Ilembe, the fastest-growing area on the east coast of South Africa, has embarked on a pilot project to increase water supplies that features selling salt extracted from a desalination plant and a shrimp-breeding farm.
The municipality of 560,000 residents north of Durban has approved a desalination plant that will supply as much as a half-million liters (132,000 gallons) of fresh water a day, recycling the salt for commercial sale. Wind turbines may be used to save on power bills.
The $6.1 million project was initiated because South Africa’s eastern coast has such a low water table that boreholes are usually unfeasible with short, fast-flowing seasonal rivers that affect the reliability of water and a dispersed rural population that makes infrastructure expensive.
Ilembe like much of the nation is looking for a long-term, self-sustaining water solution. Treasury’s 2012 Budget Review says South Africa will start running out of water 13 years from now without better management. On current projections, South Africa’s water demand will outstrip available supply by 2025 to 2030, according to the document.
“We have a 35-year master plan for water,” Ilembe Municipal Manager Mike Newton said in an interview. With a rate of growth of 5.7 percent, a 70 percent rural population, climate change and proximity to the sea, desalination is “an attractive emergency backup in case we run out.”
Using technology already in place in the Southern Cape, the project will build a portable desalination plant at Blythedale, a resort north of Durban.
Desalination plans
It will combine techniques to create a blueprint for two larger proposed desalination plants on the north and south coasts of KwaZulu-Natal to provide water for the province.
The supply will be drawn from the dunes via a borehole instead of the sea from waters already partly desalinated.
With reverse-osmosis being used in the project, the potable supply will be remineralized as desalinated water is acidic.
Phase one of the project will cost 11 million South African rand ($1.1 million) including specialized equipment, with the second phase commercializing the salt. Part of the brine would be supplied to aquaculturalists to breed saltwater shrimp, and the rest would be dried for sale.
A projected output is a ton of salt per day. The saltwater shrimp project is already linked up with the Ocean Basket chain of seafood restaurants, which started an aquaculture company, and it’s envisaged that the salt-drying project will be done in conjunction with community projects.
Phase three is to find alternative energy supplies for the plant using vertical-axis wind-turbinesor hydrogen separation. The goal is to make each plant self-sustaining.
All three phases will cost 60 million rand, amortized by selling water over the 30-year lifespan of the plant.
This desalination project is an experimental prototype for two larger planned desalination plants for KZN, one for the North Coast and another for the South Coast.
