The environmental effects of solid wastes are:

(i) Open dumps are malodorous places in which disease carrying vermins such as rats and flies proliferate.

(ii) Methane gas is released into the surrounding are due to decomposition of solid waste by microorganisms.

(iii) Liquid that oozes and seeps through solid waste heap ultimately finds its way into the soil, surface water and ground water.

(iv) Hazardous materials dissolved in the liquid contaminate underground water and soil strata.

(v) Solid waste is highly heterogeneous and is not segregated at any stage. It includes wastes from industries, hospitals and nursing homes, domestic waste etc.

(vi) The leachate consisting of a variety of chemical constituents, seeps and pollute the ground water.

(vii) Absence of landfill liners aggravate the problem.

(viii) Health hazards faced by the residents living in the nearby areas of dumping sites can not be ignored.

(ix) The present practice of collecting solid waste from individual houses results in wastage of time and thereby increases the cost of collection.

(x) Transportation of collected solid wastes openly by the tractors or trucks is unhygienic and the aesthetic look of the city is also affected.

There are different methods of solid waste management. The following are some of the recognized methods:

(i) Sanitary Landfill: This is the most popular solid waste disposal method used today. Garbage is basically spread out in thin layers, compressed and covered with soil or plastic foam. Modern landfills are designed in such a way that the bottom of the landfill is covered with an impervious liner which is usually made of several layers of thick plastic and sand. This liner protects the ground water from being contaminated because of leaching or percolation. When the landfill is full, it is covered with layers of sand, clay, top soil and gravel to prevent seepage of water.

(ii) Incineration: This method involves burning of solid wastes at high temperatures until the wastes are turned into ashes. The good thing about this method is the fact that it reduces the volume of waste up to 20 or 30% of the original volume.

(iii) Recovery and Recycling: Recycling or recovery of resources is the process of taking useful but discarded items for next use. Traditionally, these items are processed and cleaned before they are recycled.

(iv) Composting: Due to lack of adequate space for landfills, biodegradable yard waste is allowed to decompose in a medium designed for the purpose. Only biodegradable waste materials are used in

composting. Good quality environmentally friendly manure is formed from the compost and can be used for agricultural purposes.

(v) Pyrolysis: This is method of solid waste management whereby solid wastes are chemically decomposed by heat without presence of oxygen. This usually occurs under pressure and at temperatures of up to 430 degrees Celsius. The solid wastes are changed into gasses, solid residue and small quantities of liquid.