Rajasthan Board RBSE Class 10 Science Notes Chapter 11 Work, Energy and Power
Waste:
Useless product at the end of any process is called waste. Waste is thrown away because of being useless.
Types of Waste:
Waste can be solid, liquid or gas but on the basis of ability to undergo decomposition, waste is classified into two types.
- Biodegradable Waste: Waste which can be decomposed by biological factors is called biodegradable waste, e.g. fruit peels, stale food, paper, etc.
- Non-biodegradable Waste: Waste which cannot be decomposed by biological factors is called non-biodegradable waste, e.g. aluminium can, polythene bag, etc.
Sources of Waste:
- Household Source: Paper, cardboard, fruit peels, vegetable peels, soapy water, rags, etc.
- Municipality: Municipality looks after management of solid and liquid waste from households, offices and factories. Municipal waste also includes human excreta.
- Industry and Mining: Many harmful wastes are produced by industries, e.g. harmful chemicals, grease, etc. Mining activity also produces wastes like dust.
- Agriculture: Hay, dry leaves, husk, cowdung etc. are examples of farm waste.
- Medical Waste: Hospitals produce many wastes like syringe, cotton, bandage, catheters, strips, etc. Some of the hospital waste may contain harmful germs.
Harms from Waste:
- Accumulation of waste around us is not good from the point of aesthetics
- Decomposition of waste produces methane and other harmful gases. Methane causes global warming.
- A heap of waste is the breeding ground for harmful germs, houseflies and mosquitoes. These agents can cause many epidemics.
- Hospital waste can cause serious infection to a person. HIV and Hepatitis B can spread from coming in contact with infected needle.
- Plastic waste turns the soil infertile. It chokes the drainage. Stray animals often swallow plastic and die due to choking. Prolonged exposure to plastic increases thalatus in blood which hampers the development of foetus.
- Sewage from households pollutes water bodies; like rivers and ponds. It is harmful for aquatic animals and plants. It also pollutes groundwater.
Waste Management:
The practice of transportation and dumping of waste, recycling of useful material from waste, etc. are integral part of waste management. Different types of waste need different kinds of management practices.
Methods of Waste Management:
- Landfill: Waste is dumped at landfill site. When amount of waste attains a significant figure, it is covered with soil. After that, waste is allowed to decompose. Pipeline system is installed in landfill to channelize and utilize the methane gas which is produced during decomposition. This gas is utilized for power generation at many places. A landfill site is usually developed outside the city limits.
- Incineration: In this method, waste is burnt under controlled conditions so that production of polluting gases can be minimized. This method is ideal for places where land is in short supply. This method is also ideal for disposing off the medical waste.
- Recycling: Certain items from waste are segregated for recycling. Items like plastic, aluminium cans, metals, etc. are sent to recycling unit so that new items can be made from them. This not only helps in reducing the amount of waste but also in conservation of resources.
- Chemical Methods: Many wastes can be managed by using chemical methods.