Proposed Desalination Plant: Cape Town's future water fix or a high-stakes gamble?

The location of the City of Cape Town's proposed Paarden Eiland Desalination Plant in the Port of Cape Town, with an estimated yield of 50 to 70MLD. (Photo: City of Cape Town)

By Kristin Engel

26 Feb 2025

Cape Town’s proposed R5-billion permanent desalination plant at Paarden Eiland has sparked public concern over the City of Cape Town’s track record with desalination, citing alleged past failures and high maintenance costs.

Part two in a two-part series. Read part one here.

With the City’s plan to construct a permanent desalination plant at Paarden Eiland, concerns were raised about how the City will mitigate the risks associated with the water intake being so close to the harbour, where past desalination efforts brought problems.

In the face of Day Zero, the City set out to implement temporary desalination plants. Now residents and groups remain sceptical about the proposed permanent desalination plant at Paarden Eiland, based on the performance and issues that arose from the City’s previous desalination plants.

In most parts of the world, water scarcity is being exacerbated by growing water demand brought on by population growth, increased water consumption, development and economic expansion, as well as declining water supplies that are being exacerbated by pollution and climate change.

To try to secure a climate-resilient water supply in Cape Town, which faces increasing risks of drought and population growth, one of the City’s solutions is the proposed permanent desalination plant at Paarden Eiland, a fundamental part of the City’s New Water Programme.

Desalination is the process of removing salt from seawater and turning it into potable water. This plant would supply parts of the Cape Town CBD and is estimated to cost approximately R5-billion.

The recommended option for the proposed Paarden Eiland Desalination Plant in the Port of Cape Town. (Photo: City of Cape Town)

A second public meeting was held on 19 February 2025 in Milnerton, where the City sought to engage residents and solicit their views on the feasibility of it providing desalinated drinking water through an external mechanism at the proposed Paarden Eiland site.

Here residents spoke out about their concerns related to the City’s previous desalination plants.

This meeting is part of a broader public participation process, as required by Section 78(3)(b) of the Municipal Services Act (MSA).

Resident Ryan Harris said that desalination technology was good but that it was well known that SANS 241 (drinking water standard) was not sufficient for some of the contaminates that accumulated in the environment, and that RO (reverse osmosis) would not remove them.

After pre-treatment in the desalination process, the seawater goes through a treatment known as reverse osmosis where the seawater is fed under high pressure through a very fine membrane with tiny holes, which removes the salt and minerals from the water to create clean drinking water. (Photo: City of Cape Town)

Harris also highlighted that reverse osmosis was documented as a good technology but that maintenance and operational costs were a nightmare. He added: “The City has an absolutely horrific track record when it comes to reverse osmosis — the various other small-package plants were disasters.”

Daily Maverick previously reported that Peter Walsh from RethinkTheStink, who was at the meeting, also questioned the proposed Paarden Eiland location for the site.

“Where they are going to acquire that water from is probably the most polluted stretch of ocean in the whole of the Western Cape. How are they going to clean it?

“If they were extracting the water from a clean water source, we wouldn’t be having this conversation… I can’t see it (the desalination plant) happening without a higher standard because if you give me that water back to drink, I’m not going to drink it,” Walsh said.

Previous desalination plants

The main issue was at the desalination plant at the V&A Waterfront in Cape Town, which has been largely inactive due to a legal dispute between the City and the plant operators, with one of the arguments from the operators being that the sea water was dirtier than expected for this operation.

Zahid Badroodien, the City’s Mayoral Committee Member for Water and Sanitation, told Daily Maverick that this small temporary desalination plant, established by a contractor to supply the central CBD with a lifeline water supply during the Day Zero Water crisis, “did not fail to deliver water due to its location at the V&A Waterfront (harbour area)”.

“The contractor responsible for the design, operation and decommissioning of the small-scale container-based plant, unfortunately, raised numerous contractual disputes which are now close to being finalised through what have been protracted legal processes,” Badroodien said.

The City said that it could not comment further on this matter as it was currently in legal arbitration.

The other two temporary plants, established at Strandfontein and Monwabisi, were successfully operated for two years and decommissioned by another contractor following the contracts entered into with the City, according to Badroodien.

He said that the big difference between these previous desalination plants was that they were implemented in a short timeframe, specifically in response to the drought. Thus they had short operational periods, whereas now this would be a permanent plant with more considerations and steps in the treatment process.

Badroodien added that Cape Town was investing more in infrastructure than Johannesburg and Durban combined, with a capital budget 91% larger than Johannesburg and 117% larger than eThekwini Municipality over the next three years.

“Unlike other metros, Cape Town is proactively securing its water future through innovative solutions that ensure resilience against climate change and population growth,” Badroodien said.

The impact of climate change on Cape Town included less reliable rainfall and less rainfall in future, therefore, Badroodien said, relying on surface water from rainfall alone was no longer feasible long-term strategy. DM

Categories:

Tags:

DM is much better if you are signed in...

South Africa

Part two in a two-part series. Read part one here.

Previous desalination plants