Exercise

I. Tick the correct option.

1. Which of these is a biodegradable waste?

Ans:- paper cup

2. Which of these is a non biodegradable thing?

Ans:- ceramic mug

3. What is incineration?

Ans:- burning of waste

4. What is composting?

Ans:- recycling organic waste to make manure

5. How will you dispose plastic waste?

Sell it to a vendor for recycling

III. Answer the following questions in one sentence.

1. Name two biodegradable and two non biodegradable waste.

Ans:- Biodegradable waste:- i. Vegetable peeling ii. Animal waste

Non biodegradable waste:- i. plastic waste ii. Glass

2. Write one disadvantage of non biodegradable waste.

Ans:- The presence of non biodegradable waste in the soil causes soil pollution and reduces fertility.

3. What are the 3 Rs of waste management?

Ans:- The three Rs of waste management are Reduce, Reuse, Recycle.

4. Name the organism which is used in vermiculture.

Ans:- Red worm is used in vermiculture.

5. What is incineration?

Ans:- Burning of waste is called incineration.

IV. Answer the following questions in two sentences.

1. Distinguish between biodegradable and non biodegradable waste.

Ans:- Biodegradable waste: Biodegradable wastes are those substances that degrade or break down naturally. Materials like plants, animals, their waste, paper, fruits, vegetables fall under the category of biodegradable substances.

Non-biodegradable waste: Non-biodegradable wastes are those substances that do not degrade easily. Materials such as rubber, plastic, chemicals, paint plastic fall under the category of the non-biodegradable items.

2. Why should perishable food items be stored in a refrigerator?

Ans: When perishable items are kept in a refrigerator, the low temperature slows down the growth of microorganisms. Hence food item lasts longer without getting spoilt.

3. Name any three types of household waste which can be recycled?

Ans: Fruit peelings, vegetable waste, Papers.
4. How is incineration harmful?

Ans: Incineration is not a good method to manage the wastes. In this process harmful gases are released. Incineration pollutes air.

5. List three ways of controlling wastes.

Ans:- The three ways of controlling wastes are:- proper storage, Reducing use of plastics, Reusing metal tins, plastic containers.

V. Answer in about four to five sentences.

1. How is biogas produced?

Ans:- Biogas is mainly produced from cow and buffalo dung. Garbage and crop remains can also be used to obtain biogas. such waste is decomposed in a closed container to produce a mixture of various gases, known as biogas. These gases are produced when bacteria decomposes the organic material in the absence of oxygen gas.

2. Why does Switzerland not use waste for landfilling?

Ans:- Switzerland has one of the most efficient waste management systems. They do not use waste for landfilling. They treat wastes like wealth and recycle almost 50% of solid waste and sell the products. By doing so they not only able to keep their country clean but also generate employment.

3. Why should we segregate Biodegradable and non Biodegradable wastes?

Ans:- The biodegradable and non biodegradable wastes should be kept separately so that the non biodegradable waste can be recycled efficiently and the biodegradable waste can be collected to make manure or to produce biogas.  If both the biodegradable and non biodegradable wastes are kept together then the mixer may produce some toxic gas which will be harmful.

4. List the benifits of biogas.

Ans:- 

  • Biogas burns without producing smoke and therefore does not pollute air like other fuels.
  • It is a cheap and clean source of fuel.
  • Biogas is used to cook food and generate electricity.
  • The residue from a biogas plant is an excellent fertilizer.
5. How does landfilling lead to environmental pollution?

Ans:- Basically landfilling means placing the waste under ground and covering it with soil. As time passes, the organic waste under the soil decomposes and produces methane gas. This gas slowly seeps through the earth and disperse into the atmosphere polluting the air. Landfilling can also contaminate the water table, soil.

6. What are the disadvantages of polythene bags?

Ans:- Though polythene bags are useful but many ways it is a curse to the environment.

The followings are its disadvantages.

  • Once used they are just discarded and end up in a waste dump.
  • Polythene is non biodegradable so it often pollutes the water and soil.
  • Left over foods discarded in a polythene bag which are consumed by the cattle or other stray animals along with the polythene bags