Aquifer storage of treated wastewater for subsequent recovery as an important strategy for sustainable water security in Kuwait

This research explores the possibility of creating an underground water reservoir by injecting treated wastewater and evaluates the recovery efficiency and water quality under different injection/recovery scenarios. An injection/recovery well was established in the Dammam Formation aquifer in Kuwait. Six observation wells were also drilled nearby to monitor the water levels and quality. A three-dimensional (3D) numerical hydraulic and transport model was set up using the coupled version of MODFLOW and MT3DMS. Four scenarios of cyclic and continuous injection with different injection and pumping rates stretching over 5,400 days were investigated. Two dispersivity values, low (10 m) and high (200 m), were used in each scenario in order to establish the minimum and maximum recovery limits of useful water that can be expected from the site. The combination of injection rate of 650 m3/d and subsequent recovery at 1,000 m3/d proved to be the optimum option for the storage of water, resulting in good recovery efficiency and acceptable water quality. Based on these results, it was concluded that aquifer storage is a feasible strategy for mitigating growing water scarcity in the State of Kuwait and other countries in the larger Middle East.