Refuse Disposal

REFUSE DISPOSAL, the general term employed in the United States to denote the solid wastes of a community, includ ing garbage, rubbish, ashes and miscellaneous wastes. (For British practice see DESTRUCTORS.) Garbage may be defined as the waste matter resulting from the preparation, cooking and consumption of food. Rubbish is the miscellaneous material discarded by a community as being no longer of use or value. It includes paper, rags, old clothing, broken furniture and numerous other articles. The term ashes, as generally used, refers only to the residue re sulting from the operation of heating plants in homes and small business establishments or offices. In the average city (there are wide differences in various cities) of the United States, garbage comprises about 13% by weight and 18% by volume of all refuse; rubbish amounts to only 7% by weight, but to 25% by volume; ashes form approximately 8o% by weight and 57% by volume of the total. Garbage weighs from 1,000 to 1,200 lb. per cubic yard, the weight varying with the season, temperature, rainfall and other factors. Of the total weight of garbage, from 6o to 65% is moisture while the combustible matter amounts to 15 or 20%. A pound of dry garbage contains about 8,500 heat units and about 6o lb. of grease per ton can be extracted from raw garbage. Rubbish differs from garbage, which is unstable and subject to rapid decomposition, in that it breaks down slowly and relatively without objection; it has considerable fuel value, the volatile mat ter ranging from 4o to 70% of the total. Ashes collected from residences and small business establishments also have some fuel value.

Quantity of Waste.-Where

the collection service is good, the average daily amount of garbage collected ranges from o.5 to 0.75 lb. per person. The amount of garbage appears to be increas ing, and data collected from a number of cities where careful and reliable records have been kept showed that in 1927 the average production was over 200 lb. per person per year, compared to previous figures ranging from 1 so to 175 pounds. The daily pro duction varies somewhat with the season. In the Southern States, watermelon rinds form a large part of the garbage during the late summer months. The amount of rubbish collected ranges from

5o to 175 lb. per person per year, averaging about 75 pounds. The collections of rubbish remain fairly uniform throughout the year, increasing slightly during the spring and fall months. Ashes, in the Northern cities, compose a large part of the refuse collected, but where climatic conditions are milder, the amount may become unimportant. Street sweepings, night soil, manure, dead animals and other wastes vary in amount according to local conditions and local regulations governing their collection. However, the col lection and disposal of these wastes are not, in most cities, func tions of the general refuse collection organization, but are per formed by special departments. Therefore, they will not be con sidered here. The total amount of refuse collected per person per year ordinarily amounts to 1,200 to 1,700 lb. but because of the many factors influencing collection, the amounts reported by typi cal cities range from Boo to 2,50o pounds.

Collection of Wastes.-The

collection of waste is generally considered to include both the actual gathering of the garbage, rubbish and ashes, and their subsequent transportation to the point of disposal. The methods of collection vary; in separate collec tion, garbage is collected separately and apart from the other wastes which may or may not be collected together; in mixed collection, garbage, rubbish and ashes are collected at one time and from one receptacle. Separate collection of garbage is the general practice in the United States. A survey of 190 representative cities showed that garbage was collected separately from ashes and rub bish in 139 of them, while 51 cities collected mixed refuse. The practice of separate collection is based upon either utilization of the garbage, as in feeding to swine or reduction, or on cheaper disposal of the less objectionable components of the wastes. In many cities, rubbish and ashes, which comprise the great bulk of the refuse, may be dumped or used for filling within the city limits, while garbage disposal must be accomplished at some distant point. In such cases, the saving in hauling and handling costs may be much more than the extra cost occasioned by separate collection.