Study On The Treatment Efficiency And Sludge Activity Of A Sewage Treatment Plant In A Town In Northwest China Under Abnormal Operating Conditions

In recent years,the sewage treatment in Northwest China has been continuously deepened,and a large number of sewage treatment plants in small towns have been built.However,due to the lack of talents and backward technology,the effluent quality of sewage treatment plants is often substandard during commissioning and operation.At the same time,the sewage treatment plant facilities in small towns are not perfect and the water quality and water quantity fluctuate greatly,which leads to the phenomenon that the activated sludge biochemical system is easily impacted in the daily operation process,which will lead to the death of a large number of activated sludge microorganisms and then lead to the collapse of the sludge biochemical system.Therefore,this topic was aimed at the small town wastewater treatment plant operation problem,by the method of breathing pattern,water quality,sludge settling performance on the basis of research method,the water in the overweight status of some small town wastewater treatment plant in northwest debugging and optimizing operation analysis,studied the impact of different control measures and the corresponding characteristics of sludge respiration,sedimentation,and the change of water quality,examines the breathing pattern in guiding the debugging and running,the feasibility of wastewater treatment plant,and analyzes the plant effluent,the change rule of online data for new or existing sewage treatment plant in the northwest region of operation management to provide theoretical reference basis.Mainly draw the following conclusions:（1）During the commissioning and operation process of sewage treatment plant,the proportion of autotrophic bacteria in activated sludge was small,between 0% and 5%,and the proportion of heterotrophic bacteria was relatively large,above 80%.The number of autotrophic bacteria was less than that of heterotrophic bacteria,which is more sensitive to changes in operating conditions.（2）Under high organic loading（F/M）impact conditions,the characteristics of the respiratory pattern were higher the site specific oxygen uptake rate（SOUR_s）,the quasi-endogenous respiration rate and endogenous respiration rate values were higher,the autotrophic bacteria respiratory rate（SOUR_n）and heterotrophic bacteria in respiratory rate（SOUR_c）were decreased,two days after the heterotrophic bacteria respiratory rate（SOUR_c）has a slow upward trend,the autotrophic bacteria respiratory rate（SOUR_n）continues to decline,that impact of high load,autotrophic bacteria recovery ability is weak,heterotrophic bacteria more resilient;The characteristics of effluent water quality show that NH₄⁺-N,TN and TP values continue to rise;The sedimentation performance of sludge is characterized by a low SVI value,indicating that high organic load impact will reduce or inhibit microbial activity,and the ability of the system to remove pollutants decreases.（3）If the performance under the condition of determination of breathing pattern was: the site specific oxygen uptake rate（SOUR_s）,approve the quasi-endogenous respiration rate（SOUR_q）and the endogenous respiration rate（SOUR_e）increased significantly,the autotrophic bacteria respiratory rate（SOUR_n）,the heterotrophic bacteria in respiratory rate（SOUR_c）and breathing rate significantly decreased,impact of the sewage treatment plant by persistent high load or huge loss of microorganisms appear,should be timely adjustment measures.（4）Sewage treatment plant under the condition of short-term suspension shock,the characteristics of the respiratory pattern are lower the site specific oxygen uptake rate（SOUR_s）,the quasi endogenous respiration rate（SOUR_q）was basically unchanged,the autotrophic bacteria respiratory rate（SOUR_n）was lower,the heterotrophic bacteria respiratory rate（SOUR_c）was higher,it shows that sewage treatment plant to suspend operation impact of a smaller effect on the activity of heterotrophic bacteria and the effect on the activity of autotrophic bacteria;The sedimentation characteristics of sludge remain basically unchanged;The characteristics of effluent water quality showed slight fluctuations in NH₄⁺-N,TN and COD,continuous increase in TP value,large loss of phosphorusaccumulating bacteria or decrease in their activity,indicating that the temporary suspension of the sewage treatment plant had little impact on the denitrification capacity of the biochemical system,while greater impact on the phosphorus removal capacity of the system.（5）Under the condition of sewage treatment plant in sludge decay shock,the characteristics of the respiratory pattern are lower the site specific oxygen uptake rate（SOUR_s）,the quasi-endogenous respiration rate and endogenous respiration rate values were higher,the autotrophic bacteria respiratory rate（SOUR_n）was lower,the heterotrophic bacteria respiratory rate（SOUR_c）basically remain unchanged,that corruption and sludge impact of a smaller effect on the activity of heterotrophic bacteria and the effect on the activity of autotrophic bacteria;The characteristics of effluent water quality showed slight fluctuation of NH₄⁺-N and TN values,COD and TP exceeding the standard;The sedimentation performance of sludge is characterized by the increase of SVI value,indicating that the impact of putrid sludge will easily lead to the deterioration of the settlement performance of activated sludge.In the actual operation of sewage treatment plant,if the impact strength is high,sludge bulking will easily occur,thus affecting the effluent water quality.（6）For the A₂O⁺MBR treatment process in this plant,when the dissolved oxygen in the aeration pool was controlled in the range of 2³mg/L,the removal efficiency of NH₄⁺-N,COD,TP and TN were good,the removal rate were above 99%,92%,95% and 89%,respectively.The effluent water quality was far below the limit value of the national first-grade A emission standard;The proportion of quasiendogenous respiration was lower,and the proportion of endogenous respiration ranged from 8% to 16%,which was higher than that of autotrophic bacteria（SOUR_n）and heterotrophic bacteria（SOUR_c）.Sludge activity was higher,and the health state was good.（7）During the on-site period of technicians,the effluent values of NH₄⁺-N,COD,TP and TN showed a stable or declining trend;However,during the period when the technicians are not on-site,various effluent indexes fluctuate greatly,and it takes a long time for the effluent index value to recover to the original level after floating.Therefore,intelligent operation technology should be implemented in the areas with weak technical strength in northwest China to ensure the environmental benefits of water treatment facilities.