Thursday, January 3, 2013

Desalination in Karakalpakstan

The Republic of Karakalpakstan, situated in the north-western part of Uzbekistan includes the Amu Darya River delta total area covers 165,600 square kilometres (37 % of Uzbekistan). The climate is typically continental, with very hot summers and cold winters without snow. The area is experiencing severe environmental problems as a result of the shrinking of the Aral Sea.

Around Muynak in Republic of Karakalpakstan, Uzbekistan.

Photo: Muynak Rayon (desalinator in background)

There are several reservoirs in the Amu Darya basin, the largest of which is the Tuya Muyun with a storage capacity of 7,800 MCM, consisting of four separate reservoirs.

One reservoir of this system the Kaparas is used to provide drinking water for Karakalpakstan.

In Karakalpakstan there are three main water supply organisations.

o Tuya Muyun - Regional organisation for water transportation mains.
o Agrovodokanal, - Water Company for the rural area.
o Vodokanal - Regional water company.

The drinking water supply in a number of rural areas however comes from groundwater which is too saline.

For rural communities the following water supply schemes are being used:

o Supply from local fresh groundwater sources
o Connection to the group system of Tuya Muyun-Nukus trunk mains
o Truck water supply (supply of water in water trailers)
o Desalination of ground water, which is rather brackish

Current Status of Desalination:

From 1987 some 200 desalination stations were constructed in Karakalpakstan. However only  63 were  operational by 2010. They are run by the Agrovodokanal. These stations are known as EKOS plants and were assembled and built by the "Tambovmash" factory from Tambov in Russia.

Feed water is usually obtained from deep wells, ranging between 400 and 600 meters deep. The distribution system is only for public tapping points. These desalination plants use the electro dialysis process. They are very basic and robust installations and have proved very suitable for the local circumstances where ongoing maintenance is an issue.

Vodokanal also has two sites where it applies desalination using reverse osmosis. There is one plant in Takhtakupir of 2400m3/day, and there are five small plants in Muynak of 15m3/day each.

Environmental Impact. Brine that derives from the many ED desalination plants is discharged to general collectors. Brine disposal is not generally neutralised, however this is considered not to be an environmental threat since the quantities of desalinated water are so small and very local. Moreover, there are no chemicals used in the treatment process, so the composition of the water does not really change.

Camellos alrededores Moynaq, Uzbekistán - Uploaded by juanracastano on panoramio.com
Photo: Salt covers much of the land in the northern districts of Karakalpakstan

Source of Photos: http://www.tripmondo.com/uzbekistan/karakalpakstan