Stellenbosch Wastewater Treatment Works
Upgrading a wastewater treatment plant for resilience
Nestled in the heart of South Africa’s Cape Winelands, the Eerste River brings life to the surrounding agricultural and agritourism communities which is renowned for grapes, wine and other deciduous fruit.
Effluent from the Stellenbosch Wastewater Treatment Works (WWTW) flows into the Eerste River – creating a risk if not managed properly. Zutari was appointed as consulting engineers by the Stellenbosch Municipality to plan and design the treatment works, while also being responsible for the site supervision of the project.
Over a decade ago, the Stellenbosch Wastewater Treatment Works was placing the livelihoods of the surrounding communities at risk – with dilapidated infrastrucuture that was struggling to meet effluent compliance. This created a hazard to the environment and a nuisance to the surrounding community of Eerste River.
The Stellenbosch Municipality made the decision to upgrade the WWTW with a limited budget at hand. The main objectives of the upgrade were to increase capacity, improve the effluent quality and reduce the foul odour. Zutari, as Consulting Engineer, undertook the planning and design of the treatment works in 2014, and construction began in 2015 with Zutari also responsible for the site supervision of the project.
The project comprised an upgrade of the plant to a full biological nutrient removal process that is capable of handling up to 35 ML/day average dry weather flow, as well as ensuring compliance with the National Water Act.
Over a decade ago, the Stellenbosch Wastewater Treatment Works was placing the livelihoods of the surrounding communities at risk.
The plant’s design included other innovative features, such as a sophisticated control system, odour eradication, energy-efficient technologies and context-driven, sustainable design.
This upgrade comprised a new inlet works, a new 27 ML/day membrane biological reactor (MBR) lane, the rejuvenation of the existing plant to an 8 ML/day Conventional Activated Sludge (CAS) plant with UV disinfection, and new sludge treatment facilities. The upgrade will cater for flows from the town up until 2035, allowing for further development and economic growth in the area.
With a fully automated with a state-of-the-art control system, the technology used ensures the process control and operating efficiency level is optimised. To mitigate odours generated from the WWTW, high odour generation areas were equipped with odour containment covers. The plant’s design included other innovative features, such as a sophisticated control system, odour eradication, energy-efficient technologies and context-driven, sustainable design.
The WWTW was also designed to be energy efficient by minimising pumping through the works and adopting energy-efficient technologies like a fine bubble diffused aeration system in the MBR lane, which is 15-20% more energy efficient than traditional technologies.
By working collaboratively with a host of project partners, Zutari has helped upgrade the plant into a state-of-the-art infrastructure facility that places the town of Stellenbosch at the forefront of wastewater treatment in Africa. Not only is the project ensuring that wastewater is treated to the highest of standards, it also ensures resiliency for the area’s future water supply.
The project is testament of the technical skills in South Africa’s water industry, where consulting engineers like Zutari – working in partnership with stakeholders – can provide solutions that are innovative, sustainable and community-focussed.
The Stellenbosch WWTW was recognised winner in the category ‘Projects between R250 Million to R1 Billion’ at the Consulting Engineers South Africa (CESA) AON Engineering Excellence Awards in 2020.
*The Aurecon Africa business has been officially renamed Zutari as at 21 July 2020. Zutari acquired Aurecon Middle East on 20 November 2020.
