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Chapter 19

Waste Generation and Management

Class 9 - Concise Biology Selina

Multiple Choice Type

Question 1

The most convenient reusable wastes are

  1. Old newspapers ✓
  2. Broken glass
  3. Flyash
  4. Medical instruments

Question 2

The most rapidly increasing and much harmful waste today is

  1. Plastics ✓
  2. Pesticides
  3. Municipal sewage
  4. Electronic waste

Very Short Answer Type

Question 1

Name the following:

(a) The solid precipitated material produced during secondary treatment of the effluent, carried out in the Effluent Treatment Plants.

(b) The two types of devices commonly used for removing the particulate air pollutants.


(a) Sludge

(b) Scrubber, plate type electrostatic precipitators.

Question 2

Mention whether the following statements are true (T) or false (F).

(a) Some of the electronic wastes may contain valuable metals such as gold and copper.

(b) Flyash is the gaseous waste of cement industry.

(c) Electricity is one of the primary needs of human society.

Correct Statement — Electricity is not one of the primary needs but secondary needs of human society.

Question 3

Match the items in Column I with as many items as possible in Column II.

Column IColumn II
(1) Cow dung(i) Sugarcane
(2) Bagasse(ii) Raddiwalas
(3) Old newspapers(iii) Manure


Column IColumn II
(1) Cow dungSugarcane
(2) BagasseSugarcane
(3) Old newspapersRaddiwalas

Short Answer Type

Question 1

Differentiate between :

(i) degradable and non-degradable waste.

(ii) sewage and effluents.


(i) degradable and non-degradable waste.

Degradable WasteNon-degradable Waste
It is organic wastes (vegetable and fruit peelings, etc.) that can be decomposed into useful manure. Such degradation involves the activity of microorganisms.These are the wastes that cannot be decomposed by micro-organisms.
Example – Paper, ClothesExample - Plastics, Metallic cans

(ii) sewage and effluents.

Sewage (domestic waste water) is a type of waste water that is produced by a community of people as an outcome of daily activities such as washing, bathing etc and also contains fecal matter.It is the liquid waste flowing out of a factory, farm, etc. into water bodies such as rivers, ponds, lakes, etc.

Question 2

Give reasons for the following:

(a) Broken glass utensils are a kind of non-degradable waste.

(b) Landfills are coming up fast near large cities.

(c) Why is municipal sewage first separated into degradable and non-degradable wastes?


(a) Broken glass utensils are a kind of non-degradable waste as they cannot be decomposed and broken down by living micro-organisms. These need to be disposed in deeply dug pits so as to cause no harm. One of the applications of broken glass is that it can be used in glass industries in larger quantities after melting.

(b) Large cities are seeing huge population growth and they lack in the usage of efficient and safe disposal method for the waste generated in these cities. Large cities are producing large quantities of non-degradable waste that ends up in landfills for disposal. Due to these reasons, landfills are coming up fast near large cities.

(c) Municipal sewage is first separated into degradable and non-degradable wastes because degradable wastes can be broken down into non-toxic waste in septic tanks, while non-degradable waste requires to be buried at safe places in order to avoid hazardous effects.

Long Answer Type

Question 1

Define electronic waste and list at least six items which come under this category.


Electronic waste is the waste generated by discarded electrical items (i.e. the appliances that use electricity). Some items under this category are:

  1. Fluorescent tubes
  2. Lead acid batteries
  3. Mobile phones
  4. Refrigerators
  5. Electronic toys
  6. Radios

Question 2

List some of the common wastes produced in mining operation and mention how these can be reused.


Common wastes produced in mining operation are:

  • Dust
  • Coal
  • Iron
  • Copper
  • Zinc

During operation of getting minerals, a large quantity of waste material is generated. This waste material is called mine tailing. The application of mine tailing is that it can be mixed with materials for tile production and masonry cement.

Question 3

Describe the procedure usually used to produce compost.


Composting means putting the waste organic matter to decay so that it can be used for fertilizing the agricultural land. The procedure to produce compost is described below:

  1. A trench of about 5m long, 1.5m wide and 1.5m deep is dug.
  2. A layer of well mixed refuse and waste is spread in it for about 30cm thickness.
  3. This layer is fully wetted with a watery mixture of cow-dung and some mud.
  4. A second layer of mixed refuse is spread over the first layer till the heap rises to project over the ground level by about half a metre.
  5. Leave the set up undisturbed for around 3 months during which water is sprinkled at regular intervals.
  6. A trench is then opened and the material is taken out and rearranged in conical heaps and covered with a layer of soil.
  7. Compost is ready after 50-60 days to be used in fields for cultivation or in garden flower beds, etc.

Question 4

Describe the usefulness of incineration of wastes, and also mention the precautions required in it.


Incineration is the disposal of waste by burning which causes the release of fumes and other toxic substances.

Usefulness of incineration of wastes:

  1. The ash left over occupies much less landfill space.
  2. Electricity can be generated from the heat released during burning.


  1. The process should be carried out at very high temperatures.
  2. Should be equipped with pollution control devices.
  3. Incinerators should be installed away from residential areas.