Anything which is unwanted or useless is termed as waste. The waste generated from various sources can be categorized into two types: Biodegradable waste and Non-biodegradable waste.
1. Biodegradable waste includes substances that can be degraded by microbes into harmless and non-toxic substances. Agricultural and animal wastes like leaves, twigs, hay, dung are biodegradable wastes.
2. Non-biodegradable waste cannot be easily degraded. Aluminum cans, plastics, glass, electronic waste, batteries are examples of non-biodegradable wastes.
Waste can also be classified as municipal waste, hazardous waste, biomedical waste, etc. Radioactive waste comes under the category of hazardous waste.
With the increasing population size, waste generated is becoming unmanageable. Open dumps and heaps of garbage is a common site. This unhygienic atmosphere leads to problems related to human health and environment because untreated, uncovered waste is a breeding ground for flies, rats, mosquitoes and other insects which spread various diseases. The rainwater run off from such sites contaminates nearby land and water.
Cities and some villages use landfills to manage the solid waste. Also, incineration plants are used in big cities to deal with waste especially biomedical waste. Incineration is the process of burning of waste after segregating the recyclable material. The end product of this process is called ash which is then disposed off in landfills. Unfortunately incineration produces toxic gases which cause air pollution.
The best practice of waste management is to minimize the generation of waste. The 4 R’s of conservation - Reduce, Reuse, Repair and Recycle are the guiding principles for reducing waste generation.
If a waste material is processed by some means and converted to a product, we call the process recycling. It helps in efficient management of wastes and also reduces the load on natural resources. Recycling of plastics and paper, converting municipal waste into manure, and rice husk into wood particle board are some such examples. Use of cattle dung for the production of biogas is also good example of recycling of waste for the production of energy.