Great Britain took the lead in the installation of garbage furnaces, both in point of time and in superior results attained. From 1870 to 1876 several crude furnaces were tried. In the latter year the city of Manchester put in operation the prototype of the more recent and more success ful furnaces, thus antedating by many years the first furnace built for a city in the United States, which was erected at Des Moines, Iowa, in 1887. The common use of soft coal in open fireplaces in England leaves a larger percentage of combustible matter in the ashes from dwellings in that country than in the domestic ashes of American cities, while the people of the United States produce far larger quantities of watery green vegetable wastes, particularly in summer, than is the case abroad. Both of these facts favored the more rapid development of garbage furnaces, or refuse destructors, in England than in America, besides which the need for improved means of disposal was felt sooner in the former country. The tendency in America has been and still is to exclude ashes, and, to a less extent, old or broken crockery and the like, from gar bage. This was partly due to the American prac tice of feeding garbage or swill to hogs, and, in the earlier days, even to cows. Farmers from the surrounding country would gather the swill for their stock, but would refuse that containing for eign matter. These food wastes were, and are yet, sometimes gathered by the municipality, or by a general contractor, and delivered to farmers at the outskirts of the city. Originally householders may have received a small sum for their swill, but latterly they have been fortunate if they can get it taken away without expense. At present, collections by or for American farmers are gen erally restricted to small towns, or to the hotels and restaurants of the larger places. The feed ing of city garbage to either cows or hogs, par ticularly to mulch cows, should be prohibited by State and city legislation. Household wastes in the country, when so fed, are generally fresh and harmless, but in the city they are liable to be in such a state of decomposition as to affect in juriously the milk of cows and the flesh of ani mals used for food. It may be added that wher ever there is any attempt to recover paper, rags, glass. and the like from city wastes those sub stances should not be mixed with either garbage or ashes, since the sorting made necessary where mixing is allowed is a disgusting if not danger ous task for those engaged in it. The sorting is all the more objectionable because most of the work is done by women and children.
Before describing garbage furnaces and re duction plants a few words regarding the collec tion of city wastes may be said. Garbage proper should he collected in carts or boxes provided with water-tight, non-absorbent boxes or tanks, with closely fitting covers. Steel is now consid ered to be the best material for such tanks. Ashes and other dry wastes should he gathered in tight carts, well covered to prevent scattering by jolt ing or wind. The best material for the ash-wagon boxes, or tanks, is also steel, but this matters comparatively little from a sanitary standpoint, so long as the conditions named are fulfilled. The frequency of collection should vary with the character of the wastes and the population. Market wastes, the garbage of hotels and restau rants, and of houses in crowded districts, often require daily collection, particularly in the sum mer. Domestic garbage, under ordinary condi tions, requires collection from two to three times a week in warm, and once or twice a week in cool or cold weather. Ashes, paper, and all other inor ganic wastes, so long as not mixed with garbage, may be collected to suit the convenience of the householders and the municipality, the tendency being to increase the frequency with the density of population and consequent lack of room for storage. Cleansing or disinfection of garbage cans and wagon boxes or tanks is practiced in the most progressive communities. Whether garbage and refuse collection and disposal should be performed by contract or directly by the municipality is a question for each community to settle for itself. Many sanitarians favor direct
municipal performance, as giving better sani tary results. An efficient city government can secure good work under either plan, but perhaps complaints of poor service may receive more prompt attention when the work is done by the municipality. In many American cities the col lection, and in still more the final disposal, of garbage and refuse is left entirely to private scavengers, under little or no municipal control. The results are that the people having most need of good service get none whatever, being unwill ing or unable to pay for it, while the work as a whole is generally poorly done. The final dis posal, under this plan, is almost always a make shift. Whatever may be done as to ashes and inorganic wastes, good sanitation demands that the collection and disposal of garbage, offal, and dead animals should be attended to by the municipality, either under the contract or day labor system. As a matter of economy it is prob able that all the wastes considered in this article should be handled by or under the direction of the city or town.
Garbage Furnaces, or Refuse Destructors, as they are called in Great Britain, consist of one or more grates upon which the garbage is burned, ash-pits, flues, and chimneys, together with the necessary feeding holes for the garbage, and stoking holes or doors. In America supple mentary fuel is almost invariably used, generally on a separate grate. In England, as already explained, special fuel is rarely employed; a boiler for steam-raising is generally used, and it is becoming more and more common to use either steam jets or blowing fans to produce a forced draught. Most of the American furnaces have level grates, the heat from the extra fuel passing horizontally over one and sometimes two garbage grates. The English furnaces generally have one level grate, with an inclined surface leading to it from the feeding hole above, so designed that the refuse is dried and heated be fore it reaches the main fire. The English furnaces are usually composed of small units, or cells, of uniform size, each having a grate surface of 25 square feet. Any desired capacity is secured by increasing the number of cells, which are commonly placed back to back, with a central flue. In America the cells are larger. and the various manufacturers have not adopted a standard size. A few years ago it was the accepted practice in Great Britain to have a small special fire, generally of coke, in the base of the stack. This was designed to produce a high temperature for the complete combustion of all the gases from the main fires, before they passed up the chimney and into the atmosphere. These fume cremators are being discontinued in Eng land, with the introduction of forced draught and higher temperatures. They were never so gen erally used in America, but are still employed here and there in forms more or less modified from the English practice. Some form of dust arrester is often used in the later English furnaces to hold back the fine ashes which might otherwise pass up through the chimney and cause a nuisance in the surrounding territory. These are chambers or passages designed to bring the dust to rest and to retain it for future removal. Probably such devices are more essential in Eng land than in America, owing to the large quan tities of ashes put through the furnaces and the use of forced draught in the former country. The temperature of a garbage furnace should be in the vicinity of 2000° F., in order to insure complete combustion and to prevent odors froin the chimney gases. Boilers for utilizing heat from garbage furnaces should not be placed di rectly over the fire, since the water in the boiler will lower the temperature in the furnaces. To avoid this, the boilers are placed between the furnaces and the chimney, or between two fur naces. This causes a loss of heat for steaming, but sanitary considerations should come first. In the later English plants water-tube boilers are being installed.