Manual for Saving Water

Drops of Water 14 Manual for Saving Water Water is a diminishing resource! Water is a vital resource for human life, and yet, today, there is increas...
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Drops of Water 14

Manual for Saving Water Water is a diminishing resource! Water is a vital resource for human life, and yet, today, there is increasingly less of it on our planet! On Earth there is a major imbalance in the distribution of fresh water. We just have to consider that 12% of the world population consumes 85% of its water. Almost a billion people have no access to clean drinking water, about 1/4 of the world’s population! It is estimated that by 2005, due to population increase, this figure will look more like 3 billion people.That is why water has been defined as the “Blue Gold” of the future.And let’s not forget that 40% of the world’s population still lives today in terrible hygienic conditions due to lack of clean water and sanitation. The number of deaths directly caused by water transmitted diseases is shocking: almost 30.000 people (of whom 5.000 are children) die every day because they have no access to clean, safe water. How much water do you waste each day without even stopping to think about it? The water on Earth seems limitless, but it isn’t! Time to stop fooling ourselves! If we hypothesize that on Earth there is a total of 100 litres of water, then the total quantity of fresh water is equal to only 3 litres (indeed 97 litres is salt water).These 3 litres are mainly composed of ice: only 0.6% is actually accessible to humans. Of this percentage again, only a small part is readily accessible for human usage (lakes and rivers): roughly one thousandth of the total… little more than a spoonful! It is important to realize that most of our planet’s fresh water (3%) is found in the Arctic and the Antarctic, in other words in glaciers. And it should not be underestimated that in the future, due to the expanding pollution of surface and underground water, an ever increasing quantity of water will no longer be available for human use as it was in the past.

Illustration 1: © Centro Civiltà dell’Acqua Total water available on our planet: salt (97%) + fresh (3%) = 100%. Fresh water 3% (including that of glaciers). Usable fresh water 0.6% (excluding glaciers). Fresh water used by humans 0.003% (rivers, lakes and water bearing strata). Let’s learn how to save Blue Gold If we take a good look at all the foregoing, it is easy to see why water will become increasingly precious in years to come, especially in Developing countries. To make matters worse, desertification, drought and water scarcity may lead to conflict in the attempt to take control of this vital resource. That is why we all really have to make an effort to save water, starting from our everyday usage!

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MANUAL FOR SAVING WATER What would you be prepared to do to help save water? Would you melt an iceberg or take the salt out of sea water?? ... Let’s be realistic! Start saving water today so that all of us (including future generations) can use it! Saving water is extremely important! Even working on our everyday habits, however small, we can achieve great results… Here are ten pieces of advice that we can put into practice straight away in order to save an ocean of... fresh water! 1. Choose to have a shower! It takes roughly 80-100 litres of water to fill a bath. One 4 minute shower uses up 50 litres on average, so by choosing a shower to a bath, you can save up to 50 litres of water every time you wash! 2. Don’t be absent minded! When lathering yourself with soap, don’t just let the water run away needlessly….a tap left on can consume up to 10 litres of water per minute! Why not try this simple calculation: How many minutes do you spend lathering yourself in a week? And in a month? How much water, then, could you save in one year? 3. Turn off the tap when you brush your teeth! Don’t leave the tap on every time you brush your teeth! If you do, you can waste up to 20-30 litres of water! If you turn the tap right off you use only 2 litres! 4. Don’t flush the toilet unnecessarily! Each time you flush the toilet, 10 – 16 litres of water are used on average. If you choose the two button flush, you will waste less water! Alternatively try putting a stone or a full bottle in the toilet pan: that way less water will be flushed away when you go to the toilet. 5. Love your tap! Apply a water flow regulator to your tap instead of the usual filters our taps have. By doing so, you can reduce water wastage by up to 40%. 6. Reuse the water used to wash fruit and vegetables. When you wash vegetables, don’t let water run away needlessly. Rather, fill a recipient and leave them to soak. Don’t even throw this water away, use it to water the plants! 7. Plants like drinking... in the evening! Don’t water the garden at midday in the middle of summer because in the heat much of the water will just evaporate anyway! Do it in the evening to keep wastage to a minimum. 8. Collect and use rainwater! Install a cistern in your garden to collect rainwater. That way you’ll have loads of water that you can use for plants, flowers and fruit. Plants don’t like the chlorine in tap water! 9. Do a full load! One load of a dishwater uses 40-50 litres of water; a washing machine can use up to 80120 litres. So only use the dishwater and the washing machine when they are really full of dirty dishes and clothes!

10. Cars don’t need chlorine! Every time we wash the car we use between 100 and 500 litres of water (and in many countries that water could be used for drinking). In order to reduce this wastage, use a bucket rather than a hose and, where possible, use rain water!

Illustration 2: © Centro Civiltà dell’Acqua

Illustration 3: © Centro Civiltà dell’Acqua

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Illustration 4: © Centro Civiltà dell’Acqua

Illustration 6: © Centro Civiltà dell’Acqua

Illustration 5: © Centro Civiltà dell’Acqua

Illustration 7: © Centro Civiltà dell’Acqua

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GOOD HABITS – A CLOSER LOOK Collect rain water: a good habit we can all learn! Just installing a cistern at home for collecting rain water can save us about 80 litres per day! Here’s an example: If we use rain water for the toilet flush, which to function needs filtered and not necessarily drinkable water, we can save up to 60 litres of water a day, which otherwise goes right down the drain! Rain water can also be used to water the garden, flowers and vegetables. Plants dislike chlorine because it is a disinfectant, indeed giving a plant tap water to drink is like giving it poison. Illustration 8: © Centro Civiltà dell’Acqua Class Exercise: if we put all these pieces of advice into practice, how much water could you save each day? And in a month? And how much could your whole class save in one year? And you, how much water do you have? An African child who lives in a developing country does not have the same access to water as a child who lives in the west…. The country which consumes most water is the USA, with 425 litres of water per day per person. A Canadian consumes 350 litres per day. What must be taken into account here of course is the fact the USA and Canada are water rich countries… The European average is 165 litres per person a day, although this figure hides some important differences; in Italy, each inhabitant consumes around 395 litres of drinkable water per day; in France, 290. The European countries which consume the least water are Belgium and Great Britain: approximately 150-160 litres a day. In comparison, for example, an inhabitant of Angola consumes only 20 litres of water a day, whereas an Eritrean 8 litres. According to the UN, 40 litres per day is the minimum for survival.

Illustration 9: © FAO Food and Agriculture Organization of the United Nations, data processed by Centro Civiltà dell’Acqua - Per capita water consumption in various countries in the world

How does a water collection and distribution system work in the home? Rain water is collected below the ground in a tank which is reached by means of a drain. Near to this drain there is a filter to purify the water before it is stored in the tank. The tank is located below the ground in order to keep the water at a cool, constant temperature. A switchboard is set up in the home, a sort of computer which controls the transport of rain water from the tank to the flush by means of specially designed pipes.

Illustration 10: © Centro Civiltà dell’Acqua Rain harvesting and efficient water distribution at home. Get into the habit of eating fruit and vegetables which need less water! The cultivation of maize, millet and barley requires large amounts of water. There are, however, considerable differences from one crop to another. For example, we need approximately 4000-5000 litres of water to produce one kg of millet. To produce the same amount of wheat takes about 900-1300 litres of water. So, if we want to, we can choose in an informed way which crops to consume and which not…. To promote reduction of water use in agriculture, it is better to use a drip irrigation system, similar to rain fall, or to practice hydroponic agriculture. Hydroponic

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cultivations are different from others in that they are not sown in the soil, but rather grown in greenhouses. Using this method, less water is needed for irrigation. Salad, tomatoes, peppers and cucumbers are commonly grown this way.

References Chapagain, A.K. and Hoekstra, A.Y. (2004). Water footprints of nations, Value of Water Research Report Series No. 16, UNESCO-IHE, Delft, the Netherlands. www.waterfootprint.org/Reports/Report16Vol1.pdf

Even water used for industrial purposes can be reused! Industries use huge amounts of water during the production phases, and those which consume most water are steelworks, the metal and mechanical industries. A more forward looking future approach will be to recycle the water used in these industrial processes.

Chapagain A.K., Hoekstra A.Y. and Savenije H.H.G. (2005). Saving water through global trade,Value of Water Research Report Series No. 17, UNESCO-IHE, Delft,The Netherlands, www.waterfootprint.org

Did you know that most of the water industries use is for cooling machinery? In the past, drinkable water was used for these purposes, but today in many countries, desalinated sea water is used. After being used for cooling, this water must be purified and then reused within the productive cycle. Purification of water for industrial use is done using different technologies. In membrane filtration, for example, the water is cleaned by filtering it through subtle membranes which capture bacteria and impurities.These membranes, seen through a microscope, look just like sponges. The most commonly used filtration method is inverse osmosis. By forcing the osmotic pressure, you cause the solvent molecules to move from the most to the least concentrated solution. In this way, the water molecules are separated from those of other substances. Dossier compiled by:

Hoekstra, A. Y., Chapagain, A. K., Aldaya, M. M. and Mekonnen, M. M. (2011).The Water Footprint Assessment Manual. Setting the Global Standard, Earthscan. See: http://www.waterfootprint.org/?page=files/ WaterFootprintAssessmentManual Lundqvist J., de Fraiture C. and Molden D., (2008). Saving Water: from Field to Fork. Curbing Losses and Wastage in the Food Chain, Paper n. 13, Stockholm International Water Institute. See: http://www.siwi.org/documents/ Resources/Papers/Paper_13_Field_to_Fork.pdf Mekonnen, M. M. and Hoekstra, A.Y. (2010). The green, blue and grey water footprint of crops and derived crop products, vol.1, Value of Water Research Report Series No. 47, UNESCO-IHE, Delft, the Netherlands. Rockström, J., Falkenmark, M., Karlberg, L., Hoff, H., Rost, S., and Gerten, D. (2009). Future water availability for global food production: the potential of green water for increasing resilience to global change, Water Resources Research 45: W00A12, doi:10.1029/2007WR006767.

Water Civilization International Centre,Venice: www.civiltacqua.org

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Regional Bureau for Science and Culture in Europe United Nations Educational, Scientific and Cultural Organization