Methods of Purifying Water in City Systems and in Households

The idea of purifying drinking water is to reach the following goals:

drinking water should be free from noxious micro-organisms and harmful chemical substances

substances affecting taste and odor should be removed

germs should be eliminated according to the various local standards

the corrosive aspects of the water on pipes is to be minimalized

Mechanical Refinement - Coarse materials are "sieved out" and then removed. Finer particles are often removed through quartz-sand filtration.

Physical Refinement - Iron and manganese often give water a bad taste. Such water is oxidized and the ions are removed from the water through active carbon filters or ion exchangers.

Chemical Refinement - In this method the colloidal particles are removed by inserting flakes into the water. The flakes surround the colloidal particles and are then held back or sedimented in filters.

Biological Refinement - In this process, the noxious micro-organisms are destroyed through disinfection. This is done through addition of silver, copper, chlorine and its compounds(which set oxygen free in the water, which is the real disinfection agent), ozone (oxygen is again set free in the water), or through treating the water with ultra-violet rays. These methods often lead to health problems and environmental stresses. Often to get drinking water to conform to set standards, it is filtered, degerminated, desoured, deironed and demanganesed, softened, desalted, decontaminated, and clarified

Household Water Treatment

Mechanical/Physical Drinking Water Refinement - Physical water purifiers decrease the formation of lime deposits on pipes and equipment through electric or strong magnetic fields, thus changing the structure of the water so that the calcium carbonate does not seek a source outside of the water (eg pipes) to feed upon.

Active Carbon Filtering - This involves passing the water through a mechanical filter combined with active carbon granulate. The large surface area of the granules has a great absorbent quality, and causes some particles to be deposited on their surface. The active carbon binds with substances like chlorine, pesticides, etc. Smaller substances like chromium, nitrates, phosphates, as well as some bacterial and viruses may pass through the filter. It is often difficult for the homeowner to correctly assess when to change the filter before the undesired substances leach through into the drinking water if not properly informed no the replacement time tables. Some such filters are a good culture for bacteria.

Ion Exchangers - Ion exchangers help to eliminate water hardness by exchanging the cations calcium for chloride, hydroxide, or sodium. This method does not remove lead, asbestos, and chlorified carbohydrates, and leads to a high sodium content which then must be removed.

Reverse Osmosis - This method cleans the water by passing the water under pressure through a semi-permeable membrane with microscopically small pores. Larger molecules of harmful substances and minerals are held back by the membrane and then washed away. Reverse osmosis can filter out lead, cadmium, nitrates, sulphates, mercury, bacterial and viruses, and pyrogenes. It is a scientifically recognized method of filtration, resulting in pure water which does not produce the damages of calcium deposits. Because of its purity, it helps to draw impurities out of the body and assist metabolism. The process requires a minimum of 3 to 5 quarts of water (much more with poorer quality units) to produce I quart of pure water.

Steam Distillation - This method of purification has been used for many years. It removes up to 99% of all impurities by heating the water and then condensing it again. The impurities separate out, leaving the water pure. People have claimed that drinking distilled water draws vital minerals out of the body. However, some research suggests that the minerals in question are already integrated within the body, and that drinking distilled water will only draw out the sedimentary anorganic minerals, which is desirable. The main drawback to distilled water is that, although it is pure, it is energetically weak.

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