Feasibility started for South African desalination plant

A feasibility study is underway in South Africa’s Northern Cape for a 7,000 m³/d seawater desalination plant at Abraham Villiers Bay close to the town of Kotzesrus.

Royal HaskoningDHV (formerly SSI Engineers & Environmental Consultants in South Africa) is conducting the study to establish the Zandkopsdrift seawater desalination scheme on behalf of Sedex Desalination (Pty) Ltd a subsidiary of Frontier Rare Earth Pty Ltd. The plant will supply potable and process water to the Zandkopsdrift Mine.

The study will determine the configuration, sizing, phasing and lowest possible life-cycle cost of the project, while minimising the impact on the physical and social environments. The scheme’s key aspects have been identified as:

· Marine works (comprising the sea intake and outfall works)
· Desalination plant (based on reverse-osmosis and including suitable pre- and post- treatment)
· Bulk water supply infrastructure
· Bulk power supply infrastructure (to supply desalination plant and product water booster pumps with electricity from the mine)
· Road access (to desalination plant, transfer pipeline and power lines)

Project manager Jack McGhie outlines the scheme:

“Potable water will be withdrawn from a 20,000 m³/d capacity storage reservoir at the seawater desalination plant and pumped via a rising main to 191 m above mean sea level (MSL), over a distance of 6.8 km. The potable water will then gravitate 10.66 km to Kotzesrus, at 167 m above MSL.

“From Kotzesrus the water will be pumped further via a booster pump station, through a rising main to a height of 223 m above MSL, over a distance of 2.3 km,” McGhie added. “The potable water will then gravitate for the last portion of the pipeline, over a distance of 12.80 km to the Zandkopdrift Mine Raw Water Storage Reservoir, 203 m above MSL.”

Secured via competitive bidding, a Royal HaskoningDHV’s proposal drew on experienced personnel and resources, and a track record of having completed most of the country’s desalination and effluent-reuse plants. These include desalination installations at Plettenberg Bay, Knysna, Sedgefield and Mossel Bay.

Effluent-reuse plants have been completed for George and Mossel Bay Municipalities and designed for Nelson Mandela Bay Metro and the Overstrand Municipality.