深床过滤与同步生物脱氮的研究

Study on Simultaneous Denitrification in Deep Bed Filtration Process

研究了深床过滤工艺对城市污水二级处理出水的处理效果及影响因素。将两个上流式滤柱串联,其中填充以3～4mm的聚苯乙烯发泡粒子,床层高度为2m。在第一个滤柱底部曝气以集成生物硝化,在第二个滤柱的进水中投加甲醇以集成生物反硝化。研究表明,在水力停留时间为1～2h时,硝化滤柱的氨氮脱除率达到90%,反硝化滤柱的硝酸盐氮脱除率达到95%以上,最终出水的浊度<1NTU,总的脱氮负荷可达1kg/(m3填料·d)。通过试验发现HRT、进水氨氮和外碳源对生物硝化和反硝化有重要影响。过滤介质能很好地吸附微生物而形成生物膜,在扫描电镜下观察到生物膜具有复杂的网状结构及生物相。另外,反冲洗质量对保证系统稳定运行及脱氮除浊效果有重要影响。

Deep bed filtration process was used for advanced treatment of secondary effluent from urban wastewater treatment plant, and its treatment effect and affecting factors were investigated. Two upflow filter beds were cascaded and were packed with polystyrene foaming pellet with nominal diameter of 3-4 mm, the bed height was 2 m. An aerator was assembled on the bottom of the first filter bed for biological nitrification; and methanol was added into the influent to the second bed for biological denitrification. It is showed that at HRT of 1-2 h, ammonia nitrogen removal rate reaches 90% in the first bed, and nitrate nitrogen removal rate comes up to 95% more in the second bed, turbidity in the final effluent is less than 1 NTU, and total nitrogen removal loading is 1 kg N/(m3·d). It is found that HRT, influent ammonia nitrogen and external carbon source have significant effect on biological nitrification and denitrification. Microbe is well attached on filter media and then biofilm takes shape, its complex reticular structure and bio-phase are observed under the scanning electron microscope. In addition, backwashing performance brings its important role into play in ensuring steady operation, and nitrogen and turbidity removal effect of the system.