Cape Town looks towards desalination

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 14 June 2011

By: John Yeld

The City of Cape Town plans to call for tenders for a feasibility study on a large-scale seawater desalination plant, as the region runs increasingly close to using all of its available fresh water supply.

Water scarcity may require winter rainfall pumped from the Berg into Voelvlei Dam

The tender call, expected within a month, will be for a study on where such a desalination plant could be built and what capacity it should have.

The call coincides with a major effort to plug water leaks and theft that, in February last year, accounted for one quarter of all treated water in the city, and with a warning that few options remain for tapping existing surface water sources.

The city will also be looking at the large-scale re-use of water. This is the only potential major new water source at a cost lower than seawater desalination, which is very expensive because of the large amount of electricity required. This study is expected to kick off “within the next few months”.

These initiatives are among the water conservation and water demand management measures that form a major part of the strategy for providing water in the Western Cape region that is already using about 92 percent of all “safely” available water. “Safely” means with a high degree of certainty of availability, without water restrictions.

Depending on how successful these measures are and on how much the city grows, the remaining 8 percent of available water will be fully utilised anywhere between 2017 and 2019, according to projections by the Department of Water Affairs. Continue reading

Karoo direct water reclamation plant a first for South Africa

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 02 January 2011

Residents of the drought-stricken Karoo town of Beaufort West will start using recycled sewage water when the town’s direct water reclamation plant starts operating next week.

Gamka Dam - the main reservoir at Beaufort West - has dried up

The first plant of its type in South Africa, it has some local residents turning up their noses, but the plant became necessary to ease the plight of the town’s roughly 8 000 households hit by the water shortage.

Municipal officials say the demand for water has grown and the drought has been exacerbated by climate change.

The town’s main reservoir, the Gamka Dam, has dried up, forcing municipal officials to introduce a water management scheme.

The municipality was forced to cut supplies to households, while tankers supplied them with five litres of drinking water a day. Water tankers containing borehole water are available around the town for washing water.

A Stellenbosch-based company, Water & Wastewater Engineering, was commissioned to design, build and operate the plant to treat effluent from the town’s sewage treatment works.

Managing director Pierre Marais said water reclamation entailed taking treated effluent and purifying it to a drinkable standard.

The purified water will be pumped directly into the town’s reservoir. Continue reading

Huge ancient freshwater aquifer under seabed

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 10 May 2010

A marine research company has proposed a R1.8-billion project to solve the water crisis in Nelson Mandela Bay by tapping ancient water from a huge freshwater source under the seabed.

Dramatic geologic formations are displayed in the Cape Fold Belt - the folded sedimentary sequence of rocks in the south-western corner of South Africa.

In a recent presentation to the Development Bank of SA, Deep Water Research (DWR) from Cape Town said the aquifer – situated 60km off Port Elizabeth – “is larger than the Breede River Dam”. Sucked out hot from at least a kilometre beneath the floor of the sea, the supply would be “very long term and consistent”, it said.

Local experts have raised questions about the proposal, however, pinpointing the need for a comprehensive impact assessment and the need to balance the certainty of finding water in the volumes described against the funds spent searching for it. The security of the resource, the threat of seawater contamination and the geological ramifications should be taken into account, they argued.

In a presentation to the bank at its Midrand headquarters, Hugh Lloyd, a director of DWR, said there were large volumes of fresh water off the South African coast.

“A programme to explore and develop this resource on the coast, where our water resources are diminishing rapidly, has been initiated by DWR.”

The aquifers were revealed during years of oil and gas exploration, he explained. “An exploration well off Port Elizabeth intersected a potentially abundant supply of potable water.

“This resource alone has the potential to be an order of magnitude larger than the Breede River Dam. Such aquifer water resources have potential major advantages over dams as the water is not polluted, doesn’t evaporate, the supply is very long term and consistent, and it can become productive far sooner than a dam.” Continue reading

Desalinated sea water for city in four years

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 23 April 2010

By: Jeremy Westgarth-Taylor
Pioneer of Water Rhapsody Conservation Systems and winner of a WWF Green Trust Award

The Table Mountain fossil aquifer has been there for millions of years. Extraction would permanently reduce the amount of water.

Water and Environmental Affairs (DWEA) Minister Buyelwa Sonjica has said that her department was forging ahead with plans to supply desalinated water to Cape Town, and furthermore extract water from the Table Mountain (TM) aquifer.

As mentioned in the article, all rivers in the Western Cape have been dammed, and the maximum amount of water is being extracted. There is no more water that can possibly be squeezed from our rivers.  What was not said is that this water is used, polluted and largely wasted to rivers around the Western Cape with concomitant damage to riverine and marine life.

The focus has always been and remains to supply more and more water.

Now DWEA are looking at other ways, hence the aquifer extraction and sea water desalination. Has the Minister not been advised by scientists that by extracting fossil water from the TM aquifer, the relatively finite amount of water in the aquifer is being permanently reduced for all practical intents and purposes. This is a fossil aquifer, and has been there for millions of years. Not only would extraction permanently reduce the amount of water in the aquifer, but it would also jeopardise plant and animal life as well as rivers within the aquifer system. If you for instance pump water out near Cape Town, there will be a lessening of available water as far as Port Elizabeth! Continue reading

Groundwater threatened by boreholes

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 23 February 2010

Environmentalist Andrew Muir, founder of the Umzi Wethu training academy and a former The Herald Citizen of the Year, has warned that the increasing number of unregulated boreholes in Nelson Mandela Bay could permanently destroy the vast groundwater supply.

Zolile Keke, Water Affairs Department director of institutional establishments, has confirmed an increase in the number of people applying to use borehole water since the region’s water crisis started.

Provincial Water Affairs and Forestry spokesman, Mandi Zenzile, said the department now “requests” that residents in the city, who are considering drilling boreholes for “reasonable” domestic use, inform both the department and municipality.

“Information is required for the department to determine the impact and effect of the total groundwater abstraction on each specific aquifer.” “If the department observes that the aquifers are stressed and abstraction exceeds the sustainable yield of the aquifer, groundwater users will be requested to reduce their abstraction or to cease abstraction completely.”

The Water Affairs Department has admitted that it is not known how many people are using underground water, or how much.

Muir said it would be impossible to extract fresh water ever again if water in the underground wells combined with saltwater from the sea. “The problem is that our underground water supply is not endless. If the water drops below sea level, then seawater will leak into these underground wells”. “We have to treat our underground water supply as if it is a precious commodity.”

“Our underground water should be regulated and managed, now more than ever, because of the water crisis.

Source: The Weekend Post

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