Study On The Removal Of Nitrogen And Phosphorus Of MA~2/O Process

Anaerobic-Anoxic-Oxic process is generally called A-A-O, or A~2/O. Different from conventional activated sludge process, it was developed from the Anaerobic-Oxic which is the process for Biological Nitrogen Removal, and the A~2/O process can remove the nitrogen and phosphorus in a same flow. A~2/O process is a suitable technology with easy operation, high efficiency and low consumption.The paper summarized the characteristics of the operation and performance from all kinds of A~2/O process. And tries to propose a new process, which was named for MA~2/O (Modified Anaerobic-Anoxic-Oxic process)on the basis of analyzing Inverted A~2/O process and QiaoBen process, The MA~2/O process is composed of 5 parts: prior- Anoxic Anaerobic, OxicⅠ, Anoxic, OxicⅡ. The prior-Anoxic part is designed to remove the NO_x~- -N from the returned sludge, which comes from the sedimentation tank. The part of Anaerobic, OxicⅠand Anoxic is the regular process to remove the nitrogen and phosphorus. The OxicⅡis designed to blow out nitrogen and to enhance the efficiency of the system. The paper concludes several running parameter of the MA~2/O process, which are suitable for domestic wastewater disposal.The experimental study revealed that, when the system hydraulic retention time was 8.0h, the inflow surpass ratio was 30%, the hydraulic retention time of prior-Anoxic tank was around 0.5h, the COD of inflow was 173-330mg/L, TN was 11.5-33.7mg/L, TP was 2.43-4.11mg/L, sludge concentration was 2.2-2.7g/L, and the sludge loading was 0.39-0.61kgCOD/(kgMLSS·d), the removal efficiency and economic was the better, the COD of outflow was 15.6-37.8mg/L, average removal rate was 89.7%, TN was 1.2-12mg/L, removal rate was 72.7%, TP was 0.16-0.55mg/L, removal rate was 88.2%.The microbial kinetics equation of MA~2/O reactor is as follow:或:...