Caution over Bluff desalination plant

A deal was struck between eThekwini Municipality and Japanese organisation, New Energy and Industrial Technology Development Organisation for funding to be provided for the plant, which will be built at the Bluff water treatment works.

Conveniently situated along the coastline within the protected headland, the water works have ease of access to the sea, making it an ideal location.

An environmental impact assessment is already underway for the project and should the go-ahead be given, the build is expected to take three years. The plant will use non-conventional desalination technology, making it more environmentally-friendly and using less energy.

Desalination uses reserve osmosis – a process whereby salt and minerals is removed from water, making it safe for consumption and practical for agricultural and industrial purposes. Many countries have built desalination plants in times of drought to improve access to a secure water source.

In areas where fresh water is scarce, the ocean is a viable and large water source. Desalination also decreases reliance on fresh water sources, preserving them and reducing the risk of water shortages during a drought.

However, desalination is a costly enterprise, both during construction of the plant and when in operation and requires a lot of energy to produce potable water. The by-product, brine, produced during the process of desalination also has potentially harmful consequences on the environment.

Historian and former ward 66 councillor, Duncan Du Bois has some concerns about the project.

“Although there is nothing untoward in a project to test the feasibility of a desalination plant, committing to desalination as a means of addressing water supply ought to be questioned.

An article in the Mercury on March 6, 2014 noted that desalinated water would cost double that of the Umgeni Water tariff. Also of note is the large amount of electricity required for such a plant. Although the proposed demonstration model is predicted to use 30% less energy than conventional desalination plants, the phrasing of that claim does not mean that water thus produced will be cheaper than Umgeni Water.”

Du Bois cited a desalination plant in Brisbane which was side-lined because supply of water from natural sources was sufficient.

“But to keep that plant idle costs Brisbane’s ratepayers $15 million a year and has resulted in a 13% increase in the city’s water price (Brisbane Courier Mail, March 3, 2015).

With plans to build a dam on the Mkomazi River, which would boost Durban’s water supply substantially, and bearing in mind the liability of Brisbane’s desalination plant, Durban should be very cautious about committing to desalination as a means of sustaining water supply. It should also be appreciated that droughts are not continuous but are part of our historically proven weather cycle.”

The South Durban Community Environmental Alliance opposes the construction of a desalination plant. The organisation also fought against plans for plants in Ilovu and Tongaat, citing the consequences on local communities and the environment. SDCEA also believes lack of maintenance has led to the current dire water situation.

“Desalinisation is bad for the residents, marine life and the ocean.

Yes, we need water and this can be done through a number of ways such as the maintenance of leaking water infrastructure, including removing the silt that is overflowing in our dams due to the lack of a proper plan. Instead this has been allowed to increase and when it rains, the water goes over the dam walls instead of filling up because of the silt. We hear stories of workers operating the dam sluices being careless by deliberately leaving sluice gates open, allowing the dams to be emptied. We don’t need desalinisation but need proper management of our water resources,” said SDCEA co-ordinator, Desmond D’Sa.

 
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