亚铁作用下湿地基质对水中氮素和COD去除效应研究

Nitrogen and COD Removal from Water with Wetland Substrate under Ferrous Iron

采用模拟试验法,以人工湿地基质为材料,添加不同浓度的硫酸亚铁,研究湿地基质对铵态氮和硝态氮的去除效应以及COD的去除效果。结果表明:亚铁添加强化了湿地基质对铵态氮的吸附能力和硝化作用,也减少了水中硝态氮的积累,促进氮素的去除,其中150mg/L的亚铁添加基质对总氮和铵态氮的去除效果最好,其48h去除率分别为29.24%和33.66%;而100mg/L的亚铁添加对硝态氮去除效果较好,其去除率可达37.16%,但是由于硝态氮异化还原成铵过程的存在,使总氮的去除效果下降。基质对铵态氮去除效应中COD的去除效果明显低于基质对硝态氮去除效应中COD的去除效果,这说明厌氧环境有利于COD的去除。本研究结果可为改进人工湿地去除污染物能力提供理论依据。

Taking a constructed wetland substrate as the research object,its effects on removal of ammonium nitrogen,nitrate nitrogen and COD in water were studied under addition of different concentrations of ferrous sulfate by simulation test.The results showed that the ammonium adsorption capacity and nitrification of wetland substrate were strengthened under ferrous addition,which reduced the accumulation of nitrate nitrogen in water,and promoted nitrogen removal.There was the greatest removal efficiency of total nitrogen and ammonium nitrogen under 150 mg/L ferrous iron,and their removal rates were 29.24%and 33.66%at 48 h,respectively.However,the removal efficiency of nitrate nitrogen was greater at 100 mg/L ferrous iron,and the removal rate was 37.16%.But total nitrogen removal decreased because of the occurrence of dissimilatory nitrate reduction to ammonium process.The COD removal efficiency during ammonium nitrogen removal was significantly lower than that during nitrate nitrogen removal,which showed that it was in favour of COD removal under anaerobic environment.All these research results could provide certain theoretical references for improving the ability of constructed wetlands to remove contaminants.