改性石英砂生物滤池深度处理污水厂二级出水

Modified Bio-sand Filters for Advanced Treatment of Secondary Effluent of WWTP

研究了天然石英砂、亲水改性石英砂、疏水改性石英砂和铁离子改性石英砂生物滤池对污水厂二级出水中NH+4-N及有机物的去除效能。结果表明,稳定运行期,以上4种滤池对NH+4-N的平均去除率分别为72.83%、90.68%、70.84%和89.89%,对COD的的平均去除率分别为8.81%、19.08%、9.35%和18.19%。挂膜初期,疏水改性石英砂生物滤池对UV254的去除率远高于其他3种滤池;稳定运行时,亲水改性、疏水改性和铁离子改性石英砂生物滤池对UV254的去除率比天然石英砂生物滤池分别提高了1.38倍、2.08倍和1.33倍。电镜扫描发现,亲水石英砂表面呈网状立体结构,比表面积较大;铁离子石英砂表面形成了一定的团状堆积物,粗糙度和比表面积增加,这两种石英砂会使生物可附着性增强,故对污染物的去除率较高。而疏水石英砂表面极性降低,对苯环类的大分子有机物吸附性较好,但生物可附着性变差。

The removal efficiency of NH4＋ - N and organics in secondary effluent of WWTP by nat- ural bio-sand filter, hydrophilically modified bio-sand filter, hydrophobically modified bio-sand filter and iron ion modified bio-sand filter was investigated. It was indicated that the average removal rates of NH4＋ -N and COD by four bio-sand filters were 72.83%, 90.68%, 70.84%, 89.89% and 8.81%, 19.08%, 9.35%, 18.19% respectively in the stable period. In the initial period of biofilm formation, the removal rate of UV254 by hydrophobically modified bio-sand filter was higher than others. In the stable period, the removal rates of UV254 by hydrophilically modified bio-sand filter, hydrophobically modified bio-sand filter and iron ion modified bio-sand filter were 1.38 times, 2.08 times and 1.33 times more than that by natural bio-sand filter respectively. The four kinds of sands were observed by electron micro- scope. It was showed that three-dimensional network structure was formed on the surface of hydrophilical-ly modified sand with a large specific surface area. The surface of iron ion modified sand had a certain accumulation, and its roughness and specific surface area were increased. So the two modified sands had higher removal rates of pollutants for good biological adhesion. Because the surface polarity of hydropho- bically modified sand was decreased, its adsorbability of macromolecular organic matter was better while its biological adhesion was worse.