The sixteen cities in the United States where contractors were treating garbage by reduction early in 1901, with their respective populations by the census of 1900, and the method of grease extraction employed, arc as follows: It will be noted that all these cities have popu lations of over 50,000. The list includes 10 of the 19 cities in the United States having popu lations of 200,000 or more. Of the other nine cities in that class, San Francisco, Milwaukee, Louisville, and Minneapolis have furnaces; Chi cago has one small one, insignificant in com parison with its total garbage output. Balti more, New Orleans, Newark, and Jersey City treatment at Detroit and for cremation at Mil waukee.
Prominent because of the size of the cities employing it, and the completeness of the plants in many of their details, is the Arnold system, in use at New York, Philadelphia, and Boston. The New York plant has a contract capacity of 1000 short tons a day, and is said to have been crowded to a rate of 1500 tons. The only gar bage-disposal plant approaching it in size is the crematory at Berlin, Germany, with a reported capacity of 1300 long, or about 1450 short, tons. The New York works are located on Barren Island, about 25 miles, by water, from the Bat tery, or the extreme lower end of old New York. There are really two plants here, one built for New York and one for Brooklyn, before consolida tion, but the contractors operate them together. The contractors receive the garbage on scows at the various docks, tow it to the works, and treat it, for $89,990 a year, under the New York con tract, and for an average of $121,000 a year, under the Brooklyn contract; but the latter in cludes collection from houses and other buildings, as well as towage and final disposal. For the year 1899 there were treated under the New York contract 151,600 short tons, giving a rate of about 60 cents per ton for transportation and treatment. Under the Brooklyn contract, a total of 104,000 tons was collected, shipped, and treated, at an average cost to the city of $1.20 per ton. It must be understood that these quan tities do not include ashes, street sweepings, and light refuse, most of which are dumped at sea, nor quite all the garbage of Greater New York, a small part of which is burned in furnaces located in outlying districts. At Barren Island the garbage is shoveled from the scows onto con veyors, which deposit it in the digesters, from which it goes to the driers. Early in 1900 there were 96 steam digesters in use, and the addition of 16 more was proposed, which would raise the ordinary working capacity from 1000 to 1200 short tons a day. There were also 17 boilers, of about
have no improved means of garbage disposal, but something is proposed nt Baltimore, and there was once a reduction plant at New Orleans.
'The first reduction plant in the United States was put in use at Buffalo, N. Y., in or about the year 1888, under United States patents granted in 1886 to Joseph Merz, of Bruen, Mo ravia. 'the Merz system has been modified since by Charles W. Preston and F. G. Wiselogel. Merz patents were taken out abroad as early as 1882. The patents covered the extraction of grease by use of the lighter hydrocarbons. Naphtha is used in the Merz process. At one time the system was in use at Buffalo, Detroit, Milwaukee, and Saint Louis. but it has been abandoned for steam 250 horse-power each, and various engines, pumps, and accessories. An immense fan, some 20 feet in diameter, and with a face of 6 feet, was used to exhaust steam and gases from the digester and press-house, and send it to a large scrubber. The gases from the various inclosed tanks and other vessels are passed through jet condensers.
A small but compact and apparently well designed plant, built under what is known as the Holthaus system, is in use at Syracuse. N. Y. There are four digesters. in which the gar bage is treated with steam under a pressure of about 60 pounds per square inch; a cylindrical press, working under a pressure of 2000 pounds per square inch; a steam drier, a conveyor, ele vator, and screen for the dried tankage; a grease and water separator; and an evaporator for the water, besides means for treating the gases and vapors; boilers with a combined capacity of 180 horse-power, a 100 horse-power engine, an electric lighting plant, and a fertilizer factory. The daily capacity of the plant is stated as 50 tons. One of its noteworthy features is the arrangement of the digesters over the press and the press over the drier, with proper connections, so the garbage is not exposed to the air from the time it goes into the digesters until it comes out as dried tankage.
For additional information, consult: Goodrich, The Economic Disposal of Town's Refuse (New York, 1901) ; Maxwell, The Removal and Disposal of Town Refuse (London, 1898) ; Waring, Street Cleaning and the Disposal of a City's TVastes (New York, 1897). The latter, however, con tains but little on garbage furnaces or reduction plants. Goodrich's book has a chapter devoted to American practice. Many descriptions of in dividual American plants have been given in the Engineering News and Engineering Record (both of New York) during the past ten or twelve years.