生态砾石床对城市污水厂尾水深度净化研究

STUDY ON THE DEEP PURIFICATION OF TAILWATER FROM URBAN SEWAGE PLANTS BY ECOLOGICAL GRAVEL BED

为研究生态砾石床在城市污水厂尾水深度净化中的应用前景,采用多种填料(砾石、钢渣、沸石)及分区曝气的方式强化去除效果,探讨不同水力停留时间(HRT)、温度、填料粒径对生态砾石床去除COD、NH_(3)-N、TP的影响。结果显示:1)HRT对NH_(3)-N去除效果影响较大,对COD影响较小;当HRT在2~4 h,污染物去除率与HRT呈正相关;2)温度对生态砾石床运行效果影响较大,随着温度升高,微生物活性增强,污染物去除率增加;3)填料粒径对污染物去除影响较小,相比而言粒径为6~8 cm的填料处理效果更好。研究表明,适当调整参数后,生态砾石床对污水厂尾水进行深度净化的出水水质可达到地表Ⅳ类标准。

In order to study ecological gravel bed in the prospective application of tailwater from urban sewage plant,this study used a variety of fillers(gravel,steel slag,zeolite)and zone aeration to enhance removal effect,and we discussed the effects of different hydraulic retention time(HRT),temperature,and filler particle size on the removal efficiency for COD_(Cr),NH_(3)-N,TP.The results showed:1)HRT has a greater effect on NH_(3)-N removal,and less on COD_(Cr).When HRTs were 2~4 h,contaminant removal rates were positively correlated with HRT;2)Temperature greatly influenced the operating effect of ecological gravel bed.With the increase of temperature,the microbes were more active,and the rate of pollutant removal increased;3)Filler particle size had slightly impact on pollutant removal.In contrast,when fillers particle sizes were 6~8 cm,the ecological gravel bed worked better.This study shows that the ecological gravel bed had an excellent effect on the deep purification of tailwater from urban sewage plants,and the effluent water quality could meet the class IV standard of surface water when the parameters were adjusted appropriately.