Department of Civil Engineering, University of Asia Pacific, Dhaka, Bangladesh.
Environ Technol. 2021 Mar;42(7):1104-1118. doi: 10.1080/09593330.2019.1655592. Epub 2019 Sep 11.
Two wetland systems (conventional and structurally modified) were studied for the removal of organics and nutrients from municipal wastewater. Each system consisted of three vertical flow (VF) wetlands, which were filled with agricultural, construction waste materials and planted with and The wetland units were operated under constant and consecutive shock hydraulic load (HL). Input nutrients and organics load across the wetland units ranged between 4.0-116.0 g N/md, 0.5-23.0 g P/md, 1.0-527.0 g biochemical oxygen demand (BOD)/md and 16.0-686.0 g chemical oxygen demand (COD)/md. Nitrification and organic carbon availability controlled nitrogen (N) removals in first and third stage VF wetlands, respectively, during constant load phase; organics removals were influenced by dissolved oxygen concentration of municipal wastewater. Second stage VF wetlands (of both systems) were inefficient in terms of COD removals during shock load periods, which were counter-balanced by first and third stages. First stage VF wetlands achieved higher N removal rates than following stages during shock load periods. Wetland maturation provided a buffer against substantial HL increment and sharp input load decrease in latter shock and recovery phases, respectively. Agricultural waste (sugarcane bagasse) provided carbon to support denitrification; construction materials (recycled brick and crushed mortar) removed phosphorus (P) from wastewater through adsorption. Coliform removal in VF wetlands was achieved through media filtration. Structurally modified system achieved higher removals than the conventional system. BOD, COD, total nitrogen and NH-N removal percentage across two systems ranged between 76-79%, 59-63%, 73-77% and 90-95%, respectively. In general, this study enlightens potential application of appropriate waste materials for wastewater treatment.
两种湿地系统（常规和结构改良）被研究用于从市政废水中去除有机物和营养物。每个系统都由三个垂直流（VF）湿地组成，这些湿地填充了农业、建筑废料，并种植了 和 。湿地单元在恒定和连续的水力冲击负荷（HL）下运行。跨湿地单元输入的营养物和有机物负荷范围在 4.0-116.0 g N/md、0.5-23.0 g P/md、1.0-527.0 g 生化需氧量（BOD）/md 和 16.0-686.0 g 化学需氧量（COD）/md 之间。在恒定负荷阶段，硝化和有机碳可用性分别控制第一和第三阶段 VF 湿地中的氮（N）去除；溶解氧浓度的有机物去除影响市政废水。在冲击负荷期间，第二阶段 VF 湿地（两个系统）在 COD 去除方面效率低下，第一和第三阶段湿地起到了平衡作用。在冲击负荷期间，第一阶段 VF 湿地的氮去除率高于后续阶段。湿地成熟为后续冲击和恢复阶段的大量 HL 增量和输入负荷急剧下降提供了缓冲。农业废物（甘蔗渣）提供碳以支持反硝化；建筑材料（回收砖和碎砂浆）通过吸附从废水中去除磷（P）。VF 湿地中的大肠菌群去除是通过介质过滤实现的。结构改良系统的去除率高于常规系统。两个系统的 BOD、COD、总氮和 NH-N 去除率分别在 76-79%、59-63%、73-77%和 90-95%之间。总的来说，这项研究为废水处理中适当废物材料的应用提供了启示。
