GARBAGE COLLECTION AND DISPOSAL SYSTEMS AND PRACTICES IN AMERICAN CITIES--FACTORS WHICH AFFECT THE COST--OPINIONS OF EXPERTS--COST DATA

Local conditions are so variable that the problem of collecting and disposing of garbage is one of the most complex with which city officials have to deal. The results obtained by one city cannot in detail be applied to another city, although there are many characteristics common to all. Each city must study its conditions and then apply general principles with such modifications as its peculiarities make necessary.

The garbage problem divides itself into two natural divisions:

1. Collection, including house treatment and haul.

2. Final disposal.

The two are so closely related that the cost of different systems should be compared on the basis of combined cost of collection and final disposal. These two divisions may be subdivided as follows:

1. COLLECTION SYSTEMS.

1. Type:

(a) Combined (garbage, rubbish and ashes).

(b) Separate (each kind of refuse).

2. Method:

(a) By scavengers.

(b) By contract.

(c) By city.

3. Organization:

(a) Districts.

(b) Force.

4. Kind of Equipment:

(a) Receptacles.

(b) Vehicles.

(c) Loading stations.

5. Location of receptacles.

6. Frequency of collection.

7. Time of removal.

8. Enforcement of regulations.

2. DISPOSAL.

1. Method:

(a) Dumping on land, for fill or at sea.

(b) Plowing under.

(c) Feeding to swine.

(d) Incineration.

(e) Reduction.

2. By-Products.

3. METHODS OF FINANCING COST.

Types of Collection Systems

There are two types of garbage collection systems—the separate and the combined. Before deciding which is the better adapted to local conditions the method of disposal of all municipal waste—rubbish, ashes, dead animals, street sweepings and stable manure—must be considered. A further study should be made of the five combinations which have been adopted by American cities and which are outlined in the chapter on ash and rubbish collection. When garbage is collected separately, the method of disposing of it is by the reduction process, incineration or feeding to hogs. If it is collected with rubbish the two wastes must be incinerated. If ashes, rubbish and garbage are collected together the wastes are either dumped or incinerated.

As with ashes, reports generally agree, that if all wastes are collected together as a rule the cost of collection will be less than if each is collected separately. The method of final disposal, the net cost of that method after deducting revenues, and the length of haul should be considered and carefully determined before any system of collection is adopted. The same arguments presented in the chapter about ash collection for and against the combined and separate methods of gathering ashes apply with equal force to the collection of garbage.

Robert H. Wylde, sanitary expert, advocates the mixed collection. He says: “There can be no doubt that the mixed collection is preferable from practically every point of view and possesses such great advantages that it is doubtful if it is ever compensated for (from the citizen’s point of view) by economies realized from any method of disposal requiring separate collection.” He also points out that for a separate collection, a city must have three distinct styles of carts, collections should be made in the early morning or during the night, and each house should be visited daily or at least every other day. Householders must be required to keep the materials in three separate receptacles; three calls must be made at each house and the same ground must be covered by three different classes of collector.

The Chicago City Waste Report, by I. S. Osborn and J. T. Fetherston, says that combined collection requires more frequent collection of ashes and rubbish than if garbage were collected separately. If separate collection of garbage is made a more frequent collection of garbage and a less frequent collection of rubbish and ashes can be made. If all wastes are collected together, it says, as a rule the unit cost for collection will be less than if collected separately.

In smaller communities, says Samuel A. Greeley, sanitary expert, it does not seem advisable to place all classes of refuse in one receptacle as ashes can be easily disposed of. By separating the garbage the bulk to be removed is smaller, the disposal by burial requires less land, much of the garbage can be sent to the farms for feeding, and the general cost of refuse disposal is reduced without seriously lowering the efficiency. In cities of from 30,000 to 50,000, he asserts, the mixed system requiring only one can at a house and permitting incineration without the use of additional fuel, has many advantages. In such small communities, he believes, garbage does not have the advantages for reduction purposes that it has for the larger cities.

Methods of Collection

There are three methods of collecting garbage:

(1) License System, by which the city licenses certain cartmen, the individuals paying the expenses, usually under regulation of the Board of Health.

(2) Contract System, which provides that city pay a fixed amount annually for service, that certain schedule be paid by householder, or that contractor pay a certain amount to the city for privilege of collecting, and charging the householder for the service.

(3) Municipal System, by which the city does work with own or hired teams. In some cities, city employees collect a part and scavengers or collectors, or both, collect the remainder.

Experts are generally agreed that the best of the three systems is the last. They say that there is always much trouble when the contractor is allowed to collect pay from citizens served, and that to sanitary officers must be given full authority to fine those who fail to have garbage removed. Contractors’ wagons also must be under the close supervision of sanitary officers.

The Chicago Waste Commission’s report says that efficient service can be obtained by contract when the work is specified and the requirements are such as to obligate the contractor to furnish the desired service. The contractor, it asserts, must maintain an effective organization, sufficiently equipped and managed to be able to render proper service. Under this method, it points out, a rigid inspection is necessary on the part of the city and full compliance on the part of the contractor in carrying out his agreement. The report also says that efficient service can be obtained by a municipal collection when the city conducts the work with its own teams and equipment and the men employed on the work are directly responsible to their superiors who in turn are responsible to the public for the service rendered. It gives the following advantages of this method:

(a) The service is rendered as desired. It is not necessary to specify how and what work is to be done, but the work can be conducted so as to meet conditions as they may arise.

(b) The work comes directly under the control of the officials whose chief object is to render satisfactory service at a reasonable cost.

(c) Better equipment can be provided and the work planned on a more systematic basis when investments are permanent.

(d) Municipal operation eliminates the tendency on the part of the contractors (when the work is done by contract) to obtain the largest remuneration possible at the least cost.

It is impossible, says the report, to develop efficient organization or to render the best service in collection with hired teams where the driver receives his pay from the employer, who in turn receives his pay from the city for furnishing the team and driver.

In the majority of cities in the United States, the collection is done by the city, which owns its equipment and conducts the work under the supervision of its officials. It has been the experience of these cities that the results of municipal operation have, in most cases, proven satisfactory.

John H. Gregory, sanitary expert, believes that as a general rule the best results may be expected from municipal ownership and operation of collection equipment. A similar opinion is expressed in the report of the Special Commission on the Collection of Municipal Waste, Worcester, Massachusetts.

Grand Rapids, Michigan, reports that under the municipal system, the cost per householder is $1.63 a year, while under the private contract system the cost was $3.00 a year.

Whatever system and method are selected to make it successful a city must (1) provide sufficient appropriation; (2) secure or insist upon an efficient organization; (3) have or require sanitary and economical methods of work, and (4) secure and foster cooperation on the part of the public.

House Treatment

Many cities require that garbage be drained and some that it be wrapped in paper as well as drained. Wrapping aids combustion when the disposal is by incineration. Wheeling, West Virginia, claims that wrapping garbage eliminates smell, preserves can, provides fuel and makes work much less unpleasant for the collector. Dr. P. M. Hall and Samuel A. Greeley advocate wrapping if garbage is burned. Seven cities, of those from which statistics have been received, require that garbage be wrapped—Dunkirk, Jamestown, Mount Vernon, Trenton, Milwaukee, Grand Rapids and Minneapolis.

Organization

It is agreed that the number and location of districts into which a city is divided must depend upon the size, topography and population, the location of sub-stations or the place of final disposal, the frequency of collection and the hauling equipment. It is also agreed that the divisions should be made with the purpose of shortening the haul as much as possible and to avoid steep grades with loaded wagons. Some cities haul direct from the district to the place of disposal, others establish loading stations or bunkers to which the garbage is hauled in wagons and from which it is taken for disposal in automobiles, train or trolley. Still others have loaded wagons taken to a central place and from there hauled by tractors to the place of disposal.

The type of equipment, system of collection, organization of city, location of receptacles, frequency of collection and hours of removal must be considered when organizing the force. These vitally affect the cost. Some cities require one man to act as driver and collector. This system is regarded as uneconomical as the whole collection is retarded. Other cities have two men with a wagon, one to drive and the other to collect. In some cities the gang system, described in the chapter on ash collection, is used.

The Chicago Waste Commission makes these recommendations to insure an effective organization:

1. Individual responsibility for work assigned.

2. Employees should be paid for work performed instead of for hours of labor.

3. Published records of employees individually by sections under foremen and by districts under inspectors or superintendents will create a healthy rivalry and conduce to better work.

4. Unit cost of all work should be maintained and the keeping of these records will more than pay for the cost of the clerical work involved.

All agree that special effort should be made to get intelligent drivers who are willing to take pains to do the work at each house in a cleanly fashion. Others urge keeping one man on the same route.

In planning districts and force, the findings of the Chicago Civil Service Commission may assist some officials. It required on an average under ordinary conditions three hours and fifty-five minutes to collect a full load of two and one-half tons. The average in summer was 3.9 hours and in winter 4.7 hours. The average rate of haul was 3 miles per hour in summer and 2.7 miles per hour in winter. Collections were at a minimum in winter and a maximum in summer, especially in September. The quantity collected from several districts for different years was not constant, but continually decreased or increased, depending upon local conditions, such as change of character of population, growth of residence, business and manufacturing. The fluctuations make it necessary that the organization be flexible and easily adapted to changing conditions.

As the quantity will vary from season to season, the collector assigned to a district should make daily reports of work performed and territory covered. By so doing it can easily be determined whether he is delinquent or the work has increased so as to require auxiliary equipment or extra assistance. The plan is also valuable for rearranging districts.

The Ohio State Board of Health has expressed the belief that the routes should be so arranged that each collector covers about the same mileage and so that each wagon is as near as possible to the point of disposal by the time the wagon is loaded in order that the productive time of the collector, or the time he spends in collecting from houses, may be as great as possible and his unproductive time, or the time he spends in driving his loaded wagon to the point of disposal, as small as possible. In some cities, owing to poor routing, the unproductive time has been as high as 40 per cent. of the collector’s working hours. Routes should also be so arranged that grades are climbed with light loads and descended with heavy loads.

Receptacles and Vehicles

Most cities specify a standard sized can. It is agreed that this is necessary to secure the best results. The size varies in different cities and with the type of system. All reports show that the can should be metallic, water-tight and as nearly air-tight as possible, and should be securely covered. A 20-gallon can, it is claimed, will take care of an average size family for a week and is easily handled by the collector. The size of the can should be limited so as to be easily handled by one man.

For collecting garbage many types of wagons are being used by American cities. The design materially affects the cost and efficiency of results. Most cities are now using a steel tank wagon with either a bottom or rear dump, depending upon the house treatment of the garbage and whether the system is combined or separate. All reports show that any garbage wagon to be sanitary and satisfactory must be metallic, fitted with covers, easily cleaned and disinfected, and as large as consistent with the grades and type of pavement on the routes traversed. Particular attention should be given to the loading height. This should be at a convenient distance from the ground so that the collector can easily empty the can. The arrangements for dumping are also important. They should be quick and simple. It is claimed that bottom dumping wagons are best, but these cannot be used for raw garbage unless wrapped. They can be used for mixed refuse. Many cities successfully use the rear dump wagon, which is tilted by a hand-turned gear at front.

The right kind of cover is also important. Greeley says the most satisfactory cover is the light fixed roof, arched over the top of the wagon at sufficient height to give a free space above the whole of the garbage, and to allow trap doors in the side of the wagon for emptying the can. Many cities use canvas covers. The Worcester Waste Commission reports that its inquiries show that wooden or iron covers are impracticable because they do not allow expansion of load during periods when the amount of garbage is greatest. It says that wooden covers warp, do not fit tightly and need repairs often and are much in the way during collection. Iron covers, it avers, are almost universally condemned on account of their weight, and if very light get out of shape easily, wear loose and in a short time become a noisy nuisance. Some types of wagons are equipped with rubber buffers to lessen the noise and others have automatic covers.

Wagons made for garbage collection range in cost from $150 to $375 each.

The capacity of the average garbage wagon has been from a yard to two yards cubic contents. The tendency in many large cities is to increase this to four and five yards and even larger. Greeley believes that a wagon having a capacity of about three cubic yards is desirable.

A few cities which have adopted the can collection system have wagons built with two tiers. Some are using automobile trucks constructed in this way. The Ohio State Board of Health, in its report, says that platform wagons are somewhat less economical than tank wagons but are entirely suited for small cities where the quantity is not large.

It seems to be the opinion of those who have had experience that automobile trucks for refuse collection are neither economical nor convenient, owing to the many stops and starts and the slow general progress. None of the 224 cities from which data have been received uses automobile trucks exclusively. Several have automobile trucks in service but practically all of these use them for hauling from transfer stations over long distances to the place of disposal. At some of these loading stations a crane is used to lift the detachable body or tank from the wagon and place it on the truck. Another method adopted by a few cities is to use wagons for collection and tractors for hauling. The horse drawn wagons when filled are taken from a common meeting place to the disposal site by a tractor which draws them as a trailer. The horses are hitched to empty wagons and continue collecting.

R. T. Dana has compiled statistics which will interest those who contemplate using motor trucks. He says for hauling ashes, street pavement, etc., it is cheaper to use horses if the haul is less than one mile. If motor power is used for a haul of a quarter of a mile the loss is 1.8 per cent.; if half a mile, 9.1 per cent. loss. For one mile haul there is no difference in cost. Above that the saving is in favor of motor trucks. Similar investigations have been made at the Massachusetts Institute of Technology. These show that for distances greater than 1.7 miles, electric driven vehicles are cheaper than either horse drawn or gasoline driven and that gasoline driven are cheaper than horse drawn.

Investigations made by the Efficiency Division of the Chicago Civil Service Commission showed that electric trucks are more efficient than gasoline trucks where the short hauls with many stops are encountered. Its conclusion was that for the long hauls electric trucks were more economical than horse drawn or gasoline driven trucks. The following table gives a detailed comparison of the advantages of gasoline and electric trucks as determined by the Commission:

Gasoline Truck	Electric Truck
(a) Greater average speed possible.	(a) More efficient where the haul with many stops are encountered.
(b) Can be run continuously day and night.	(b) More efficient within its limits of operation, 50 to 60 miles per eight hour day.
(c) Are essential outside of the radius of operation of the electric truck.	(c) More economical motive power.
(d) Can do more work in a given time if speed restrictions do not interfere.	(d) Less average per cent. maintenance and repair costs.
(e) Less balking on unimproved streets.	(e) Less per cent. depreciation.
	(f) Requires less skill to drive.
	(g) Affected less in winter by temperature.

The Commission’s study led to the following conclusion: “That at the present prevailing cost of team hire the saving in the use of electric motor trucks for hauling garbage in such wards as have a considerable haul, would amount to 5.1 per cent. of the total cost of removing such garbage by teams. 2. That either the gasoline or electric power trucks can handle the hauling of garbage with approximately equal satisfaction. 3. That the more economical power truck has been found to be electric. This is governed in a measure by the low cost rate of electrical energy from the Sanitary District to the city for night power and by the fact that the rates for depreciation, maintenance, repair and insurance are less than for the gasoline truck. 4. That the haul below which an electric truck carrying three tons would not be economical when measured against a $5.50 per day team is found to be about 1.8 miles and when measured against a $6 per day team is 0.8 miles. 5. That the three ton gasoline truck at present cost price would not haul economically when traveling in the city at the economical rate of speed, as would the horse drawn vehicle at either $5.50 or $6 per day and traveling at the rate of speed found by experiment on garbage wagons.”

Greeley believes that the cost of loading a motor truck will be greater per hour and the rate of load will have to be increased proportionately to make the cost comparable with loading a team drawn wagon. The cost of hauling by motor will be less. He contends that the use of trucks in refuse collection service will increase and that the cost of loading can be reduced by limiting the motor truck to transportation after the loading of the wagon by the tractor and trailer system.

St. Louis recently made computations comparing the existing cost of hauling garbage from the long haul district with mule teams and the probable cost of haul with or by tractors. The motor apparatus was assumed to be a Knox tractor with two trailers and the assumed haul of seven miles. This would replace ten teams. The investment for a ten-ton tractor would be $3,750, and two trailers, $1,000, with a total of $4,750 for the motor apparatus. Ten teams of mules cost $3,000 and ten wagons, $1,350, a total for animal power of $4,350. The cost of operating per day is assumed to be for the motor, making three trips a day, 42 miles, $4.07.

This computation assumes a loading station located at the center of the long-haul district, which, including lot, building, paving, platform, sewer and water connections, would cost $6,300. The equipment would therefore be $10,650. Interest on the investment is computed at 6 per cent. The annual charges against the motor equipment would therefore become $3,034.92. The year is assumed at 156 days, as the district is collected from three times a week. The charges against the team equipment amount to $6,503.88. The saving in adopting the truck system is thus $3,468.96 a year from this long-haul district. Under these assumptions the equipment is idle one-half the time.

The New York City Department of Street Cleaning made a test of motor trucks and proved their efficiency over the present system, giving a possible 18 per cent. for time lost in hauling, loading and returning light as against 43 per cent. under the existing system. A ten-year test in England proved the superiority of motor trucks.

The Worcester Commission reports that for heavy, long hauls and under conditions where a truck can be kept moving, a motor truck is probably more economical than a horse drawn vehicle of the same capacity. It concludes that the motor trucks are not economical for short hauls with many stops.

The Health Commissioner of Seattle in 1913 made the claim that auto trucks save from one-fourth to one-fifth as much time as is consumed by horse drawn vehicles. He expressed the belief that 45 cents on a dollar is saved by using auto trucks. Seattle hauls its garbage by auto from bunkers to place of final disposal.

A few cities haul from transfer stations to place of final disposal by trolley and steam cars and by barges. Greeley estimates that assuming 600 cu. yds. of refuse weigh 375 tons, the cost of trolley transportation will be 40 cents per ton. Barge transportation, he estimates, will be about 22 cents per ton. Transportation by steam railroads, he says, depends upon switching charges. These will range from $5 to $15 per car. He figures the switching charges will average about 20 cents per ton.

Collection Regulations

The location of the receptacle and the time and frequency of collection have a very important bearing on the efficiency and cost of the service. The degree of cleanliness desired and the convenience of the householder are the chief factors which determine these questions.

Most cities specify where the can must be left for collection and to what place it must be returned. Some collect from the curb, areaway or alley, but the majority of them take the can from and return it to the house or back yard. Garbage can be collected much more speedily if the cans are left at the curb for collection days, but most cities object to the unsightliness of the thoroughfares which results. The citizens, for their own convenience, and to eliminate the objection of a littered street, are willing to pay the extra cost of having the garbage taken from the yard or the house.

The almost universal practise in America is to collect garbage during the daytime. Of those from which facts have been received and whose systems are described in the accompanying tables, only two collect all garbage at night. One collects at night during the summer and four collect at night in the business section. Two collect during both day and night.

The number of collections made in a stated period of time depends entirely upon the amount of garbage, the density and character of population, the climate and the season of the year. Some cities maintain a daily service in all except the outlying sections. Practically all collect at least once a week. In cold climates more collections are required during the summer than during the winter. Usually the collections are more frequent in the business sections than in the residential sections and less frequent in the outlying districts than in the residential sections, the density of population being the determining factor.

As with ash collection the promulgation and enforcement of specific regulations are very helpful in increasing or maintaining the efficiency of a garbage collection system. Cooperation of the public is essential and this can be secured to a great extent by an efficient system. All reports agree that regular collections should be made at stated intervals and so far as possible at the same time each day according to a regular schedule. Laxity on the part of the collection department will breed indifference among the householders. The Chicago Waste Commission expresses the opinion that where the householders become accustomed to a systematic service they will depend upon the collector and will more readily comply with laws and ordinances. All experts agree that the regulation as to house treatment of refuse should not only be enforced, but that considerable time should be spent by officials in educating and training people to cooperate for mutual advantage. Such time will be well spent, and eventually it will reduce the cost of operation.

The rules and regulations respecting the collection of garbage and refuse in a small progressive New York State city are as follows:

“All persons intending to have their ashes, garbage and other refuse removed by the collector, shall provide sufficient standard ash cans, sixteen to twenty inches in diameter, and twenty-six inches high, manufactured of galvanized iron with proper handles and cover.

“Into this can should be put old bottles, rubbers, tin cans, broken bottles and glass, old shoes, sweepings, paper and other rubbish.

“Ash cans containing swill, water, offensive and decomposing material, or the contents of which are frozen and not easily removed, will not be emptied by the collector.

“Provide sufficient garbage cans composed of galvanized, G. I. Standard make, with covers and handles, to hold one week’s accumulation. Put into this can all swill and other kitchen refuse. Garbage cans containing ashes, old bottles, tin cans, glass, shoes, sweepings, paper or other rubbish, or the contents of which are frozen, will not be emptied by the collector.

“The cans must be placed where the collector can conveniently have access to them, and if placed on the sidewalk or in front yard, must be returned as soon as emptied.

“The collector will collect but once each week and on the day and at the time specified for the street on which you reside.

“Burn as much rubbish, paper, sweepings, etc., as possible.

“Piles or accumulations of garbage, old bottles, tins, papers and any other substances, liquid or solid, or of anything that may become a breeding place for flies or mosquitoes, or which in any way may become a nuisance, are prohibited.

“Accumulations of garbage or other refuse of more than one week is prohibited.

“Any incivility on the part of any collector, or any complaint should be made at once in writing to the Clerk of the city.”

Cost of Collection

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	203?
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. Manhattan)	82,503 cu. yds.	89,568 cu. yds.	76,550 cu. yds.	84,628 cu. 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 lbs.	350 tons	330 tons, 655 lbs.	398 tons, 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 tons	1,250.280 tons	2,247.790 tons	1,748.700 tons
Utica	40 tons daily	40 tons daily	35 tons daily	35 tons daily

---

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 department	375.92
	$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.”

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.

Glens Falls and Oneonta, N. Y., report that they have no systems.

---