DOMESTIC WATER-SUPPLY PLANTS
Until recent years, no thought was given to private water-supply plants, in any except the more pretentious residences. It was formerly supposed that the cost of machinery and installation of such plants prohibited the use of a water system in the average home. As an item of expense in building, a satisfactory water-supply system may be installed at a lower cost than is paid for plumbing and bathroom fixtures.
In recent years much attention has been given to the design of small water-supply plants for isolated homes, such as are required for suburban and rural dwellings, with the result that the necessary apparatus to suit any conditions may be obtained of any enterprising dealer.
The degree of completeness with which the plant is to be arranged will depend on the funds to be expended, but in the most modest dwelling some form of water-supply plant is possible. Where opportunity is given to make the plant complete, its appointments of construction may be elaborated to almost any extent. A suburban or country residence may be made as perfect in point of toilet, kitchen and laundry conveniences, as where city water and sewer service are available. The water-supply plant may be operated by hand or by power, and if so desired may be made completely automatic in action.
Gravity Water-supply Plant.
—In point of simplicity, the plant shown in Fig. 143 represents a water system that answers every purpose of a cottage and yet is only an elevated tank for storage of water, combined with a house force pump. The tank in this case may be made of wood or metal and is open at the top. The water is sent into the tank by the pump, and gravity furnishes the force for carrying it to the fixtures in the kitchen and bathroom.
In using a tank of the kind shown in the drawing, provision should be made for the possibility of leakage. This is arranged for by having the tank set in a shallow pan, so constructed that in case of accident the water may be carried away without doing damage. This type of plant is not usually employed in cold climates, unless some provision is made to prevent the water in the tank from freezing. Tanks of this kind are sometimes used in cold climates but a much more desirable plant for the purpose is described below. In Fig. 143 the water from the cistern W is raised by the pump P, which also forces it into the tank above the kitchen. The gravitational force given the water, because of its elevated position is all that is necessary to carry the water to the fixtures in the bathroom and kitchen sink. As shown in the drawing, it furnishes a complete water system that will perform all of the requirements of water distribution for a small family.
Fig. 143.—Sectional view of a cottage containing a simple gravity water-supply plant.
The pipes from the range boiler are attached to the water heater, which forms a part of the kitchen range as explained on pages [116] to [120]. It receives the supply of cold water directly from the tank through the pipe marked C, and the hot water from the range boiler is supplied through the pipe H. Cold water is also taken from the tank directly to each of the cold-water taps.
The pump P is a house pump, such as is shown in Fig. 130. It is a small force pump, designed to suit the conditions of domestic use and is made to send water into the sink or into the supply tank as desired.
Pressure-tank System of Water Supply.
—The water-supply plant shown in Fig. 144 is another simple construction, somewhat more elaborate than the last, so arranged that the danger of freezing is practically eliminated. This is a simple pressure-tank system in which a tightly built metal water tank takes the place of the elevated tank of the previous figure, and a tank pump is used for lifting and giving pressure to the water. It is a more complete plant than the first and intended to accommodate a larger dwelling. The drawing shows all of the fixtures and connecting pipes that are required in the average home. It shows all of the appliances for connecting the pressure tank and range boiler with the wash trays in the basement, with all of the fixtures in the bathroom and with the fixtures in the kitchen sink. The range boiler is the same as those previously described and connected to the heater in an identical manner.
The original source of supply in this case is a cistern, sunk below the basement floor. The water is lifted from the cistern by the pump and forced into the pressure tank through a pipe near the bottom where it furnishes the supply for the house.
The pressure tank may be of any size to suit the requirements of the house and may be placed in either a vertical or horizontal position. It is sometimes galvanized, as a precaution against rust, but this is not a necessary requirement. The pipe which conveys the water from the pump connects with the tank near the bottom. As the water enters, the contained air above its surface is compressed into smaller and smaller space. The pressure that is developed by the compressed air furnishes the force by which the water is driven out of the tank and through the distributing pipes to the various parts of the system.
If the air in the tank when empty is compressed to one-half its original volume, then the gage pressure will be about 15 pounds to the square inch; if the air is compressed to one-third its original volume, that is, when the tank is two-thirds full of water, the gage pressure will be about 30 pounds to the square inch, which is enough to supply water at any point of a two-story building with ample force. By pumping more water into the tank, a pressure of 50 or 60 pounds may be obtained without difficulty; but 40 pounds is generally sufficient for all the demands of a house plant. This is an application of the Boyle’s law which as stated in text books of physics is: “The temperature remaining the same, the pressure on confined gas varies inversely as its volume.” As the volume of such a confined body of gas is made smaller, the pressure increases in like ratio. The desired pressures are easily attained with a hand force pump such as is shown in the drawing.
Fig. 144.—The pressure-tank system of water supply as it appears in a dwelling.
The gage-glass G on the side of the tank is intended to show the height of the water in the tank at any time, and the pressure gage attached to the supply pipe shows the amount of pressure sustained by the water.
The Pressure Tank.
—The water leaves the tank by a pipe attached near the bottom and branches to supply each fixture, to which the water is to be conducted. In the drawing, the pipe may be traced from the point where it leaves the tank to the various fixtures. The cold-water pipe terminates at the range boiler, for at that point the hot-water system begins. The range boiler is connected by two pipes to the water heater in the kitchen range. The water heater is a part of the fire-box of the kitchen range and so long as the fire is kept burning, water is heated and stored in the range boiler. Where the house is furnace-heated, the furnace fire is sometimes utilized for heating the water by use of a coil of pipe above the fire and which may take the place of the range heater. Various other means are also employed for heating the water as described under range boilers. In Fig. 145 is shown a nearer view of a pressure tank with the pump attached. The pump is in this case identical in its action to the one shown in Fig. 132, but differs slightly in mechanical design. The drawing shows the gage-glass G, for indicating the height of water; the pressure gage P, which indicates the pressure to which the water is subjected; the attachment of the supply pipe S, and the delivery pipe D. The water tap T is provided to draw off the water when the tank is to be emptied.
Fig. 145.—The pressure tank complete, with the pump and gages as used for domestic water supply.
In operation, the air in the pressure tank furnishes the force which sends the water through the pipes to the various points, and forces it through the taps at the desired rate. If for any reason the air in the tank escapes, the propelling force is destroyed. This may occur by reason of absorption of the air by the water, due to the pressure to which it is subjected; or to small air leaks that may develop in the joints, which allow the air to escape. To overcome the possibility of these occurrences, arrangement is made whereby air may be pumped into the tank by the same pump as that which supplies the water. In this way, the air is introduced with the water, which bubbles up through it to the surface. If at any time the pressure in the tank is lost, it may be replaced by pumping air alone into the tank.
Power Water-supply Plants.
—Where the pump is expected to furnish water to any considerable amount beyond that for household use, it is desirable that the plant be power-driven. If the work of watering stock, lawn sprinkling, etc., is intended, the tank and pump must be enlarged to suit the desired amount of water, and a gasoline engine, windmill or electric motor will be used for power. Where local conditions will permit, a hydraulic ram may be substituted for the pump and the pressure tank used for additional pressure and storage.
Fig. 146.—Tank pump operated by a small gasoline engine.
Fig. 146 shows a plant in which the pump is driven by a gasoline engine. In the figure, the engine E is shown connected by a belt to a speed-reducing device or “jack,” marked J. The object of this machine is to reduce the speed of rotation and charge it to the required motion for operating the pump. The jack is connected to the pump by a rod attached to a large gear, so as to produce the desired crank motion; and the opposite end of the rod is attached to the pump handle. The rod may be detached at any time and the pump worked by hand.
Electric Power Water Supply.
—Fig. 147 shows another type of power plant in which an electric motor operates the pump. In this style of plant, the pulley on the electric motor M is connected by a belt to the large wheel W, from which the crank motion is secured for driving the pump P. This machine is provided with an automatic starting and stopping device, which automatically controls the supply of water in the system. Whenever the pressure in the tank falls to a certain point, the change of pressure produced on the diaphram valve A starts the motor, and the pump sends water into the tank until the pressure in the tank again reaches the amount for which the valve is set, at which time the valve disconnects the electric contact to the motor and the pump stops working.
Fig. 147.—Pressure tank supplied by an electrically driven pump.
Wind-power Water Supply.
—In Fig. 148 is shown a larger and more complete plant than the former, in which a windmill furnishes the power for pumping and a large underground tank is utilized for the main supply of water. The tank marked, Well Water Pressure Tank, in this case is so placed that the end is exposed in the well curb, where the height of the water may be observed at any time. The pump is operated as any other of its kind, but is provided with an automatic pressure cylinder, which controls the operation of the mill through the rise and fall of the water in the tank. At any time the water in the tank falls to a certain point, the pump is thrown into gear by the pressure cylinder, and the water is pumped into the tank until a definite height is reached; at this point the pump is automatically thrown out of gear and remains inactive until an additional supply of water is required. The plant is therefore automatic in its action and requires only that the mill be kept oiled and in running order.
As shown in the drawing, the large tank receives its supply of water from the well and aside from providing a reserve supply furnishes power for pumping cistern water. The water from the large tank is piped into the house for use as required, and from the same pipe is taken a hydrant for lawn sprinkling; in addition, this water is piped to the barn where it is used for watering stock. A branch of the same pipe is intended to operate a water lift, which in turn furnishes the house with soft water from the rain-water cistern for bathing, laundry, and kitchen purposes.
Fig. 148.—This diagram shows the arrangement of domestic water-supply apparatus, in which a windmill furnishes the pressure necessary for operating the entire plant.
The Water Lift.
—The water lift is a combined water engine and pump, the motive power for which is the pressure from the well-water tank. The soft water, pumped by the water lift, is stored in the smaller pressure tank marked Soft Water Pressure Tank in the drawing, and furnishes a supply for the purposes mentioned. The water lift is so constructed that when the pressure in the soft-water tank equals the pressure in the well-water tank, the lift will stop working and will not start again until water has been drawn from the taps. Whenever water is drawn from any part of the system, the pressure will be reduced and the lift will immediately begin pumping more water and will continue until the pressure of the two tanks are the same. The system is entirely automatic, each part depending on the power originally supplied by the windmill. The plant could be just as successfully operated by substituting a gasoline engine or other source of power for the windmill. The machinery for such a plant is not at all complicated neither is it difficult to manage, yet it is complete in every particular and furnishes an almost ideal arrangement for a country or suburban home.
Fig. 149.—The water lift.
In order to be assured of a supply of water over periods of atmospheric quiet, the well-water tank must be sufficiently large to supply water for 3 or 4 days; but in case of emergency water may be pumped by hand.
A nearer view of the water lift is shown in Fig. 149. In the figure, the right-hand cylinder with its valve V is the water engine which furnishes the power for operating the pump, enclosed in the left-hand cylinder. The water pressure of the main supply furnishes the energy which drives the engine, the piston rod of which is attached to the pump piston. The engine receives its supply of water through the pipe marked Inlet and the waste water is discharged to the sewer by the waste pipe on the opposite side of the cylinder. The operation of the lift is governed by an automatic regulator which so controls the engine that it starts pumping whenever the pressure in the system falls to a certain point. The regulator marked Adjustable Regulator in the drawing may be adjusted to suit the water pressure desired in the distributing system.
Fig. 150.—The terms by which the parts of a force pump are designated.
CHAPTER VIII
SEWAGE DISPOSAL
The disposal of sewage, in a convenient and sanitary manner is a problem of serious importance in the equipment of isolated dwellings with modern household conveniences. The manner of heating, lighting and of water supply are questions of selection among a number of established systems, but the problem of sewage disposal must in a great measure be determined by local conditions. Unless the natural surroundings are such as will permit sewage to be emptied directly into a stream of considerable volume, the problem of its safe disposal becomes one of serious importance.
Sewage is understood to mean the fluid waste from the kitchen, toilet and laundry and has nothing whatever to do with garbage. Sewage disposal has to do with conducting away the house waste and disposing of it in a sanitary manner. Sewage disposal does not necessarily have anything to do with sewage purification; although a sewage disposal plant may be so constructed as to discharge a purified effluent, it usually is understood to have to do alone with its disposal in a manner that does not offend the aesthetic sense. A simple sewage plant is anything that will take the sewage away from the house in such a way as to produce no unsightly accumulations that will decay and produce offensive odors.
A sewage purification plant is one in which the raw sewage from the house drain is first liquefied, after which the liquid is passed into a filter where it undergoes a process of bacterial disintegration and the organic matter reduced to the inorganic state, where no further change is possible. The water which flows from such a filter is clear and sparkling, and is often taken for spring water. The degree of purification given to the sewage will depend on the style of filter and the length of time necessary for the water to pass through it.
Sewage is composed of organic matter in a fluid or part fluid condition, contained in a large volume of water. It is not usually the dark, heavy, foul-smelling fluid that is imagined by many, but a turbid liquid possessing only a few of the qualities usually ascribed to sewage. Under favorable conditions practically all of the organic matter will be readily dissolved and the sewage will become entirely liquid.
As a liquid, the raw sewage is in the most favorable condition for rapid decay and if left standing in the air it soon develops properties that render it highly objectionable.
The decay of all organic matter is a process of disintegration that ultimately ends in the elements from which it came. In the disposal of sewage, the aim is to permit this disintegration to take place under conditions that will be least offensive to the aesthetic sensibilities, and in some cases to render it free from harmful properties should there be present the bacteria of communicable disease.
The successful disposal of sewage from cities is accomplished under a great variety of conditions. It is much easier to arrange for sewage purification on a large scale than in a small way. The reason for this is that in the care of a city the sewage-disposal plant is under the supervision of a competent person, whose business it is to see that the conditions are kept at the highest efficiency. Private plants are left almost entirely without care, until they fail from causes that are usually preventable. Sewage may be successfully purified under a great many conditions, but no type of plant has as yet proven itself successful that does not receive intelligent attention.
The most successful of small sewage disposal plant is the septic tank system alone or in connection with an adequate form of bacterial filter. Cesspools are not to be countenanced by people of intelligence. The cesspool has been so universally condemned by authorities on sanitation, that all intelligent people look upon it as a thing filthy beyond description. Although the septic tank is little more than an improved cesspool, the condition under which it acts is entirely different from that which takes place in the latter and with care and watchfulness, it may be made to work to a degree of perfection that is surprising. The one great cause of the failure of small sewage-disposal plants is the lack of proper care.
The process of sewage purification as now practised in the most successful plants is largely mechanical, but bacterial action plays a part of great importance in the completion of the process. It consists of two stages: the tank treatment, in which the sewage is liquefied; and the process of filtration where the liquefied sewage—commonly called the effluent—from the septic tank undergoes a process of filtration and bacterial purification.