亚热带丘陵区绿狐尾藻人工湿地处理养猪废水氮磷去向

Nitrogen and Phosphorus Removal in Surface Flow Constructed Wetland Planted with Myriophyllum elatinoides Treating Swine Wastewater in Subtropical Central China

以亚热带丘陵区为研究区,采取野外定位观测的研究方法,选取耐高氮(N)、磷(P)的绿狐尾藻为湿地植物,建立稻草基质池+6级绿狐尾藻表面流湿地系统,湿地总面积1597 m^(2),水力负荷0.06~0.14 m·d^(-1),水力停留时间31 d,研究此湿地系统对养猪废水(NH_(4)^(+)-N:535.4~591.09 mg·L^(-1)、TN:682.09~766.96 mg·L^(-1)、TP:57.73~82.29 mg·L^(-1)和COD:918.4~1940.43mg·L^(-1))的治理效果,旨在为亚热带高负荷猪废水的生态治理提供参数依据.结果表明,湿地系统对NH_(4)^(+)-N、TN、TP和COD的平均去除率为97.4%、97.1%、91.0%和90.2%,其中以CW1累积贡献率最大(37.3%、38.4%、43.3%和27.4%).植物N、P吸收量在23.87~79.96 g·m^(-2)和5.34~18.98 g·m^(-2)之间,占湿地N、P去除量的19.1%和20.2%;底泥N、P吸附量在19.17~56.62g·m^(-2)和10.59~26.62 g·m^(-2)之间,占去除量的19.8%和61.7%.湿地N、P去除率与影响因子间的关系表明,环境因子解释了湿地N、P去除率的79.9%和70.1%.其中,DO是湿地系统N去除的主要因子,底泥P吸附是P去除的关键.

The loss of nitrogen(N)and phosphorus(P)from aquaculture has caused eutrophication of freshwater systems.Here,surface flow constructed wetland(SFCW)planted with Myriophyllum elatinoides were used to treat swine wastewater from a mediumsized hoggery in subtropical Central China.Inflow concentrations of NH_(4)^(+)-N,TN,TP,and COD ranged from 535.4 to 591.09,682.09 to 766.96,57.73 to 82.29,and 918.4 to 1940.43 mg·L^(-1),respectively.The mean removal efficiencies of NH_(4)^(+)-N,TN,TP,and COD were 97.4%,97.1%,91.0%,and 90.2%,respectively,and CW1 had the largest contributions of 37.3%,38.4%,43.3%,and 27.4%,respectively.Plant N and P uptake ranged 23.87-79.96 g·m^(-2)and 5.34-18.98 g·m^(-2),accounting for 19.1%and 20.2%of removal,respectively.Sediment N and P accumulation ranged 19.17-56.62 g·m^(-2)and 10.59-26.62 g·m^(-2),accounting for 19.8%and 61.7%of removal,respectively.Multiple linear regression showed that environmental factors explained 79.9%of the N removal and 70.1%of the P removal;DO was the main factor affecting N removal,and sediment adsorption was the key process in P removal.These results show that M.elatinoides constructed wetland can efficiently treat swine wastewater,thereby reduce the discharge of pollutants downstream.