Veolia Water Secures Desalination Plant Upgrade In Namibia

Aqua Services & Engineering (ASE), a company of Veolia Water Solutions & Technologies operating in Namibia, has secured a contract to upgrade and refurbish a 400 m3/day seawater desalination plant in Walvis Bay. The project will help increase potable water supply for domestic use, and provide enough process water to a Walvis Bay factory.

The source seawater's high organic content requires that ASE adapts an air flotation filtration system design, making it suitable for use as a pre-treatment step. "Our engineers will introduce a vortex mixer to generate micro bubbles, which are fed into the flocculated raw seawater stream," says Christian Stöck, Managing Director at ASE. "This will help lighter organic particles float to the surface, and allow for heavier particles to settle."

These settled particles will then be filtered by an ultrafine filtration bed where, unlike with an additional pumping step, minimal break-up of the flocculated particles will occur. This pre-treatment will ensure that the raw seawater, often affected by red tide and sulphur eruptions, meets the required standards for effective desalination in reverse osmosis membranes.

To help the plant optimise its energy consumption, ASE will install an energy recovery system to the reverse osmosis membrane system. "This high-end technology will help the plant reduce its reliance on municipal power sources by up to 42%," says Stöck.

The plant should be operational within five to six months, and will provide much needed relief to Walvis Bay, where water scarcity has been a longstanding problem.

"Over the last 15 years, we have built up detailed knowledge of the Namibian coastal waters, and we have gained valuable experience from building and operating numerous seawater treatment plants. This will help ASE deliver the best possible solution to treat the often tricky Namibian seawater," concludes Stöck.