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Massive upgrade underway at Zandvliet Wastewater Treatment Works


The R1,7 billion upgrade of the Zandvliet Wastewater Treatment Works (WwTWs) is set to unlock development in one of the fastest growing catchments in Cape Town. The Zandvliet WwTWs treats effluent from the southern parts of Kuils River, Delft, Blackheath, Blackheath Industria, Blue Downs, Eerste River, De Wijnlanden, Thembokwezi, Mxolisi Phetani and Khayelitsha. 

In its current form, the WwTWs has the capability to handle 72 million litres of wastewater per day. Upon completion of the massive upgrade project, the plant will be able to process an additional 18 million litres per day bringing the total capacity to 90 million litres per day. This significant increase will foster investment in the area, as it will have the capability of safely catering for housing developments, schools, commercial developments and, by association, job opportunities.

In addition to the increased capacity that will be created, a new preliminary treatment process and upgrade of the existing treatment modules will ensure that the quality of the treated effluent being discharged is of an acceptable standard and complies with the license conditions issued by the National Department of Water and Sanitation.

‘The treatment processes applied at the facility, being biological activated sludge processes, are considered best practice for municipal wastewater treatment. Additionally, the existing Membrane Bioreactor Module, which incorporates membrane technology for solid and liquid separation, was the first application of this technology in the municipal sector in South Africa. 

The City of Cape Town is among the highest performers nation-wide, in terms of treated effluent being discharged from WwTWs, within the standards required by the Regulator. Additionally, the plants operate in accordance with ISO standards,’ said the City’s Mayoral Committee Member for Water and Waste, Councillor Xanthea Limberg.

The current scope of work will see the construction of a membrane bioreactor, sludge dewatering facilities, new inlet works, pump stations, primary settling tanks and disinfection facilities.

‘Visiting the site and witnessing the staggering scale of the project really drove home how much work has been done thus far, and how much still lies ahead in this mammoth upgrade of the Zandvliet WwTWs. The City is committed to ensuring that it continues to evolve its processes to manage waste and to ensure that it does everything in its power to put in place enhanced processes for sustainable urban management,’ said Councillor Limberg.

Rapid population growth, and changing wastewater characteristics over the years have placed a huge strain on our existing wastewater treatment processes. As such the City considers upgrades of several wastewater treatment plants a priority, and has over R9 billion worth of upgrades to WwTWs that are either underway, or at some stage of the procurement process.

The commissioning of the new plant is anticipated to be by December 2023. Soon thereafter, further expansion will be implemented to cater for continuing urban growth in the area. The existing plant will continue to operate and treat wastewater throughout this period.

‘The City is immensely pleased that construction work is now well underway at the Zandvliet Wastewater Treatment Works. The project has been beset by various delays since 2010, including five (unsuccessful) tender appeals, a High Court appeal, and a land claim. Now that these have been resolved and boots are on the ground, it’s all systems go to adequately cater for one of the fastest growing catchments in the city,’ added Councillor Limberg.