Although the words trash, garbage, rubbish and refuse-are often used as synonyms in casual discussions, each has a different and specific technical meaning. Trash refers to things like old paper, newspaper, boxes, cans, containers, and so on- generally, objects that are “dry” and no edible. Garbage refers to “wet” discarded matter, such as old food remains, yard waste like grass clippings, dead animals, leftovers from meat packing operations and butcher shops (such as the viscera of slaughtered animals), and so on.
Generally, garbage is edible and was often kept separate from trash in the past so that it could be fed to pigs. Today some types of garbage are useful for composting. Refuse technically refers to both trash and garbage, while rubbish includes not only refuse but also construction and demolition debris, such as old boards, bricks, cinderblocks, beams, tar paper, shingles, and so on. Ultimately, all of these sorts of rubbish are finding their way into our modern landfills.
Here we should point out that no matter what we want to call it or how we wish to define it, waste is a characteristically human concept. Generally, waste is not found in nature (although “pollution” may occur naturally in some instances, as when a volcano releases gases that promote acid rain).
In a typical ecosystem, there is no waste-the “waste” of one organism is the necessary raw material that another organism depends upon. Only humans typically discard waste that cannot be readily recycled and reused by other parts of the biosphere.
Solid waste, “Materials (non liquid or gaseous) which are mainly generated through anthropogenic activities and are discarded as useless or unwanted are called solid wastes.”
Certainly, household garbage, trash, refuse, and rubbish are all solid waste, but so too are solids, various semisolids, liquids, and even gases that result from mining, agricultural, commercial, and industrial activities. Often substance such as liquids and gases are confined in solid containers and disposed of with more conventional solid wastes.
Sewage effluent and wastewater from commercial enterprises, organizations, and private homes are not solid waste, but once wastewater is treated and various residues are removed from the water t form sludge, the sludge is usually treated as a form of solid waste.
Solid waste may be divided into two broad categories depending on its origination: municipal solid waste (produced by various institutions, businesses, and private homes) and industrial solid waste. Another useful distinction is between hazardous waste and nonhazardous waste.