“The softener is put on the market in granular form and may be purchased and used with apparatus other than that furnished by manufacturers. The granules are about ¼ inch in diameter and permit a ready passage of the water through the interspaces. The material lasts indefinitely.
“As the water passes through the apparatus, the large exposed surface of the granules entirely absorbs the calcium and magnesium, which produce hardness, making it soft and ready for immediate use. The water does not require being in contact with the softener any longer than the time taken to pass through and it emerges almost as fast as from the faucet. The softener must be reactivated after it has softened a certain amount of water. This is accomplished by filling the tank with a common salt solution which is contained in the second tank. The water supply is temporarily shut off and the salt solution allowed to fill the softening tank. After remaining in contact with the granules for a time the chemical action of the salt releases the calcium and magnesium, which are flushed out with the excess of salt solution, into the sewer. The softener thus renewed is ready for softening another supply of water. Since this renewal is a simple application of the law of mass action, an excess of the salt must be used. The renewal may be repeated indefinitely.
“The amount of any particular sample of water which can be softened before renewal depends on the amount of material in the apparatus and the hardness of the water. Five gallons of the water per pound of softener would not be far from the average capacity. Where a large amount of soft water is required at one time, it may be prepared in advance and accumulated in a tank or cistern.
“The cost of softening, aside from the original cost of the plant, is nominal, as the value of the salt solution is the only expense.
“The water produced by this process is absolutely soft and suitable for drinking, domestic and industrial purposes. In the case of very hard water the saving in soap for washing is more than equal to the cost of operation. There are at least three firms manufacturing softening plants of the kind at the present time: The Permutite Co. of New York; the Cartright Co. of Chicago, whose product is called Borromite; and the Des Moines Refining Co., manufacturers of Refinite.
“A comparative test of various forms of water-softening materials may be obtained from the Regulatory Department, North Dakota Agricultural College.”
Chlorine.
—The presence of chlorine in water may indicate the presence of polluting matter in the form of sewage but only when the amount is considerably above the normal amount of chlorine that is contained in the soil in the community from which the water is taken. An increase of the chlorine in the water would indicate a probable pollution from sewage.
Polluted Water.
—Well water that is roily or that possesses objectionable taste or odor may be suspected of containing polluting matter and should be boiled before being used for drinking purposes until such time as may be required to have it examined. Sickness due to the use of polluted water does not necessarily develop as specific diseases, unless the water contains disease-producing bacteria. Typhoid fever, one of the commonest and most dreaded of diseases, is usually transmitted by water. Typhoid is a disease of human origin, the germ of which develops in the alimentary tract of the human kind alone. The germs may be spread by the waste from the typhoid patient by being thrown on the ground where it is taken up by the water and passes into streams or it may enter wells from privies or cesspools. A single case of typhoid has been known to so pollute the water of a stream, as to produce an epidemic of the disease throughout the entire length of the stream, among the people who drank its water; while water from a polluted well often transmits disease to a neighborhood.