铁矿石和生物炭添加对潜流人工湿地污水处理效果及温室气体排放的影响

人工湿地是温室气体的重要排放源,为了探索减少其温室气体排放的措施,通过在温室内构建了空白-人工湿地(湿地Ⅰ)、铁矿石-人工湿地(湿地Ⅱ)、生物炭-人工湿地(湿地Ⅲ)和铁矿石+生物炭-人工湿地(湿地Ⅳ)4组湿地,研究了铁矿石和生物炭基质的添加对潜流人工湿地污水处理效果和温室气体排放的影响.结果表明,4组湿地的平均出水CO...

Effects of hematite and biochar addition on sewage treatment and greenhouse gases emissions in subsurface flow constructed wetland

Constructed wetland is an important source of greenhouse gas emissions. In order to explore measures to reduce their greenhouse gases emissions, in this study, four groups of wetlands, including blank constructed wetland (wetland I), hematite constructed wetland (wetland II), biochar constructed wetland (wetland III) and hematite-biochar constructed wetland (wetland IV) were built to investigate the effect of hematite or biochar addition on the sewage treatment and greenhouse gas emissions of subsurface flow constructed wetlands. The results showed that the average effluent COD concentrations of the four wetlands were (34.99±1.60), (35.57±1.69), (30.87±1.65) and (27.52±2.37) mg·L−1, respectively, and all the COD removal rates reached higher than 90%. The average TN concentrations of the four wetland systems were (24.75±0.96), (24.99±0.72), (15.04±0.61) and (15.63±0.61) mg·L−1, respectively, and the average TN removal rates of wetland III and wetland IV were 65.73% and 64.41%, respectively, both of them were higher than those of wetland I (43.61%) and wetland II (43.08%). Similar to TN, the ${rm{NH}}_4^ + $-N removal rates of the four wetland systems were 45.04%, 43.92%, 67.52% and 65.19%, respectively. The addition of hematite-biochar also had a certain effect on the reduction of CH4 and N2O emissions in the system. With a GWP of 1 g·m−2 CO2 as 1, the average integrated global warming potential (GWP) values of the wetland Ⅱ and wetland Ⅲ systems were 69.88 and 22.73, respectively, and they decreased by 32.39% and 78.01% compared with wetland (103.36), respectively. The GWP value of the CH4 and N2O emissions of wetland IV was similar to that of wetland III with the addition of biochar alone, which was 24.62. Compared with hematite, the addition of biochar caused better sewage treatment effect and lower CH4 and N2O emissions. The biochar in the hematite-biochar wetland plays a major role in removing pollutants and reducing greenhouse gas emissions. This study can provide effective suggestions for the improvement of constructed wetlands.