Abstract: With the deterioration of eutrophication in China, nitrogen and phosphorus removal from wastewater have caught more and more attention, while influent C/P ratio is one of the most important influence factors. To investigate the effects of feed water C/P ratio on the performance of anaerobic-anoxic-oxic process, four different feed water C/P ratios were designed, that is 55, 45, 34,23, so as to study the variations of COD, TN, PO^3-₄-P and sludge characteristics with the C/P ratio. The results showed that when the C/P ratio was lower than 32, P removal efficiency increased as C/P ratio increased linearly, while the C/P ratio was higher than 32, the P removal efficiency maintained at 90%～98%, and effluent P concentration was lower than 0.5 mg•L^-1.In contrast, regardless of the C/P ratio, excellent COD (90%) and good total nitrogen removal (75%～84%) were maintained throughout the experiments.However, P percentage in the wasted activated sludge (WAS) increased as the C/P ratio decreased. It was also found that denitrifying P removal existed under different C/P ratios by controlling the operation, and nitrogen and phosphorus removal efficiency could be improved.

Key words: A²/O工艺, 进水C/P比, 生物脱氮除磷

摘要： 我国当前面临着严重的水体富营养化问题，A²/O工艺是一种有效的同步脱氮除磷工艺，但其中进水C/P比是其运行效果的重要影响因素，为深入考察不同进水C/P比对A²/O工艺运行性能的影响，试验设计了4种进水C/P比 (55、45、34、23)，研究了A²/O工艺中COD、总氮、磷和污泥特性的变化.实验结果表明，当进水C/P比小于32时，磷的去除效果随C/P比的降低而线性降低;当进水C/P比高于32时，磷的去除效果稳定在90%～98%，出水磷浓度小于0.5 mg•L^-1.但是C/P比的变化，对COD和总氮的去除率影响较小，平均去除率分别高于90%和75%.而剩余污泥中磷含量则随C/P比的下降而增加.实验发现，不同C/P比系统均存在反硝化除磷现象，可以实现“一碳两用”，有利于氮磷去除效果的提高.

关键词: A²/O工艺, 进水C/P比, 生物脱氮除磷