Refuse Disposal

Where garbage is collected separately, it is the usual practice to collect it three times a week in the summer and twice a week in the winter, though nearly 20% of the cities make daily collections of garbage in the summer. Mixed refuse may be collected less fre quently and at longer intervals because decomposition is slower and the usual practice is to make two collections a week. Ashes and rubbish are collected weekly or at longer intervals. Most of the large cities collect refuse by municipal employees.

Satisfactory collection and handling of refuse is impossible without proper receptacles for the storage of waste materials, and most cities have regulations covering the size, material of con struction and quality of garbage receptacles. They are usually required to be watertight, of impervious materials and to have a tight cover. The usual capacity is 9 to 15 gallons. Few cities require any special receptacle for rubbish or ashes, but generally provide that the former be tied in bundles, or placed in boxes or barrels; ashes should be placed in non-combustible, covered con tainers. Receptacles may be placed at the back door, at the alley line or at the curb line. It costs more to collect from the back door, but it is the usual practice in the United States. Reports from 190 cities showed that 115 collected from the back door, 51 from the curb and 24 from either place.

Collection Equipment.

The employment of motor trucks in refuse collection is increasing and about one-half of the cities of the United States use motor equipment, though on house-to-house work in residential sections, where the amount collected from each house is small, horse-drawn equipment may operate more cheaply. For garbage collection, the 2-yd. body mounted on a i or if-ton chassis is probably the most popular, though larger bodies mounted on 2 and 3-ton chassis are used in many places. In ash and refuse collection 3- to 5-ton trucks are more economical.

Disposal.

Many methods of refuse disposal are in use in the United States, probably due to the differing conditions existing. The methods in use include dumping on land and in water, filling, ploughing under, burial, feeding to hogs, incineration, reduction, sorting and utilization. Garbage from cities is relatively rich in food values. If these values can be reclaimed, the net cost of disposal may be reduced. In addition to the food value of the gar bage, the facilities for the cheap and ready disposal of rubbish and in thin layers, and covered immediately with earth, ashes or other inorganic material. Ashes make good filling material and are used in many cities for making fills. Rubbish is frequently dumped, but

because of the time required for the fill to compact, and the mis cellaneous material composing rubbish, it is not as generally satis factory. Dumps are almost certain to catch fire, resulting in ob jectionable fumes. To obviate this, many cities burn the combusti ble matter as it comes to the dump. Paper is usually collected, baled and sold. Picking over the materials on the dump is quite a general custom and usually affords the city some revenue.

Sorting.

While in most cities, sorting is done mainly on the dumps, as previously mentioned, a more systematic procedure is employed in a number of places. A belt conveyor, upon which the refuse is dumped, and beside which a number of pickers stand, is the usual arrangement. Each picker takes from the moving belt one or more types of material from the refuse. Among the more valuable materials salvaged are paper, glass, bottles, metals, rags and tin cans. While the revenue from this work is frequently con siderable, few cities have found it to be sufficient to pay for the labour and overhead of the plant.

Burial.

Few cities dispose of their garbage by burial. In case of the breakdown of other methods of disposal, burial is sometimes employed as a temporary measure. The usual practice is to place the garbage in trenches about 2 ft. deep and 4 to 6 ft. wide, the garbage being deposited in layers from 12 to 18 in. deep. Before covering, the garbage should be sprayed liberally with disinfectant ashes and the availability of easily accessible sites for incinerators will be factors in the choice of the method to be used.

Disposal of refuse by filling low places and reclaiming marshes and swamp lands is quite common among the smaller cities; in larger places sites for dumps are rarely available except at a con siderable distance, and the longer haul thus necessitated increases the cost. Garbage cannot be dumped satisfactorily, unless extreme precautions are taken, and disposal in this manner is rare, except in cases of emergency. For satisfactory disposal by dumping, gar bage must be treated with a deodorant or disinfectant, spread out or crude oil. A cover of 12 to 18 in. of earth appears to give best results. For winter disposal, the trenches must be dug before the ground freezes, and covering can be done in early spring. Sandy, well-drained soil is most suitable, and where conditions are fa vourable, the land can be reused in 3 to 5 years. Ploughing under of garbage is a little used method. The cover secured is very thin, and men with hoes must follow the plough to cover particles not turned under.