Borough of Richmond, New York City: West New Brighton incinerator uses clinker in manufacture of brick by mixing cement with ground clinker.
New Orleans, La.: Plans perfected to light streets and public buildings. Claimed that from 500 tons of garbage daily 30,000,000 K. W. can be generated a year.
Savannah, Georgia: Ninety-five per cent. of coal fuel previously used at pumping station is now saved by destructor. To operate water works pumping station it cost $81.90 per day. To operate the station and destructor it costs $46.50 per day, or a difference of $12,921 per year, this being 10 per cent. of the cost of the plant. This is expected to provide for repairs and amortization charges. Besides, the city has all of its refuse disposed of without cost at a central point and in a sanitary manner with freedom from nuisance. The clinker is used for road building and is estimated to have a value equal to the cost of hauling it from the plant.
All reports agree that destructors are very successful from a sanitary 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 andrubbish 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.
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 hasbeen 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:
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 toallow 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.
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 greatestadvantages 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 garbagecontains 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 VIIMETHODS AND COST OF DISPOSING OF GARBAGENameMethod of DisposalBy Whom DoneCity Own Dump? If Not, Annual RentalCity Own Farm and Hogs?Is farm Rented by City?Kind of PlantCapacityWhen BuiltDesignAny Odor?Annual Cost of OperationBy- ProductsWhat is Done with By-ProductsAnnual Revenue from By-ProductsNet Cost of Disposal[53]Net ProfitPer TonYearNew York City[54]Reduction.Contract. Building municipal plant.Reduction.2,000 tons.1896Arnold.Grease and tankage.$112,500 a yr.BuffaloDumping and Incineration.Contract.Some of them.Incineration.40 tons.1903Heenan-Froude.$1.25RochesterReduction.Contract. City has decided to own its plant.Reduction.1907Genesee Reduction Co.Grease and tankage.AlbanyFed to pigs.Contract.No.No.BinghamtonFeeding and burning.Private sanitary companies.No.No.SchenectadyReduction.City.Reduction.30 tons.1914Chamberlain.Yes.$27,000.00Tankage and grease.Sold.$3,000.0010.23$34,200.00SyracuseReduction.Contract, planning municipal operation.At times.TroyDumping.Contract.$12,000YonkersIncineration.City.Incineration.9 tons.1839N. Y. Garbage Crematory.No.3,380.501.403,880.50UticaReduction.Contract.Reduction.Very little.Grease.Sold for soap, residue used for fuel.4,100.00New RochelleIncineration.1917Morse-Boulger.WatertownFeeding to pigs.No.No.AuburnDumping and ploughing under.BeaconDumping for fill.No. No rental.MechanicvilleDumping for fill.Contract.No. No rental.DunkirkFeeding and ploughing under.No.No.No.SaratogaDumping.$50 per yr.MiddletownDumping for fill.No.KingstonDumping.No.JamestownPloughing under.Contract.No.FultonDumping for fill.Yes.600.00Port JervisDumping.Contract.No.960.00[55]ElmiraIncineration and dumping.Dumping only by city.No. $300.Incineration.Uses about half city garbage.1906No.None.SalamancaDumping.City.RomeDumping.Niagara FallsDumping in river.CortlandDumping.Contract.No.200.00[56]CohoesDumping.Owned by contractor.PlattsburghDumping on land and in water.One dump.IthacaDumping for fill.City.Some. No rental.OleanFeeding to hogs.No.No.JohnstownDumping.No. $100 per year.OgdensburgDumping.GloversvilleDumping.Contract.Yes.HudsonFeeding to hogs.Contract.No.No.No.Little FallsFeeding to hogs.Contract.No.No.North TonawandaPloughed under.Contract.No. No rental.NewburghFeeding and ploughing under.Contract.No.No.NorwichDumping.No. $50.Mount VernonFeeding and dumping for fill.Contract.Contractor rents it.No.No.LockportFeeding and dumping.City.Yes.No.No.HornellFeeding and ploughing under.City.No. $50.No.No.RensselaerFeeding and dumping.City.Yes.No.No.BataviaDumping and feeding.City.Yes.No.No.TonawandaFeeding and dumping.Contract.No.No.No.CorningFeeding to hogs.Contract.Contractor owns farm.No.No.OswegoDumping on land.CanandaiguaFeeding to hogs.Private company.No.No.Borough of QueensCrematories, dumping and reduction.Crematories and dumps by city. Reduction by contract.No.3 crematories.30 tons.[57]1900.161 cu. yd.[58]AmsterdamIncineration.City.PoughkeepsieDumping.City.No.Atlanta, Ga.Incineration.Contract.Incineration.250 tons.1913Destructor Co.None from operation.25¢ per tonCinders.Dumped.None.[59][59][59]Columbus, OhioReduction.City.Reduction.200 tons.1910Slight.$1.86Grease, tankage, hides.Sold.$66,772.35$1.226 per tonCincinnati, O.Reduction.Contract.Reduction.Heenan-Froude.Not 50 feet outside wall$68,892.45Electric power.Operates pumping station.$10,000.00$1.26[60]Milwaukee, Wis.Incineration.City.Incineration.300 tons.1910Detroit, Mich.Reduction.Contract.Reduction.Detroit Reduction Co.City pays nothing.Washington, D. C.Reduction.Contract.Reduction.1900Arnold.40 miles from city.Grease and tankage.Sold.$2.31[61]$1.89 per ton[62]St. Louis, Mo.Reduction.Contract.Reduction.400 tons.1913OccasionallyGrease and tankage.Sold..87[63]Lawrence, Mass.Feeding to pigs.Two loads daily sent to Poor Farm. Rest sold.$1.25 a load.New Orleans, La.Dumping for fill.City.Yes.Hartford, Conn.Feeding to pigs and burned.City.Yes.No.Baltimore, Md.Reduction.Contract.68,000.00[64]Bridgeport, ConnReduction.Contract.Reduction.60 tons.1910Occasionally.50[64]Cleveland, O.Reduction.City.Reduction.300 tons.1905Newburgh Reduction Co.Very little.$132,890.00Grease and tankage.Sold.$195,000.00$1.49½ per tonLowell, Mass.Fed to pigs.$5,919.77Cambridge, Mass.Fed to pigs.$15,000.00[65]Louisville, Ky.Dumping.No.Pittsburgh, Pa.Reduction.Contract.Reduction.Yes.$2.25$290,000.00Denver, Col.Fed to hogs.Contract.No.Free.Savannah, Ga.Incineration.City.Incineration.130 tons.1914Heenan-Froude.No..615[56]Steam and clinker.Used on roads..36Chicago, Ill.Reduction and incineration.City.Reduction.900 tons.1913Arnold.Very little.Dried garbage.Sold.$144,744.00Kansas City, Mo.Fed to pigs.Contract.No.Boston, Mass.Reduction.Contract.Reduction.$925,318.56[66]Lynn, Mass.Fed to pigs.Grand Rapids, Mich.Fed to pigs.No.45¢ per ton.Minneapolis, Minn.Incineration.City.Incineration.1905Decarie.No.Power.Heats buildings, lights buildings and streets.$27,000.00.85$16,000.00St. Paul, Minn.Fed to hogs.No.80¢ per ton.Jersey City, N. J.Dumping for fill.Contract.Passaic, N. J.Burial.Paterson, N. J.Incineration.City.Incineration.60 tons.1912Destruction Co.No.None..877[67]$9,527.42$1.18Trenton, N. J.Incineration.City.Incineration.65 tons.1901Davis.No.Only ashes.None..48[69]$7,108.37[69]Dayton, O.Reduction.City.Reduction.125 tons.1915Slight.Grease and tankage.Sold.Providence, R. I.Fed to pigs.No.Charleston, S. C.Dumping.Nashville, Tenn.Feeding to hogs.Seattle, Wash.Dumping for fill.City.Spokane, Wash.Incineration.City.Incineration.120 tons.1908Decarie.No.Ashes.Sold.$5.00.60Oakland, Cal.Dumping in ocean and incineration.Contract.Incineration.100 tons.1907Decarie..60New Bedford, Mass.Reduction.Contract.Reduction.30 tons.1905No.$25,500.00Springfield, Mass.Reduction.Contract.Reduction.75 tons.1913Some.[68][68][68]Portland, Ore.Incineration.City.Incineration.150 tons.1910F. P. SmithNo.34[56]per ton..34[69]Philadelphia, Pa.Reduction and feeding to pigs.Contract.Reduction.500 tons.Yes.Grease and tankage.Scranton, Pa.Incineration.City.Incineration.80 tons.Lewis & Kitchen Co.No..28Ashes.Sold.Reading, Pa.Incineration.City.Incineration.100 tons.1914No.$1.00[70]Richmond, Va.Incineration.City.Incineration.100 tons.1910Morse, Boulger & Decarie.Los Angeles, Cal.Reduction and feeding to pigs.Contract.Reduction.300 tons.1915No.Grease and tankage.51¢ per ton for reduction, $1 for feeding.San Francisco, Cal.Reduction.Contract.Reduction.750 tons.1897Chas. Thackery patents.Much.None..60[71]Newark, N. J.Reduction.Contract.Indianapolis, Ind.Reduction.Contract.Toledo, O.Worcester, Mass.Feeding to pigs.City.Yes.No.Manure and hogs.Sold.$38,838.67New Haven, Conn.Feeding to pigs and composting.Yes.Birmingham, Ala.Dumping on land.City.Memphis, Tenn.Incineration and dumps.City.Yes.Incineration.50 tons.Yes, at times.30¢ to 40¢Omaha, Neb.Feeding to pigs.No.Fall River, Mass.Feeding to pigs.Contract.No.No expense.