by Stephanie Nieuwoudt
Stellenbosch Municipality was earlier this year nominated for a CESA Engineering Excellence Award for its innovative and cost efficient wastewater treatment works (WWTW) at Wemmershoek.
The municipality appointed Royal HaskoningDHV for the design and implementation of the works which uses new Nereda technology.
The old works in Franschhoek as well as the old Wemmershoek works could no longer fulfil the needs of the Franschhoek Valley
It was clear that a new works was imperative and from an economic point of view it was more cost-effective to have one rather than two plants. The most practical area was Wemmershoek because it is downstream from the Berg River and no pump station was needed.
However, the site is quite compact and the challenge was to build a works with a small footprint. The Nereda process fulfils this need. It is also economical from an operations as well as a financial point of view. Construction on the works started in February 2012.
The project was completed at the end of 2014. The Nereda system makes use of aerobic granular sludge technology to purify wastewater. Advantages include: the aerobic granules have great settling properties allowing for higher biomass concentrations, the need for secondary clarifiers is eliminated and there is no need for major sludge recycle pumping.
The result is a compact, simple system that requires significantly less chemicals and energy while still offering excellent effluent quality.
Being nominated for the CESA Award is a wonderful acknowledgement that the municipality is on track in its mission to be an innovative municipality. Not only is the municipality willing to investigate new and innovative technology, but is also willing to invest in these technologies. Furthermore, the municipality looks at alternative methods to find solutions that are economically speaking to the benefit of all residents in the area.
Conrad Sidego, Executive Mayor of Stellenbosch says the Wemmershoek WWTW is just another example of how innovative solutions can address many challenges.
“What happens to wastewater is not exactly the kind of thing ordinary citizens think about daily. But there is a certain kind of satisfaction knowing that the municipality has addressed a major challenge in a sustainable and innovative way. These are the kinds of solutions that make Stellenbosch a truly innovative town.”
“We have experienced a few problems, but this is normal for a project of this scope,” says Sidego. “As challenges occur we address them immediately.”