The active sludge seniment accumulated in the setting tank is to be returned to the aeration tank for reproduction of aerobe medium and retreating.

• 在接触氧化室内挂有软性填料，充作生物膜，有机物得到进一步消解，在沉淀柜内累积的活性污泥沉淀物再被返送至曝气柜作为菌种繁殖和再处理。