standpoint and have the advantage over other methods in that the
different classes of waste can be destroyed by one process and gathered
in one collection. Several also agree that the destructors when properly
constructed and operated, may be centrally located, thus reducing the
cost of haul. Another point mentioned is that there is some revenue. The
disadvantages pointed out by experts are that, if not properly designed
and operated, there will be dust and odors, all refuse must be hauled to
the plant and expert workmen must be employed.
The cost of operation varies from city to city, and in each city from
month to month, depending upon the season of the year, composition of
the garbage and climate. Most incinerator companies guarantee to operate
their furnaces at full capacity at about 50 cents per ton. Milwaukee
operates for about 57 cents per ton. The cost, including maintenance,
depreciation and fixed charges, and operating expenses, averages $1.50
to $2.50 and sometimes $3.00 per ton. The State Board of Health of Ohio
found in its investigation that incineration cost from $1.97 to $2.50 in
Canton, Ohio; $2.00 to $2.66 in Marion; $1.00 to $1.84 in Steubenville;
and $2.58 in Zanesville, during a period of several years. These figures
include interest, depreciation, maintenance and repair charges.
J. W. Turrentine, of the United States Department of Agriculture, who
made a study of garbage disposal plants, says in a Department bulletin
that the average net cost of incineration per ton as obtained in a
number of instances is $2.11 per ton, and that in one of the cities
considered there is a credit for power generated of 22 cents per ton of
garbage incinerated.
Most garbage incinerator manufacturers claim a life of 20 years for
their plants with reasonable renewals.
Morse figures that when fuel is necessary the cost of destroying refuse
and garbage in crematories is approximately 50 cents per ton. He also
says that the cost of operating destructors is from 50 cents to 70 cents
per ton for actual labor expenses, while the cost of operating the
modern high-temperature destructor will not exceed from 50 cents to 60
cents per ton. Deducting credit for power, the cost will drop, he says,
to 30 cents or less per ton. Depreciation and capital expenses are not
included in Morse’s calculations.
Greeley asserts that the cost of operation will range from about $1.00
to $1.50 per ton, “but local conditions may alter these limits.”
C. O. Bartlett, sanitary engineer, says: “So far as disposal of garbage
is concerned, in incinerators, it is coming to be generally understood
that this method is far from sanitary and is essentially wrong in that
it neglects to obtain the value for the products so collected.”
Rudolph Herring, Sanitary Expert, says: “In incineration, if sufficient
fuel is added, the combustion can be made perfect and the garbage can be
destroyed without offense and converted into inodorous gases, ashes and
clinker. Whatever sanitary objection has been made to this process has
resulted from preventable causes. Unless ashes and rubbish are combined
with garbage in sufficient quantities to produce the necessary heat, the
steam production is deficient and other fuel must be added.”
Robert H. Wylde favors incineration at a high temperature: “Here we have
a method that is at once sanitary, expeditious and economical in first
cost and maintenance.” He also says that this method is free from
nuisance, the plant may be centrally located, cost of collection
minimized owing to the relative shortness of hauls, not necessary to
maintain a separate collection, nor is there any necessity to keep
refuse in separate cans.
W. F. Goodrich, Sanitary Expert, maintains that modern destructors are
perfectly satisfactory and that there may be no fear of nuisance
wherever they are located. He maintains that it should be the aim of
officials to utilize the power produced for the best interests of the
community.
William M. Venable believes that cities of from 10,000 to 40,000
population should burn garbage and refuse, the problem to be solved
being the advisability of attempting to utilize the heat generated by
burning.
Reduction
When the reduction method is used only garbage and dead animals can be
destroyed, but when these kinds of wastes are broken down by means of
heat, valuable by-products are recovered. This may be done in two ways,
the processes being known as cooking, or digestor system, and drying. In
the first, garbage is cooked in large closed retorts by means of steam
under pressure. It is then pressed, leaving grease and a dry cake known
as tankage, which is used for fertilizer. In the drying method the
grease is extracted by some volatile solvent like naphtha. The relative
advantages of these two methods is disputed. At the present time the
majority of plants are operated by the cooking or digestor method.
Within the last year or two a new reduction process has been evolved.
The raw garbage is placed in sealed, air-tight tanks with jacketed walls
and bottom. The solvent is pumped into the reducer and steam admitted to
the jacketed walls. The heat causes the evaporation of the solvent and
the water in the garbage. When the garbage has been dried, the solvent
is pumped into the reducer and dissolves the grease. In an evaporator
the solvent is vaporized and carried to a condenser where it is again
liquefied and then conveyed to storage tanks. After the extraction of
the grease, the garbage is further dried by steam, and as tankage, is
used for fertilizer. The chief advantage claimed for this system is that
it is odorless. The cost of plant operation is much greater than that of
the digestor system, but the value of the recovered products is
considerably greater. Plants of this type are being operated in Los
Angeles, Cal., and in New Bedford, Mass. The plant now being constructed
for handling the garbage of New York City will also employ this new
process.
C. O. Bartlett, Sanitary Expert, says that the cooking method does not
permit of the recovery of any considerable portion of grease, but does
provide for the retention of most of the solids in dry form, after which
they may be ground up to serve as a base for fertilizers. He also says
that it is open to some objection on account of escaping gases from the
stack unless there are sufficient scrubbers.
Irwin S. Osborn, sanitary engineer, sums up as follows the advantages
and disadvantages of each process:
Drying Process
_Advantages._—Cost of plant is less, due to equipment and space
required; the operating costs are less, due to amount of labor and power
required.
_Disadvantage._—Carbonizing of the grease in the dryer, due to high
temperature required, so that the maximum amount of grease is not
recovered; the material is not broken down so that solvent will act as
readily on grease particles to allow maximum recovery; the mechanical
condition of by-products is not as desirable without additional
treatment; there is a greater volume of gases to be deodorized.
Cooking Process
_Advantages._—The cells of the material are more completely broken down
so that a larger amount of grease can be more readily recovered; all
material is enclosed during the process so that the gases are more
readily deodorized with less volume to be deodorized; in the modern
plants the mechanical condition of the by-products is better.
_Disadvantages._—Increased fixed cost of building and equipment;
increased operating cost; increased maintenance cost.
Osborn believes that by-products produced by either method have the same
relative market value. In plants that have been operated by both
methods, the experience has been that the additional amount of grease
recovered by the cooking method has more than offset the increased costs
and at the same time the odors were eliminated to a larger extent.
In establishing a reduction plant, Rudolph Herring says that the great
fear is creating a nuisance. He further asserts that, owing to
unpleasant odors apt to arise at the works, it is necessary to have good
ventilation and also a subsequent treatment of some of the vapors and
liquids which result from the process. These contingencies make it
advisable, he thinks, to locate the plant in a neighborhood where the
possibility of occasional unpleasant odors will not materially injure
value of adjoining property.
The Chicago Waste Commission gives this suggestion as a solution of the
odor problem: “In addition to the steam and electrical power that can be
furnished from a destructor plant to operate a reduction plant, the
exhausting of all gases carrying odors from the reduction works and
passing them through the destructor would prove one of the greatest
advantages from a sanitary and economical standpoint to be derived from
a combined method of disposal of all municipal wastes.”
Osborn says: “Economical results may be obtained by utilization of heat
in the disposal of garbage mixed with other refuse, by burning, but to
prove satisfactory the maximum sanitary results must be obtained at a
minimum cost, and when the quantity is such that it will warrant
utilization the reduction method will continue to show more economical
results, and with proper attention given to details and sanitary
features the work can be conducted without nuisance.”
Reduction is a method which can be adopted only by large cities. It
seems to be usually agreed that cities with less than 100,000 population
and producing less than 75 tons of garbage daily will find the reduction
process will not pay as a business venture. One writer says in no place
of less than 150,000 population can these kind of plants be operated
successfully. Venable places the minimum population at 100,000. He says
that as approximately 80 per cent. to 90 per cent. of kitchen garbage is
water and only 10 per cent. to 20 per cent. is composed of grease and
other substances it takes a large amount of garbage to make reduction
plants profitable.
The cost of a reduction plant will range from $1,500 to $3,000 per ton
daily capacity, according to published reports.
The gross cost of garbage destruction by the reduction method varies
from $1.50 to $2.50 per ton of raw garbage. In only a few instances does
the sale of the by-products meet or exceed expenses. In a majority of
cases, the process is carried on by private companies, the most being
subsidized by cities to amounts varying from 50 cents to $2.50 per ton.
A few companies pay the city for all garbage delivered to the plant.
The by-products of the reduction method are grease and tankage. It is
generally agreed that ordinary garbage contains from 2 per cent. to 3
per cent. by weight of grease and must yield from 200 to 400 pounds of
tankage per ton.
Columbus, Ohio, has been conducting experiments in making alcohol from
green garbage and its reports indicate that cities having reduction
plants may produce another by-product from their waste. The experiments
were carried on for some time under the direction of the assistant
superintendent in cooperation with Dr. James J. Morgan, a Chicago
chemist who has patented a process of distilling the alcohol from
chemically-treated garbage. It requires only a slight addition to the
present processes of the plant. The garbage is treated with a two per
cent. solution of sulphuric acid for cooking, then with lime and finally
with yeast for fermentation. The claim is made that the amount of grease
and tankage is not reduced by the process, and it is estimated that
every ton of garbage will yield about six gallons of alcohol. The
superintendent of the Division of Garbage and Refuse Disposal in
November, 1917, informed the New York State Bureau of Municipal
Information that the final report on the experiment “was favorable to
the process, but our city council did not see fit to authorize the
installation of the necessary equipment for the process.”
J. W. Turrentine says that on a basis of figures obtained in the
operation of a number of reduction plants, it is shown that the average
cost of reduction is $2.41 per ton, and the gross receipts $3.30 per
ton, giving a profit of 89 cents per ton raw garbage. He asserts that
when consideration of cost of collection is excluded, the rendering of
garbage is distinctly more profitable than incineration.
Cleveland and Columbus have been the cities most successful in operating
municipal reduction plants. In one year the Columbus plant received
21,628.97 tons of garbage, or 211 pounds of garbage per capita. From
this and the 183 large dead animals received, the actual production was
as follows: Grease, 1,186,985 pounds; tankage, 1,753 tons; hides, 183.
The value of these by-products were: Grease, $57,672.21; tankage,
$12,987.84; hides, $1,062.30, or a total of $66,772.35.
Each ton of garbage produced 54.87 pounds of grease and 162.1 pounds of
tankage. The grease value per ton of garbage was $2,435; the tankage, 60
cents, and the hides 5 cents, or a total of $3,085 per ton of garbage.
The actual cost of operation was $40,220.78 or $1,859 per ton. The net
profits were $26,502.57 or $1.226 per ton of garbage.
Cleveland in one year produced 2,940,000 pounds of grease and 10,016,000
pounds of tankage, the city receiving for them $151,162.48. This
reduction cost per ton of green garbage was $1.97½ and the earnings per
ton of green garbage was $3.47, making the net earnings per ton of
garbage $1.49½.
New York City is selling its garbage to a private company. It made a
contract for 1914 to 1916, inclusive, and the right to renew the
contract for two more years on the same terms and conditions. The city
receives at the rate of $62,500 for the first, $87,500 for the second,
and $112,500 for the third and each of the succeeding two years. Plans
are now being made to operate a municipal plant.
Table VII
METHODS AND COST OF DISPOSING OF GARBAGE
─────────────┬───────────────┬────────────┬─────────────┬───────┬──────
Name │ Method of │By Whom Done│ City Own │ City │ Is
│ Disposal │ │Dump? If Not,│ Own │ farm
│ │ │Annual Rental│ Farm │Rented
│ │ │ │ and │ by
│ │ │ │ Hogs? │City?
│ │ │ │ │
│ │ │ │ │
─────────────┼───────────────┼────────────┼─────────────┼───────┼──────
New York │Reduction. │Contract. │ │ │
City[54] │ │ Building │ │ │
│ │ municipal │ │ │
│ │ plant. │ │ │
Buffalo │Dumping and │Contract. │Some of them.│ │
│ Incineration.│ │ │ │
Rochester │Reduction. │Contract. │ │ │
│ │ City has │ │ │
│ │ decided to│ │ │
│ │ own its │ │ │
│ │ plant. │ │ │
Albany │Fed to pigs. │Contract. │ │No. │No.
Binghamton │Feeding and │Private │ │No. │No.
│ burning. │ sanitary │ │ │
│ │ companies.│ │ │
Schenectady │Reduction. │City. │ │ │
│ │ │ │ │
│ │ │ │ │
Syracuse │Reduction. │Contract, │ │ │
│ │ planning │ │ │
│ │ municipal │ │ │
│ │ operation.│ │ │
Troy │Dumping. │Contract. │$12,000 │ │
Yonkers │Incineration. │City. │ │ │
│ │ │ │ │
│ │ │ │ │
Utica │Reduction. │Contract. │ │ │
│ │ │ │ │
│ │ │ │ │
│ │ │ │ │
│ │ │ │ │
New Rochelle │Incineration. │ │ │ │
│ │ │ │ │
Watertown │Feeding to │ │ │No. │No.
│ pigs. │ │ │ │
Auburn │Dumping and │ │ │ │
│ ploughing │ │ │ │
│ under. │ │ │ │
Beacon │Dumping for │ │No. No │ │
│ fill. │ │ rental. │ │
Mechanicville│Dumping for │Contract. │No. No │ │
│ fill. │ │ rental. │ │
Dunkirk │Feeding and │ │No. │No. │No.
│ ploughing │ │ │ │
│ under. │ │ │ │
Saratoga │Dumping. │ │$50 per yr. │ │
Middletown │Dumping for │ │No. │ │
│ fill. │ │ │ │
Kingston │Dumping. │ │No. │ │
Jamestown │Ploughing │Contract. │No. │ │
│ under. │ │ │ │
Fulton │Dumping for │ │Yes. │ │
│ fill. │ │ │ │
Port Jervis │Dumping. │Contract. │No. │ │
Elmira │Incineration │Dumping only│No. $300. │ │
│ and dumping. │ by city. │ │ │
│ │ │ │ │
Salamanca │Dumping. │City. │ │ │
Rome │Dumping. │ │ │ │
Niagara Falls│Dumping in │ │ │ │
│ river. │ │ │ │
Cortland │Dumping. │Contract. │No. │ │
Cohoes │Dumping. │ │Owned by │ │
│ │ │ contractor.│ │
Plattsburgh │Dumping on land│ │One dump. │ │
│ and in water.│ │ │ │
Ithaca │Dumping for │City. │Some. No │ │
│ fill. │ │ rental. │ │
Olean │Feeding to │ │ │No. │No.
│ hogs. │ │ │ │
Johnstown │Dumping. │ │No. $100 per │ │
│ │ │ year. │ │
Ogdensburg │Dumping. │ │ │ │
Gloversville │Dumping. │Contract. │Yes. │ │
Hudson │Feeding to │Contract. │No. │No. │No.
│ hogs. │ │ │ │
Little Falls │Feeding to │Contract. │ │No. │No.
│ hogs. │ │ │ │
North │Ploughed under.│Contract. │No. No │ │
Tonawanda │ │ │ rental. │ │
Newburgh │Feeding and │Contract. │ │No. │No.
│ ploughing │ │ │ │
│ under. │ │ │ │
Norwich │Dumping. │ │No. $50. │ │
Mount Vernon │Feeding and │Contract. │Contractor │No. │No.
│ dumping for │ │ rents it. │ │
│ fill. │ │ │ │
Lockport │Feeding and │City. │Yes. │No. │No.
│ dumping. │ │ │ │
Hornell │Feeding and │City. │No. $50. │No. │No.
│ ploughing │ │ │ │
│ under. │ │ │ │
Rensselaer │Feeding and │City. │Yes. │No. │No.
│ dumping. │ │ │ │
Batavia │Dumping and │City. │Yes. │No. │No.
│ feeding. │ │ │ │
Tonawanda │Feeding and │Contract. │No. │No. │No.
│ dumping. │ │ │ │
Corning │Feeding to │Contract. │Contractor │No. │No.
│ hogs. │ │ owns farm. │ │
Oswego │Dumping on │ │ │ │
│ land. │ │ │ │
Canandaigua │Feeding to │Private │ │No. │No.
│ hogs. │ company. │ │ │
Borough of │Crematories, │Crematories │No. │ │
Queens │ dumping and │ and dumps │ │ │
│ reduction. │ by city. │ │ │
│ │ Reduction │ │ │
│ │ by │ │ │
│ │ contract. │ │ │
Amsterdam │Incineration. │City. │ │ │
Poughkeepsie │Dumping. │City. │No. │ │
Atlanta, Ga. │Incineration. │Contract. │ │ │
│ │ │ │ │
Columbus, │Reduction. │City. │ │ │
Ohio │ │ │ │ │
│ │ │ │ │
Cincinnati, │Reduction. │Contract. │ │ │
O. │ │ │ │ │
│ │ │ │ │
Milwaukee, │Incineration. │City. │ │ │
Wis. │ │ │ │ │
Detroit, │Reduction. │Contract. │ │ │
Mich. │ │ │ │ │
│ │ │ │ │
Washington, │Reduction. │Contract. │ │ │
D. C. │ │ │ │ │
St. Louis, │Reduction. │Contract. │ │ │
Mo. │ │ │ │ │
Lawrence, │Feeding to │ │ │Two │
Mass. │ pigs. │ │ │ loads│
│ │ │ │ daily│
│ │ │ │ sent │
│ │ │ │ to │
│ │ │ │ Poor │
│ │ │ │ Farm.│
│ │ │ │ Rest │
│ │ │ │ sold.│
New Orleans, │Dumping for │City. │Yes. │ │
La. │ fill. │ │ │ │
Hartford, │Feeding to pigs│City. │Yes. │No. │
Conn. │ and burned. │ │ │ │
Baltimore, │Reduction. │Contract. │ │ │
Md. │ │ │ │ │
Bridgeport, │Reduction. │Contract. │ │ │
Conn │ │ │ │ │
Cleveland, O.│Reduction. │City. │ │ │
│ │ │ │ │
│ │ │ │ │
Lowell, Mass.│Fed to pigs. │ │ │ │
Cambridge, │Fed to pigs. │ │ │ │
Mass. │ │ │ │ │
Louisville, │Dumping. │ │No. │ │
Ky. │ │ │ │ │
Pittsburgh, │Reduction. │Contract. │ │ │
Pa. │ │ │ │ │
Denver, Col. │Fed to hogs. │Contract. │ │No. │
Savannah, Ga.│Incineration. │City. │ │ │
│ │ │ │ │
Chicago, Ill.│Reduction and │City. │ │ │
│ incineration.│ │ │ │
Kansas City, │Fed to pigs. │Contract. │ │No. │
Mo. │ │ │ │ │
Boston, Mass.│Reduction. │Contract. │ │ │
Lynn, Mass. │Fed to pigs. │ │ │ │
Grand Rapids,│Fed to pigs. │ │ │No. │
Mich. │ │ │ │ │
Minneapolis, │Incineration. │City. │ │ │
Minn. │ │ │ │ │
│ │ │ │ │
│ │ │ │ │
│ │ │ │ │
│ │ │ │ │
St. Paul, │Fed to hogs. │ │ │No. │
Minn. │ │ │ │ │
Jersey City, │Dumping for │Contract. │ │ │
N. J. │ fill. │ │ │ │
Passaic, N. │Burial. │ │ │ │
J. │ │ │ │ │
Paterson, N. │Incineration. │City. │ │ │
J. │ │ │ │ │
Trenton, N. │Incineration. │City. │ │ │
J. │ │ │ │ │
Dayton, O. │Reduction. │City. │ │ │
│ │ │ │ │
Providence, │Fed to pigs. │ │No. │ │
R. I. │ │ │ │ │
Charleston, │Dumping. │ │ │ │
S. C. │ │ │ │ │
Nashville, │Feeding to │ │ │ │
Tenn. │ hogs. │ │ │ │
Seattle, │Dumping for │City. │ │ │
Wash. │ fill. │ │ │ │
Spokane, │Incineration. │City. │ │ │
Wash. │ │ │ │ │
Oakland, Cal.│Dumping in │Contract. │ │ │
│ ocean and │ │ │ │
│ incineration.│ │ │ │
New Bedford, │Reduction. │Contract. │ │ │
Mass. │ │ │ │ │
Springfield, │Reduction. │Contract. │ │ │
Mass. │ │ │ │ │
Portland, │Incineration. │City. │ │ │
Ore. │ │ │ │ │
Philadelphia,│Reduction and │Contract. │ │ │
Pa. │ feeding to │ │ │ │
│ pigs. │ │ │ │
Scranton, Pa.│Incineration. │City. │ │ │
│ │ │ │ │
│ │ │ │ │
Reading, Pa. │Incineration. │City. │ │ │
Richmond, Va.│Incineration. │City. │ │ │
│ │ │ │ │
│ │ │ │ │
Los Angeles, │Reduction and │Contract. │ │ │
Cal. │ feeding to │ │ │ │
│ pigs. │ │ │ │
│ │ │ │ │
San │Reduction. │Contract. │ │ │
Francisco, │ │ │ │ │
Cal. │ │ │ │ │
Newark, N. J.│Reduction. │Contract. │ │ │
Indianapolis,│Reduction. │Contract. │ │ │
Ind. │ │ │ │ │
Toledo, O. │ │ │ │ │
Worcester, │Feeding to │City. │ │Yes. │No.
Mass. │ pigs. │ │ │ │
New Haven, │Feeding to pigs│ │ │Yes. │
Conn. │ and │ │ │ │
│ composting. │ │ │ │
Birmingham, │Dumping on │City. │ │ │
Ala. │ land. │ │ │ │
Memphis, │Incineration │City. │Yes. │ │
Tenn. │ and dumps. │ │ │ │
Omaha, Neb. │Feeding to │ │ │No. │
│ pigs. │ │ │ │
Fall River, │Feeding to │Contract. │ │No. │
Mass. │ pigs. │ │ │ │
─────────────┴───────────────┴────────────┴─────────────┴───────┴──────