The term "water purity" is used with wide range of water qualities used by human.
(1) Purity of drinking water- of course meant for human. Cattles may drink it from anywhere.
(2) Distilled and sterilized water- bear completely different meaning in biological laboratory experiments.
(3) De-mineralized water- a widely used solvent in chemical analysis.
I guess, it is the type (1) you are talking about.
Water for drinking purpose must contain minerals. It is not demineralised water. So, it scores no point by removing all sorts of chemicals from drinking water. Rather, you may call a drinking water non-demineralised sterilized water.
Do we need water to be entirely sterilized? Well, we know how much harm is caused to human health by a cell of mycobacterium or salmonella or E. coli. We must remove them from water before consuming it.
Do we require all types of contamination to be removed from our drinking water? No, there are a few microbes which are difficult to remove either from natural or from processed water. They are harmless and do not spread up diseases. But, their numbers determine the extent of contamination of water. Thus, they should be limited in numbers in water sample. Most of them are air-borne microbes (aerosol).
The economy of the process of water purification largely depends on the quality of water available at a specific geographic location. The underground water is contaminated with pesticides and chemical fertilizers from farm land, mineral oils and acid/base radicals present in soil. Organic wastes add up to nitrates and nitrites. Rain water sometime is contaminated with nitric acids. An excess of sulphate is undesirable, while a little sodium and chlorides should be present in our drinking water. All these are biological concepts and are already standardized. From processors point of view, economy lies in choosing the correct method of purification and avoiding unnecessary steps which add on to processing cost. Again if water contains lot of iron and if during processing it is overlooked; serves no useful purpose putting lot of money in processing minerals without removing iron at the initial stage. Excess acidity and excess alkalinity are undesirable. It is human who is either actively or passively responsible for contaminating water. If you leave the process to mother nature, she would balance all odds herself. The cost of processing will definitely be lowered if we do not dispose sewage and wastes into our rivers and lakes, if we check emissions from our factories and cars, use limited fertilizers and pesticides and do not block the natural flow of water-streams by building up dams, etc. and what not?!
That would definitely prevent your money from going into water.
December 29th, 2009 - 5:55 am
Economic factor: Purification of water often involves the use of sand filters. Sand filters are cheap and effective, however, membrane filters will purify water much more effectively (including many microscopic organisms). Membrane filters are expensive, and so most of the time a water purification facility will not use them in community water supplies.
Chemical factor: It is hard to remove dissolved elements as some elements are hard to precipitate (not to mention expensive). Even if precipitation is possible, low concentrations will be hard to filter out (and it can be hard to guess how much needs to be added to precipitate the entire amount, resulting in even further impurities from the added element, and so this chemical factor can limit water purity.
References :
December 29th, 2009 - 6:29 am
The term "water purity" is used with wide range of water qualities used by human.
(1) Purity of drinking water- of course meant for human. Cattles may drink it from anywhere.
(2) Distilled and sterilized water- bear completely different meaning in biological laboratory experiments.
(3) De-mineralized water- a widely used solvent in chemical analysis.
I guess, it is the type (1) you are talking about.
Water for drinking purpose must contain minerals. It is not demineralised water. So, it scores no point by removing all sorts of chemicals from drinking water. Rather, you may call a drinking water non-demineralised sterilized water.
Do we need water to be entirely sterilized? Well, we know how much harm is caused to human health by a cell of mycobacterium or salmonella or E. coli. We must remove them from water before consuming it.
Do we require all types of contamination to be removed from our drinking water? No, there are a few microbes which are difficult to remove either from natural or from processed water. They are harmless and do not spread up diseases. But, their numbers determine the extent of contamination of water. Thus, they should be limited in numbers in water sample. Most of them are air-borne microbes (aerosol).
The economy of the process of water purification largely depends on the quality of water available at a specific geographic location. The underground water is contaminated with pesticides and chemical fertilizers from farm land, mineral oils and acid/base radicals present in soil. Organic wastes add up to nitrates and nitrites. Rain water sometime is contaminated with nitric acids. An excess of sulphate is undesirable, while a little sodium and chlorides should be present in our drinking water. All these are biological concepts and are already standardized. From processors point of view, economy lies in choosing the correct method of purification and avoiding unnecessary steps which add on to processing cost. Again if water contains lot of iron and if during processing it is overlooked; serves no useful purpose putting lot of money in processing minerals without removing iron at the initial stage. Excess acidity and excess alkalinity are undesirable. It is human who is either actively or passively responsible for contaminating water. If you leave the process to mother nature, she would balance all odds herself. The cost of processing will definitely be lowered if we do not dispose sewage and wastes into our rivers and lakes, if we check emissions from our factories and cars, use limited fertilizers and pesticides and do not block the natural flow of water-streams by building up dams, etc. and what not?!
That would definitely prevent your money from going into water.
References :