Field Study on Dephosphorization for Rural Sewage Treatment

为了开发适合农村等小型污水处理厂的新型铁滤池除磷工艺，在3个不同系统的实际污水处理厂进行了现场试验。1.在平山地区的接触曝气法中的应用在第一次试验中，将1160块铁滤池浸没在接触曝气池中。利用生物膜的生长，通过细菌腐蚀铁滤池，使铁离子溶出，从而实现稳定的除磷;第二阶段，将2400片铁滤池浸没在厌氧池中，由于生物膜的堵塞，磷的去除率逐渐降低.在Hanami地区的转盘法应用在该工厂，60张塑料盘被替换为铁盘。塑料圆盘处理出水磷浓度平均为4.1mg/l，而铁圆盘处理出水磷浓度平均为2.2mg/l，更换铁圆盘后1.5a内平均去除率为53%.间歇曝气法在居安寺地区的应用无铁滤池的处理池出水磷浓度逐月波动较大。但带有浸入式铁过滤器的水箱中的含量几乎总是低于1 mg/l。实验期间平均去除率在60%~ 80%之间。浸没式铁滤池对BOD、COD和氮的高去除率无不利影响。

In order to develop the new treatment method of phosphorous using submerged iron filter, adaptable to the small-scale sewage treatment plants such as those of rural community, field expeiments were carried out in three practical treatment plants of different systems.1.Application to contact aeration method at Hirayama districtIn the first experiments, 1160 pieces of iron filter were submerged in the contact aeration tank. Iron ion was desolved from the iron filter with bacteria corrosion according to the growth of biological menbrane, and then the stable dephosphorization was achieved.In the second, in which 2400 pieces of iron filter were submerged in anaerobic tank, phosphorous removal rate was gradually decreased by the blockage of biological menbrane.2. Application to rotary disc method at Hanami districtIn this plant, 60 sheets of plastic discs were replaced by the iron discs. Although the phosphorous concentration of treated water in plastic discs was 4.1 mg/1 in average, that of iron discs was 2.2 mg/1 in average, and the average removal rate was 53% during 1.5 years after replacing iron discs.3. Application to intermittent aeration method at jyouanji districtThe phosphorous concentration of treated water from the tank without iron filter was remarkably fluctuated month by month. But those from the tank with submerged iron filter were almost always less than 1 mg/1. The average removal rate was between 60 and 80% in the period of experiment. Submerged iron filter did not show any detrimental influences on high rate removal of BOD, COD and that of nitrogen.