Optimal Operation Study Of Improved A/A/O In An Qing Chengdong Treatment Plant

Anqing Chengdong sewage treatment of Anqing uses modified A/A/O technology, which can treat sewage of 70000m³/d, run since March of 2007. Stability in the trial operation period, the task force study and analysis of the modified A/A/O technology on pollution;a flow test and aerobic pool of the optimization of operating parameters were done to study of the removal of the effect and removal mechanism.The results showed that stable operation: improved A/A/O for the removal of COD average 83.5%, NH₄⁺-N removal rate for an average of 93.1%, SS average removal rate was 86%, the effluent quality to the "urban sewage Treatment plant pollutant discharge standards "(GB18918-2002) 1B standards, but for the average removal TN was 33.8%, TP's average removal rate was 21.3%. The results showed that material balance: the anaerobic pond, dissolved organic matter was microbial cells absorb sewage concentration of COD dropped, NH₄⁺-N because of the cell, which was partly removed. In the biological selection pool, a pool hypoxia, denitrifying bacteria in the use of sewage for organic carbon, will be back in the mixture into the large number of NO3--N and NO2--N reduced to N2 released to the air. In aerobic pond, organic chemical and biological degradation by microorganisms and continues to decline, organic nitrogen was ammoniated then be nitrification. Process of COD, N balance of the respective percentages of up to 83% and 93%, removal of organic pollutants and the mechanism of traditional A/A/O technology similar. Test results show that aerobic ponds are dead ends or short-circuit flow, and there are some back-mixing phenomenon. East aerobic one tank close to a complete mixed flow; East overall aerobic 1,2tank close to gradually push flow; aerobic pool of the process flow model should be a certain number of push-reactor (PFR) and full-Francis reactor (CSTR) combination. Mobile computing model of PFR and CSTR share of the volume, improve the reactor can be used as the basis for the function.Aerobic pool of operating parameters for the better: SV3015% around, BOD5 sludge load to 0.10 - 0.30 kgBOD5 / (kgMLSS·d), within three corridor aerobic oxygen tank than to 1.64:1:1.