Refuse is discarded waste matter. The term solid refuse is now applied to refuse from houses, street sweepings, commercial, industrial and agricultural operations. Refuse is also called litter.

Health hazard: The accumulation of refuse in man's environment is a health hazard. It is because (1) refuse decomposes and favours fly breeding. (2) It attracts rats and vermin. (3) The pathogenic organisms which may be present in refuse may be conveyed back to man's food through flies and dust. (3) There is a possibility of water and soil pollution and (5) heaps of refuse present an unsightly appearance and are nuisance. Therefore, refuse should be promptly collected, removed and disposed off in a sanitary manner.

Methods of refuse disposal

Burning

By far the best method of refuse disposal is by burning or incineration. Hospital refuse which is likely to be more infectious than the street refuse is best disposed off by burning. The burning operation is usually carried out in incinerators. If the refuse contains sand, dust and other inorganic material like pieces of glass and tin, it may create problems in burning. These need to be sorted out. Although burning is a good method of refuse disposal, its chief drawback is that that refuse is a loss to the community in terms of manure.

Dumping

A simple method of refuse disposal is by dumping in low lying areas where in course of time, refuse gradually shrinks and decomposes into manure. This is also a method of reclaiming low-lying areas and the reclaimed land may be used for cultivation or growing vegetables. But open dumping is not a good method of refuse disposal because the refuse, since open, attracts flies and rodents besides being a nuisance where this method is employed. The dumping ground must be located well outside the main city.

Controlled tipping

There is by far the best method of refuse disposal. That refuse is buried in trenches of bits, 3 feet deep for periods varying from 3 to 6 months. During this period, the refuse is slowly broken down into simpler chemical substances and converted into manure by bacteria action. At the end of 3 to 6 months, the pits are dug opened and the manure is brought to the surface. The pits are reused. In controlled tipping, there is no fly nuisance or nuisance rodents. Where land is available, controlled tipping should be the method of choice for refuse disposal.

Composting

In some Indian towns and small cities, refuse along with human excreta is disposed off by a method known as composting. Pits or trenches are dug 3 feet deep. Then alternative layers of refuse and night soil are spread in the trenches in the proportion of 6 feet and two feet thickness of refuse and lightsoil are spread in the trenches in the proportion of 6" and 2" thickness of refuse and night soil respectively. The top layer should be of refuse. When the contents reach above the ground level, the pits are covered with earth and compacted. As a result of bacterial action, intense heat is generated within the compos pits. At this temperature, the pathogenic and other organisms are killed. The pits gradually cool down. At the end of 4 to 6 months, decomposition is complete and the resulting product is manure which is highly valued for agriculture purposes. This method of refuse and night soilq disposal is also known as hot fementation process.

It must be added that composting, however well done, cannot be a sanitary method as it involves handling of human excreta by human labour. By far the best method of refuse disposal is by controlled tipping followed by burning.