The contract for the construction of the Sterkwater Waste-Water Treatment Works (WWTW) was a brownfields project undertaken by Stefanutti Stocks Civils & Coastal for the Mangaung Metropolitan Municipality. The project increased the capacity of the WWTW from 4 Ml-a-day to a hydraulic capacity of 20 Ml-a-day.
The project scope included the construction of:
- elevated inlet works,
- biological reactor,
- blower building,
- motor control centre (MCC) building,
- three secondary settling tanks,
- return-activated sludge (RAS) / waste- activated sludge (WAS) building,
- chlorine contact tank,
- wash-water pump station,
- return flow pump station,
- medium voltage (MV) building,
- guard house,
- GRP pipe network, and
- paving and landscaping.
“As the project progressed the management of the water table an interesting aspect to manage,” says senior site agent Craig Cock. “At times the freeboard from ground level to the current water table was 5,5 metres and the majority of all our excavations exceeded, on average, seven metres. The biological reactor, which covers a footprint of 4,500m2 is the deepest at 8,5 metres.”
The high standards of safety and housekeeping on site translated into exceptional levels of workmanship. The biological reactor has proven to be the site’s stand-out structure, with the concrete finished to an incredible accuracy and standard.