Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, School of Ecology and Environmental Science, Yunnan University, Kunming, 650500, China; Yunnan Field Scientific Station for Restoration of Ecological Function in Central Yunnan of China, Yunnan University, Kunming, 650091, China; Institute of International Rivers and Eco-security, Yunnan University, Kunming, 650500, China.
Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, School of Ecology and Environmental Science, Yunnan University, Kunming, 650500, China; Yunnan Field Scientific Station for Restoration of Ecological Function in Central Yunnan of China, Yunnan University, Kunming, 650091, China.
Environ Res. 2024 Dec 15;263(Pt 2):120124. doi: 10.1016/j.envres.2024.120124. Epub 2024 Oct 10.
Import of agricultural runoff containing nutrients considerably contributes to eutrophication of receiving water bodies. Surface-flow constructed wetlands (SFCWs) are commonly applied for agricultural runoff purification, but the performance is usually unsatisfactory. In this study, suspended bio-balls filled with zeolite and iron-carbon (Fe-C) composite substrates, submerged macrophyte (Ceratophyllum demersum) and functional denitrifying bacteria were collectively added into SFCW microcosms to enhance the remediation efficiency for real agricultural runoff with high nutrient concentrations and low content of bioavailable organic matter. The bio-ball added SFCWs achieved notably higher pollutant removal efficiencies (21.1%, 80.2% and 47.5% for chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP), respectively) than the control (COD: 6.9%, TN: 64.4%, TP: 27.9%), because of the versatile functions of filling materials for pollutant removal. C. demersum plantation (COD: 44.2%, TN: 82.8% and TP: 53.7%) and functional bacteria inoculation (COD: 51.8%, TN: 85.8% and TP: 55.1%) further enhanced the efficiency of the SFCWs for agricultural runoff remediation. Bio-ball addition and C. demersum plantation significantly increased the humification degree and reduced the molecular weight of dissolved organic matter (DOM) in the agricultural runoff. Moreover, the two intensification measures also notably reduced organic and nitrogen contents in the wetland sediment. Remarkable distinction in bacterial community distribution patterns was observed in the SFCW sediment and filling substrates in bio-balls. Keystone genera including Clostridium_sensu_stricto_1 and Bacillus in the zeolite, Sphingomonas and Exiguobacterium in the Fe-C substrates and Sediminibacterium in the sediment might be critical for agricultural runoff remediation in the SFCW microcosms. The study highlights a high potential of the intensified SFCWs by these coupling measures for agricultural runoff remediation.
农业径流中的养分输入对受纳水体的富营养化有重要贡献。表面流人工湿地（SFCWs）常用于农业径流的净化，但效果通常不尽人意。本研究在 SFCW 微系统中共同添加了填充沸石和铁碳（Fe-C）复合材料的悬浮生物球、沉水植物（金鱼藻）和功能反硝化细菌，以提高对高浓度营养物质和低生物可利用有机物含量的实际农业径流的修复效率。与对照组（COD：6.9%，TN：64.4%，TP：27.9%）相比，添加生物球的 SFCWs 对污染物的去除效率显著提高（COD：21.1%，TN：80.2%，TP：47.5%），因为填充材料具有多种去除污染物的功能。金鱼藻种植（COD：44.2%，TN：82.8%，TP：53.7%）和功能细菌接种（COD：51.8%，TN：85.8%，TP：55.1%）进一步提高了 SFCWs 对农业径流修复的效率。生物球的添加和金鱼藻的种植显著提高了农业径流中溶解性有机物（DOM）的腐殖化程度和降低了其分子量。此外，这两种强化措施还显著降低了湿地沉积物中的有机氮含量。在 SFCW 沉积物和生物球填充基质中观察到细菌群落分布模式的显著差异。沸石中的 Clostridium_sensu_stricto_1 和芽孢杆菌、Fe-C 基质中的节杆菌和鞘氨醇单胞菌以及沉积物中的 Sediminibacterium 等关键属可能对 SFCW 微系统中农业径流的修复至关重要。该研究强调了这些耦合措施强化的 SFCWs 对农业径流修复的高潜力。
