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The Torreele facility produces infiltration water for indirect potable re-use through artificial recharge of the dune aquifer of St-André. The secondary wastewater effluent is treated by ultrafiltration (UF), using the submerged Zeeweed system, prior to reverse osmosis (RO), using brackish water low energy membranes. The Torreele experience showed that combining UF and RO enables the treatment of wastewater effluent in an effective and reliable way; RO being the major and ultimate barrier against both microbial and chemical contamination. The produced filtrate is of excellent quality and enables sustainable groundwater management in an area with high ecological interest. The biggest challenges for the Torreele facility are the changing conditions, based on the meteorological and seasonal variations, the scaling and fouling problem and the concentrate. Bio-fouling is prevented by monochloramination and scaling by dosing of antiscalant combined with pH adjustment. The Intermunicipal Water Company of the Furnes Region (IWVA) studied alternative treatment, mainly using natural systems, with the objective to mitigate the impact of the concentrate disposal into surface water and to reduce the charges set for this disposal. Concerning groundwater recharge, IWVA is studying alternatives to optimize the infiltration capacity. [ABSTRACT FROM AUTHOR]

Abstract: The Intermunicipal Water Company of the Veurne region (IWVA) reuses wastewater effluent for groundwater recharge of an unconfined dune aquifer since July 2002. The ‘Torreele’ reuse plant has a production capacity of 2,500,000 m3/y. Due to the sensitive environmental nature of the dune area, the quality of the infiltration water is subject to stringent standards. The combination of membrane filtration techniques proved capable of producing this quality and enabled a sustainable groundwater management of both dune water catchments owned by the IWVA. [Copyright &y& Elsevier]

At the Torreele facility the Intermunicipal Water Company of Veurne-Ambacht (IWVA) treats secondary wastewater effluent for indirect potable re-use via groundwater recharge in the dune water catchment of St. Andre. The treatment combining ultrafiltration (UF), using the submerged ZeeWeed system, and reverse osmosis (RO), using brackish water low-energy membranes, enables to produce a high-quality infiltration water, and this leads to sustainable groundwater management of the dune water catchment of St. Andre. Since start-up, in July 2002, different measures have been taken to optimize the membrane performance. Intermittent use of air on the UF system and variable recovery on the RO system reduced energy consumption per cubic metre produced. The latter also resulted in lower chemical consumption as did the pauses in chloramination. The backwash water and RO concentrate are discharged into a brackish canal, together with the effluent that is not reused. Since 2003, IWVA performed tests using natural systems to further treat this water. [ABSTRACT FROM AUTHOR]