Chapter D: C. Faber, Industrial Engineer of the Iowa State College, goes so far (4)

The cost of collection is vitally affected by so many different factors and by local conditions that any attempt to compare the economy of the system in one city with that in another will generally be unsatisfactory. Also actual cost data are kept by very few cities, and where they are available the methods of determining them often vary so that they are misleading for comparative purposes. The cost depends upon the cost of loading and the cost of hauling, as described in the discussion of ash collection. Such facts about the cost as are available in printed reports and as have been sent to the New York State Bureau of Municipal Information by the cities will be found in the accompanying table.

An investigation by the Ohio State Board of Health in Ohio cities showed that the cost averaged from $2 to $2.75 per ton. The report says that the cost of collection in Cleveland for several years averaged $2.17 to $2.79 per ton; Dayton, $2.11; Zanesville, $2.13. In the smaller cities where hauls are comparatively short, the cost frequently did not exceed $1.50 per ton, and “on the average with proper routing should not exceed $2.00 per ton.”

The cost of the collection and disposal may be met by a draft on the general fund, by assessment upon property benefited, or by assessment upon the people directly served. The particular method selected will be determined by the legal limitations, the difficulty of collection, tax limitations, and so forth.

Per Capita Production

Experts have agreed within fifty pounds as to the per capita garbage output of a community. W. F. Morse, Sanitary Expert, gave one hundred and ninety pounds per capita per year as approximate figures for an estimate. William N. Venable estimated the annual amount per capita to be from 150 to 200 pounds.

Recent reports from six cities which have complete collection systems show considerable variation in the per capita amount collected. These cities report as follows:

┌────────────┬──────────────────────────┐
│ │Lbs. of Garbage per Capita│
├────────────┼──────────────────────────┤
│Columbus │ 203⅓│
│Grand Rapids│ 97 │
│Buffalo │ 80 │
│Worcester │ 127 │
│Rochester │ 260 │
│Cleveland │ 162 │
└────────────┴──────────────────────────┘

The average weight of garbage per cubic yard according to statistics from nine large American cities has been from 1,100 to 1,475 pounds, and the number of pounds per one thousand of population per day from 331 to 875.

The food conservation campaign throughout the nation since our entry into the world-wide war, however, has created havoc with garbage production figures and estimates. Although it was known for many years that the American housewife has been a most notorious profligate in the waste of food, it was not until the war forced upon America the necessity for food conservation that there was any decrease in the contents of the garbage pail. Remarkable changes have been reported by cities, the following reductions by New York State cities being typical:

┌─────────────┬───────────────────────────────────────────────────────┐ │Name of City │ Amount of Garbage Collected During │ ├─────────────┼─────────────┬─────────────┬─────────────┬─────────────┤ │ │ June, 1916 │ July, 1916 │ June, 1917 │ July, 1917 │ ├─────────────┼─────────────┼─────────────┼─────────────┼─────────────┤ │Rochester │ 2563 tons │ 2580 tons │ 1,870 tons │ 2,167 tons │ │New York City│ │ │ │ │ │ (Boro. │ 82,503 cu. │ 89,568 cu. │ 76,550 cu. │ 84,628 cu. │ │ Manhattan) │ yds. │ yds. │ yds. │ yds. │ │ (Boro. │ │ │ │ │ │ Brooklyn) │ │ │ │ │ │Kingston │ 140 tons │ 140 tons │ 120 tons │ 120 tons │ │Cortland │ 37½ tons │ 37½ tons │ 31½ tons │ 31½ tons │ │Schenectady │312 tons, 680│ 350 tons │330 tons, 655│ 398 tons, │ │ │ lbs. │ │ lbs. │ 1,400 lbs. │ │[52]Syracuse │ 1,100 tons │ 1,373 tons │ 1,062 tons │ 1,087 tons │ │Albany │ 954 bbls. │ 1,094 bbls. │ 786 bbls. │ 877 bbls. │ │Buffalo │ 2,319.770 │ 1,250.280 │ 2,247.790 │ 1,748.700 │ │ │ tons │ tons │ tons │ tons │ │Utica │40 tons daily│40 tons daily│35 tons daily│35 tons daily│ └─────────────┴─────────────┴─────────────┴─────────────┴─────────────┘

-----

Footnote 52:

Increase probably due to change from contract to municipal system of
collection.

Omaha, Nebraska, reports that for the year 1917 the bulk of garbage was about the same as the previous year, but that no meats, bread or potatoes were found in it. The collection of garbage has been a little over one-third less since the conservation of food went into effect.

What percentage of this reduction will continue after the war is problematical, but it is agreed by all experts that never again will the American garbage pail be so productive as it has been in the past.

Garbage Disposal

A choice of seven methods is offered for the disposal of garbage. They are feeding to swine, dumping on land, dumping into large volumes of water, disposing by sanitary fill, burial, incineration and reduction. In selecting its disposal system a city should bear in mind the importance and cost of a collection system.

Some cities collect and dispose of their garbage by contract, others collect by contract and dispose of it themselves, or vice versa, and still others have all the work done by the municipality. Experience has proved that a city can operate a disposal plant just as efficiently as they can a collection system.

Feeding to Swine

Most of the smaller cities in this country dispose of a part of or all their garbage by feeding to swine, but so far as the State Bureau of Municipal Information has been able to learn, only four maintain municipal piggeries. These are Worcester, New Haven, Brockton, and Taunton, Massachusetts. The others either collect their garbage by contract and sell it or give it to farmers or those operating piggeries, or maintain a municipal collection and sell to a contractor who maintains a piggery.

Among the cities which dispose of their garbage by feeding to pigs and derive a revenue are the following:

Denver, Colo.—Collected by a Hog Growers’ Association which disposes
of it by feeding.

Cambridge, Mass.—Sells to hog farmers at 70¢. per cd. foot and has
no difficulty in disposing of all. Cost of collection, $50,000 a
year; receipts, $16,000 a year.

Grand Rapids, Mich.—Sold to live stock company for 45¢. per ton f.
o. b. cars. Last year collection cost $28,659 and receipts were
$4,450.20.

Camden, N. J.—Incinerator burned and since then garbage has been
collected and fed to hogs.

Brockton, Mass.—Municipal piggery (description below).

Colorado Springs, Colo.—Contractor pays $1,440 a year for the
privilege of removing all table refuse from city. Feeds to hogs.
Garbage must be sterilized before feeding.

Salem, Mass.—City Poor Farm uses about 200 loads a year. Remainder
is sold to contractor, who pays $13,255 for five years. Last year
city paid $10,948.30 for collection.

Taunton, Mass.—Municipal piggery.

Somerville, Mass.—Sold to farmers for 50¢. per cord foot. Cost of
collection last year, $25,134.80; receipts, $8,865.50.

Lawrence, Mass.—Sold for $1.25 a load. Ready and increasing demand.
Two loads used daily at Poor Farm piggery. Cost of collection,
$10,000 a year. Estimated receipts, $6,000 a year.

New Haven, Conn.—Cost of collection, $18,000 a year. Fed to hogs on
farm owned by city (description below).

Fall River, Mass.—City pays contractor $7,800 a year for the removal
of garbage. He feeds it to pigs on farm owned by him.

Worcester, Mass.—Municipal piggery (description below).

Corning, N. Y.—Contractor pays city $122 a year for privilege of
collecting at 10¢. a can. Garbage taken by him to his hog farm.

The city of Brockton, Massachusetts, owns the land and buildings necessary for feeding swine, also the horses and teams necessary for collection. The Mayor’s office reports that the city has not been able to make any profit on this method of disposal. In fact, for the last ten years the average cost to the city has been about $5,000 annually.

Taunton, Massachusetts, collects garbage only in the center of the city. The remainder is taken by private parties. The city has only two teams and two men at work. The Secretary of the Board of Overseers says that “in consequence of doing things in this way it is of little or no expense and gives quite good satisfaction.”

The expense and receipts during one year for the piggery were as follows:

┌─────────────────────────────────────────────────────────────────────┐ │Wages of employees $1,299.90│ │ │ │Expenses, not including board of two horses belonging to 375.92│ │ department │ │ —————————│ │ $1,675.82│ │Receipts from swine 3,260.91│ └─────────────────────────────────────────────────────────────────────┘

New Haven, Connecticut, pays $18,000 a year for the collection of its garbage, which is hauled to a farm rented by the city and fed to hogs owned by the city. The Board of Health reports: “Outside of some complaints from the piggeries we have got along. Our Board has repeatedly recommended the destruction of the same, but as yet nothing has materialized.”

A special commission made an investigation and report on the collection and disposal of municipal waste in Worcester, Massachusetts. After investigating all methods of disposal it reached these conclusions: “That the disposal by feeding is the most economical method; that the greatest intrinsic value of the garbage, the feeding value, is made use of; that the garbage of Worcester can not only be disposed of without cost but that the revenue from the sale of hogs has almost been sufficient to pay for the collection.”

The Commission recommended that the present method of feeding to swine be continued.

In its report it gives the per capita cost of collection and disposal as $.072 for Worcester and $.095 for Brockton.

The Worcester municipal piggery is the largest and most successful. The garbage collected by the city is fed to a herd of hogs numbering about 1700 in winter and 4000 in summer. During the winter practically all hogs are housed.

The necessity for sterilizing garbage before it is fed to hogs is disputed. Salem, Cambridge, Grand Rapids, Taunton and Brockton report that garbage is not sterilized. New Haven reports that some is sterilized. Colorado Springs and Omaha require all garbage to be sterilized.

In his report of the sanitary survey of St. Joseph, Missouri, J. H. White, Surgeon, United States Public Health Service, makes the following statement with regard to the disposal of garbage in that city:

“Kansas City, Providence, Denver, Omaha, Colorado Springs and other cities have their garbage fed to hogs, with the uniform result that the cost of removal is reduced to some extent to the city and that the contractor, according to his business capacity, is able to make more or less profit from the feed so obtained. There is no danger in this system under proper handling. Any supposed danger to the hogs can be prevented by prompt handling of the garbage to prevent unnecessary fermentation and by the use of the hog cholera serum to prevent disease. The proper cleaning of the pens, if in the city, eliminates any danger to man. The Board recommends this system and I heartily concur with them that it offers the best available solution of the garbage problem.”

The Worcester Commission reports the figures for hogs sold to a packing company during the last year from the Home Farm. Of the 2,276 hogs sold, the Commission says only 11 were condemned by the United States Government Meat Inspectors, an average of only 0.48 per cent. of one per cent., which average is much lower than it is on hogs shipped in from the West to the same packing house. It further says: “The feeding method, however, has been practised with success in many cities, especially those in New England, for many years. The great difference of opinion is explained by the efficiency with which the sanitary conditions at the farm are maintained.” It emphasizes the fact that farms must be kept clean and in a sanitary manner, and that this method of garbage disposal requires careful and intelligent supervision, as is the case with any other method of disposal. No method of disposal will run itself.

Following are comments received regarding this particular plan of disposal:

Health Officer C. C. Slemons, of Grand Rapids, Michigan, says: “From observation I am of the opinion that one of these farms (municipal piggery), properly conducted, is a paying proposition, but I do not think to the extent of paying for collection. From my observation I would be rather skeptical of a city going into this business. It is a business that needs very close supervision and unless a person is financially interested in it I doubt very much if the experiment would pay.”

Mayor Fred. W. Keller, South Bend, Indiana: “Some of this work was done several years ago. However, there was some objection on the part of taxpayers to it being hauled out of the city with municipal teams. It should be fairly profitable, but the farm and hogs should be owned by the city or the garbage disposed of to the concern that does own the hogs and farm and this done by receiving competitive bids. I make this latter suggestion in order to avoid criticism by taxpayers.”

Lawrence, Massachusetts, reports: “Those who have looked into this question contend that the city swill can be utilized to support a municipal piggery at considerable profit.”

In a recent report, the Iowa State College says of this method of disposal: “The only advantage which may be stated in favor of this method is that it probably costs less, under existing conditions about most of our cities, than any other available method.”

In one of its annual reports, the Massachusetts State Board of Health says: “It is objectionable and unsanitary in the extreme, as health authorities are constantly pointing out. Prominent among the objections to this method are the great nuisance it usually creates and the uncertainty of its operation.” The Board says epidemics among pigs create the uncertainty of operation. It also says that they are breeding places for flies and rats.

The Chicago Waste Commission’s comment on this method is that it is not applicable or desirable in a large city, except under inspection and for restricted private collection.

The _New York Medical Journal_ reported that the garbage collected by Grand Rapids, at cost of $26,320, is taken by a contractor who last year paid 45 cents per ton and fed to hogs. It says that over 10,000 hogs are sold yearly at a value of $135,000 and that 2,400 tons of fertilizer are produced at a value of about $36,000.

Samuel A. Greeley, Sanitary Expert, says that 75 pigs are required to dispose of a ton of garbage per day. The equipment at the farm prescribed by him is: Tracks and cars for distributing the garbage along concrete feeding platforms; substantial and well-kept sleeping and warming pens; tanks for sterilizing garbage; apparatus for vaccinating pigs against cholera; a means of disposing of unconsumed garbage by burial or incineration and plenty of washing facilities. He further says: “There should be some method of sorting the garbage before feeding it to pigs so that the stale garbage may be discarded and buried or burned. Some places disinfect it by boiling in large caldrons before feeding. In such cases the cooked garbage is commonly used only as a base for the feed given to pigs. The method is a most profitable one and warrants consideration in small cities where isolated farm sites are available.”

Dumping on Land

It is the consensus of opinion in all reports and of all experts that this method is objectionable especially where there is a large quantity to be disposed of. A long haul is necessitated by the location of the dumps at a remote distance where the decomposition of any part of the refuse will not be offensive to neighboring property owners. When the garbage is deposited in sufficient quantity offensive odors due to fermentation and decomposition may create a nuisance. Unless special attention is given to the treatment of these dumps, this method will not be found desirable. A thorough mixing of garbage with ashes and rubbish will prevent the nuisance and the fires that are otherwise liable to occur, creating odors and nuisance from the smoke and unconsumed gases.

A report of the Iowa State College states that dumps where ashes and rubbish and other refuse are deposited are not only unattractive in appearance, but are detrimental to the health of those living in the immediate vicinity, and as a city grows, it usually becomes increasingly difficult to find locations where these dumps can be maintained without incurring the objections of those living in the neighborhood.

The _Scientific American_ says this method “is one that cannot be defended either from an æsthetic or sanitary standpoint. The dumps become an ideal breeding place for flies.”

Dumping in Large Bodies of Water

Only a few cities use this method. In most places where it has been tried, it has been prohibited because the material is washed on the neighboring shores.

Disposal by Sanitary Fill

This method is practised by some cities, among them Seattle, Davenport, and New Orleans, which report its success. It is given more serious consideration than heretofore by several large cities. The method is different than that of burial, in that it is carried on by filling excavations, vacant low lying ground and natural ravines.

The garbage, rubbish and ashes are dumped and then mixed with sufficient earth to insure oxidation and thorough digestion of the decomposable wastes. The activity of the bacteria of the soil breaks down and mineralizes the organic matter and when there is sufficient oxygen, i. e. air, no putrefaction or other odors result. Success depends upon the following treatment:

(1) The garbage must not be buried so deep that bacterial activity is reduced.

(2) The garbage must not be spread in a thick layer on the surface of the ground.

(3) The ground must be sufficiently open and drained so that air can penetrate to a sufficient depth.

(4) The garbage must not overload the soil, but must be sufficiently diluted with earth, ashes and rubbish, so that putrefaction may take place, due to the presence of an ample supply of air in the pores of the soil.

The Chicago Waste Commission believes that this method “has been demonstrated to be not only sanitary, free from nuisance when properly carried out, but economical as well.” Incidentally, adds the Worcester Commission, it adds valuable taxable property from which the city subsequently derives an income.

At Davenport, 1.3 cubic yards of materials are required per ton of garbage and the total cost of upkeep, including rent of land, labor, etc., was 50 cents per ton. The garbage is received and buried by one foreman and three men in summer and one foreman and one man in winter. The city by this method is creating a valuable river front.

New Orleans seeds its dumping grounds as soon as a sufficient filled area is available, and later trims and plants the land for use as small parks and play grounds.

The Health Commissioner of Seattle, in a letter to the _Municipal Engineering Journal_, describes the system and results as follows:

“This method of filling works very satisfactorily in this climate, but I believe it necessary to include all waste materials, as ashes, boxes, tin cans, etc. These all assist oxygenation and nitrification. I do not believe pure garbage can be handled in this way.

“We also find that it is best to keep as little of the face of the fill exposed as possible. It is always best to keep a man constantly on the job, whose duty it is to rake down to the bottom of the fill all boxes, rough materials, etc., thus leaving the ashes to form a covering on top. When this is not sufficient, we cover with a layer of earth about five inches thick.

“The success lies in the proper mixtures of waste materials, and next the fill must be properly covered to protect from flies. Chemicals can also be used to protect it. This covering also prevents the slight sour odor of fresh garbage and by keeping out the sunlight, at the same time encourages bacterial growth by increasing the warmth inside the fill. People residing within one hundred feet of these fills make no complaint, but the public has to be educated when you first adopt this method. We aim to fill city property, as ravines, swampy lands or docks on the lake or salt water front.

“Our laboratory findings show that the process is simply one of slow incineration by nature, instead of the expensive method of burning by incinerators, and at the same time help prove that there is nothing detrimental to public health in these fills.

“We have eleven fills distributed over our city, thus making short hauls, and these are taken care of by eleven laborers disposing of approximately three hundred and fifty tons per day by this method alone, while one incinerator with about an equal payroll will only dispose of sixty to seventy-five tons per day, running twenty-four hours. A fill increases the value of property, while the refuse from our incinerator has to be hauled away at an added cost.”

After spreading, there is applied to the garbage an antiseptic spray of crude carbolic acid, rosin and caustic soda to kill eggs and larvæ of flies, mosquitoes and other insects that might breed.

Burial

Garbage may be buried by putting it in shallow trenches and covering with the excavation from the trenches for the next day’s deposit, or by plowing under. It digests and is thoroughly taken up by or oxidized by the action of the soil. Experience has shown that for open soil 1.5 acres are required to handle each daily ton of garbage for one year, the same soil being in shape to re-use after two years. For heavy soils and those containing clay, about three acres are required and this can be used again after three years.

The Worcester Commission reports that cities which have buried by plowing have experienced more than occasional nuisance. Milwaukee and Columbus successfully disposed of their garbage by burying in trenches, before they constructed disposal plants. Milwaukee paid forty cents a ton to dispose of its garbage by this method.

A summary of the opinions indicates that disposal by burying when properly conducted and when the point of disposal is suitably located gives no cause for objection from a sanitary standpoint. The principal objections are the extremely long haul, the amount of land necessary and no direct income. In small communities this method is entirely satisfactory. It is usually not applicable to large communities.

Disposal Plants

There are two methods of disposing of garbage in plants—incineration and reduction. There is a wide diversity of opinion among experts and city officials as to which is the better from a sanitary and financial standpoint. There is, however, nearly universal opinion upon the following:

1. That the revenue from the by-products of municipally owned and operated plants will not pay the combined cost of collection and disposal.

2. That with only a few exceptions the revenue from the by-products of municipally owned plants does not pay the cost of disposal.

3. That the price received by cities from contractors is, with very few exceptions, not sufficient to pay the cost of collection.

4. That the disposal of garbage by the reduction process is uneconomical for a city with a population of less than 100,000. Some experts increase the size to 150,000 and one to 200,000.

5. That incineration is better than reduction for a city with a population less than 100,000.

The reduction in the per capita production of garbage, due to less wastage of food in the American home since the war, may make it necessary in the future to increase the size of the city which can profitably employ the reduction method, or should use the reduction method.

In the report of the Chicago Waste Commission, some general rules are laid down for the design of a disposal works, irrespective of method. It says that the design should permit the plant to be operated as a whole, or in part, so that each part can be operated as an independent unit. This will permit one or more parts to receive attention and be repaired during the season when the minimum quantity of refuse is to be disposed of. The details of the plant should be such as to permit cleanliness at all times and hosing and washing so as not to permit garbage dust or dirt to accumulate, flies to breed and material to decompose. All material, so far as possible, should be enclosed during the process of disposal, and the odors eliminated or confined or deodorized. The handling of material in the plants, so far as possible, should be eliminated, where mechanical means can economically be adopted. Special attention should be paid to ventilation and the elimination of dust where men are required to work.

The odors or nuisances caused from disposal plants will usually arise from one or more of the following sources: Garbage or refuse, incomplete combustion or combustion temperatures not sufficient to eliminate odors, congestion of carts in one locality and creation of dust. The odors arising from raw garbage which are found in all plants are mostly local and will not create a nuisance a short distance from the point of handling and the housing of equipment used in hauling.

A method of determining the kind of a plant to be built and operated which will meet with local conditions is described as follows by Rudolph Herring, sanitary engineer.

“Locate suitable central points where incinerators can be built convenient for reception of refuse and delivery of steam and clinker. Estimate annual cost, including fixed charges and operation, as follows: First, of wagons and other means of collecting from house to works all garbage, ashes and rubbish combined; and, second, of the works for incineration. The sum of these two estimated costs will give probable annual cost of entire plant from origin to finish. This sum must then be credited with the annual value of steam and clinker. The result will be the net annual cost to the city of collecting and finally disposing of the above parts of general refuse.

“A. Locate suitable place where reduction process can be carried on economically and conveniently for reception of garbage and delivery of products, with a capacity to serve, if practicable, the entire city. Estimate annual cost, including fixed charges and operation, as follows: First, of wagons and other means of collecting the garbage from house to works; second, works for reduction. The sum of these two estimated costs will be the probable annual cost to the city of the collection and reduction of the garbage. This sum must be credited with annual value of products of reduction, as derived from sale of oils, grease and fertilizers. The result will be the net cost, perhaps profit, of disposing of city garbage.

“B. Locate suitable central point where incinerator can be built, which will be convenient for the reception of ashes and rubbish and the delivery of steam and clinker. Estimate annual cost, including fixed charges of operation as above of the collection and works for disposal of ashes and rubbish, if these are to be incinerated together.

“If only rubbish is to be collected and delivered for incineration, then there should be added the cost of collection and final disposal of ashes by dumping. This cost should again be credited with annual value of steam and clinker and perhaps of land-making by dumping of ashes.

“By adding results of A and B, we obtain the total net cost to a city of collecting and finally disposing of the above parts of general refuse. A comparison between these estimates of cost, of both collection and incineration of garbage, ashes and rubbish as one project and of both collection and reduction of garbage and the collection and incineration of rubbish and dumping of ashes as the other project, will indicate the most economical method in the city for which these cost estimates have been made. It is necessary to analyze carefully local conditions to determine the most economical method.”

Incineration

Two kinds of plants are used for this method of disposal—crematories and destructors. Many destructors are in operation in America, but of the crematories which have been built, many have been abandoned. Heat for destruction must be obtained not only from the garbage itself, but also from ashes and other combustible waste. It is here that the difference between destructors and crematories enters. In the former, heat is obtained from the refuse itself; in the latter, garbage is burned at the expense of coal, wood or oil. It seems to be the prevailing opinion that in order to make incineration a success the material must be burned at a high temperature and rapid rate of combustion.

Morse claims that destructors require twenty per cent. less area of ground, cost fifteen per cent. more for boiler and machinery; that the construction is more durable; no addition of fuel; that the gases of combustion are consumed, and that this method has by-products of clinker and power and destroys all combustible refuse; and that the net cost of operation is less per ton.

Crematories, Morse says, require more ground and more time for disposal, but cost less. They are less durable, require addition of fuel, gases are incompletely destroyed, cannot develop power, the residue has no value and they can burn only garbage and rubbish. The gross cost of operation is a trifle less, but the net cost is more.

Tests of garbage crematories in Ohio, according to the State Board of Health, show that “the plants as operated fail usually to dispose of the garbage at a temperature high enough to avoid the production of odors.” This, says J. T. Fetherston, Commissioner of Street Cleaning of New York City, is significant and conclusive.

Regarding mixed refuse destruction, Fetherston says: “Three features may be noted: No added fuel is required, steam power is produced and quite a residue (clinker) results. Compared with tests of garbage crematories the average destructor temperatures in connection with the gas analyses indicate freedom from odor due to unconsumed gas. Thus the mixed refuse type of plant corrects the inherent defects of the garbage crematory.”

The cost of incineration plants depends upon the garbage to be handled. The various incinerator companies usually estimate the capacity of the plant at about one ton per 1,000 population.

Reports show that disposal by incineration in Ohio is confined to cities of from 20,000 to 80,000 population, and that its success has been confined to the very large and to the rather small cities of the country. Some assert that it is applicable in the very large cities only when the collection systems are suitable to provide for the burning of mixed refuse. In small cities it is the custom to cremate the garbage alone, the other classes of waste being dumped or buried.

The cost of construction, reports show, ranges from $600 to $1,000 per ton capacity. The Worcester Special Waste Commission says that “from a calculation based on some 30 incinerators it has been found that the cost per ton daily capacity varies from $250 to $1,000, the average being between $600 and $700.”

The by-products are clinker and the steam generated.

Robert W. Wylde claims that the cost of operating destructors “is in a great measure offset and frequently quite overbalanced by the revenue” from the sale of steam and clinker. One hundred tons of refuse burned during 16 hours a day produces 800 engine H. P. Clinker from 100 tons might amount to 30 tons per day and would bring $1.00 a ton in many localities. Another expert says that one pound of refuse has been found to produce one-half to one and three-fourths pounds of steam. The value of refuse as a fuel is estimated by one expert to be 49 cents per ton.

The Chicago Waste Commission’s report points out, “that experience in connection with the development of power from refuse furnaces demonstrates that it is not easy to find an available use whereby the power can be utilized regularly as produced and the furnace operated continuously. In the majority of plants constructed, it has not been possible to utilize all the power available, and in most cases the use is limited to the operation of the plant. When power developed is used in lighting and power stations, the demand only comes during a part of the day. Supplementary coal-fired boilers are usually found in connection with destructor-electric lighting stations, or else the destructor is much larger than would be required to deal with the refuse alone. The power produced from refuse furnaces will be best utilized by some local industry, such as ice-making plants or electro-chemical plants, which require continuous operation. When power is used in connection with pumping plants, it is found good practise to operate the refuse plant only as an auxiliary to the power plant of the pumping station. The saving that results or credit that can be given the destructor plant will amount to the value of the fuel equal to that which it requires to produce the amount of steam developed and used. The fluctuating amount of power developed in most cases can be depended upon only for the average minimum production. In selecting a site for a refuse disposal plant from which power is developed it is not always profitable to utilize the power where the demand is not constant and where the demand would be constant, suitable sites are not always available.”

William M. Venable, sanitary engineer, believes that if a city has a steam power plant, it will pay, but it will not pay to build one for that purpose.

In a suburb of Montreal, the refuse destructor is constructed in connection with a municipal electric light power station and power is used in generating electricity for lighting purposes. The plant is operated only during the time when lighting load is in demand, and the material as delivered is stored during the day and burned at night. Only a part of the power is furnished by the refuse furnaces, the remainder being obtained from a coal-fired boiler plant.

In Savannah, Georgia, the water works boilers are kept in service, with banked fires, to use in case of shortage of garbage.

The following are some of the reports from cities which receive a revenue from by-products:

Minneapolis: The steam generated lights and heats hospital and workhouse buildings, also lights 31 miles of streets. Estimated annual revenue, heat $6,293.89; light $1,080.62; street lights ($60 per arc) $4,657.48; total, $12,031.99.

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.”