Presently, active sludge method, or the establishment ofsecondarysewagetreatment plants has been mainly adopted to treat urban sewage.
目前，对城市污水的处理主要采用活性污泥法即兴建城市二级污水处理厂。
2
The secondary treating water from urban domestic sewagetreatment plant was treated by fine membrane with the way of periodic counter-flow static type.
本研究对城市生活污水处理厂二次处理水，采用周期逆洗型静态过滤方式进行了精密膜过滤。
3
Aiming at the poor effect of amino nitrogen degradation in conventional refinery oil sewagetreatment, the secondary biochemical test was carried with biological aeration filter pool.