Municipal housecleaning

by William Parr Capes; Jeanne Daniels Carpenter

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.”