Lemley Daniel A, Lakane Chuene P, Taljaard Susan, Adams Janine B
Botany Department and the DSI/NRF Research Chair in Shallow Water Ecosystems, Nelson Mandela University, Gqeberha 6031, South Africa; Institute for Coastal and Marine Research (CMR), Nelson Mandela University, PO Box 77000, Gqeberha 6031, South Africa.
Institute for Coastal and Marine Research (CMR), Nelson Mandela University, PO Box 77000, Gqeberha 6031, South Africa; Council for Scientific and Industrial Research (CSIR), PO Box 320, Stellenbosch 7599, South Africa.
Mar Pollut Bull. 2022 Jun;179:113727. doi: 10.1016/j.marpolbul.2022.113727. Epub 2022 May 7.
This study investigated the nutrient removal efficiency of a constructed wetland (CW) piloted to treat urban runoff before entering an estuary. Physico-chemical, dissolved inorganic nutrient (DIN and DIP), and stormwater inflow volume data were measured. The CW removal efficiency of DIN was negligible (5% uptake), while it acted as a consistent source of DIP (68% efflux) to the receiving estuarine waters. There was low water residency within the small CW (0.8 ha) that has been compounded by a 10-fold increase in flow volume since 2016. The surface area of the CW would need to be increased to 46 ha to cope with current daily inputs (ca. 6300 m d). The lack of maintenance (e.g., macrophyte harvesting, sediment desludging) has reduced nutrient uptake and increased autochthonous inputs. The conversion of an abandoned saltpan into an extension of the CW has been considered to manage the high flow volume and remove nutrients.
本研究调查了一个人工湿地（CW）在处理进入河口前的城市径流方面的养分去除效率。测量了物理化学参数、溶解无机养分（DIN和DIP）以及雨水流入量数据。该人工湿地对DIN的去除效率可忽略不计（吸收5%），而它却成为接收河口水体中DIP的持续来源（流出68%）。在面积较小（0.8公顷）的人工湿地中，水的停留时间较短，自2016年以来流量增加了10倍，这使情况更加复杂。人工湿地的表面积需要增加到46公顷，以应对当前的每日输入量（约6300立方米/天）。缺乏维护（如大型植物收割、沉积物清淤）降低了养分吸收并增加了本地输入。已考虑将废弃盐田改造成人工湿地的扩展区域，以管理高流量并去除养分。
