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NORTH CAROLINA HISTORY OF HEALTH DIGITAL COLLECTION Bulletin of the North Carolina Board of Health Volume 24 (April 1909 – March 1910) DOCUMENT NO. NCHH-03-024 || http://hsl.lib.unc.edu/specialcollections/nchealthhistory || This item is part of the North Carolina History of Health Digital Collection. Some materials in the Collection are protected by U.S. copyright law. This item is presented by the Health Sciences Library of the University of North Carolina at Chapel Hill for research and educational purposes. It may not be republished or distributed without permission of the Health Sciences Library. The North Carolina History of Health Digital Collection is an open access publishing initiative of the Health Sciences Library of the University of North Carolina at Chapel Hill. Financial support for the initiative was provided in part by a multi-year NC ECHO (Exploring Cultural Heritage Online) digitization grant, awarded by the State Library of North Carolina, and funded through the Library Services and Technology Act (LSTA). For more information about the collection, or to search other volumes, please visit: || http://hsl.lib.unc.edu/specialcollections/nchealthhistory || : • Dr T H Manning BTTX-iX-ijBTXIN" OF THE NORTH CAROLINA BOARD OF HEALTH Published Monthly at the Office of the Secretary of the Board, Raleigh, N. C. G. G. Thomas, M. D., Pres., Wilmington. I Edw. C. Register, M. D., Charlotte. Washington. Thomas E. Anderson, M. D., Statesville. | David T. Tayloe, M. D., J. Howell Way, M. D., Waynesville. J. A. Burroughs, M. D., Asheville. W. O. Spencer, M. D., Winston-Salem. ! J. L. Ludlow, C. E., Winston-Salem. Richard H. Lewis, M. D. t Secretary and Treasurer, Raleigh. Vol. XXIV. APRIL, 1909. No. 1. CESSPOOLS. As similar inquiries are made of this office, we print below an ex- cellent article on the subject of cesspools from the Bulletin of the Kansas Board of Health. We regret that we cannot reproduce the cut referred to, but anyone wishing to install such a plant as is indi- cated can obtain plans from a sanitary engineer. Our position on the ordinary cesspool for sewage disposal—even when made with cement walls, as cracks are liable to occur, or they are sure to overflow unless regularly emptied—where the water sup- ply is obtained from wells, has always been and is one of uncompro- mising hostility. But when ((instructed as a septic tank, arranged for the automatic dumping at proper intervals of the sewage which lias been liquefied and, to a considerable extent, purified by the action of the anserobic bacteria in that closed receptacle, into properly laid drain tiles, thus finally disposing of it by subsurface irrigation, we think it allowable, provided that it is located sufficiently far from the well to prevent its possible contamination. CESSPOOLS. Numerous inquiries have been received by this department con- cerning the cesspool method of disposal of house sewage. The ques- tions involve the following propositions, viz. A BULLETIN N. C. BOARD OF HEALTH. 1. Does the uncemented cesspool menace the purity of the neigh- boring ground-water supply used for domestic purposes? 2. If s<>. how may a cesspool be constructed so as to be sanitarily safe? 3. Should abandoned wells be used as cesspools? 4. What are the dangers, if any. from the open-vault cesspool? The first proposition must be answered in the affirmative. Natu- rally, the degree of pollution of a ground-water supply depends on the nature of the soil into which the sewage discharges. If the soil is a close sand or clay, the filtration of the liquid portions of the sewage would be slow and a greater degree of purification obtained than if the soil were a loose sand and gravel, permitting the cesspool to be rapidly emptied with comparatively little filtration directly into the water-bearing stratum. So, also, if there is an intervening stratum of clay or rock between the drainage of the cesspool and the water- bearing stratum, there might be an impervious barrier to the sewage reaching the water below such formation. It must be borne in mind, however, that the piercing of such presumably impervious stratum in boring or digging a well, and the constant possibility of a natural fault or fissure, subjects such barrier to a doubt, or at least indicates the possibility of the sewage finding its way to the underlying water. It seems, therefore, that the only safe cesspool in a community that uses the underground water as its source of supply is the cemented, water-tight one. It has been proven that sewage from cesspools will in time perco- late over 200 feet horizontally, and it must be self-evident that as time goes on the area of infection of the surrounding soil constantly increases: therefore it is asserted that, while a newly constructed cesspool will for a time adequately filter or purify the sewage in a comparatively short distance, the actual distance in which purifica- tion takes place is increased in direct proportion to the length of time it has been in use. assuming the sewage to be constant and similar in character. • The second question is a pertinent one, in that the cesspool seems to be a necessity in the towns and cities that are without a sewage system, for the modern house requires some system of sewage dis- posal. This may be accomplished by the construction of a water- tight cesspool from four to six feet wide and eight to ten feet deep, with several drains of perforated tile near the top and running in different directions and placed immediately below the frost line. Such a cesspool would operate in the nature of a septic tank, much of the organic material being broken up by anaerobic bacterial action, the liquid portion of the sewage draining away through the perforated tile drains, making a fine system of subirrigation for grass, trees, etc., and at the same time protecting the water-bearing stratum from pollution. BULLETIN N. C. BOARD OF HEALTH. 13 Prof. William 0. Hoacl, the board's sanitary and civil engineer, has kindly drawn plans for a sanitary residential sewage-disposal plant, which are herewith reproduced. It is confidently hoped that these plans may be generally adopted throughout the State, particu- larly in those towns located in the valleys where the ground-water supply lies close to the surface. XOTES OX A RESIDENTIAL SEWAGE-DISPOSAL PLAXT. The disposal plant shown in the drawing is planned for an ordi- nary residence, and is designed to treat the liquid wastes from the kitchen sink, bathroom, laundry, and all other waste water coming from the house. The principle of purification employed is that of the septic tank followed by subsurface irrigation. The sewage first enters the septic tank, where suspended matter is held until it is disintegrated by the intense bacterial activity in the tank. The clari- fied effluent then flows out into the dosing chamber where, by means of either the tipping tray or the automatic siphon (depending upon which device is used) it is flushed out into the distribution pipes of the subsurface irrigation system. Here the sewage trickles out through the open joints of the pipes into the surrounding soil, where it becomes food material for the plant life of the lawn or field. The drawing shows a tank built of brick, though it could be con- structed of either stone masonry or concrete just as well. The tank should be carefully plastered on the insi*h> so as to be water-tight. and the inlet and outlet pipes should be set accurately to the eleva- tions shown. The tipping tray in the dosing chamber can be made by any tinner, while the automatic flushing siphon, which may be used in place of the tipping tray if a somewhat better and more permanent form of construction is desired, can be secured from the manufacturers of automatic flushing appliances.* Whether the flush- ing siphon or the tipping tray is used for flushing the sewage out into the distribution pipes, the device should be tested after being set in position, to make sure that it is in good working order. The connection from the house to the septic tank should be of four-inch vitrified clay pipe with bell and spigot joints, carefully laid To a uniform grade, and having the joints well filled with cement mortar. This careful cementing of the joints is particularly impor- tant in case the house connection is carried through a grove of trees. The pipes for the distribution system should be sound, hard-burned, three-inch agricultural drain-tile, in foot lengths. They should be laid from a foot to 18 inches below the surface of the ground, and should be laid on a grade of 3 inches to 100 feet. The pipes should be carefully laid so that the ends match. The matter of grade or "fall" should receive careful attention, since, if the grade be too great the lower end of the pipe will receive more than its fair proportion of sewage, while if the grade be too small the upper end will receive too much. The length of this three-inch pipe should be proportioned according to the nature of the soil. If the soil is open ami sandy, approximately 200 feet is sufficient for the sewage from an ordinary residence, while if the soil is of a closer texture 300 or 400 feet will be necessary. The system is not well adapted to very tight and retentive clay soils, though it has been used successfully in soils of this character. *A three-inch siphon, arranjred to discharge under a head of fifteen inches of "* sewage, can be purchased of the Pacific Flush Tank Company, of Chicago, for fifteen *+> dollars.

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