OCR Text |
Show Your Doctor Says... The following is one of a series of articles written by members of the Utah State Medical Association and published in cooperation with your local newspaper. These articles are scheduled to appear every other week throughout the year in an effort to better acquaint you with problems of health, and designed to improve the well-being of the people of Utah Your Drinking Water Every person has an abiding confidence con-fidence in a public water supply; that is, we accept as a fact that the water we get from the tap is always pure and uncontaminated. We do this in spite of the fact that within the last 20 years "water-borne" typhoid fever has occurred in several communities. We must recognize that at the beginning of the century the horse and buggy was an acceptable and up-to-date means of transportation, just as the untreated water from our canyons was believed to be pure and without contamination. We, in the intermountain west, have more or less accepted as a fact that the water in our canyons, because it was clear for the most of the year and because it was cool and sparkling, was without any contamination or disease-producing qualities. That this was not true is indicated by the fact that before Salt Lake City began to chlorinate its water supplies, we had a typhoid fever epidemic every summer. We know that the eastern cities remove vast quantities of muddy water from their big rivers to purify it for the consumption of their citizens. How is this done, and what are the steps to make this water pure and safe for human consumption ? First - The water is often "slowed down", or the flow decelerated. In this way much of the particulate matter suspended in the water is removed by falling to the bottom when the flow of the water is slowed. This process also carries with it many bacteria. If the water is quite clear to begin with, often chemicals are added to produce a "flocculation". Flocculation can in many respects be compared to a snow storm in the water. As a snow storm clears our air in the process of falling to earth, the chemical flocculation in the water as it settles, carries with it many bacteria. Following flocculation, if the bacteria count in the water is still high, it is sent through rapid sand filters. These filters are composed of graduated particles of sand. The water is pumped through them and many of the bacteria adhere to the sand. Following this process, the water is chlorinated. Chlorine is an element which is green in color and is a gas at ordinary temperatures tempera-tures and pressures. Chlorine has a capacity to destroy organic matter by "oxidation", which is another way of saying "burning". Enough chlorine is added to burn up all the organic matter present and leave a little residual. In other words, we put in enough to purify, plus a little bit over so that the purification process will last. Ammonia Am-monia is also used to" help preserve the "burning capacities" of the chlorine. By following the above-mentioned processes we know the water is safe for human consumption. To be completely safe, all water, even deep well water, should be proved to be safe by frequent bacteria tests. Surface supplies should have the above described treatment. All water used for human consumption should be checked frequently because bacteria bac-teria have many ways of entering our supply; constant vigilance lis essential to protect our water. |