Class 9th ICSE Biology Solutions Chapter 19 Waste Generation and Management
Question 1.
How will you categorise the following under domestic and industrial wastes?
Rags used containers, old newspapers, mine tailing (leftovers), flyash, kitchen waste, broken bricks.
Answer:
Domestic wastes :
- rags,
- used containers,
- old newspapers,
- kitchen waste.
Industrial wastes :
- mine tailing,
- flyash,
- broken bricks.
Question 2.
What is bagasse?
Answer:
The plant residue (portion of the stems left after extracting the juice of sugarcane by the sugar mills) is called bagasse. This is used in the paper industry or as firewood.
Question 3.
Name any two categories of chemicals which are washed of as wastes from agricultural fields
Answer:
- Pesticides
- Fertilizers
These are washed of with the irrigation and rain and thus polluted water to river and pond pollution.
Question 4.
What are the two portions into which the municipal sewage is separated?
Answer:
The municipal sewage is separated into :
- The degradable portion (the sewage is broken down chemically into nontoxic parts) septic tanks are used to degrade the degradable parts.
- The non-degradable portions. Non-degradable part is dumped or buried at safe places.
Question 5.
In which category of wastes will you included the non-functioning discarded
(i) Mobile phones, (ii) Thermometers,
(iii) Photocopying machines.
Answer:
- Mobile phones = Electronic waste
- Thermometers = Electronic waste
- Photocopying machines = Electronic waste
Progress Check
Question 1.
Name the three categories of wastes under segregation …………………..
Answer:
Categories of wastes under segregation.
- Reusable: Wastes can again be used as newspapers, books (old) answer books
- Degradable: Organic wastes (as vegetable and fruit: peels) can be decomposed and used as manures.
- Non-degradable: Such as plastics are non-degradable and are dumped.
Question 2.
Which categories of wastes require dumping?
Answer:
Non-degradable wastes such as certain plastic require dumping.
Question 3.
Is it true that composting is a useful method contributing in crop farming?
Answer:
The waste organic matter is left to decay and it is used as fertilizer for the agriculture land. Compost mainly from garbage and left overs and human sewage (might soil) is left for decay and then it is used in the fields as manure. So compost is useful for the crops.
Question 4.
What is sludge?
Answer:
The waste water from the industries and the municipal sewerage system is treated in the Effluent Treatment Plants and then it is used in the fields or disposed into the water bodies. The waste water is pumped into the oxidation ponds and here it is subjected to by micro-organisms (as bacteria, algae etc.) and during the process CO2 is released. The solid precipitated material settles down. This solid material is called sludge. Metals, pathogens, chemicals are removed from the waste water and then it is released into the fields or into the streams.
Question 5.
Can incineration lead to certain kind of pollution? Yes/No :
Answer:
No doubt the incineration reduces the volume and weight of the pollutants or wastes but during incineration it releases,
fumes and harmful substances as ash, thus incineration leads to pollution.
Question 6.
Name two types of devices used for removing particulate air pollutants.
Answer:
There are two types of devices used for removing particulate air pollutants as
- Scrubber
- Electrostatic precipitator
Review Questions
A. Multiple Choice Type :
(Select the most appropriate option in each case)
Question 1.
The most convenient reusable wastes are
(a) Old newspaper
(b) Broken glass
(c) Flyash
(d) Medical instruments
Answer:
(a) Old newspaper
Question 2.
The most rapidly increasing and much harmful waste, today is
(a) plastics
(b) pesticides
(c) municipal sewage
(d) electronic waste
Answer:
(a) plastics
B. Very Short Answer Type :
Question 1.
Name the following :
(a) The solid precipitated material produced during secondary treatment of the effluent of carried out in the suffluent Treatment Plants.
(b) The two types of devices commonly used for removing the particulate air pollutants.
Answer:
(a) Material produced is sludge.
(b) Two types of devices are :
(i) Scrubber
(ii) 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. (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)
Answer:
(a) True
(b) True
(c) True
Question 3.
Match the items in Column I with as many items as possible in Column II.
| Column I | Column II |
| 1. Cow dung | (i) Sugarcane |
| 2. Bagasse | (ii) Raddiwalas |
| 3. OId newspapers | (iii) Manure |
Answer:
| Column I | Column II |
| 1. Cow dung | (i) Sugarcane |
| 2. Bagasse | (ii) Raddiwalas |
| 3. OId newspapers | (iii) Manure |
C. Short Answer Type:
Question 1.
Differentiate between degradable and non-degradable type of waste.
Answer:
Degradable waste organic wastes as vegetables, fruits peels can be decomposed by the bacterial activity and can be broken into simpler substances and form manures which are useful for agriculture.
Non-degradable wastes non-degradable wastes cannot be decomposed into simple substances. Such as plastics.
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.
Answer:
(a) Yes broken glass utensils are non-degradable wastes.
These should be disposed off in deep dug out pits so that they may not cause any harm.
- But sometime the broken glass if in large quantities can
- be used in glass industries after melting them.
(b) As construction activities are very active. New colonies ‘ are being raised and construction units are very active, These produce large quantities of waste stones, pebbles, broken bricks, wood waste. Mostly these are used as landfills. One can see heaps of landfills in the suburbs. ‘
(c) Municipal sewage is separated into degradable and non degradable wastes. As the non-degradable part of the sewage is useless and separated and dumped at safe places.
But the degradable is put into oxidation ponds and micro- forganisms act on it and C02 is released and solid matter
is left and it is called sludge and it is used as manure and the waste water is used in the fields or left in the rivers.
D. Long Answer Type :
Question 1.
Define electronic waste and list at least six items which come under this category.
Answer:
Electronic wastes are discarded appliances using electricity. These may have harmful and useful materials. Discarded goods like
- old computers,
- TV’s,
- refrigerators,
- lap-tops,
- radios,
- mobile phones are electronic wastes.
Question 2.
List some of the common wastes produced in mining operation and mention how these can be reused.
Answer:
In India we have hundreds of mines and we extract copper, silver, iron, coal, zinc, aluminium etc. During operation of getting these minerals a large quantity of waste material is produced. This waste material is called mine tailing. This is left over. The mine tailing can be mixed with materials to produce tiles and masonry cement.
Question 3.
Describe the procedure how compost is usually produced.
Answer:
Procedure to prepare compost:
- A trench measuring 5 m long, 1.5 m wide and 1.5 m deep is dug. ,
- A layer of dung, leftovers of animals, peels of vegetables and refuse is mixed and a layer of about 30 cms in thickness of these materials is put into this, trench.
- Then this layer is wetted with watery mixture of cow-dung and mud.
- Then a second layer of refuse is spread over the first layer. Then this set up is left as such for 3 months.
- Then this refuse is subjected to micro-organisms.
- After 3 months the trench is opened and the material is taken out and rearranged in conical heaps and it is covered by earth for 50 to 60 days. After this brownish, blackish material is ready.
- This mass is called compost and it is used in the fields and flower beds.
Question 4.
Describe the usefulness of incineration of wastes, and also mention the precautions required in it.
Answer:
Incineration is disposal of wastes by burning. It serves many purposes:
- It reduces the volumes of the waste.
- It reduces the weight of the waste and toxic wastes become less toxic or even the wastes become nontoxic.
Precautions :
- Incineration should be carried out at very high temperatures.
- It should be equipped with pollution control devices.
- Incinerators should put up away from the residential areas.
ICSE Class 9 Biology Solutions