ICSE Solutions for Chapter 19 Waste Generation and Management Class 9 Biology Selina
Progress Check
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:
(i) Degradable part: capable of being broken down chemically into non-toxic parts
(ii) Non-degradable part: They are dumped and buried at safe places.
5. In which category of wastes will you include the non-functioning discarded
Mobile phones, Thermometers, 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:
(i) Reusable
(ii) Degradable
(iii) 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:
(i) Scrubbers
(ii) Plate type electrostatic precipitators
Review Questions
A. Multiple Choice Type
1. The most convenient reusable wastes are
(a) Old newspapers
(b) Broken glass
(c) Flyash
(d) 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
(a) Plastics
(b) Pesticides
(c) Municipal sewage
(d) Electronic waste
Solution
(a) Plastics
Plastic is a domestic waste that is usually given out from homes.
B. Very short answer type
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.
Solution
(a) Sludge
(b) Scrubber, Plate type electrostatic precipitator
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. T/F
(b) Flyash is the gaseous waste of cement industry. T/F
(c) Electricity is one of the primary needs of human society. T/F
Solution
(a) True.
(b) True.
(c) False. Electricity is one of 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 II |
|
Cow dung |
Sugarcane |
|
Bagasse |
Raddiwalas |
|
Old newspapers |
Manure |
Solution
|
Column I |
Column II |
|
Cow dung |
Sugarcane , Manure |
|
Bagasse |
Sugarcane |
|
Old newspapers |
Raddiwalas ,Sugarcane |
C. 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 |
|
The waste that can be decomposed by micro-organisms is called degradable waste. |
The waste that cannot be decomposed by micro-organisms is called non-degradable waste. |
|
Example: Vegetable peel, Paper, clothes |
Example: Plastic |
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 is first separated into degradable and non-degradable wastes?
Solution
(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 off in deep dug out pits so that they do not cause any harm. However, sometimes broken glass in large quantities can be used in glass Industries after melting them.
(b) Landfills are coming up fast near large cities due to huge population growth and lack of using efficient and safe disposal method. As construction activities are very active, new colonies are being raised and construction units have become very active. These produce large quantities of waste stones, pebbles, broken bricks and wood waste. Mostly, these are used as landfills. One can see heaps of landfills in the suburbs.
(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 needs to be dumped or burled at safe places to avoid any hazardous effects.
D. Long Answer Type
1. Define electronic waste and list at least six items which come under this category.
Solution
Electronic waste is the waste generated by discarded electrical appliances. Items which come under the category of electronic waste:
- Fluorescent tubes
- Medical instruments
- Toys
- Lead acid batteries
- Mobile phones
- Radios
2. List some of the common wastes produced in mining operation and mention how these can be reused.
Solution
Common wastes produced in mining operation: Coal, Dust, Iron, Copper, Zinc, etc.
Reusing of wastes produced in mining operation: During operation of getting minerals, a large quantity of waste material is produced. This waste material is called mine tailing. It is the left over. The mine tailing can be mixed with materials to produce tiles and masonry cement.
3. Describe the procedure usually used to produce compost
Solution
The rotting and conversion of organic waste into manure is known as composting. The product formed after composting is called compost.
Method of preparing compost:
- A trench of about 5 m long, 1.5 m wide and 1.5 m deep is dug.
- A 30 cm thick layer of well-mixed refuse and waste is spread on it. This layer is completely wetted with a watery mixture of cow dung and some mud.
- A second layer of mixed refuse is spread over the first layer, till the heap rises about half a metre.
- The set-up is kept undisturbed for about 3 months, during which water is sprinkled over it at regular intervals.
- A trench is then dug, its material is taken out and rearranged in conical heaps and covered with a layer of soil.
- After 50-60 days, compost is ready for use in cultivation fields 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:
- It reduces the weight of the waste.
- It reduces the volume of the waste.
- It renders toxic wastes into less toxic or even non-toxic wastes.
Precautions required for incineration:
- It should be carried out at very high temperatures.
- It should be equipped with pollution control devices.
- It should be installed away from residential areas.