ABSTRACT

The Dan Region Reclamation Project, which is in operation for the last 25 years annually, reclaims some 110–130 million cubic meters of effluents. The facility, which yields reclaimed water for unrestricted irrigation, exploits a coastal Quaternary sandstone aquifer, which is a major freshwater resource. The operation includes intermittent flooding and drying of spreading basins, controlled passage of effluents through the unsaturated zone and subsequent pumping of reclaimed wastewater after at least 50 days of residence time. The procedure allows for simultaneous freshwater production in adjacent boreholes managed through a comprehensive system of production and monitoring boreholes. An asymmetric low water-level buffer zone controls the isolation of the facility with minimal freshwater losses. Raised water-levels at recharge sites up to 11 m above their surroundings also pushes back the sea-freshwater interface by reshaping seaward gradients and allows for exploitation of a large one-time freshwater reserve.