Monwabisi plant helping City to learn about desalination

The Monwabisi desalination plant is one of the City of Cape Town’s three temporary desalination projects. These projects are helping the City to learn more about this technology which is adding to Cape Town’s existing water supply.
The Monwabisi desalination plant is now fully commissioned and is running at capacity producing some seven million litres per day.

This water, which is sea water that has been treated to meet national drinking water standards, is being pumped into the City’s water network.

‘This plant, which has helped to add drinking water to our water network during the most severe drought that we’ve ever had, is also teaching us valuable lessons about how to possibly one day have a permanent desalination plant for Cape Town. We are looking at reducing our dependence on rainfall as the sole source of our drinking water. We are also looking at recycled water and groundwater as alternative resources,’ said the City’s Mayoral Committee Member for Area East, Councillor Anda Ntsodo.
‘Our dam levels are very much improved, but we urge all of our residents to continue thinking about what you are using precious drinking water for,’ said the City’s Mayoral Committee Member for Informal Settlements, Water and Waste Services; and Energy, Councillor Xanthea Limberg.

The plant will be in operation for two years per the service agreement in which the City agreed to buy water from the service provider, Water Solutions Proxa – JV.
What is desalination?

Desalination is a process that produces fresh drinking water by removing salt and impurities from sea water. The Monwabisi plant is a Sea Water Reverse Osmosis (SWRO) plant.

How does an SWRO plant work?

• Sea water is abstracted offshore and conveyed to the SWRO plant via a pipeline
• The plant produces high-quality drinking water from the sea water and injects it straight into the City’s water reticulation network
• The waste product from this desalinisation process is called brine, which is simply concentrated salt water. This is conveyed back to the sea via a pipeline, and released into the ocean through a diffuser which is designed to ensure that any potential environmental impact is limited

Source: City of Cape Town

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