SOURCES OF WATER POLLUTION

SOURCES OF WATER POLLUTION

The physical characteristics of water works, such as pumping engines, pipe systems, reservoirs, standpipes, filters, water intakes and conduits, tunnels and compensating tanks, together with the various smaller details, like water meters, pressure regulating valves, air reliefs, etc., are now generally so well understood that a paper on these, unless directed to some special feature of construction, or operation, would possess small interest to water works managers, and 1 propose therefore to use the time at my disposal to-day to a brief discussion of a few points which affect the quality of public water supplies. From my experience as a member of the State Board of Health for a period of five years, rather than from ray experience as a designer and builder of public water works, I came to a realization of some of the difficulties in obtaining satisfactory sources of water supply for many of the smaller anil some of the larger cities and towns in the State. There are many settlements in Ohio which have grown into populous villages and cities by reason of local conditions which have affected their prosperity, and when they have reached the size and dignity of a large village, or a small city, and sought to obtain the usual sanitary conveniences now considered as essentials of populated centers, have found that there was no convenient sources of public water supply, or convenient and safe points of disposal for sewage, both of which are essential to the life and growth of any considerable village or city to-day. Other problems with respect to the disposal of city wastes also arise as villages and cities grow in numbers and density of population; but the chief and first problems are an adequate and safe water supply, and a convenient and safe method of disposing of village and city sewage. The sources of public water supply in this State are now level lakes, like Lake Erie, rivers, creeks, wells and impounded water. There are a few small natural lakes at high elevation in the State, from which water can be drawn by gravity. But with no exception that T now remember can such water be considered wholesome and safe for drinking purposes in its natural condition. Water from Lake Erie, the Ohio River, or any other river or creek in the State, cannot be used in safety to health without some artificial purfieation. This fact is recognized now, although it was not a few years ago. There may he some spots in Lake Erie, far removed from its shores, where the water is safe for domestic purposes, but these spots are not within practicable reach, and may not at all times be safe. The lake is shallow and simply a wide stream for the discharge of all the polluted water that reaches it from the other three Great Lakes and numerous sewage polluted rivers and creeks, which discharge into it. In addition to the sewage from municipalities and other land sources which reaches the lake, there is the constant discharge of sewage from the vessels which traverse it. So that if there are sources in the lake from which a safe water supply can be drawn to-day, there can be no assurance that the source will be safe to-morrow. Safetv is here meant to apply to water for drinking and domestic uses, and not to wafer for commercial purposes, or for flushing sanitary appliances. Water for the bath and the lavatory should he free from infectious organisms, if it is to be used without risk to health. Driven wells, if the yield of water is sufficient, are generallv regarded as our best sources of public water supply in this part of the cduntry, but care must be exercised that the naturally pure water at the bottom of a driven well is not polluted and cannot become polluted by organic and perhaps infectious matter from surface and ground sources. Surface sources of water, excepting from uninhabited mountain districts where there is no domestic animal life which can impart a taint to the runoff from rainfall, cannot be regarded as safe for drinking purposes without purification by artificial means. Epidemics of typhoid fever have been traced in Switzerland and in this country to water impounded from the rainfall and runoff on grazing lands. Many farm houses clustered together may be as much of a menace to the water running off from the lands, as will small villages which, as it is known, have furnished the germs for the origin of a typhoid fever epidemic in a community wich has used such water for drinking purposes. Impounded water in this State is seldom safe for domestic uses without filtration, or without the use of some germicide which is sure to destroy all possible pathogenic bacteria. Of all the sources of water supply possible in this State, water from deep tubular wells is the safest for sanitary uses. But nearly all the deep wells furnish hard water which, aside from organic infection, has objectionable properties which require consideration before it is acceptable for domestic purposes. Water containing salts of lime and magneseia are difficult of use for laundry purposes, requiring that they should be “broke” or have the hardening salts preciptated before they can be conveniently used for this purpose. In the pioneer days the farmer made “lye” from hickory ashes on his own premises, and employed this to soften the “hard” well water when wash day came around. For steam purposes hard water is objectionable from the standpoint of coal economy, and sometimes is a source of real danger in boiler operations, by the deposition of lime and other salts on boiler tubes, thus impairing the circulating and perhaps sometimes leading up to boiler explosions. There is no corrosion from the deposited lime, but the safety, as well as economic effect of steam boilers, is dependent on a free and active circulation of the water around or in the tubes and flues, and the lining or covering of a boiler tube with a litne scale impairs the circulation. Lime salts in drinking water contributes to “arterial sclerosis”, or hardening of the arteries, bv the deposition of calcareous matter in the blood vessels, rendering them brittle and liable to rupture under sudden increased blood pressure. It will thus appear that a well water while absolutely safe from the infectious disease point of view, may contain other objectionable properties, which should be removed or counteracted before it will become in all respects safe for domestic and commercial uses. Water softening apparatus is now so well exploited and so well understood that every public water works drawing from limestone sources should investigate the matter and adopt some approved method for removing the hardening salts from a a well water supply before the water is sent through the mains to consumers. It should be born in mind that water consumers who depend upon the public water supply are helpless in matters affecting water quality, and if you who own, operate or conduct water works in the interest of a municipality, do not look after these matters in the interest of your consumers, your consumers certainly cannot do it for themselves. In early childhood, it is believed that a water containing marked quantities of lime, magnesia and sodium, is good for the development of the bony system, f?r these and phosphates constitute the principal elements of the bones. But after the bones have reached their full development then an excess of lime and similar salts in the water may be a detriment to the human system, and in late life may be a positive menace to health. Iron similarly in excess in a w’ater supply may enrich the blood too much in adult life and lead to boils and other kinds of blood poisoning, the blood then furnishing a favorable “nidus” for the germs of septic poisoning derived from the air, water etc. Sometimes a water rich in iron like “chalybeate water” may be necessary for people who are “anaemic,” but those in good health do not need it, and such water may work great harm to people who are otherwise in good health. Blood poisoning, as usually considered, is not a disease, but an accident, and the cause is not infrequently the use of water with iron in excess. The State Board of Health in this and other states protects us as well as they can from dangerous public water supplies, but the chief work in this direction must be done by the men who are in control of the municipal and privately owned public water works of the State. It is possible to drive a tube well through imper ious strata to a reasonable depth alongside a reeking privy vault, and obtain a water wholly free from sewage contamination, but the risk is great and a safe thickness and imperviousness of clay strata are so seldom found that the practice is not to be recommended, and safety lies in having such wells so far removed from sources of contamination that by no chance can surface pollution reach the W’ater bearing strata penentrated by the well. Ponds that are sometimes used as sources of water supply, while free from defined sewage pollution from animal or human sources, often contain algal growths which are productive of disease, although perhaps not of a fatal nature. Certain flora in stagnant ponds, or even in ponds with a slight current, impart odor and taste to the water and often are the cause of sickness due to the products of decay. While this objection may not be serious from the health standpoint, nevertheless in some parts of the country, and perhaps in this State, it has been the cause of considerable complaint and some real distress, and where such ponds are otherwdse acceptable as sources of w’ater supply, great care should be exercised to see that they are free from all algae by the application of copper sulphate, or some other chemical which will inhibit the growth of vegetation. There may not be many ponds used as sources of water supply in Ohio, nor are there a great many that are capable of such use. and this objection ispointed out mainly to guard against an ill advised attempt to adopt some such sources in the absence of careful investigation as to the character of the water and its probable influence on health. And where such ponds are liable to be used as sources of water supply, consideration must be given not only to the prohibition of floral life in, and around the edges of the pond, but also to the probability of the water becoming at some time affected from the runoff front farm lands lying at higher elevation on the watershed, when the use of water from such a source will always require filtration, or some other effective method of purification. If the filtration in such instances is accomplished by a so-called mechanical, or rapid sand filter, with the addition of a chemical to form a coagulant to intercept the suspended matter on the beds of filter sand, or precipitate it in settling basins, this chemical, with filtration or sufficient sedimentation, will also take care of any objection which may arise from the floral growth; although there may be a few instances, even in this State, where if the floral matter was not permited to grow by the application of proper chemical to the water such water might be used without filtration, or other mode of purification. It will thus be seen from this brief statement that a selection of a source of water supply is not an easy matter, and particularly is it diffcult where deep well sources are unavailable, or where the water thus obtained would be subject to other objections than those herein mentioned. For example, a water tainted with sulphur while safe from every other point of view, could not, and would not, be continuously used by any community, although a small amount of sulphur in the water might not be objectionable. Water in falling on the earth and passing through the materials overlying the rock and through the fissures and pores in the stratafied rock, dissolves and takes up more, or less, of the mineral matter with which it comes in contact, and from this source is obtained lime, magnesia, sodium, iron and other salts which are found in water samples on analysis. Sometimes arsenic is found in water samples from mining operations, and this mineral, as we all know, is very dangerous to the human system. In many instances, especially with small towns and cities where it seems extremely difficult to obtain satisfactory sources of public water supply, it has occurred to me that this difficulty mght be overcome, although perhaps at considerable expense, by selecting some source from which a supply could be had large enough to meet the requirements of a number of such towns and cities, and provide that the pumping, and purification if required, shall all be done at one point, and the water then distributed to the various towns and villages requiring it. Such source might in its natural condition be unfit for drinking water and other domestic uses, but when purified by some approved method, the water then would go to all the towns requiring it in a condition that would be safe to health, and if it happened to be a “hard” water it could be also softened at the point of collection and pumpage, when afterward it would also be entirely satisfactory for all commercial purposes. Much of this paper, Mr. President and gentlemen, has grown out of five years’ experience as a member of the State Board of Health, during which time I happened to be on the F.ngineering Committee, and by association with the other members of the committee we have investigated a good many of these conditions and found that nothing short of the utmost care would bring about an entirely safe water supply. There is no reason why the water we drink should not be absolutely safe from the health standpoint, and there is no reason why the water should not be equally satisfactory for commercial operations, and it is very clear to me, in the smaller towns, and in the larger ones as well, that whatever we do to correct the natural decrease in the water supply must be done by the municipal water works or by the private water company, because the water consumer is in no position to apply local remedies successfully.

*Abstract of p*per re(i at Convention of Central States Section of American Water Works Association, Columbus, O., 1915.

John W. Hill, C. E.

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