Stability Evaluation And Short-term Fault Analysis Of Sewage Treatment Plant

At present,the sewage treatment plants ubipuity bio-pool bubble,the second settling tank sludge floating and the effluent water quality not up to standard,resulting in the sewage treatment plant not run stably.In the sewage plant operation process,due to sudden power cut,equipment failure and other reasons,causing sewage plant to stop running in short term,and aeration tank to stop aeration,this is one of the reasons that sewage plants cannot be stable.In this study,five sewage treatment plants in Xi'an were first investigated,and the indexes of water quality,sedimentation performance and respiration map of each sewage treatment plant were measured,and the change characteristics of each index were studied with time.According to the research results,the mathematical statistics method is used to construct the evaluation index and the standard system of the stable operation of the sewage treatment plant,and the data of the sewage treatment plant are verified by field investigation,and the evaluation system is feasible.And then use the laboratory equipment to simulate the characteristics of water quality,extracellular polymer substences and respiratory map in the short-term stopping operation mode of the WWTP to analyze the effect of the running time of the sewage treatment plant on the activated sludge.The results are as follows:(1)Through the investigation results of different sewage treatment plants,the effluent water quality was not up to standard,the difference of the settling performance of the activated sludge was large and the fluctuation of the respiratory map was obvious,which indicated that the operation of the sewage treatment plant was unstable;(2)Using the mathematical statistics method,the standard deviation coefficient,skewness and the range coefficient of water ammonia nitrogen,effluent COD,MLSS and SVI were calculated to reflect the fluctuation of the effluent quality and the settling performance of the activated sludge.Constructing the evaluation index and standard system of the stability evaluation of the WWTP,and evaluating the sewage treatment plant by the comprehensive weight,the results are in agreement with the actual sewage treatment plant,the evaluation system is feasible.(3)Under the condition of suspended operation of the WWTP,the TP and COD in the water quality index increased obviously,the ammonia nitrogen and the nitrogen were gradually decreased and the nitrite nitrogen remained.In the EPS index,the protein content in TB-EPS changed abruptly within 12 h,The contents of polysaccharides in LB-EPS and TB-EPS were decreased by about 50% at 24 h,and the content of polysaccharides in S-EPS was almost unchanged.The content of polysaccharides in LB-EPS and S-EPS increased slightly.(4)In the respirogram indicators,the current status respiratory rate changes obviously,the respiration rate of the heterotrophic bacteria and the total respiration rate were the second,and the respiration rate,the endogenous respiration rate and the respiration rate of the autotrophic bacteria were smaller.(5)The proportion of endogenous respiration continued to decline after the suspension of the WWTP.When the suspention time was 36 h,the microbial activity of the activated sludge will change greatly,which will affect the normal operation of the sewage treatment plant.