The R1.9-billion upgrade at Zandvliet Wastewater Treatment Works, in Cape Town, has seen the completion of a new membrane biological reactor (MBR). 

Membrane technology is capable of treating wastewater to near drinking water standards.

The Zandvliet facility upgrade will expand the existing treatment capacity of wastewater by 18-million litres a day, bringing it to a daily total of 90-million litres a day. 

The project is on track to be completed by September next year.

The Zandvliet works services one of the fastest growing catchments in Cape Town, including Delft, Mfuleni, Blue Downs and Khayelitsha.

Besides the increased capacity, the upgrade will ensure that a high quality treated effluent is released, meeting or exceeding all licence requirements as laid out by the Department of Water and Sanitation, says the City of Cape Town.

“Wastewater treatment works perform the critical function of treating sewage/wastewater coming from homes, businesses and industries, referred to as influent, before releasing this as effluent into the environment via our waterways,” explains the city.

“Overall treated effluent compliance has increased to 85% following the implementation of the upgrade, which started construction in 2018. 

“This will improve further with the broader upgrade, ensuring high standards of treated wastewater leaving Zandvliet, which is particularly important as it will be used for water reuse in the future.”

“Today’s handover of the completed MBR is a key milestone . . .This is encouraging progress on one of the big focus areas of our government – better sanitation services for all in Cape Town,” says Cape Town mayor Geordin Hill-Lewis.

“We know that decent sanitation is the beginning of dignity, and so much of our capital budgets over the next few years are focused on sewer pipe, pump station and wastewater works upgrades.”

The MBR contains ultrafiltration membrane cassettes about 2.4 m in length, 2.4 m wide and 2.8 m high. They weigh around 2 t.

The cassettes consist of submerged hollow-fibre type membranes which resemble spaghetti, hanging vertically in the sewage. 

The hollow fibres have microscopic pores through which liquid is extracted, leaving behind solids and contaminants. The extracted liquid then continues through the treatment process.