The question of the removal of kitchen refuse, manure, etc., from barracks next calls for notice. The great principle to be observed in removing the solid refuse from barracks is that every decomposable substance should be taken away at once. This principle applies especially in warm climates. Even the daily removal of refuse entails the necessity of places for the deposit of the refuse, and therefore this principle must be applied in various ways to suit local convenience. In open situations, exposed to cool winds, there is less danger of injury to health from decomposing matters than there would be in hot, moist, or close positions. In the country generally there is less risk of injury than in close parts of towns. These considerations show that the same stringency is not necessarily required everywhere. Position by itself affords a certain degree of protection from nuisance. The amount of decomposing matter usually produced is also another point to be considered. A small daily product is not, of course, so injurious as a large product. Even the manner of accumulating decomposing substances influences their effect on health. There is less risk from a dung heap to the leeward than to the windward of a barrack. The receptacles in which refuse is temporarily placed, such as ash pits and manure pits, should never be below the level of the ground. If a deep pit is dug in the ground, into which the refuse is thrown in the intervals between times of removal, rain and surface water will mix with the refuse and hasten its decomposition, and generally the lowest part of the filth will not be removed, but will be left to fester and produce malaria. In all places where the occupation is permanent the following conditions should be attended to:
1. That the places of deposit be sufficiently removed from inhabited buildings to prevent any smell being perceived by the occupants. 2. That the places of deposit be above the level of the ground—never dug out of the ground. The floor of the ash pit or dung pit should be at least six inches above the surface level. 3. That the floor be paved with square sets, or flagged and drained. 4. That ash pits be covered. 5. That a space should be paved in front, so as to provide that the traffic which takes place in depositing the refuse or in removing it shall not produce a polluted surface.
In towns those parts of the refuse which cannot be utilized for manure or otherwise are burned. But this is an operation which, if done unskillfully, without a properly constructed kiln, may give rise to nuisance. One of the best forms of kiln is one now in operation at Ealing, which could be easily visited from London.
The removal of excreta from houses.—The chief object of a perfect system of house drainage is the immediate and complete removal from the house of all foul and effete matter directly it is produced. The first object—viz., removal of foul matter, can be attained either by the water closet system, when carried out in this integrity; but it could, of course, be attained without drains if there was labor enough always available; and the earth closet or the pail system are modifications of immediate removal which are safe. Cesspools in a house do not fulfill this condition of immediate removal. They serve for the retention of excremental and other matters. In a porous soil it endangers the purity of the wells. The Indian cities afford numerous examples of subsoil pollution. The Delhi ulcer was traced to the pollution of the wells from the contaminated subsoil; and the soil in many cities and villages is loaded with niter and salt, the chemical results of animal and vegetable refuse left to decay for many generations, from the presence of which the well water is impure. There are many factories of saltpeter in India whose supplies are derived from this source; and during the great French wars, when England blockaded all the seaports of Europe, the First Napoleon obtained saltpeter for gunpowder from the cesspits in Paris. Cesspools are inadmissible where complete removal can be effected. Cesspits may, however, be a necessity in some special cases, as, for instance, in detached houses or a small detached barrack. Where they cannot be avoided, the following conditions as to their use should be enforced:
1st. A cesspit should never be located under a dwelling. It should be placed outside, and as far removed from the immediate neighborhood of the dwelling as circumstances will allow. There should be a ventilated trap placed on the pipe leading from the watercloset to the cesspit. 2d. It should be formed of impervious material so as to permit of no leakage. 3d. It should be ventilated. 4th. No overflow should be permitted from it. 5th. When full it should be thoroughly emptied and cleaned out; for the matter left at the bottom of a cesspit is liable to be in a highly putrescible condition.
Where a cesspit is unavoidable, perhaps the best and least offensive system for emptying it is the pneumatic system. This is applicable to the water closet refuse alone. The pneumatic system acts as follows: A large air-tight cylinder on wheels, or, what answers equally, a series of air-tight barrels connected together by tubes about 3 in. diameter, placed on a cart, brought as near to the cesspit as is convenient; a tube of about the same diameter is led from them to the cesspit; the air is then exhausted in the barrels or cylinder either by means of an air pump or by means of steam injected into it, which, on condensation, forms a vacuum; and the contents of the cesspit are drawn through the tube by the atmospheric pressure into the cylinder or barrels. A plan which is practically an extension of this system has been introduced by Captain Liernur in Holland. He removes the fæcal matter from water closets and the sedimentary production of kitchen sinks by pneumatic agency. He places large air-tight tanks in a suitable part of the town, to which he leads pipes from all houses. He creates a vacuum in the tanks, and thus sucks into one center the fæcal matter from all the houses. Various substitutes have been tried for the cesspit, which retain the principle of the hand removal of excreta. The first was the combination of the privy with an ashpit above the surface of the ground, the ashes and excreta being mixed together, and both being removed periodically. The next improvement was the provision of a movable receptacle. Of this type the simplest arrangement is a box placed under the seat, which is taken out, the contents emptied into the scavenger's cart, and the box replaced. The difficulty of cleansing the angles of the boxes led to the adoption of oval or round pails. The pail is placed under the seat, and removed at stated intervals, or when full, and replaced by a clean pail. In Marseilles and Nice a somewhat similar system is in use. They employ cylindrical metal vessels furnished with a lid which closes hermetically, each capable of holding 11 gallons. The household is furnished with three or four of these vessels, and when one is full the lid is closed hermetically, the vessel thus remaining in a harmless condition in the house till taken away by the authorities and replaced by a clean one. The contents are converted into manure. In consequence of the offensiveness of the open pail, the next improvement was to throw in some form of deodorizing material daily. In the north of England the arrangement generally is that the ashes shall be passed through a shoot, on which they are sifted—the finer fall into the pail to deodorize it, the coarser pass into a box, whence they can be taken to be again burned—while a separate shoot is provided for kitchen refuse, which falls into another pail adjacent.
Probably the best known contrivance for deodorizing the excreta is the dry earth system as applied in the earth closet, in which advantage is taken of the deodorizing properties of earth. Dry earth is a good deodorizer; 1½ lb. of dry earth of good garden ground or clay will deodorize such excretion. A larger quantity is required of sand or gravel. If the earth after use is dried, it can be applied again, and it is stated that the deodorizing powers of earth are not destroyed until it has been used ten or twelve times. This system requires close attention, or the dry earth closet will get out of order; as compared with water closets, it is cheaper in first construction, and is not liable to injury by frost; and it has this advantage over any form of cesspit—that it necessitates the daily removal of refuse. The cost of the dry earth system per 1,000 persons may be assumed as follows: Cost of closet, say, £500; expense of ovens, carts, horses, etc., £250; total capital, £750, at 6 per cent. £37 10s. interest. Wages of two men and a boy per week, £1 12s.; keep of horses, stables, etc., 18s.; fuel for drying earth, 1s. 6d. per ton dried daily, £1 10s.; cost of earth and repairs, etc., 14s.; weekly expenses, £4 14s. Yearly expenses, £247 (equal to 4s. 11d. per ton per annum); interest, £37 10s.—total, £284 10s., against which should be put the value of the manure. But the value of the manure is simply a question of carriage. If the manure is highly concentrated, like guano, it can stand a high carriage. If the manuring elements are diffused through a large bulk of passive substances, the cost of the carriage of the extra, or non-manuring, elements absorbs all profit. If a town, therefore, by adding deodorants to the contents of pails produces a large quantity of manure, containing much besides the actual manuring elements—such as is generally the case with dry earth—as soon as the districts immediately around have been fully supplied, a point is soon reached at which it is impossible to continue to find purchasers. The dry earth system is applicable to separate houses, or to institutions where much attention can be given to it, but it is inapplicable to large towns from the practical difficulties connected with procuring, carting, and storing the dry earth.
With the idea that if the solid part of the excreta could be separated from the liquid and kept comparatively dry the offensiveness would be much diminished, and deodorization be unnecessary, a method for getting rid of the liquid portion by what is termed the Goux system has been in use at Halifax. This system consists in lining the pail with a composition formed from the ashes and all the dry refuse which can be conveniently collected, together with some clay to give it adhesion. The lining is adjusted and kept in position by a means of a core or mould, which is allowed to remain in the pails until just before they are about to be placed under the seat; the core is then withdrawn, and the pail is left ready for use. The liquid which passes into the pail soaks into this lining, which thus forms the deodorizing medium. The proportion of absorbents in a lining 3 in. thick to the central space in a tub of the above dimensions would be about two to one; but unless the absorbents are dry, this proportion would be insufficient to produce a dry mass in the tubs when used for a week, and experience has shown that after being in use for several days the absorbing power of the lining is already exceeded, and the whole contents have remained liquid. There would appear to be little gain by the use of the Goux lining as regards freedom from nuisance, and though it removes the risk of splashing and does away with much of the unsightliness of the contents, the absorbent, inasmuch as it adds extra weight which has to be carried to and from the houses, is rather a disadvantage than otherwise from the manurial point of view.
The simple pail system, which is in use in various ways in the northern towns of England, and in the permanent camps to some extent at least, and of which the French "tinette" is an improved form, is more economically convenient than the dry earth system or the Goux or other deodorizing system, where a large amount of removal of refuse has to be accomplished, because by the pail system the liquid and solid ejections may be collected with a very small, or even without any, admixture of foreign substances; and, according to theory, the manurial value of dejections per head per annum ought to be from 8s. to 10s. The great superiority, in a sanitary point of view, of all the pail or pan systems over the best forms over the old cesspits or even the middens is due to the fact that the interval of collection is reduced to a minimum, the changing or emptying of the receptacles being sometimes effected daily, and the period never exceeding a week. The excrementitious matter is removed without soaking in the ground or putrefying in the midst of a population.
These plans for the removal of excreta do not deal with the equally important refuse liquid—viz., the waste water from washing and stables, etc. As it is necessary to have drains for the purpose of removing the waste water, it is more economical to allow this waste water to carry away the excreta. In any case, you must have drains for removing the fouled water. Down these drains it is evident that much of the liquid excreta will be poured, and thus you must take precautions to prevent the gases of decomposition which the drains are liable to contain from passing into your houses.