1. Hydrogen and water Mariam Farooq

2. o o o 3. o o 2H2 + O2 2H2O 4. CuSO4 H2O CuSO4.5H2O (White) (Blue) 5. Imagine life without water. Impossible! People, animals, plants - we all need water to survive. For cooking food, for cleaning and drinking. For cultivating food. For transport and recreation. For cleaning. For plants and animals to live in. For factories, industries and power stations. 6. Water is essential to life on this planet. However, the very water required to sustain life can also lead to illness and death if it is not clean. Clean water can be defined as: Water that can be consumed by individuals without risk of illness or long term harm. In its pure form, the water molecule consists of one oxygen atom and two hydrogen atoms (H2o). The structure of water affords it unique properties that enable it to dissolve more substances than any other liquid. Water is thereby called the universal solvent. 7. The water that we drink contains many dissolved substances such as sodium, potassium, magnesium, chloride and others that are essential to human health. These Minerals can be dissolved in water as it is moving through cracks in the rocks, or when its running in streams and lakes on the Earths surface. The ability of water to dissolve many substances puts it at risk of harbouring dangerous or toxic organisms and chemicals as well. 8. Dissolved substances Beneficial Sodium Potassium Magnesium Chloride Harmful Dissolved Fertilisers Lead Mercury Cadmium Industrial wastes Farm Lands 9. When fresh water is artificially supplemented with nutrients, it results in an abnormal increase in the growth of water plants. This is known as Eutrophication. When fertilizer from a field is carried into a stream by rain, in the form of run-off Fertilizers contain nutrients such as nitrates and phosphates. In excess levels, nutrients over stimulate the growth of aquatic plants and algae. Excessive growth of these types of organisms consequently clogs our waterways, use up dissolved oxygen as they decompose, and block light to deeper waters. This, in turn, proves very harmful to aquatic organisms as it affects the respiration ability or fish and other invertebrates that reside in water. 10. Industrial Effluents: Waste water from manufacturing or chemical processes in industries contributes to water pollution. Industrial waste water usually contains specific and readily identifiable chemical compounds. Effluent or industrial discharge dumped into rivers contains harmful chemicals like heavy metals ( Hg, Cd and Pb) and detergents. Oil pollution from accidents and oil spillages at sea are some of the other water pollutants. 11. Water purification generally means : freeing water from any kind of impurity it contains, such as contaminants or micro organisms. Water purification is not a very one-sided process; the purification process contains many steps. The steps that need to be progressed depend on the kind of impurities that are found in the water. This can differ very much for different types of water. 12. Settling Before the purification process begins some contaminants, such as oil, can be settled in a settling tank. They can then be removed easily, after they have reached the bottom of the tank. Removal of dangerous microorganisms Often polluted water has to be freed from microorganisms. The water is than disinfected, usually by means of chlorination. 13. Removal of dissolved solids Microrganisms are not only a threat to water; they can also be an advantage when it comes to water purification processes. They can convert harmful contaminants to harmless substances. This biological purification process usually takes a long time and it is only used for water that is polluted with contaminants that the microrganisms, usually bacteria, can convert. 14. Physical/ chemical techniques When treatment by microrganisms is not an option we often use different treatment techniques, called physical/ chemical treatment techniques. Chemical treatment often deals with the addition of certain chemicals, in order to make sure that the contaminants change structure and can then be removed more easily. Fertilizers such as nitrates are removed this way. Removal of contaminants can also be done through more difficult specific chemical processes. It takes a lot of education to fully understand these purification steps. Physical treatment usually deals with purification steps such as filtration. 15. Thirsty? How about a cool, refreshing cup of seawater? Humans cannot drink saline water. But, saline water can be made into freshwater, which everyone needs everyday. The process is called Desalination. Desalination/Distillation is one of mankind's earliest forms of water treatment, and it is still a popular treatment solution throughout the world today. In ancient times, many civilizations used this process on their ships to convert sea water into drinking water. 16. Today, desalination plants are used to convert sea water to drinking water on ships and in many arid regions of the world, and to treat water in other areas that is fouled by natural and unnatural contaminants. Distillation is perhaps the one water treatment technology that most completely reduces the widest range of drinking water contaminants.