A 1,500 m³/d reverse-osmosis (RO) brackish-water desalination plant has been supplied to a mine in Mauritania by Veolia Water Solutions & Technologies South Africa, with a heat-exchanger to cool the water.
The contract included design, fabrication and supply.
Raw water from on-site boreholes is pumped to multimedia filters and then to a filtered water tank, before being sent through a set of heat-exchangers. This step is necessary due to the high ambient temperatures of the area, which can see the water reaching temperatures as high as 50°C.
Before RO treatment can begin, the water temperature has to be reduced to a maximum of 30°C. This is achieved through a cooling system consisting of two air-cooled chiller systems, each with a plate heat-exchanger at the process interface.
“This project posed a few challenges that required innovative solutions. Its remote location in a very harsh desert environment brings climatic challenges,” explains André Loots, Veolia project engineer. “The client also had high level specifications, such as all motor-driven equipment being rated for high and premium energy efficiency.”
To fulfil this requirement, Veolia included optimum energy efficiency in the design for the motor-driven equipment.
The plant is due for commissioning towards the start of 2013. Veolia has offered assistance in the form of supervision during the installation and commissioning phases to ensure that they are carried out according to specified procedure. In addition, Veolia has assumed responsibility to ensure that operators receive the necessary training.