TYPES of WATER • in General, Water for Drinking and Cooking Should Be Wholesome
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TYPES OF WATER • In general, water for drinking and cooking should be wholesome. It should be both potable and palatable. It must be bacteriologically and chemically safe for drinking and be good tasting. • It should be clear, colourless, and have no unpleasant taste or odour. • In general chemistry, we need at least three basic types of water of somewhat different quality, depending on the requirements of each use. 1 NATURAL WATER • This is water that comes naturally i.e . from rain and has dissolved minerals indigenous to the source. • Natural, untreated, spring waters, are naturally carbonated and may be slightly alkaline or salty. • Numerous health claims have been made for the benefits arising from the traces of a large number of minerals found in solution. • They are claimed to have therapeutic effect. • This water is useful for drinking • It has the following ions Na,K,Mg,CO32-,Cl2-,Fe2- 2 3 POTABLE WATER • Potable water is fresh water that is sanitized with oxidizing biocides such as chlorine to kill bacteria and make it safe for drinking purposes. • it may be hard Water . • This is saturated with calcium, iron, magnesium, and many other inorganic minerals. 4 • All water in lakes, rivers, on the ground, in deep wells, is classified as hard water. • Potable water is fit for human consumption. • It has pathogens that are removed by 1. aeration 2. chlorination 3. filtration • It may be odorless and tasteless. • unsuitable for pharmaceutical use 5 Aeration • Aeration is a treatment process in which water is brought into close contact with air for the primary purpose of increasing the oxygen content of the water. • The close contact between water and air required for aeration may be achieved by allowing water to trickle through one or more well- ventilated, perforated trays containing small stones, as shown in Figure below. 6 Diagram illustrating aeration 7 • This water must be collected in a container and allowed to stand for about 30 minutes in order to settle suspended particles. 8 CHLORINE TREATMENT • To disinfect by chlorination, use ordinary household chlorine bleach. {Sodium hypochlorite with a concentration of 5.25 to 6 percent should be the only active ingredient in the bleach}. • Add 16 drops (1/4 teaspoon) of liquid chlorine bleach per gallon of water, or 10 drops per 2-liter bottle of water. Stir to mix. If you do not have a dropper, use the following table to measure the correct amount of bleach 9 AMOUNTS OF BLEACH FOR ORDINARY CONTAINERS • 1 quart bottle 4 drops of bleach • 2 liter soda bottle 10 drops of bleach • 1 gallon jug 16 drops of bleach (1/8 tsp) • 2 gallon cooler 32 drops of bleach (1/4 tsp) • 5 gallon bottle 1 teaspoon of bleach 10 adv, • it’s effective against almost all pathogens, including viruses. • inexpensive Dis, • affects taste of water • Its temperature sensitive • not recommended for long term use Bleach loses it strength with time: products which have been on the shelf for one year will be only 50% as effective. In that case the amount used will have to be doubled 11 Filtration • Filtration is the passage of polluted water through a porous medium (such as sand). The process uses the principle of natural cleansing of the soil. • Figure 4 shows a modified simple upward rapid flow filter. 12 Fig. 4 - A simple upflow rapid sand filter A simple upflow rapid sand filter 13 • Simple filters may be put together inside clay, metal or plastic containers. • The vessels are filled with layers of sand and gravel and pipe work arranged to force the water to flow either upwards or downwards through the filter. • A filter such as this could be built from a 200 litre drum. It has a filter bed made up coarse sand (of about 0.3m depth) of grain size between 3 and 4mm diameter, and supported by gravel covered by a perforated metal tray. The effective filtration rate of such a filter could be as high as 230 litres14 per hour. Pros and cons of Filtration • The procedure is suitable for treatment of drinking water and pre – treatment of water intended to be later processed to purified water. • Such filters must be dismantled regularly to clean the sand and gravel and remove any settled silt. • such filters are not effective for removing the pathogens. Therefore the water must be disinfected or stored for 48 hours in order to make it safe. 15 WATER FOR INJECTION • Water for Injection Description • Sterile Water for Injection, is sterile, non pyrogenic, distilled water in a single dose container for intravenous administration after addition of a suitable solute. • It may also be used as a dispensing container for diluent use. No antimicrobial or other substance has been added. • The pH is (6.0 to 7.0). • The osmolarity is 0. 16 Water for Injection - Clinical Pharmacology • Sterile Water for Injection, is used for fluid replacement only after suitable additives are introduced to approximate isotonicity. • serve as a vehicle for suitable medications. • Made by distillation of portable water where carbon free/air free is required. 17 • freshly prepared distillate is boiled for 20mins with little air exposure. • its distilled into final container and sterilized by autoclave. • used for preparing injections and weakly acidic drugs. • Its PH is 5 -7 18 Distilled water • Is water that has many of its impurities removed through distillation . • Distillation involves boiling the water and then condensing the steam into a clean container. • In a gradual evaporation process taking place in a boiler the substances get separated due to their different initial boiling point . The vapour then condenses after passing through a cooler. • distillation also works as a technique of water purification. 19 20 The Process: • The distillation process utilizes a heat source to vaporize water. • The objective of distillation is to separate pure water molecules from contaminants with a higher boiling point than water. • In the distillation process, water is first heated until it reaches its boiling point and begins to evaporate. • The temperature is then kept at a constant. 21 • The stable temperature ensures continued water vaporization, but prohibits drinking water contaminants with a higher boiling point from evaporating. • Next, the evaporated water is captured and guided through a system of tubes to another container. • Finally, removed from the heat source, the steam condenses back into its original liquid form. 22 • NB: • Contaminants having a higher boiling point than water remain in the original container. • This process removes most minerals, most bacteria and viruses, and any chemicals that have a higher boiling point than water from drinking water. • For this reason, distillation is sometimes valued as a method of obtaining pure drinking water. 23 single-effect distiller 24 Pros • provides mineral-free water to be used in science laboratories or for printing purposes, as both functions require mineral-free water. • It removes heavy metal materials like lead, arsenic, and mercury from water and hardening agents like calcium and phosphorous . 25 • used as the preferred water purification method in developing nations, or areas where the risk of waterborne disease is high, due to its unique capabilities to remove bacteria and viruses from drinking water. 26 qualities that make it undesirable . • they do not remove chlorine, byproducts . • These chemicals, which have a lower boiling point than water, are the major contaminants of municipally treated water. • Most dangerous metals and bacteria are removed from water prior to its arrival at a home’s plumbing system. Thus, a distillation system, targeted at the removal of these contaminants, is unnecessary and irrelevant for most people. • Furthermore, distillation is an incredibly wasteful process. Typically, 80% of the water is discarded with the contaminants, leaving only one gallon of purified water for every five gallons treated. 27 Distilled water Bottle for Distilled water 28 • Quick Facts... • The human body can survive for weeks without food, but only a few days without water. • In preparing for an emergency, store at least a three-day supply of water for each member of your family. • You can minimize the amount of water your body needs by reducing activity and staying cool. • Water can be purified for drinking by filtering and then either boiling or adding household bleach. 29 To be continued……. 30 PURIFIED WATER BP • Purified water refers to all types of water from which chemicals are removed via a variety of different processes • This is specially treated water free of impurities, ions and microorganisms. • It is used in different branches for many purposes. • However, it is vulnerable to fast contamination from the surrounding environment and therefore cannot be stored . 31 • Processes by 1. distillation, 2. demineralization{deioniz ation } of portable. • Has a PH of 5-7 • Useful for preparing water for injection. • Its tasteless and odorless 32 Water purifying methods • Purified water production represents a very demanding technological process . Various methods are available differing in the technology and the process efficiency level. • A combination of more methods is commonly used or, variantly, multiple use of a single technology is applied. • Such an approach guarantees the best results. 33 Demineralization via ion – exchanger (deionization) • Demineralized water is water that has had its mineral ions removed. • Mineral ions such as cations of sodium, calcium, iron, copper, etc and anions such as chloride, sulphate, nitrate, etc are common ions present in water. • Demineralization (deionization) is a method of capturing these ions through an agent referred to as ionex or ion – exchanger. 34 Ion – exchangers • Application of ion – exchangers is further step to increase the quality of finished water • Cations of dissolved salts are removed by cation exchangers and anions of dissolved salts are removed by anion exchangers • The station may consist of separate cation exchanger and anion exchanger filling or combined cation and anion exchanger column.