复合介质渗透反应格栅去除地下水中的氨氮

针对受低浓度氨氮污染的地下水,实验筛选组合了不同的反应介质,利用串联的多介质填充柱模拟渗透反应格栅,通过物理吸附及生物硝化-反硝化作用来实现氮的去除。结果表明,在进水氨氮浓度为10 mg/L、流速为0.5 m/d的条件下,模拟柱对氨氮的去除率达到98%以上,且不会出现亚硝酸盐及硝酸盐浓度的升高。水体经过释氧柱后溶解氧由2mg/L升高至10 mg/L以上,表明释氧材料可提供硝化细菌所需的好氧环境。好氧柱中填充易于生物挂膜的生物陶粒及对氨氮有较强吸附能力的沸石,二者联用通过生物硝化-物理吸附协同作用实现对氨氮的去除,其中生物作用实现的氨氮去除量占总去除量的50%左右。后续厌氧反应柱填充海绵铁除氧并利用松树皮颗粒作为碳源,创造反硝化菌生长条件,硝酸盐氮浓度可由10 mg/L降低至5 mg/L以下,实现对好氧反应阶段所产生的硝酸盐的去除,避免了地下水的二次污染。

Removal of ammonium from groundwater using multi-material permeable reactive barriers

This paper described a multi-material permeable reactive barriers for the ammonium-contaminated water remediation,using abiotic ion exchange and microbial degradation processes (nitrification and denitrification).A sequential setup combining different reactive materials and removal processes was designed in the laboratory-scale column test.The results showed that ammonium and its products(nitrite & nitrate) were removed to levels below the regulatory discharge limits,under the conditions of the flow velocity of 0.5 m/d and influent ammonium concentration of 10 mg/L.Oxygen releasing materials could supply enough oxygen for microbial nitrification.The concentration of dissolved oxygen in groundwater increased from 2 mg/L to 10 mg/L.Ammonium was efficiently removed in the first microbial nitrification column filled with bio-ceramsite and zeolite,in which 50% of the ammonium was removed through the biological process.The subsequent microbial denitrification columns filled with sponge iron and pine bark were used to remove nitrate formed in microbial nitrification compartment.Sponge iron could provide anaerobic environment,pine bark dissolved slowly in water and supplied enough carbon for the microbial growth.The ammonium concentration decreased from 10 mg/L to 5 mg/L after flowing through the anaerobic column,realizing the effective removal of nitrate formed in the first nitration compartment and avoiding the groundwater secondary pollution.