不同运行模式下CAST工艺脱氮除磷性能研究

采用三个结构相同的循环式活性污泥法（CAST）反应器,对常规模式、缺氧好氧模式、缺氧好氧交替模式运行下系统的脱氮除磷性能进行了研究,分析了CAST工艺脱氮除磷的限制因素,并且比较了不同运行工况下的系统污泥沉降性能.结果表明：温度为24,℃时,反应器在三种运行工况下总氮的平均去除率分别为67.32%,70.64%8,2.43%,脱氮过程中的限制性因素为曝气时间及温度;增设缺氧搅拌可以提高系统脱氮效率,从而降低回流液体的硝态氮浓度,进而有助于正磷酸盐去除率的提高,三种工况下系统正磷酸盐的去除率分别为65.66%,81.40%,98.01%;三种运行工况下系统内污泥均未发生污泥膨胀,工况三模式下的反应器中的污泥的SVI值在80,mL/g左右,沉降性能最好.

Research on Nitrogen and Phosphorus Removal Performance of CAST Process under Various Operation Modes

Three uniform laboratory-scale Cyclic Activated Sludge Technology（CAST） reactors were operated to evaluate nitrogen and phosphorus removal performance under three operation modes： conventional mode,anoxic/oxic mode,anoxic and oxic alternating mode respectively.Limiting factors of nitrogen and phosphorus removal were analyzed,at the same time the sludge settle abilities under various operation modes were investigated.Results showed that when the temperature was 24 ℃,the total nitrogen removal efficiencies under three operation modes were 67.32%,70.64% and 82.43% respectively,which indicated that the limiting factors of nitrogen removal in the CAST reactor were aeration time and temperature.The total phosphorus removal efficiencies were 65.66%,81.40%,98.01% separately,due to the anoxic stirring phase added in the cycle and the drop of NO3-N concentration in the return liquid.Under three operation modes,there was no sludge bulking existing in the system.The SVI value of the sludge under the third operation mode was around 80 mL/g with the best sludge settle ability.