Dissertation > Environmental science, safety science > Processing and comprehensive utilization of waste > General issues > Wastewater treatment and utilization

Regulation and Control for Enhancing the Efficiency of An A~2/O System Treating Cold Wastewater

Author GuoYaQiong
Tutor LiJianZheng;ZhangFuGui
School Harbin Institute of Technology
Course Environmental Engineering
Keywords Low temperature wastewater Biological Nutrient Removal A ~ 2 / O process Anaerobic phosphorus release Performance of sludge
CLC X703
Type Master's thesis
Year 2011
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Low winter temperature conditions Songhua River water pollution is serious, the reality of low efficiency of sewage treatment facilities, in preliminary studies low temperature A 2 / O system performance control strategy in the proposed in the secondary settling tank additional the anaerobic phosphorus removal process unit ideas to through the stimulation of anaerobic conditions, strengthen the sludge anaerobic phosphorus release, while increasing aerobic metabolic activity of microorganisms, to achieve the full increase A 2 / O system, the purpose of the processing performance. The trial of the study and build A 2 / O low temperature sewage treatment system, run through the regulation explored to improve the processing performance strategies and methods. The test results of processing the low temperature of 14 ± 1 ℃ sewage the A 2 / O system has good removal effect of COD, nitrogen and phosphorus removal effect is less than ideal, so the need for system nitrogen and phosphorus removal performance optimized control. First, in the case of the system does not consider Dephosphorization, denitrification performance of the system is optimized, the results indicate that the return sludge in settling tanks, in more than 75%, the nitrification liquid reflux ratio of 100% under conditions TEMPERATURE A 2 / O system can be made better nitrogen removal system average effluent ammonia nitrogen, TN concentrations were 13.40 mg / L, 28.23 mg / L, the average removal rates were 74.61% and 55.35%. To further enhance the low temperature A 2 / O performance of phosphorus removal in the secondary settling tank after the addition of anaerobic phosphorus release pool, and in the static tests to determine the initial anaerobic phosphorus release pool run control parameters on the basis of further investigated continuous flow state under anaerobic phosphorus release activated sludge reflux than A 2 / O system nitrogen and phosphorus removal performance. The results indicate that the anaerobic phosphorus release pool suitable operating parameters: The sludge load between 0.015 0 .02 gCOD / gMLSS the of NO 3 - concentration of less than 5 mg / L, SRT 12 h, stirring slowly. Anaerobic phosphorus release sludge return ratio increases to improve the system synchronization nitrogen and phosphorus removal, reflux ratio of 75%, the average effluent COD, ammonia nitrogen, TN and TP concentrations were less than 30 mg / L, 5 mg / L, 15 mg / L, 0.5 mg / L. Low temperature A 2 / O system sludge characteristics analysis showed that the removal of pollutants significantly reduced with the decrease of the MLSS. Scanning electron microscopy of the activated sludge, anaerobic zone, anoxic and aerobic segment of the dominant flora Brevibacterium, the long bacilli and single cocci; the aerobic sludge bulking phenomenon segment mainly by the large number of filamentous bacteria the breeding cause, accompanied by high viscous sludge bulking to take increases DO, organic load and measures to increase the mud amount of sludge bulking can be effectively controlled after 35 d.

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