOD₅≤5mg/L,SS≤3mg/L,NH₃-N≤1mg/L,TP≤1mg/L.The effluentWater quality index standard is better than level of A standard of the urban sewagetreatment plant emissions standards （GB18918-2002）.In this paper, the engineering application in wastewater of activated sludge wasbriefly introduced in the beginning, also, the application and characteristics of highconcentration activated sludge process was summarized. Engineering designmaterials and the process flow were also described in system. Then thedomestication and cultivation of activated sludge in initiating stage was illustrated.Running conditions and influencing factor were studied in training process ofcontinuous flow. After36days,the debugging was successfully accomplished，effluent was in a stable state and sludge concentration was at about4500mg/l,Sludge sedimentation performance was well.Although the space is divided, a large proportion of the ring inside backflow,activated sludge is in a mixed state. So in this paper influencing factor in aerationzone is analyzed，the best process parameter was decided and overall operation costwas analyzed. The effluent quantity had satisfied the design requirements In theprocess of stable operation，inflow water quality was analyzed. And also theanalysis of the removal effect of the Primary stage of processing was given. The removal effect of each index and the influencing factor were studied.In this paperinfluence of stock load,temperature and DO concentration to system was presented.And also a decision was made that the stock load had a small influence on system.And when the temperature is low, the result was not well; the effluent quantity inlow temperature was less than that in highly temperature, especially for ammonianitrogen removal effect. In the state of low dissolved oxygen, about sludgeconcentration was maintained at5000mg/l and Sludge sedimentation performancewas well and effluent was in a good state.After the debugging, the optimal operation parameters were decided: DOconcentration in aeration zone was at around0.3～0.6mg/l. DO concentration instrengthen aeration zone was at about2.0mg/l～3.0mg/l and Reflux ratio wascontrolled in0.8.Theaverage COD concentration in the effluent is about30mg/L.The BOD₅concentration in the effluent is5～10mg/L, the SS concentration in theeffluent is1～10mg/L, the NH3-N concentration in the effluent is0～3.0mg/L, theaverage TN concentration in the effluent is less than15.0mg/L. The effluent Waterquality index standard is better than level of A standard of the urban sewagetreatment plant emissions standards （GB18918-2002）.If the process parameterswere well controlled, the effluent meet the design requirement.