生物滤池/生态砾石床处理含氮微污染地表水

采用生物滤池/生态砾石床组合工艺进行了微污染地表水(含低碳、高NO3--N浓度)的脱氮研究,通过投加乙酸钠为碳源考察了C/N值、温度、水力负荷对反应器脱氮效能的影响。结果表明,C/N值对反应器的脱氮效能影响较大,在C/N值为10时可以取得较高的反硝化效率(>90%)。在低温下(2～10℃)反应器的反硝化效能受到严重抑制;在13～17℃条件下,反硝化效率恢复到60%左右;当水温>20℃时,在水力负荷为8 m3/(m2.h)的条件下(此时生物滤池和生态砾石床的水力停留时间分别为15、30 min),对NO3--N的去除率能够达到90%以上。生态砾石床能够将生物滤池出水中残余的碳源去除,保证了出水的水质安全。

Nitrogen Removal from Micro-polluted Surface Water by Combined Process of Biofilter and Ecological Gravel Bed

Nitrogen removal from micro-polluted surface water with low carbon and high NO-3-N by the combined process of biofilter and ecological gravel bed was studied.The influence of C/N ratio,water temperature and hydraulic loading on nitrogen removal efficiency was investigated using sodium acetate as carbon source.The results show that C/N ratio has significant influence on nitrogen removal efficiency,and the denitrification rate of more than 90% can be achieved when C/N ratio is 10.The denitrification efficiency of the reactor is inhibited at low water temperature of 2 to 10 ℃,and the denitrification rate is recovered to about 60% at 13 to 17 ℃.The removal rate of NO-3-N can reach more than 90% at water temperature of more than 20 ℃,hydraulic loading of 8 m3/(m2·h),HRT of 15 min in biofilter and 30 min in ecological gravel bed.The remaining carbon source in the effluent from biofilter can be removed in ecological gravel bed,thus ensuring the water quality safety.