LU. S. DEPARTMENT OF AGRICULTUREj FARMERS' BULLETIN No. SEWAGE SEWERAGE HOMES if Rec'd UCB ENVi MAY 271986 DISPOSAL OF FARM SEWAGE in a clean man- ner is always an important problem. The aims of this bulletin are twofold: (1) To emphasize basic principles of sanitation; (2) to give directions for constructing and operating home sewerage works that shall be simple, serviceable, and safe. Care in operating is absolutely necessary. No in- stallation will run itself. Continued neglect ends in failure of even the best designed, best built plants. If the householder is to build and neglect, he might as well save expense and continue the earlier practice. Washington, D. C. Issued January, 1922 SEWAGE AND SEWERAGE OF FARM HOMES. GEOEGE M. WAEREN, Hydraulic Engineer, Bureau of Public Roads. Introduction CONTENTS. Page. o Plans and advice Sewage, sewers, and sewerag fined. Nature and quantity of sewage 4 Sewage -borne diseases and their avoidance- Page. How sewage decomposes 9 Importance of air in treatment of 10 11 _. 90 Grease traps ~ ~ 3 General procedure sewage Practical utilities. Septic tanks .. INTRODUCTION. The main purpose of home-sewerage works is to get rid of m such way as (1) to ^ against the transmission of e germs through drinking water, flies, or other means; (2) to avoid creating nuisance. What is the best method and what the best outfit are questions not to be answered offhand from afar. A treatment t is a success m one location may be a failure in another. In every instance decision should be based upon field data and full knowledge of the local needs and conditions. An installation planned from assumed Conditions may work harm. The householder may be misled as to the purification and rely on a protection that is not real P r M d r and find a nuisance has been PLANS AND ADVICE. Though specific plans can not be sent in the absence of definite in- formation and though plans and specifications can not be prepared e> meet individual requirements, the Division of Agricultural Engi- neering Bureau of Public Roads, gladly gives such help as is pos- b e. To those who contemplate installing sewerage works on farms 1 who furnish the information outlined under the caption "Field ta, on page 52, plans, advice, or suggestions will be sent. Local equirements are frequently met or approximated by one of the de- i hand; working drawings in the form of blue prints will then 4 Farmers' Bulletin 1227. be furnished. Sometimes the designs, slightly modified, may suit the needs. In other instances it is sufficient to send published bulletins or give written suggestions of a practical nature. SEWAGE, SEWERS, AND SEWERAGE DEFINED. Human excrements (feces and urine) as found in closets and privy vaults are known as night soil. These wastes may be flushed away with running water, and there may be added the discharges from washbasins, bathtubs, kitchen and slop sinks, laundry trays, washing vats, and floor drains. This refuse liquid product is sewage, and the underground pipe which conveys it is a sewer. Since sewers carry foul matter they should be water-tight, and this feature of their construction distinguishes them from drains removing relatively pure surface or ground water. Sewerage refers to a system of sewers, including the pipes, tanks, disposal works, and appur- tenances. NATURE AND QUANTITY OF SEWAGE. Under average conditions a man discharges daily about 3J ounces of moist feces and 40 ounces of urine, the total in a year approximat- ing 992 pounds. 1 Feces consist largely of water and undigested or partially digested food ; by weight it is 77.2 per cent water. 2 Urine is about 96.3 per cent water. 2 The excrements constitute but a small part of ordinary sewage. In addition to the excrements and the daily water consumption of perhaps 40 gallons per person are many substances entering into the economy of the household, such as grease, fats, milk, bits of food, meat, fruit, and vegetables, tea and coffee grounds, paper, etc. This complex product contains mineral, vegetable, and animal substances, both dissolved and undissolved. It contains dead organic matter and living organisms in the form of exceedingly minute vegetative cells (bacteria) and animal cells (protozoa). These low forms of life are the active agents in destroying dead organic matter. The bacteria are numbered in billions and include many species, some useful and others harmful. They may be termed tiny scaven- gers, which under favorable conditions multiply with great rapidity, their useful work being the oxidizing and nitrifying of dissolved organic matter and the breaking down of complex organic solids to liquids and gases. Among the myriads of bacteria are many of a virulent nature. These at any time may include species which are the cause of well-known infections and parasitic diseases. * Practical Physiological Chemistry, by Philip B. Hawk, 1916, pp, 221, 359, 9 Agriculture, by F. H. Storer, 1894, vol. 2, p, 70, Sewage and Sewerage of Farm Homes. 5 SEWAGE-BORNE DISEASES AND THEIR AVOIDANCE. Any spittoon, slop pail, sink drain, urinal, privy, cesspool, sewage tank, or sewage distribution field is a potential danger. A bit of spit, urine, or feces the size of a pin head may contain many hundred germs, all invisible to the naked eye and each one capable of produc- ing disease. These discharges should be kept away from the food and drink of man and animals. From specific germs that may be carried in sewage at any time there may result typhoid fever, tuber- culosis, cholera, dysentery, diarrhea, and other dangerous ailments, and it is probable that other maladies may be traced to human waste. From certain animal parasites or their eggs that may be carried in sewage there may result intestinal worms, of which the more common are the hookworm, roundworm, whipworm, eelworm, tapeworm, and seat worm. Sewage, drainage, or other impure water may contain also the causative agents of numerous ailments common to live stock, such as tuberculosis, foot-and-mouth disease, hog cholera, anthrax, gland- ers, and stomach and intestinal worms. Disease germs are carried by many agencies and unsuspectingly received by devious routes into the human body. Infection may come from the swirling dust of the railway roadbed, from contact with transitory or chronic carriers of disease, from green truck grown in gardens fertilized with night soil or sewage, from food prepared or touched by unclean hands or visited by flies or vermin, from milk handled by sick or careless dairymen, from milk cans and utensils washed with contaminated water, or from cisterns, wells, springs, reservoirs, irrigation ditches, brooks, or lakes receiving the surface wash or the underground drainage from sewage-polluted soil. Many recorded examples show with certainty how typhoid fever and other diseases have been transmitted. A few indicating the responsibilities and duties of people who live in the country are cited here. In August, 1889, a sister and two brothers aged 18, 21, and 23 years, respectively, and all apparently in robust health dwelt tp- f ether in a rural village in Columbiana County, Ohio. Typhoid Bver in particularly virulent form developed after use of drinking water from a badly polluted surface source. The deaths of all three occurred within a space of 10 days. In September and October, 1899, 63 cases of typhoid fever, result- ing in 5 deaths, occurred at the Northampton (Mass.) insane hos- pital. This epidemic was conclusively traced to celery, which was eaten freely in August and was grown and banked in a plot that had been fertilized in the late winter or early spring with the solid residue and scrapings from a sewage filter bed situated on the hospital grounds. 6 Farmers' Bulletin 1227. Some years ago Dr. W. AV. Skinner, Bureau of Chemistry, Depart- ment of Agriculture, investigated the cause of an outbreak of typhoid fever in southwest Virginia. A small stream meandered through a narrow valley in which five 10-inch wells about 450 feet deep had been drilled in limestone formation. The wells were from 50 to 400 feet from the stream, from which, it was suspected, pollution was reaching the wells. In a pool in the stream bed approximately one- fourth mile above the wells several hundred pounds of common salt were dissolved. Four of the wells were cut off from the pump and the fifth was subjected to heavy pumping. The water discharged by the pump was examined at 15-minute intervals and its salt con- tent determined over a considerable period of time. After the lapse of several 15-minute intervals the salt began to rise a^nd continued to rise until the maximum was approximately seven times that at the beginning of the test, thus proving the facility with which pollution may pass a long distance underground and reach deep wells. - Probably no epidemic in American history better illustrates the dire results that may follow 7 one thoughtless act than the outbreak of typhoid fever at Plymouth, Pa., in 1885. In January and February of that year the night discharges of one typhoid fever patient were thrown out upon the snow near his home. These, carried by spring thaws into the public water supply, caused an epidemic running from April to September. In a total population of about 8,000, 1 } 104 per- sons were attacked by the disease and 114 died. Like plants and animals, disease germs vary in their powers of resistance. Some are hardy, others succumb easily. Outside the body most of them probably die in a few days or weeks. It is never certain when such germs may not lodge where the immediate sur- roundings are favorable to their life and reproduction. Milk is one of the common substances in which germs multiply rapidly. The experience at Northampton shows that typhoid-fever germs may survive, several months in garden soil. Laboratory tests by the United States Public Health Service showed that typhoid- fever germs had not all succumbed after being frozen in cream 74 days. (Public Health Reports, Feb. 8, 1918, pp. 163-166.) Ravenel kept the spores of anthrax immersed for 244 days in the strongest tanning fluids without perceptible change in their vitality or virulence. (Annual Report, State Department of Health, Mass., 1916, p. 494.) Unsafe practices. Upon thousands of small farms there are no privies and excretions are deposited carelessly about the premises. A place of this character is shown in figure 1. Upon thousands of other farms the privy is so filthy and neglected that hired men and visitors seek near-by sheds, fields, and woods. A privy of this char- acter is shown in figure 2. These practices and conditions exist in every section of the country. They should be abolished. Deserving of severe censure is the old custom of conveying excre- ments or sewage into abandoned wells or some convenient stream. Such a practice is indecent and unsafe. It is unnecessary arid is contrary to the laws of most of the States. Sewage and Sewerage of Farm Homes. 7 Likewise dangerous and even more disgusting is the old custom of using human excrement or sewage for the fertilization of truck land. Under no circumstances should such wastes be used on land devoted to celery, lettuce, radishes, cucumbers, cabbages, tomatoes, melons, or other vegetables, berries, or low-growing fruits that are eaten raw. Disease germs or particles of soil containing such germs may adhere to the skins of vegetables or fruits and infect the eater. Upon farms it is necessary to dispose of excretal wastes at no great distance from the dwelling. The ability and likelihood of flies carrying disease germs direct to the dinner table, kitchen, or pantry are well known. Vermin, household pets, poultry, and live stock may spread such germs. For these reasons, and also on the score of odor, farm sewage never should be exposed. FIG. 1. One of many farms lacking the simplest sanitary convenience. Important safety measure. The farmer can do no other one thing so vital to his own arid the public health as to make sure of the con- tinued purity of the farm water supply. Investigations indicate that about three out of four shallow wells are polluted badly. Wells and springs are fed by ground water, which is merely natu- ral drainage. Drainage water usually moves with the slope of the land. It always dissolves part of the mineral, vegetable, and animal matter of the ground over or through which it moves. In this way impurities are carried into the ground water and may reach distant wells or springs. Th 3 great safeguards are clean ground and wide separation of the well from probable channels of impure drainage water. It is not 8 Farmers' Bulletin 1227. enough that a well or spring is 50 or K>0 feet from a source of filth or that it is on higher ground. Given porous ground, a seamy ledge, or long-continued pollution of one plat of land, the zone of conjtami- nation is likely to extend long distances, particularly in downhill directions or when the water is low through drought or heavy pump- ing. Only when the surface of the water in a well or spring is at a t higher level at all times than any near- by source of filth is there assurance of safety from impure seepage. Some of the foregoing facts are shown dia- grammatically in figure 3. Figure 4 is typical of those insanitary, poorly drained barnyards that are almost cer- tain to work injury to wells situated in or near them. Figure 5 illustrates poor relative location of privy, cess- pool, and well. Figure 6 is a typical example of a nuisance. Accumula- tions of filth result in objectionable odor and noxious drainage. Sewage or impure drainage water should never be discharged into or upon ground draining toward a well, spring, or other source of w r ater supply. Neither should such wastes be dis- charged into openings in rock, an abandoned well, nor a hole, cesspool, vault, or tank so located that pollu- tion can escape into w r ater-bearing earth or rock. Whatever the system of sewage disposal, it should be entirely and widely separated from the water supply. Further information on lo- cating and constructing wells is given in Farmers' Bulletin 941, " Water Systems for Farm Homes," copies of which may be had upon request to the Division of Publications, Department of Agriculture. Enough has been said to bring home to the reader these vital points : 1. Never allow the farm sewage or excrements, even in minutest quantity, to reach the food or water of man or live stock. 2. Never expose such wastes so that they can be visited by flies or other carriers of disease germs. 3. Never use such wastes to fertilize or irrigate vegetable gar- dens. BPR-REI383 FIG. 2. The rickety, uncomfort- able, unspeakably foul, dangerous ground privy. Neglected by the owner, shunned by the hired man, avoided by the guest, who, in preference, goes to near-by fields or woods, polluter of wells, meet- Ing place of house flies and disease germs, privies of this character abide only because of man's in- difference. Sewage and Sewerage of Farm Homes. 9 4. Never discharge or throw such wastes into a stream, pond, or abandonee! well, nor into a gutter, ditch, or tile drainage system, which naturally must have outlet in some watercourse. HOW SEWAGE DECOMPOSES. When a bottle of fresh sewage is kept in a warm room changes occur in the appearance and nature of the liquid. At first it is light 1379 FIG. 3. How an apparently good well may draw foul drainage. Arrows show direction of ground Wcater movement. A-A, Usual water table (surface of free water in the ground) ; B-B, water table lowered by drought and pumping from well D ; C-C, water table further lowered by drought and heavy pumping ; E-F, level line from surface of sewage in cesspool. Well D is safe until the water table is lowered to E ; further lower- ing draws drainage from the cesspool and, with the water table at C-C, from the barn. The location of well G renders it unsafe always. in appearance and its odor is slight. It is well supplied with oxygen, since this gas is always found in waters exposed to the atmosphere. BPR-RE 1385 PIG. 4. An insanitary, poorly drained barnyard. (Board of Health, Milwaukee.) Liquid manure or other foul drainage is sure to leach into wells situated in or near barnyards of this character. In a few hours the solids in the sewage separate mechanically ac- cording to their relative weights ; sediment collects at the bottom, and 85868 24 2 10 Farmers' Bulletin 1227. a greasy film covers the surface. In a day's time there is an enormous development of bacteria, which obtain their food supply from the dissolved carbonaceous and nitrogenous matter. As long as free oxygen is present this action is spoken of as aerobic decomposition. There is a gradual increase in the amount of ammonia and a de- crease of free oxygen, the latter going to support bacterial life. When the ammonia is near the maximum and the free oxygen is ex- hausted the sewage is said to be stale. Following exhaustion of the oxygen supply, bacterial life continues profuse, but it gradually diminishes as a result of reduction of its food supply and the poison- ous effects of its own wastes. In the absence of oxygen the bacterial BPR-RE isse FIG. 5. Poor relative locations of privy, cesspool, and well. (State Department of Health, Massachusetts.) Never allow privy, cesspool, or sink drainage to escape into the plot of ground from which the water supply is taken. action is spoken of as anaerobic decomposition. The sewage turns darker and becomes more offensive. 'Suspended and settled organic substances break apart or liquefy later, and various foul-smelling gases are liberated. Sewage in this condition is known as septic and the putrefaction that has taken place is called septicization. The odor eventually disappears, and a dark, insoluble, mosslike sub- stance remains as a deposit. Complete reduction of this deposit may require many years. IMPORTANCE OF AIR IN TREATMENT OF SEWAGE. Decomposition of organic matter by bacterial agency is not a complete method of treating sewage, as will be shown later under Sewage and Sewerage of Farm Homes. 11 " Septic tanks." It is sufficient to observe here that in all practical methods of treatment aeration plays a vital part. The air or the sewage, or both, must be in a finely divided state, as when sewage percolates through the interstices of a porous, air-filled soil. The principle involved was clearly stated 30 years ago by Hiram F. Mills, a member of the Massachusetts State Board of Health. In discuss- BPR-RE 1387 FIG. 6. A typical nuisance. (Board of Health, Milwaukee.) A yard like this is an eyesore, a fire menace, a breeding place for mosquitoes and vermin, a refuge for rats and mice, a source of noxious odors and foul drainage, and a violation of every sani- tation code. ing the intermittent filtration of sewage through gravel stones too coarse to arrest even the coarsest particles in the sewage Mr. Mills said: "The slow movement of the sewage in thin films over the surface of the stones, with air in contact, caused a removal for some months of 97 per cent of the organic nitrogenous matter, as well as 99 per cent of the bacteria." PRACTICAL UTILITIES. Previous discussion has dealt largely with basic principles of sanitation. The construction and operation of simple utilities em- bodying some of these principles are discussed in the following order : (1) Privies for excrements only; (2) works for handling wastes where a supply of water is available for flushing. 12 Farmers' Bulletin 1227. PIT PRIVY. *, Figure 7 shows a portable pit privy suitable for places of the character of that shown in figure 1, where land is abundant and cheap, and in such localities has proved practical. It provides, at minimum cost and with least attention, a fixed place for depositing excretions where the filth can not be tracked by man, spread by animals, reached by flies, nor washed by rain. The privy is light and inexpensive and is placed over a pit in the ground. When the pit becomes one-half or two-thirds full the privy is drawn or carried to a new location. The pit should be shallow, preferably not over 2 feet in depth, and never should be located in 2"x4'-3'Long Prepared Roofing / "Boards ~2"x4'-3' Long l 'Boards 6$ 8' 'Screened Vent PERSPECTIVE FIG. 7. Portable pit privy. For use where land is abundant and cheap, but unless handled with judgment can not be regarded as safe. The privy is mounted on run- ners for convenience in moving to new locations. wet ground or rock formation or where the surface or the strata slope toward a well, spring, or other source of domestic water supply. Be- sides standing on lower ground the pit should never be within 200 feet of a well or spring. Since dryness in the pit is essential, the ground should be raised slightly and 10 or 12 inches of earth should be banked and compacted against all sides to shed rain water. The banking also serves to exclude flies. If the soil is sandy or gravelly, the pit should be lined with boards or pales to prevent caving. The privy should be boarded closely and should be provided with screened openings for ventilation and light. The screens may consist of standard galvanized or black enameled wire cloth having 14 squares Sewage and Sewerage of Farm Homes. 13 to the inch. The whole seat should be easily removable for cleaning. A little loose absorbent soil should be added daily to the accumu- lation in the pit, and when a pit is abandoned it should be filled immediately with dry earth mounded to shed water. A pit privy for use in field Avork, consisting of a framework of | -inch iron pipe for corner posts connected at the top with J-inch iron rods bent at the ends to right angles and hung with curtains of unbleached muslin, is described in Public Health Report of the United States Public Health Service. July 26, 1918. A pit privy, even if moved often, can not be regarded as safe. The danger is that accumulations of waste may overtax the purify- ing capacity of the soil and the leachings reach wells or springs. Sloping ground is not a guaranty of safety ; the great safeguard lies in locating the privy a long distance from the water supply and as far below it as possible. SANITARY PRIVY. The next step in evolution is the sanitary privy. Its construction must be such that it is practically impossible for filth or germs to be spread above ground, to escape by percolation underground, or to be accessible to flies, vermin, chickens, or animals. Furthermore, it must be cared for in a cleanly manner, else it ceases to be sanitary. To secure these desirable ends sanitarians have devised numerous types of tight-receptacle privy. Considering the small cost and the proved value of some of these types, it is to be regretted that few are seen on American farms. The container for a sanitary privy may be small for example, a galvanized-iron pail or garbage can, to be removed from time to time by hand ; it may be large, as a barrel or a metal tank mounted for moving; or it may be a stationary underground metal tank or masonry vault. The essential requirement in the receptacle is per- manent water-tightness to prevent pollution of soils and wells. Wooden pails or boxes, which warp and leak, should not be used. Where a vault is used it should be shallow to facilitate emptying and cleaning. Moreover, if the receptacle should leak it is better that the escape of liquid should be in the top soil, where air and bac- terial life are most abundant. Sanitary privies are classified according to the method used in treating the excretions, as dry earth, chemical, liquefying. DRY-EARTH PRIVY. Pail type. A very serviceable pail privy is shown in figures 8 and D. The method of ventilation is an adaptation of a system that has proved very effective in barns and other buildings here and abroad. 14 Farmers' Bulletin 1227. A flue with a clear opening of 16 square inches rises from the rear of the seat and terminates above the ridgepole in a cowl or small roofed housing. Attached to this flue is a short auxiliary duct, 4 by 15 inches, for removing foul air from the top of the privy. In its upper portion on the long sides the cowl is open, allowing free movement of air across the top of the flue. In addition the long sides of the cowl are open below next to the roof. These two open- ings, with the connecting vertical air passages, permit free upward movement of air through the cowl, as indicated by the arrows. The combined effect is to create draft from beneath the seat and from the top of the privy. The ventilating flue is 2 by 8 inches at the seat and 4 by 4 inches 5 feet above. The taper slightly increases the Rebate /"for l/ent Hue - PERSPECTIVE PERSPECTIVE OF FRAMING FIG. 8. Pail privy. Well constructed, ventilated, and screened. With proper care is sanitary and unobjectionable. labor of making the flue, but permits a 2-inch reduction in the length of the building. In plan the privy is 4 by 4J feet. The sills are secured to durable posts set about 4 feet in the ground. The boarding is tight, and all vents and windows are screened to exclude insects. The screens may be the same as for pit privies or, if a more lasting material is de- sired, bronze or copper screening of 14 squares to the inch may be used. The entire seat is hinged, thus permitting removal of the receptacle and facilitating cleaning and washing the underside of the seat and the destruction of spiders and other insects which thrive in dark, un- clean places. The receptacle is a heavy galvanized-iron garbage can. Heavy brown-paper bags for lining the can may be had at slight cost, and their use helps to keep the can clean and facilitates empty- Sewage and Sewerage of Farm Homes. 15 0/-.P- 16 Farmers' Bulletin 1227. ing. Painting with black asphaltum serves a similar purpose and protects the can from rust. If the contents are frozen, a little heat releases them. Of nonfreezing mixtures a strong brine made witlj common salt or calcium chloride is effective. Two and one-half to 3 pounds of either thoroughly dissolved in a gallon of water lowers the freezing point of the mixture to about zero. Denatured alcohol or wood alcohol in a 25 per cent solution has a like low freezing point and the additional merit of being noncorrosive of metals. The can should be emptied frequently and the contents completely buried in a thin layer by a plow or in a, shalloAV hand-dug trench at a point below and remote from wells and springs. Wherever intestinal dis- ease exists the contents of the can should be destroyed by burning or made sterile before burial by boil- ing or by incorporation with a strong chemical disinfectant. A privy ventilated in the manner before described is shown in figure 10. The cowl, however, is open on four sides instead of two sides as 1 shown in figures 8 and 9. The work- ing drawings (fig. 8 and 9) show that the construction of a privy of the kind is not difficult. Figure 11 gives three suggestions whereby a privy may be conveniently located and the ap- proach screened or partially hidden by latticework, vines, or shrubbery. Vault type. A primitive and yet serviceable three-seat dry-earth privy of the vault type is shown in figure 12. This privy was constructed in 1817 upon a farm at TV 7 estboro, Mass. The vault, made of bricks, was 6 feet long by 5 feet wide, and the bottom was 1 foot below the surface of the ground. The brickwork was laid in mortar, and the part below the ground surface was plastered on the in- side. The outside of the vault was exposed to light and air on all four sides. Across the long side of the vault in the rear was a door swinging upward through which the night soil was removed two or three times a year, usually in the spring, summer, and fall, and hauled to a near-by field, where it was deposited in a furrow, just ahead of the plow. Especial attention is called to the shallowness of the vault and the lightened labor of cleaning it out. The swinging door at the rear facilitated the sprinkling of dry soil or ashes over the contents of the vault, thus avoiding the necessity of carrying dirt and dust into the BPR-RE 1382 FIG. 10. A well-ventilated privy in Montana. Sewage and Sewerage of Farm Homes. building and dust settling upon the seat. This privy was in use for nearly 100 years without renewal or repairs. When last seen the original seat, which always was kept painted, showed no signs of 11 CD decay. Modern methods would call for a concrete vault of guar- anteed water-tightness, 3 proper ventilation and screening, and hing- ing the seat. - Directions for mixing and placing concrete to secure water-tightness are contained in an article entitled " Securing a dry cellar." U. S. Department of Agriculture Yearbook, 1919 ; published also as Yearbook Separate No. 824, and obtainable for 10 cents from Jhe Superintendent of Documents, Government Printing Office, Washington, D. C, 85868 24 3 18 Farmers Bulletin 1227. P inch that Working drawings for a very convenient well-built two-seat vault privy are reproduced in figures 13 and 14. The essential features are shown in sufficient detail to require little explanation. With con- crete mixtures of 1 :2 : 3 (1 volume cement. 2 volumes sand. 3 volumes stone) for the vault and 1:2:4 for the posts there will be required a total of about 2 cubic yards of con- crete 4 , taking 3^ barrels of cement. 1 cubic yard of sand, and H cubic yards of broken stone or screened gravel. The stone or gravel should not exceed 1 in diameter, except a few cobblestones may be embedded where the vault wall is thickest, thus effecting a slight sav- ing of materials. CHEMICAL CLOSET. A type of sanitary privy in which the excrements are received direct!}' into a water-tight receptacle con- taining chemical disinfect- ant is meeting with consid- able favor for camps, parks, rural cottages, schools-:, hotels, and railway stations. These chemical closets, 4 as they are called. -are made in different forms and are known by various trade names. Tn the simplest form a sheet -metal recepta- cle is concealed in a small metal or wooden cabinet, and the closet is operated usually in much the same manner as the ordinary pail privy. These closets are very simple and compact, of good appearance, and easy to install or move 4 Among publications on chemical closets are the following : " Chemical Closets," Re- print No. 404 from the Public Health Reports, U. S. Public Health Service, June 29, 1917, pp. 1017-1020 : " The Chemical Closet," Engineering Bulletin No. 5, Mich. State Board of Health. October, 1916: Health Bulletin, Va. Department of Health, March, 1917, pp. 214-219. I3O4 FIG. 12. A primitive vault privy in Massachu setts. Note the tight, shallow, easily cleaned vault. A, Brick vault ." by <; feet, boltom about 1 foot in the ground; B, watertight plastering; C, rowlock course of brick ; D, door hinged at top: /:. door button; /'. thnx'-panc window hinged at lop;