Clean water for 500 000 Gauteng residents

In a joint venture with a local construction, concessions and manufacturing group, WEC Projects has designed and built a water treatment plant that will supply potable water to a large community in Gauteng.

The R270 million plant is designed to provide 60 Mℓ/day and was commissioned as part of a R1 billion upgrade project for the community, which has experienced a considerable increase in demand for potable water over the last few years. The scope of work for WEC Projects included mechanical, electrical and instrumentation work.

WEC Projects, with a joint venture partner, was awarded the contract to expand the existing facility in 2016. However, due to the complexity of the project and the need for buy-in from the local communities benefiting from the treatment plant, final commissioning only took place in 2021.

Treatment process Raw water is drawn from a nearby dam and pumped to the facility – where it undergoes clarification to remove suspended solids. After the primary clarification process, the water undergoes dissolved air flotation to remove any remaining solids and oils.

The clarified water then enters a rapid gravity sand filtration system to remove particles. This type of filtration system was specified due to the higher filtration rate it provides compared to conventional sand filters – which is

necessary for a plant required to supply more than 500 000 people.

After exiting the sand filter, the water is pumped to the ozonation facility for rapid oxidation and disinfection. It is then put through a second filtration process – this time through a filter system containing granular activated carbon. This process removes organic chemicals and other similar impurities.

The final process is the chlorification of the water to ensure that any harmful impurities such as bacteria are removed.

“This was a challenging project. The design of the plant required the water to undergo a complex processing solution to achieve the quality level required by the local municipality. We were also required to integrate the new plant module into the existing treatment plant. As a result, the plant uses a sophisticated and advanced control and instrumentation system to ensure consistent quality and plant uptime. While the requirements were for a water treatment plant capable of delivering 60 Mℓ/day, the new plant has been tested successfully to 120 Mℓ/day, ensuring that it will be able to handle increased demands well into the future,” concludes Wayne Taljaard, MD of WEC Projects.

The new plant can successfully treat 120 Mℓ/day of water