International Symposium on
Drylands Ecology and Human Security

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New Solar Powered Direct Osmosis Water Treatment Technique

Renat Khaydarov & Rashid Khaydarov

Department of Development of Devices, INP, Uzbekistan Academy of Sciences, Tashkent, Republic of Uzbekistan


Water management and its interrelation with agriculture and energy are considered the highest priority in Uzbekistan. As some of remote rural areas of Uzbekistan in drylands do not have enough access to electricity; therefore usage of solar energy for powering effective water treatment devices seems to be a very perspective trend. The paper deals with a novel solar-powered water treatment technique based on direct osmosis process. The separation is driven by natural osmosis, which does not require external pumping energy as in the reverse osmosis process. Therefore, the specific power consumption of the desalination process is reduced from approximately 5 kWh per cubic meter for seawater reverse osmosis to a value of less than 1 kWh per cubic meter. The pilot device with productivity of 1000 liters/hour has been constructed. It consists of solar batteries with capacity of 500 W for pumping various fluids (feed, brine, product, working solution) of the desalination device, solar thermal exchangers for recovery of working solution, water pretreatment unit on the base of special fiber sorbents and oligodynamic water disinfection device with energy consumption of 0.1 W-h. Due to the financial support of UNESCO in 2005 the device was installed in a village of Aral Sea Region to remove salts and organic contaminants with total concentration of about 17 g/l. Test results of the constructed pilot device having capacity of 1 m3/hr with various real water samples taken in villages of Aral Sea region have been discussed. The product salinity after the treatment was about 50 mg/l. Water treated by the proposed technique might be reused as a substitute for potable quality water in many applications.