温度和pH值对活性污泥法脱氮除磷的影响

Effects of temperature and pH on nitrogen and phosphorus removal by activated sludge

温度和pH值是影响污水脱氮除磷效果的2个重要因素。试验采用连续搅拌槽式反应器(continuous stirredtank reactor,CSTR),通过对不同温度和pH值条件下的硝化、反硝化、释磷和吸磷反应速率的测定,总结出温度和pH值对活性污泥生化反应速率的影响规律。试验表明,硝化和反硝化速率随温度的升高而加快。在5℃和33℃时,硝化速率分别为0.01 kg NH4+-N/(kg VSS.d)和0.28 kg NH4+-N/(kg VSS.d);在5℃和30℃时,反硝化速率分别为0.097 kg NO3--N/(kg VSS.d)和0.476 kg NO3--N/(kg VSS.d);但温度对吸磷和释磷速率的影响不大。pH值对硝化、反硝化、吸磷和释磷速率均有显著影响,在pH值为7.74时,硝化速率为0.095 kg NO3--N/(kg VSS.d);而在pH值为4.9和10.08时,硝化速率仅为0.005 kg NO3--N/(kg VSS.d)和0.006 kg NO3--N/(kg VSS.d)。在pH值为7.85时,反硝化速率达到最大值0.36kg NO3--N/(kg VSS.d);而在偏酸性和碱性条件下,反硝化速率显著下降。

Temperature and pH are two key factors affecting the biological nitrogen and phosphorus removal in sewage treatment. The experiment, adopting CSTR（continuous stirred tank reactor）, through measuring the nitrification and denitrification rate as well as the phosphorus＇ releasing and adsorbing rates at different temperatures and pH conditions, summarizes the effects of temperature and pH on the biochemical reaction rate of activated sludge. The experiment indicates that the nitrification and denitrification rates accelerate along with rising of the temperature. The nitrification rates are 0.01 kg NH4^＋ -N/（kg VSS ·d） and 0.28 kg NH4^＋-N/（kg VSS ·d） at 5℃ and 33℃ respectively. The denitrification rates are 0. 097 kg NO3^- -N/（ kg VSS · d） and 0. 476 kg NO3^- - N/（kg VSS · d） at 5℃ and 30℃ respectively. The pH has a great effect on nitrification and denitrification, phosphorus＇ releasing and adsorbing rates. The nitrification rate is 0. 095 kg NO3^- -N/（ kg VSS · d） at the pH of 7.74. The nitrification rates decrease to 0. 005 kg NO3^- -N/（kg VSS ·d） and 0. 006 kg NO3^- -N/（kg VSS · d） at the pH of 4.9 and 10.08 respectively. The denitrification rate reaches the maximum of 0.36 kg NO3^--N/（kg VSS · d） at the pH of 7.85 and it dramatically decreases under weak acid and alkalic conditions.