人工湿地对氮磷去除效果试验研究

为考察人工湿地系统对不同氮磷浓度污水的处理效果,采用改良混合式平面流人工湿地系统在户外自然条件下进行试验,并将湿地植物按夏冬季节类型进行混搭栽培,基质按粒径和孔隙率不同进行有层次配置。结果显示,试验第1阶段,进水为成都犀池富营养化水体,水力停留时间为3 d时,水质净化经过了非稳定和稳定2个时期,在系统总体上运行到25 d后逐渐趋于稳定,各级湿地不同水层pH始终稳定在中性偏酸性范围,TP、TN的平均去除率可达到60%、80.46%;随后提高进水中氮磷浓度(模拟生活污水),进入试验第2阶段,水力停留时间仍为3d,在21 d的运行周期内,系统一直保持比较高的抗冲击和稳定性,TP、TN的平均去除率可达到86.8%、90.08%,出水水质达到地表水环境质量Ⅲ类标准(GB3838—2002)和《城镇污水处理厂污染物排放标准》(GB19818—2002)中一级A类标准。研究结果表明,本人工湿地系统对不同水质中N、P都有很好的去除效果,并且能实现湿地系统的周年循环处理污水的效能,加之其低投资、低能耗及低成本管理等特点,无疑是处理小城镇生活污水以及富营养化水体行之有效的技术。

Study on Removal of Nitrogen and Phosphorus in Wastewater by Constructed Wetland

To study the effects of constructed wetland system on the treatment of wastewater of different nutrient concentrations,an experiment was conducted by employing a hybrid planar flow,cultivating plant types in different seasons,and configuring the size and porosity of the substrate in different layers under outdoor natural conditions.The process consisted of two phases.In the first phase,where Xichi pool eutrophic water was used as the inflow,the water quality experienced two periods of instability and stability,and was stable after the 25th day.The average removal rates of total phosphorus(TP),and total nitrogen(TN) were 60%,80.46%,respectively.In the second phase,the system maintained relatively high impact resistance and stability,with average removal rates of TP,TN reaching 86.8%,90.08%,respectively.As a result,the effluent water quality met the Surface Water Environment Quality Standard Class and Urban Sewage Treatment Plant Emission Standards(an A class standard).The results demonstrated that this wetland treatment system can effectively remove N,P from the wastewater with different qualities,and still have treatment capability for sewage in a one-year cycle.