Aquaduin started reusing wastewater effluent for infiltration, Cf. managed aquifer recharge (MAR), in its dune water catchment St-Andre in 2002. The treatment train at the Water Production Centre Torreele is based on multiple barrier approach with submerged ultrafiltration prior to reverse osmo-sis (RO). The project not only resulted in enhanced ecological values of the dunes but during the recent longer periods of drought, the combination of reuse/MAR proved to be a robust and safe way to ensure drinking-water production and thus is a potential solution to mitigate the impact of climate change [1]. Concentrate disposal is an issue when using RO. However, as Aquaduin oper-ates in a coastal area, disposal could be managed; the concentrate was discharged in a canal that drained to the sea. To mitigate the impact of this discharge, treatment of RO concentrate using wil-lows has been tested since 2007. This research resulted in the full-scale implementation of a wil-low field or marsh, that is based on the concept of a horizontally constructed wetland combined with short rotation coppice using willows (Salix). The construction started in 2021 and early 2022 the willow marsh became operational. In 2022 a total volume of 538.446 m3 was treated by the willow marsh, 85% of the total volume of RO concentrate produced. This paper will present the preliminary research, construction and initial results of the treatment. |
