Aquifer recharge with reclaimed water: life-cycle assessment of hybrid concepts for non-potable reuse

Aquifer recharge with reclaimed water is a promising means to store and supply on demand reclaimed water of high quality for further non-potable reuse. The reuse applications may include indirect agricultural or landscape irrigation, saltwater intrusion barriers, subsidence mitigation or aquifer replenishment. As an alternative to high-pressure or double-membrane systems, hybrid schemes consisting of a disinfection/filtration step prior to aquifer recharge were assessed in this study regarding their environmental footprint and energy efficiency. A simplified life-cycle assessment (LCA) for a hypothetical case study in a water-scarce country was conducted to compare these hybrid schemes to a double-membrane system working under similar conditions. The results show that there is a significant margin for lowering the environmental impact, energy demand and operational costs if non-potable water quality is targeted. While the hybrid schemes outperform high-pressure membranes for these factors, land footprint and final water quality also need to be considered in the choice of solution for specific conditions.