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  1. 1. Hard drinking water is generally not harmful to one's health, but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water. In domestic settings, hard water is often indicated by a lack of suds formation when soap is agitated in water, and by the formation of lime scale in kettles and water heaters. Wherever water hardness is a concern, water softening is commonly used to reduce hard water's adverse effects. Water's hardness is determined by the concentration of multivalent cations in the water. Multivalent cations are cations (positively charged metal complexes) with a charge greater than 1+. Usually, the cations have the charge of 2+. Common cations found in hard water include Ca2+ and Mg2+. These ions enter a water supply by leaching from minerals within an aquifer. Common calcium-containing minerals are calcite and gypsum. A common magnesium mineral is dolomite(which also contains calcium)
  2. 2. Temporary hardness Temporary hardness is a type of water hardness caused by the presence of dissolved bicarbonate mineral (calcium bicarbonate and magnesium bicarbonate). When dissolved these minerals yield calcium and magnesium cations(Ca2+, Mg2+) and carbonate and bicarbonate anions (CO32-, HCO3). The presence of the metal cations makes the water hard. However, this "temporary" hardness can be reduced either by boiling the water, or by the addition of lime (calcium hydroxide) through the softening process of lime softening. Permanent hardness Permanent hardness is hardness (mineral content) that cannot be removed by boiling. When this is the case, it is usually caused by the presence of calcium sulfate and/or magnesium sulfates in the water, which do not precipitate out as the temperature increases. Ions causing permanent hardness of water can be removed using a water softener, or ion exchange column. Total Permanent Hardness = Calcium Hardness + Magnesium Hardness The calcium and magnesium hardness is the concentration of calcium and magnesium ions expressed as equivalent of calcium carbonate. Total permanent water hardness expressed as equivalent of CaCO3 can be calculated with the following formula: Total Permanent Hardness (CaCO3) = 2.5(Ca2+) + 4.1(Mg2+)
  3. 3. With hard water, soap solutions form a white precipitate (soap scum) instead of producing lather, because the 2+ ions destroy the surfactant properties of the soap by forming a solid precipitate (the soap scum). A major component of such scum is calcium stearate, which arises from sodium stearate, the main component of soap: 2 C17H35COO- + Ca2+ → (C17H35COO)2Ca Hard water also forms deposits that clog plumbing. These deposits, called "scale", are composed mainly of calcium carbonate(CaCO3), magnesium hydroxide(Mg(OH)2), and calcium sulfate(CaSO4). Calcium and magnesium carbonates tend to be deposited as off-white solids on the inside surfaces of pipes and heat exchangers The presence of ions in an electrolyte, in this case, hard water, can also lead to galvanic corrosion, in which one metal will preferentially corrode when in contact with another type of metal, when both are in contact with an electrolyte
  4. 4. The water that lathers readily with soaps are called soft water. It describes type of water that contain few or no minerals like calcium(Ca) or magnesium(Mg) ions. The term is usually relative to hard water, which does contain significant amounts of such ions. Soft Water mostly comes from peat or igneous rock sources, such as granite but may also come from sandstone sources, since such sedimentary rocks are usually low in calcium and magnesium. However, soft water does have negative side effects and can be bad for the heart. Thus it should be drunk in moderation if at all.
  5. 5. What is energy? Energy is the capacity to do work and transfer heat. Work is performed when an object or substance is moved over some distance. Energy is needed to carry out processes, such as boiling water or burning candles. Energy is also the heat that flows from a hot object or substance to a cold one, when they come in contact. A clear example of this is the fact that water heats up when you put in a water boiler device. Energy has many forms, such as light, heat, electricity, chemical energy (stored in chemical bonds) and mechanical energy (moving matter, such as flowing water). All energy forms are divided up between two main kinds of energy. The first main kind of energy is kinetic energy, the energy of motion and action. Heat is a total of kinetic energy of atoms, ions or molecules. When these chemical compounds are in motion due to kinetic energy they will warm up. You cannot always detect heat that originates from kinetic energy, because sometimes the heat of a substance can rise without an additional rise in temperature. The second main kind of energy is potential energy, energy that is stored and potentially available for use. Before potential energy can be used it is transferred into kinetic energy
  6. 6. Hydroelectric power is electricity that is supplied by generating energy from falling or streaming water. Hydroelectric power is a so-called renewable energy source. This means that the source, which provides the energy, can be renewed. This is because, unlike non-renewable energy sources such as crude oil, we will not run out of water fully. It can be renewed after we have used it for energy generation. Water, like many substances, contains two kinds of energy. The first kind of energy is called kinetic energy. This is energy that is used during the execution of processes, such as movement. Because of kinetic energy water can flow and waves can exist. But water can also contain potential energy. This is energy that is stored in the water. Stored, but not used. This energy can become useful when water starts to flow. It will be transferred to kinetic energy and this will cause movement.
  7. 7. How is energy generated in a hydroelectric power plant? Read more: A hydroelectric power plant consists of a high dam that is built across a large river to create a reservoir, and a station where the process of energy conversion to electricity takes place. The first step in the generation of energy in a hydropower plant is the collection of run-off of seasonal rain and snow in lakes, streams and rivers, during the hydrological cycle. The run-off flows to dams downstream. The water falls through a dam, into the hydropower plant and turns a large wheel called a turbine. The turbine converts the energy of falling water into mechanical energy to drive the generator. It turns a shaft, which rotates a number of magnets in the generator. When the magnets pass copper coils a magnetic field is created, which aids the production of electricity. Step-up transformers will than increase the voltage of the electricity, to levels needed for the journey to communities. After this process has taken place electricity is transferred to the communities through transmission lines and the water is released back into the lakes, streams or rivers. This is entirely not harmful, because no pollutants are added to the water while it flows through the hydropower plant.
  8. 8. Production of electricity from waves and tides is an option today. About twice a day in high as well as low tides, water flows in and out of coasts and estuaries. This water can spin turbines, in order to produce electricity. But analysts have been taking a closer look at this form of energy supply and they believe that tidal power can only make a tiny contribution to the world's energy supply, because of the few suitable sites, the high construction costs and the risk of equipment destruction by saltwater corrosion. However, there are a few areas with the right conditions to produce tidal power. France and Canada own the largest tidal energy facilities right now.
  9. 9. Reclaimed water or recycled water, is former waste water (sewage) that is treated to remove solids and certain impurities, and used in sustainable landscaping irrigation or to recharge groundwater aquifers. The purpose of these processes is sustainability and water conservation, rather than discharging the treated water to surface waters such as rivers and oceans. In some cases, recycled water can be used for stream flow augmentation to benefit ecosystems and improve aesthetics
  10. 10. Recycled water is filtered, treated and disinfected, and is suitable for a range of uses All of our water reclamation plants produce Class C recycled water or better. This water can be used for various purposes including irrigating sporting grounds, public ovals, golf courses, crops and produce. In the near future, Class A recycled water will be available for residential use.
  11. 11. Treatment of wastewater is actually a remarkably simple process that utilizes very basic physical, biological, and chemical principles to remove contaminants from water. Use of mechanical or physical systems to treat wastewater is generally referred to as primary treatment, and use of biological processes to provide further treatment is Raw sewage is 99.9% water. Large objects such referred to as secondary treatment. Advanced as sticks and rags are removed from raw sewage as it passes through bar screens. secondary treatment usually involves applying chemical systems in addition to biological ones, such as injecting chlorine to disinfect the water. In most of the United States, wastewater receives both primary and secondary treatment. Tertiary treatment methods are sometimes used after primary and secondary treatment to remove traces of chemicals and dissolved solids. Tertiary Next, wastewater is slowed so that settle able treatment is expensive and not widely practiced organics settle to the bottom while fats, oils, and greases float to the top. except where necessary to remove industrial contaminants.
  12. 12. IT IS USED FOR: agriculture landscape public parks golf course irrigation cooling water for power plants and oil refineries processing water for mills, plants toilet flushing dust control, construction activities concrete mixing artificial lakes