2.西南大学含弘学院,重庆 400715
1.State Cultivation Base of Eco-Agriculture for Southwest Mountainous Land, College of Resources and Environment, Southwest University, Chongqing 400715, China
2.Institute of Hanhong, Southwest University, Chongqing 400715, China
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COD分别是(34.99±1.60)、(35.57±1.69)、(30.87±1.65)和(27.52±2.37) mg·L
,COD去除率均达到90%以上。4组湿地系统的出水平均TN浓度分别是(24.75±0.96)、(24.99±0.72)、(15.04±0.61)和(15.63±0.61) mg·L
O排放量。铁矿石生物炭联合添加的湿地中生物炭起主要的污染物去除和温室气体减排作用。以上研究结果可为人工湿地的改进提供有效建议。
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
, 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
, 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
-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 CH
O emissions in the system. With a GWP of 1 g·m
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 CH
O 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 CH
O 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.
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Schematic diagram of lab-scale subsurface constructed wetland
典型周期内不同湿地系统COD、DO值的变化
Changes of DO and COD in different constructed wetland systems during typical cycles
concentrations in different constructed wetland systems during typical cycles
Changes of pH and Eh in different constructed wetland systems during typical cycles
in different constructed wetlands during typical cycles
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