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1ST. EDITION Dubai 2014
Desalinated Water for Wildlife
The Environment Agency – Abu Dhabi (EAD) uses innovative solar desalination techniques to provide its protected, remote areas with fresh water. Part of the mandate of the Environment Agency – Abu Dhabi (EAD) is to promote and enhance wildlife and habitats within protected areas. Some of the protected areas are remote, difficult to access and do not have any naturally occurring surface water. The top of the groundwater table under the protected areas is around 30 metres deep and the water is mainly saline. Any infrastructure introduced into protected areas to provide water needs to be environmentally friendly, efficient and low maintenance. Solar desalination units were identified as a good option and EAD now operates 30 units distributed within protected areas across Abu Dhabi. Design criteria for the 30 reverse osmosis units powered by solar photovoltaic Feed water
Groundwater with a salinity of 35,000 ppm
Unit production capacity
4 m3 x 6 hours = 24m3 per day
Produced water quality
Between 500 – 1000 ppm more than suitable for livestock and irrigation
Energy source
Solar PV
Desalination Technology
Membrane – Reverse Osmosis (RO)
Photovoltaic (PV) efficiency
PV modules are approx. 18% efficient.
Recovery ratio (fresh water/brine)
Between 50 and 60%
By HE Razan Al Mubarak
The units can operate around the design specification; however, variability of the salinity of the groundwater means that the units require constant fine tuning and balancing. The salinity of the groundwater can spike up to 50,000 ppm which shortens the life of the membranes and requires a higher power input to keep the water production constant. This high salinity also alters the ratio of fresh water to brine production; at 50,000 ppm more brine is produced than fresh water. The harshness of the environment in which these units are operating also presents some additional challenges. The units are located in remote areas amongst dunes and are constantly challenged from shifting sands and the dustiness of the environment; this means that the photovoltaic panels require regular cleaning and maintenance. The brine produced also needs to be removed and disposed of correctly. These challenges mean that the units require near constant supervision and have a higher maintenance footprint than was envisaged. To summarise, the technology works, however not at the performance level given by the manufacturers, due to the harshness of the desert environment and the hyper saline concentrations of some of the locations. To overcome these challenges, EAD is relocating some of the units to less remote and more accessible locations to cut down the time and cost involved with maintenance. For other units that need to remain in remote and challenging locations,
the introduction of telemetry and remote sensing is being considered to provide early warning signals if the units are malfunctioning, which should lead to a reduction of the frequency of speculative maintenance visits. When reflecting upon the option of groundwater solar desalination in remote areas, careful consideration must be given to the operational maintenance costs, manpower and location prior to a decision being made.
ABOUT HE RAZAN AL MUBARAK Razan is Secretary-General of the Environment Agency Abu Dhabi (EAD). She leads the organisation in achieving its mandate of protecting the environment by reducing pollution and enhancing the Emirate’s biodiversity. Razan is also the Managing Director of the Emirates Wildlife Society in association with the WWF (EWS-WWF) as well as the Mohamed Bin Zayed Species Conservation Fund.