Acclimatization Of Multiple Microorganisms For Nitrogen And Phosphorus Removal In Wastewater At Low Temperature

The efficiency of sewage treatment is too low to meet standards of nitrogen andphosphorus emissions due to low temperature during winter in northern China. So it issignificant to develop technologies and products about low-temperature wastewatertreatment. The aim of the research was to acclimatize nitrification function flora,simultaneous nitrogen and phosphorus removal function flora and denitrifyingphosphorus functional flora by means of different control methods in a sequencingbatch reactor （SBR） at15℃. Nitrogen and phosphorus removal function floras werestudied for providing foundation for separatation of denitrifyingphosphate-accumulating organisms further and developing enhanced nitrogen andphosphorus removal technologies based on efficient low-temperature sewage treatment.The results in acclimatizing low-temperature nitrification function flora and tests ofammonia oxidation activity showed inoculated activated sludge could obtain a betterammonia oxidation activity after acclimatized, with a specific ammonia nitrogen（NH₄⁺-N） removal rate of54.26g/kg-MLSS·d and specific nitrite nitrogen （NO₂^--N）producing rate of29.07g/kg-MLSS·d at an initial NH₄⁺-N of46mg·L^-1at15±1℃. TheNH₄⁺-N removal was achieved more than85%in the SBR when treating urban sewage.The acclimatized activated sludge also illustrated a better potential in treating highammonia nitrogen wastewater. The specific NH₄⁺-N removal rate could reach at52.54g/kg-MLSS·d and111.97g/kg-MLSS·d in the SBR when the initial NH₄⁺-Nconcentrations were91.01mg·L^-1and163.37mg·L^-1, respectively. Nitrite oxidizingbacteria （NOB） was more sensitive to pH than Ammonia oxidizing bacteria （AOB） inthe function flora. The ammonia oxidation rate was the highest at an initial pH of9.0and nitration rate was the highest at an initial pH of8.0. The Na₂CO₃was a goodcatalyst in acclimatizing process of activated sludge and the nitrification efficiency ofacclimatized activated sludge was increased by low concentration of COD and NaCl.Simultaneous nitrogen and phosphorus removal function flora was obtained fromconventional activated sludge through operation of anaerobic-aerobic-anoxic mode.Nitrogen and phosphorus removal was highest, with NH₄⁺-N removal rate, TN removalrate, TP removal rate and COD removal rate were98.80%,90.83%,85.80%and93.56%, respectively at the influent COD of400mg/L （C:N:P=200:20:2.5）.Phenomenon of sludge bulking appeared in SBR at influent COD of500mg/L.Denitrifying phosphorus function flora could be cultured by two stages ofanaerobic-aerobic and anaerobic-anoxic in the SBR, the NH₄⁺-N removal rate, TNremoval rate, TP removal rate and COD removal rate were97.62%,89.79%,94.12%and81.11%, respectively at influent COD of200mg/L（C:N:P=200:20:2.5）, meeting thenational level emission standards of A. Biofacies and microbial population variation of different periods in three function flora were investigated, corresponding to the impactof water quality and regulatory conditions. A denitrifying phosphate-accumulatingorganisms named Strain J6was isolated from low-temperature function flora, whichbelonged to Acinetobacter sp.by means of16S rRNA.