Abstract
To be able to overcome water shortages, Abu Dhabi Emirate started an Aquifer Storage and Recovery (ASR) project with desalinated seawater (DSW) as source water near Liwa. It is the largest DSW-ASR project in the world (stored volume ~10 Mm3/year), and should recover potable water for direct use. DSW is infiltrated into a desert dune sand aquifer using “sand-covered gravel-bed” recharge basins. In this study, we evaluate the hydrogeological and hydrogeochemical stratification of the (sub)oxic target aquifer, and water quality changes of DSW during trial infiltration runs. We predict water quality changes of DSW after 824 d of infiltration, during 90 d of intensive recovery (67% recovered) without storage (scenario A), as well as after 10 years of storage (scenario B, with significant bubble drift). Monitoring of preceding trials revealed a lack of redox reactions; little carbonate dissolution and Ca/Na exchange; much SiO2 dissolution; a strong mobilization of natural AsO43−, B, Ba, F, CrO42−, Mo, Sr and V from the (sub)oxic aquifer; and immobilization of PO4, Al, Cu, Fe and Ni from DSW. The Easy-Leacher model was applied in forward and reverse mode including lateral bubble drift, to predict water quality of the recovered water. We show that hydrogeochemical modeling of a complex ASR-system can be relatively easy and straightforward, if aquifer reactivity is low and redox reactions can be ignored. The pilot observations and modeling results demonstrate that in scenario A recovered water quality still complies with Abu Dhabi’s drinking water standards (even up to 85% recovery). For scenario B, however, the recovery efficiency declines to 60% after which various drinking water standards are exceeded, especially the one for chromium.
Highlights
Water scarcity has driven many countries in arid zones, such as the Middle East and Abu Dhabi in particular, to desalinate large volumes of seawater for fresh water supply [1]
We present the peculiar characteristics of an eolian-fluvial,oxic, calcareous sand(stone) aquifer system in a desert environment, the unique water quality changes during an ASR
In the applied Easy-Leacher model, pilot observations on retardation, leaching andpermanent concentration changes are combined with a strong schematization of the complex basin–ASR system, groundwater flow and hydrogeochemical processes
Summary
Water scarcity has driven many countries in arid zones, such as the Middle East and Abu Dhabi in particular, to desalinate large volumes of seawater for fresh water supply [1]. In 2001, Abu Dhabi started its pioneer projects for developing strategic fresh water resources to face any emergency condition using the Aquifer Storage and Recovery (ASR) technique by infiltrating the surplus of desalinated water into the groundwater aquifer system. One of these projects is the strategic fresh water reserve project at Liwa. The project passed with success through the phases of first a feasibility study and subsequently a pilot study in 2003–2004 [8] In this pilot, desalinated water was infiltrated in a dune sand aquifer system using injection wells as well as an underground recharge basin. The basin performed better than the ASR wells, and was selected for implementation in the construction phase
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
