Selina Solutions for Class 9 Biology Chapter 19 - Waste Generation and Management

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Questions are persistent, whichever field of study it is. Answering, however, is an art. It is a great tool to assess the knowledge and level of information absorbed by the student. These skills of the students are assessed in examination through different types of questions such as application type of questions, multiple-choice questions, matching items from two different columns etc. This also helps the student to get an insight into his own preparations.

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1. How will you categorize the following under domestic and industrial wastes?

   Rags, used containers, old newspapers, mine tailing (left overs), flyash, kitchen waste, broken bricks.

   Solution:

   Domestic waste	Industrial waste
   Rags	mine tailing
   used containers	flyash
   old newspapers	broken bricks
   kitchen waste

2. What is bagasse?

   Solution:

   It is the plant residue left after extracting the sugarcane juice. It is used as firewood or in the paper industry.

3. Name any two categories of chemicals which are washed off as wastes from agricultural fields.

   Solution:

   The chemicals that are washed off as wastes from agricultural fields are – Pesticides and Fertilizers.

4. What are the two portions into which the municipal sewage is separated?

   Solution:

   The two portions into which the municipal sewage is separated are:

   • Degradable part – capable of being broken down chemically into non-toxic parts
   • Non-degradable part – They are dumped and buried at safe places.
5. In which category of wastes will you include the non-functioning discarded
   1. Mobile phones,
   2. Thermometers,
   3. Photocopying machines.

   Solution:

   The category of waste in which the non-functioning discarded mobile phones, thermometers and photocopying machines can be included is e-waste. E-waste is the abbreviation of electronic waste and consists of the discarded appliances using electricity.

6. Name the three categories of wastes under segregation

   Solution:

   The three categories of wastes under segregation are:

   • Reusable
   • Degradable
   • Non-degradable
7. Which categories of wastes require dumping?

   Solution:

   The categories of waste that require dumping is a non-degradable waste.

8. Is it true that composting is a useful method contributing in crop farming?

   Solution:

   Yes, it is true that composting is a useful method contributing to crop farming as composting means putting the waste organic matter to decay so that it can be used for fertilizing the agricultural land.

9. What is sludge?

   Solution:

   Sludge is a solid precipitated material produced during second treatment of wastewater (effluent) when it is pumped into oxidation ponds where the microbes oxidize the organic matter releasing carbon dioxide during the process, carried out in the Effluent Treatment Plants.

10. Can incineration lead to a certain kind of pollution/ Yes/No.

    Solution:

    Yes, incineration can lead to certain kind of pollution as, during the process of incineration, fumes and harmful substances are released.

11. Name two types of devices used for removing particulate air pollutants.

    Solution:

    The two types of devices used for removing particulate air pollutants are:

    • Scrubbers
    • Plate type electrostatic precipitators

Multiple Choice Type

1. The most convenient reusable wastes are
   1. Old newspapers
   2. Broken glass
   3. Flyash
   4. Medical instruments

   Solution:

   a) Old newspapers

   They are common wastes that are recycled for its reuse in the paper industry.

2. The most rapidly increasing and much harmful waste today is
   1. Plastics
   2. Pesticides
   3. Municipal sewage
   4. Electronic waste

   Solution:

   a) Plastics

   Plastic is a domestic waste that is usually given out from homes.

Very short answer type

1. Name the following:
   1. The solid precipitated material produced during secondary treatment of the effluent, carried out in the Effluent Treatment Plants.
   2. The two types of devices commonly used for removing the particulate air pollutants.

   Solution:

   1. Sludge
   2. Scrubber, plate-type electrostatic precipitators.
2. Mention whether the following statements are true (T) or false (F).
   1. Some of the electronic wastes may contain valuable metals such as gold and copper-T/F
   2. Flyash is the gaseous waste of cement industry T/F
   3. Electricity is one of the primary needs of human society T/F

   Solution:

   1. The statement is true.
   2. The statement is true.
   3. The statement is false. Electricity is not one of the primary needs but the secondary needs of human society.
3. Match the items in Column I with as many items as possible in Column II.
   

   Column I	Column I
   Cow dung	Sugarcane
   Bagasse	Raddiwalas
   Old newspapers	Manure

   Solution:

   Column I	Column I
   Cow dung	Sugarcane , Manure
   Bagasse	Sugarcane
   Old newspapers	Raddiwalas ,Sugarcane

Short Answer Type

1. Differentiate between degradable and non-degradable type of waste.

   Solution:

   The differences between the degradable and non-degradable type of wastes are:

   Degradable Type of waste	Non-degradable type of waste
   It is the waste that can be decomposed by micro-organisms	These are the wastes that cannot be decomposed by micro-organisms
   Example – Paper, clothes	Example – Plastic

2. Give reasons for the following:
   1. Broken glass utensils are a kind of non-degradable waste.
   2. Landfills are coming up fast near large cities.
   3. Why is municipal sewage is first separated into degradable and non-degradable wastes?

   Solution:

   1. It is because they cannot be decomposed and disintegrated by living micro-organisms. They are required to be disposed of 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 them.
   2. It is because of the tremendous growth in population and lack of using efficient and safe methods of disposal. The newer construction activities in new colonies produce large quantities of waste stones, broken bricks, pebbles and wastes from wood which are used as landfills observed in suburbs.
   3. It is because degradable wastes can be decomposed into non-toxic waste in septic tanks but non-degradable waste requires to be buried at safe places in order to avoid hazardous effects.

Long Answer Type

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

   Solution:

   The electronic waste consists of discarded appliances that use electricity such as old computers, TVs, refrigerators, cell phones etc.

   Items under this category are:

   • Medical instruments
   • Lead-acid batteries
   • Mobile phones
   • Refrigerators
   • Electronic toys
   • Fluorescent tubes
2. List some of the common wastes produced in mining operation and mention how these can be reused.

   Solution:

   Some of the common wastes produced in mining operation and their reuse is as follows:

   • Dust
   • Coal
   • Iron
   • Copper
   • Zinc

   During the process of mining, a large quantity of waste material is generated which is referred to as mine tailing which is the residue or the leftover. The application of mine tailing is that it can be mixed with materials for tile production and masonry cement.

3. Describe the procedure usually used to produce compost

   Solution:

   Composting is the process of rotting and conversion of organic waste into manure and the product formed during the process of composting is called compost.

   Method to prepare compost:

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

   Solution:

   Incineration is the disposal of waste by burning which causes the release of fumes and other toxic substances. The residue after incineration contains about 25% of wastes in the form of ash which should be deposited in landfills.

   Usefulness of incineration of wastes:

   • The leftover ash occupies much lesser landfills.
   • Electricity can be generated from the heat released during burning.

   Precautions:

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

Selina Solutions for class 9 Biology Chapter 19 – Waste Generation and Management

ICSE Class 9 Biology Chapter 19 – Waste Generation and Management chapter is classified under Unit – VI of Biology textbook – Health & Hygiene. Health refers to the normal and healthy state of the body in all the three aspects namely – physical, mental and social wellness while Hygiene concerns with the conditions and practices in order to maintain health and prevent any chance of diseases.

The chapter – Waste Generation and Management intend to provide students with the basics on wastes, different sources of wastes, different categories of wastes, namely:

• Domestic waste
• Industrial waste
• Agricultural waste
• Municipal waste
• E-waste

The chapter covers the following types of questions in order to assess students at different levels, they are:

• Multiple-choice questions
• Matching items from two given Columns
• State whether statements are true or false
• Very short answer type questions
• Short answer type questions
• Long answer type questions

List of subtopics covered in Chapter 19 – Waste Generation and Management

List of Exercise

Selina Solutions for class 9 Biology Chapter 19 – Waste Generation and Management

Waste generation and management is one of the topics covered under Health and Hygiene. Students are required to know about the basics of waste, different categories of wastes and the basis of classification of these wastes. Waste is a substance that is disposed of after primary use and is of no use.

The categories of wastes are as follows:

• Domestic waste
• Industrial waste
• Agricultural waste
• Municipal waste
• E-waste

Some other topics that are discussed in this chapter are science teaching and research laboratories wastes, methods of safe disposal of wastes such as segregation, dumping, composting and drainage, treatment of effluents before discharge, incineration etc.

Key Features of Selina Solutions for class 9 Biology Chapter 19 – Waste Generation and Management

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