When viewed from space the Earth is a magnificent blue planet which seems to have a limitless supply of water and in fact 70% of the surface is covered by water. The problem is that most of this is salt water, located mainly in oceans and seas. Only 3% of the water is fresh water, safe for drinking. However, most of this is unavailable for use with ¾ of all freshwater being part of the frozen ice caps and glaciers. What remains is 1% and of this a full 2/5 are tied up in America's Great Lakes and Russia's Lake Baikal.
But fresh and potable water is critical for humans and animals. The human body is about 72% composed of water with the brain being 85% and blood some 82%. While one can survive for weeks without food, lack of water will kill a human being within a few days. A 5% loss of body fluids results in thirst, nausea and weakness. A 10% loss sees dizziness, headache, inability to walk and a tingling sensation in the limbs. A 15% loss results in dim vision, painful urination, swollen tongue, deafness and a numb feeling in the skin. Any loss greater than 15% normally results in death.
The recommended intake of this precious fluid for a human is in the region of 4,5 l per day for men. If you want to consider the total consumption of relatively well off people this is increased by 40 l/person for sanitation and if you include water for bathing and cooking requirement it rises to almost 250 l per person.
Of a population of say 6 billion, more than 1 billion lack access to potable water. About 5 million people die each year from poor drinking water (from one of six major diseases and this does not include typhoid which is common in South Africa), poor sanitation or a dirty home environment (resulting from water shortage).
A third of the world's population lives in countries that find it difficult or impossible to meet water needs, a proportion that is expected could double by 2025.
War over water?
Some people predict (excluding America's ill-conceived wars in Iraq and Afghanistan) that the next wars that we will see will be over water. Rivers typically pass through many countries and the sound plans of one to conserve water for its own consumption can dramatically affect their downstream neighbours in terms of water for both consumption and irrigation. Examples are numerous. Israel controls the head waters of the Jordan River whose flow is through both Jordan and Syria. The Rio Grande used to flow all the way through American states and Mexico where it was still a major river. A few years ago as a result of American dams and a drought, Mexico did not receive one drop. The waters of the Blue Nile have for a long time been a source of heated contention between Egypt and Ethiopia. Egypt's existence depends on the Nile which supplies 98% of its water needs and Ethiopia wanted to build dams. In Turkey a major project is poised to divert half the flow of the Euphrates River. The Tigris and Euphrates Rivers both rise in Turkey and flow unimpeded to Syria and Iraq where they provide the bulk of irrigation water required by those countries. Turkey has proposed building a series of dams that would reduce water flow and that is causing alarm downstream.
Environmental change
In the West at least, droughts and floods are largely attributed to weather cycles and the temperatures of the ocean. The changes we have seen in weather patterns over the last few years (including the increased number of violent typhoons in North America) have been blamed on global warming. If this is true we can expect more extensive changes to weather patterns as the once sleeping giants like China require vast increases in energy demand and China is rich in fossil fuel like coal. Remember it is in discussions with Sasol about the possibility of erecting oil from coal plants based on Sasol's technology. It makes good business sense for Sasol and would reduce CO2 and other emissions compared to coal fired power stations although the latter will probably still be required. China is like South Africa in that coal is centred in specific regions and other means have to be found for electricity generation. China has invested heavily in nuclear technology and has its own 'pebble bed reactor' technology under development.
Desalination
It is estimated that more than 7500 desalination plants are in operation worldwide, of which 60% are located in the Middle East. Desalinated water at the moment serves the needs of about 100 million people worldwide. There are several processes of desalination with reverse osmosis and distillation being the most common. The common methods of distillation include multistage flash (MSF), multiple effect distillation (MED) and vapour compression (VC). Distillation is self explanatory and a benefit is that salt which can be sold is generated). Reverse osmosis is the most recent technology and here the feedwater is pumped at high pressure through permeable membranes. Water quality can be improved by adding a second pass of the membranes. Desalination plants use seawater in general or brackish groundwater or reclaimed water. A major disadvantage of desalination is the use of electricity for power although a Chinese scientific team claims that they have developed a desalination plant that will run with a new solar power collection and heating device. South Africa is not behind either in innovation and William Graham started registering patents in regard to desalination since 1992. Although his techniques still have to be adopted in his own country they are in use in large desalination plants in Singapore and other countries.
Some examples
Desalination is a major area for the I&C industry although implementation of the technology in South Africa is still limited. It can be used to treat brackish water or salt water, although the second application is the most used, and one Middle East state relies on the technology for some 90% of its potable water.
The Middle East was the first region to enter desalination in a big way and Libya introduced it during the 1960s. The technologies available at that time were not ideal but the country had no choice and MSF distillation was adopted. Libya is today the largest operator of desalination plants in North Africa and the Mediterranean basin. While early plants were designed to treat brackish water, from the early seventies a series of mid sized plants were constructed to address the complete issue of shortage of water supplies. The total installed capacity exceeds 600 000 cubic metres per day.
In Tunisia the capacity is 72 000 cubic metres per day and the plants are modern and based on either reverse osmosis or electro-dialysis reversal. Most plants are used to treat brackish water. Morocco has several seawater plants operating, and plans to significantly increase this supply for major cities. The world's largest plant is in Saudi Arabia and it produces 128 mega gallons per day of desalted water.
While the Middle East may be the largest user, desalination plants are found as far away as California. To date only a limited number of plants have been built (10 in total) as the cost of water is higher than the other techniques used, such as water transfer and ground water pumping. However, as drought conditions continue to occur the concern for water availability increases and desalination plants are being proposed at numerous locations in the state. The two technologies used are reverse osmosis and distillation. In California the focus is on seawater desalination. Even European countries like Spain have locked on to the technology and it is currently building 20 RO plants in the southeast to supply over 1% of the country's water. Even in the UK a 150 000 m³/day plant has been proposed for the lower Thames where it will use brackish water.
The power for desalination usually is derived from thermal sources so it is contributing to global warming. In Russia the BN-350 fast reactor at Aktau (Kazakhstan) has produced 80 000 m³ per day of desalinated potable water for the last 29 years which proves the point for nuclear reactors. The potential use of nuclear power for these plants is on the increase. China is looking at the possibility of using a 200 MW reactor to produce 160 000 m³ of desalinated water. India has been engaged in desalination research since the 1970s and is about to set up a demonstration plant coupled to twin reactors. The project will be a hybrid reverse osmosis/multistage flashplant. Morocco has completed a pre-project study with China to use a 10 MW heating reactor to produce 8000 m³ of potable water by distillation. Argentina has also developed a small nuclear reactor for desalination. With the threat of global warming there is no doubt that nuclear power will be used to desalinate water in the future and of course seawater is available for water cooled reactors. A great awareness for the need to produce desalinated water exists in China. By 2005 it was producing between 100 000 and 150 000 tons of seawater every day to satisfy the demands of about 7,5 million people. By 2010 the capacity is expected to increase to between 200 000 and 300 000 tons per day.
Icebergs
The rumours and jokes about towing icebergs from Antarctica may still be a long way off, but not so in the northern hemisphere. Canadians have long been worried about the water they drink and some entrepreneurs have taken to bottling iceberg water. Large icebergs flow down past Canada at certain seasons and smaller pieces break off. These chunks are harvested for water after being towed the short distance to the mainland. One of these entrepreneurs is harvesting and processing 1000 tons of ice water per month (about 1 million litres) and has 18 full time employees. His current plans are to open a new plant that will bottle 1,25 million cases of the icy brew (much like the spring water business). This product, Pollack's Original Iceberg Water is currently sold in the UK, US and Japan and interest has been expressed by the Philippines, India and Egypt. The Antarctican source of ice is being looked at seriously by countries close to the source, such as Australia.
The South African situation
South Africa is blessed with natural resources except for water. On average rainfall is less than 500 mm per year with the drier regions receiving less than 200 mm and the wettest in excess of 2500 mm per year! As usual rain does not fall where it is most needed and water can be classified as a very scarce resource in this country. With few natural lakes we depend on rivers and dams. With dams the problem is that the country is not suited for their construction with very few deep valleys or gorges. The result is that most dams are shallow with a large surface area so water evaporation is a major problem. The adjacent Lesotho water scheme whose major customer is South Africa does not suffer from this problem. Intercatchment transfer schemes are in common use where water is piped from one dam to another. Tentative plans have been put forward to buy water from neighbouring states such as from the Zambezi River in Zimbabwe.
South African river water is heavily polluted, often from the sanitation requirements of informal settlements and this leads to the regular outbreak of diseases such as typhoid, cholera and gastroenteritis. Historical figures from 1980 to 1987 show that between half a million and one million South Africans contracted cholera. Informal settlements without sanitation are not going to disappear overnight so this disease scenario must be watched carefully.
Some large industries such as Sasol and Eskom already recycle water for re-use in their plants. Regional water suppliers such as Rand Water also recycle water but the percentage is still low. There are indications that KwaZulu-Natal is going to invest in plants for communities like Blythedale Coastal Resort (north of Balito) which would produce 8 million litres per day. The other location for a smaller plant (1 million l/day) is Zinkwazi. The town of Kenton-on-Sea has been producing desalted drinking water for up to 30 000 people since 1997. Other coastal towns are considering desalination plants and at least one claims that the water will be cheaper than what it currently receives from the Umgeni water board. The final fact of interest was recently published in the National Water Strategy document (infrastructural projects in the 2006 to 2026 timeframe) where an author commenting on it said "that not long ago would have been considered radical - the desalination of seawater". The Western Cape, the Eastern Cape and KwaZulu-Natal were already considering desalination options, sobering for those who thought desalination to be a long way off.
The downside to desalination according to local guru, William Graham, is the initial investment. A 100 Ml plant such as one Perth is investigating would cost more than R400 million. However, over 15 years, it would be producing water at under R3/l, including the initial investment, running and maintenance.
What is in it for the local C&I industry?
It is clear that almost every country in the world will be forced to look for easy water alternatives. This applies equally to South Africa as the roll-out of water to the previously disadvantaged proceeds apace. This implies more recycling of water, better treatment of waste water and the building of desalination plants along the coast as there are many suitable sites. The use of nuclear power for desalination is also interesting as this could be a route followed by smaller municipalities using the Pebble Bed technology (which does not require water cooling so could be used inland as well). The opportunities for the control and instrumentation industry are thus huge over the next few decades as considerable infrastructure will be required to be built.
Dr Maurice McDowell has many years' experience as a technical journalist, editor, business manager and research scientist. His third party analyses of world-class companies and processes, as well as his insight into industry and technology trends are well respected.
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