Existing Solutions

renewable energy, solar power, desalination, RO, Brackish groundwater, water supply

technical

Towards suing environmental friendly technology to save the required fresh water resources for remote areas, Environment Agency – Abu Dhabi (EAD), started its pilot project in 2009 for using solar powered desalination plants to desalinate brackish groundwater with salinity ranges between 10,000 ppm and 35,000 ppm. Feasibility study was carried out to compare between using fossil fuel and solar energy. The project considers the utmost reduction of negative environmental impacts by employment of latest technologies, innovative solutions and best management practice to produce fresh water in remote areas.

The project consists of modular and semi-mobile photovoltaic solar cells power supply system with a capacity of 45 K Watt/hr working during the day hours only to reduce the cost of energy storage. The generated electrify is used to operate a high efficient RO desalination plant for brackish groundwater treatment. The capacity of each RO unit is 5 m3/hr with a recovery ratio of 60%. The system is provided with an ultraviolet filtration and disinfection system. The raw water is abstracted from a groundwater with a submersible pump operated by the solar energy also. Various alternatives and options for brine water discharge were evaluated and it was found that the optimal solution is use evaporative lake. However and some areas where the raw water salinity is less than 10,000 the produced brine water can be used for irrigating native desert plant species (salt tolerant species). It has been found that this system is feasible and the consumption of the energy ranges between 3.0 to 5.0 Kwatt/m3.

The main objective of these plants is to provide habitat improvements (through small size irrigated plots) and provision of watering points to sustain wildlife (native and release) in the network of protected areas managed directly or indirectly by EAD including the required water for labors in these remote areas.

EAD started with one pilot project at Umm Zommoul Area in the eastern region of Abu Dhabi Emirate (about 200 km far from Abu Dhabi City). Then another 30 locations were selected in 2010 for more assessment of this technology. (attached is the location map)

EAD started this initiative as part from its role to assess the environmental friendly technology to minimize the ecological footprint for water desalination. Many stakeholders were engaged in this initiative including ADWEA and MASDR. EAD is the main actor of implementing this solution however the stakeholders were engaged from the begging and during the planning for the implementations and preparing the design. A technical team was following up the implementation process. However, a third party (international experts) was selected to review the process and help in assessing the results of the project.

EAD developed an optimized solar desalination system by implementing specific improvements in the system initially installed at Umm Zommoul, which could make it more competitive against using conventional fossil fuel. This helped to provide the remote protected areas with enough fresh water sources for domestic use for labors and also to rehabilitate the habitats for wildlife animals in these areas. 

EAD performed detailed cost calculations for the suggested configuration to assess their feasibility and cost effectiveness. These calculations are done in view of the mitigation measures for environmental impact of all available alternatives including using solar panels against using fossil fuel costs.

The main output for this solution is:

1. Save the required fresh water using environmental friendly solution.
2. Specific electricity consumption in the range from 3.3 to 5 kWeh/m³ of desalinated water.
3. High reliability of the system, as no major problem was observed in the coupling of the solar PVC field with the RO desalination plant.

From the results obtained during Phase I, it was possible to identify potential relevant improvements that could be implemented in the RO solar system to increase its efficiency and competitiveness. This project can continue to deliver tangible impacts on the long term.

In the process of effectively implementing this solution, what are some of the key qualitative and quantitative indicators of success over time (i.e. what would you expect to see change, where and when)?*

• Improving the efficiency of solar powered desalination
• Using less energy for desalination of brackish water in remote areas (less
• Environmental friendly solution
• Improving the O&M process
• Provide an effective solution for supplying remote areas with fresh water
• The RO plant is normally operated at ambient temperature, which reduces the headache of scale formation and corrosion problems, especially when the pretreatment system is properly designed and kept under control.
• Again this will reduce maintenance cost.
• The process is electrically driven. As a result, it is readily adaptable to powering by solar panels.
• The modular structure of the used RO process increases flexibility in building desalination plants within a wide range of capacities.

• This solution is very important for the arid regions specially the remote areas where no access to fresh water.
• The improvements would considerably reduce the specific cost of distillate produced by the optimized solar RO desalination system which could help the poor people in remote areas.
• With more research and focus on how to achieve more improvements this will help to reduce the environmental impacts of desalination system.
• This technology can minimize the cost required to deliver the water to remote poor communities. 

The pilot project results and the techno economic study indicated that the solar powered desalination unites with a capacity of 30 m³/day using RO plants is feasible for remote areas where there is no connection to electricity grid and it is too difficult to transfer traditional fuel.

There are many design options included a diesel-assisted PV-RO plant, a fully diesel driven RO plant and a fully solar-driven PV-RO plant available and the optimal solution depend in many facotros which should be studies in more details.

What is the minimum investment necessary (in terms of human resources, time,

energy, infrastructure, financial resources, political will, etc.) in order to effectively implement this

solution?* What are the main factors of success that you wish to emphasize?*

• Design and selecting the suitable option. Optimal design selection depends primarily on the cost of primary energy and cost of solar panels where the solar-driven plant
• Preparation of TOR and the plants specification is very important
• Site selection
• Calculations of required fresh water quantity
• Construction supervision
• O&M plan. As for such small capacity RO plants in remote areas, the labor cost becomes a significant cost item when estimating water cost.

Have some organisations/institutions/committees already committed to implement or replicate this solution?*

• Yes, MASDR

Dr. Mohamed A. Dawoud

Manager

Water resources Department

Environment Agency – Abu Dhabi

P.O. Box 45553

Abu Dhabi, UAE

Tel. +971 2 6934680 (office)

Email: mdawoud@ead.ae

www.ead.ae