CITY OF CAPE TOWN
Zandvliet’s mega expansion showcases excellence The City of Cape Town’s R1.8 billion investment at Zandvliet Wastewater Treatment Works (WWTW) will increase current capacity from around 72 to 90 million litres per day. Main contractor Stefanutti Stocks Coastal expands on the project complexities of seamlessly interconnecting the old and new plants.
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erving one of Cape Town’s fastest growing catchment areas, the completion of the Zandvliet WWTW expansion will cater for around 150 000 additional people using stateof-the-art technology to optimise process efficiencies. In the meantime, the existing WWTW continues to serve its catchment, which covers the south of Kuils River, Delft, Blackheath, Eerste River and the township of Khayelitsha plus surrounds. The 18 Mℓ Zandvliet WWTW expansion extends over an 18 ha footprint and provides for a new enlarged inlet works, two new screw pump stations, four new primary settling tanks, a primary sludge pump station, a sludge dewatering building, sundry holding tanks (two primary sludge and two WAS), An aerial perspective taken in May 2020: to the left of the central roadway is the sludge dewatering building forming part of Portion A. To the right of the roadway are the four primary settling tanks forming part of Portion B
pipelines, access roads, and minor services like site drainage. Once the plant goes live, around 60 tonnes of dewatered sludge will need to be removed from the facility daily.
Community consultation From the onset, Stefanutti Stocks engaged with the community. Initially, this involved ward 109 bordering the site, but was extended to include the adjacent wards 95 and 96. A community liaison officer was appointed for each ward. The fact that the project includes a sizeable building component presented oppor tunities for the employment of skilled trades. Since mobilising on-site in November 2018, Stefanutti Stocks has forged ahead on this multifaceted construction programme, harnessing its extensive experience built up over the past decade in the water and wastewater treatment sector. In addition to Zandvliet, Stefanutti Stocks is also working on numerous other water cluster projects
PROJECT DATA Concrete
13 500 m³
Reinforcing
1 440 t
Formwork
35 783 m²
Excavation
259 880 m³
Backfill
180 000 m³
Pipe laying
4 973 m
nationally, located in Gauteng, KwaZulu-Natal and the Western Cape.
Parallel programme The Zandvliet expansion is divided into three portions, namely A, B and C. Portion A was originally due for completion in March 2020 but moved out slightly to May due to the national Covid-19 lockdown; Portion B was scheduled for completion in November 2020 (and now shifts to December); while Portion C is on track for completion in October 2022. Elements in A and B have run in parallel, forming the critical path, with C incorporating the final electromechanical installation, testing and commissioning phase. Towards the end of Portion C (March 2022), Stefanutti Stocks will return to site to complete the demolition of the old treatment building structures and connect the existing and new plants. For this purpose, a large concrete culvert was built flush with the wall of the existing adjacent inlet works to act as a future conduit.
ZANDVLIET WWTW PROJECT Location Khayelitsha Client City of Cape Town Consulting engineer Aurecon Contractor Stefanutti Stocks Construction contract value Approximately R325 million Total project value (including mechanical and electrical) R1.8 billion
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IMIESA May 2020
