Solid waste, or refuse, are residues of human activity, and encompass all biodegradable and non-biodegradable, combustible or non-combustible solid wastes except human body wastes.

These include garbage, ashes, household, industrial, and street refuse; dead animals, abandoned vehicles, demolition and construction, sewerage, and hazardous refuse. The classifications are:

1. Residential Waste

   This is composed of garbage, rubbish, trash, ashes and old appliances. The garbage comes from food preparations, the rubbish, ashes and trash come from homes and consist of paper, boxes, tree branches, yard trimmings, tins and bottles.

2. Commercial Waste

   This is derived from wholesale and retail trades, hotels, restaurants, supermarkets and other commercial houses. Such wastes include garbage, trash, bulky material, cartons, tins and bottles.

3. Industrial Waste

   This is derived from manufacturing activities such as waste chemicals, bottles, wood, tin cans, glass, plastic, paper, cardboard and other metallic wastes.

4. Municipal Wastes

   The are derived from street clearings discarded auto bodies, ashes, sludge from sewers, dead animals and wastes from public markets and parks. Most of these wastes are accumulated on the side-walks and gutters and consists of leaves, construction material, paper, plastic cups, foam containers, metal lids, cigarette butts. Waste from the cleaning of commercial establishments are the most common types of litter on streets.

5. Institution Waste

   These are derived from hospitals, prisons and such institution. Hospital wastes need special attention because they are considered highly infectious. Such wastes include garbage, trash and disposable material.