地下渗滤系统基质组配及脱氮效果

Subsurface Wastewater Infiltration System Matrix Assembly and Nitrogen Removal Efficiency

采用4组平行尼米槽式地下渗滤模拟装置,在传统基质的基础上,通过组配膨润土、粉煤灰、稻壳等不同材料作为地下渗滤的辅助基质,以解决地下渗滤脱氮效率较低的问题。结果表明,组配膨润土可以明显提高对NH_4^+-N的去除效果,组配稻壳有利于系统对TN的去除,组配粉煤灰对脱氮效果影响较小;当水力负荷为0.25 m^3/(m^2·d)时,综合考虑NH_4^+-N和TN的去除,同时组配膨润土、稻壳的4~#系统对NH_4^+-N和TN的去除率分别为78.35%和67.6%,相比对照组1~#系统分别提高了12.44%和11.86%,出水水质均满足《城镇污水处理厂污染物排放标准》(GB18918—2002)的一级A标准。通过基质组配,耦合混合基质的吸附作用和微生物的反硝化作用,是强化地下渗滤系统脱氮的主要途径。

Utilizing four parallel simulators of the NiiMi process of the subsurface wastewater infil- tration system （SWIS）, on the basis of the traditional matrix, bentonite, fly ash, rice husk and other materials were assembled as auxiliary matrices in the SWIS to resolve the low removal rate of nitrogen. The results showed that bentonite was useful to the removal of NH4＋ - N, rice husk was beneficial to the denitrification, while fly ash had limited effect on the nitrogen removal. With a hydraulic loading of 0.25 m3/（m2 ·d）, the removal rates of NH4＋ - N and TN were 78.35% and 67.6% in the 4# system which assembled both bentonite and rice husk. The average removal rates of NH4＋ - N and TN increased by 12.44% and 11.86%, respectively, compared with the negative control system. The effluent met the first grade A in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant （GB 18918 - 2002）. Assembling the matrixes and coupling the adsorption and denitrification effects is the principal method to enhance the nitrogen removal.