ICSE Class 9 Biology · Solutions for Class 9 ICSE Concise Biology Selina · 30 solved questions
How will you categorise the following under domestic and industrial wastes ?
Rags, used containers, old newspapers, mine tailing (left overs), flyash, kitchen waste, broken bricks.
| Domestic | Industrial waste |
|---|---|
| Rags | Mine tailing (left overs) |
| Used containers | Flyash |
| Old newspapers | Broken bricks |
| Kitchen waste |
What is bagasse?
Bagasse is the plant residue left after extracting the sugarcane juice. It is used as fire wood or in paper industry.
Name any two categories of chemicals which are washed off as wastes from agricultural fields.
Pesticides and fertilizers
What are the two portions into which the municipal sewage is separated?
In which category of wastes will you include the non-functioning discarded
Name the three categories of wastes under segregation.
Which categories of wastes require dumping ?
Non-degradable
Is it true that composting is a useful method contributing in crop farming ?
Yes, composting is a useful method contributing in crop farming as compost is good for soil and plant health.
What is sludge ?
Sludge is solid precipitated material which is produced during secondary treatment of effluents and it can be used as a manure.
Can incineration lead to certain kind of pollution? Yes/No.
Yes, incineration leads to certain kind of pollution as it results in release of fumes and gases.
Name two types of devices used for removing particulate air pollutants.
The 'Municipal solid waste' is the term used to describe what kind of solid waste ?
Non-hazardous
Reason — The 'Municipal solid waste' consists mostly of domestic wastes of township which is non-hazardous.
The most rapidly increasing and much harmful waste today is
plastics
Reason — Plastics are non-degradable and are extremely harmful for environment.
Out of the following, which substance can be recycled many times?
Aluminium
Reason — Aluminium can be recycled many times as its quality is not hampered after recycling.
Which of the following is not a waste from construction sites?
Bagasse
Reason — Bagasse is sugarcane plant residue left after extraction of sugarcane juice.
Which of the following is a kind of gaseous waste?
Fly ash
Reason — It is gaseous waste and contains very fine solid particles.
Assertion (A): Waste is any substance which is worthless and of no use.
Reason (R): Wastes are the substances discarded after primary use by humans.
A is False and R is True.
Reason — Waste is often considered useless in its current form but not all waste is worthless. Many wastes can be reused, recycled, or repurposed.
Waste refers to items that are discarded after their initial use, regardless of whether they still have potential value.
Assertion (A): Clothes that are very old and torn are termed as rags. Rags are a kind of domestic waste.
Reason (R): Rags can be considered as a municipal waste which cannot be reused or recycled.
A is True and R is False.
Reason — Old, torn clothes are commonly referred to as rags, and they fall under domestic waste. Rags are part of municipal solid waste, many rags can be reused or recycled, for example, as cleaning cloths, stuffing material, or in textile recycling.
Assertion (A): Incineration is the disposal of waste by dumping it in a pit.
Reason (R): Incineration is harmful as it releases fumes and harmful substances.
A is False and R is True.
Reason — Incineration is the process of burning waste at high temperatures to reduce its volume. Disposal of waste by dumping it in a pit is known as landfill.
While incineration reduces waste volume, it can release toxic gases and particulate matter, which can be harmful to health and the environment if not properly managed.
Assertion (A): Electronic wastes do not contain any harmful substances or valuable materials.
Reason (R): Computers, mobile phones, batteries, etc. contain lead, cadmium, silver and copper.
A is False and R is True.
Reason — E-waste contains both harmful substances (like lead, mercury, cadmium) and valuable materials (like gold, silver, copper). That is why proper recycling is essential—to recover valuable metals and prevent environmental harm.
These electronic items contain toxic heavy metals (like lead and cadmium) and valuable metals (like silver and copper), which are extracted during e-waste recycling.
Assertion (A): Electrostatic precipitators remove gaseous air pollutants by attracting them to electrically charged plates.
Reason (R): The electrostatic precipitators can remove upto 90% of particulate matter from thermal plants.
A is False and R is True.
Reason — Electrostatic precipitators are designed to remove particulate matter (like dust, ash, and soot), not gaseous pollutants.
Electrostatic precipitators are highly efficient and can remove up to 90–99% of particulate matter, depending on their design and maintenance. This helps reduce harmful emissions and improve air quality.
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.
(c) The process of disposal of waste by burning.
(d) The solid waste residue left after burning.
(e) The category of wastes given out from homes.
(a) Sludge
(b) Scrubbers, Electrostatic precipitators
(c) Incineration
(d) Ash
(e) Domestic wastes
Correct the following statements by changing the first/last word only.
(a) Some of the electronic wastes may contain valuable metals such as potassium.
(b) Sludge is the gaseous waste of cement industry.
(c) Drains are used to remove gaseous and particulate air pollutants.
(d) Industrial liquid waste is termed as sewage.
(e) Rags are the plant residue left after extracting the sugarcane juice.
(a) Some of the electronic wastes may contain valuable metals such as gold, silver and copper .
(b) Fly ash is the gaseous waste of cement industry.
(c) Scrubbers are used to remove gaseous and particulate air pollutants.
(d) Domestic liquid waste is termed as sewage.
(e) Bagasse are the plant residue left after extracting the sugarcane juice.
Match the items in Column I with as many items as possible in Column II.
| Column I | Column II |
|---|---|
| Cow dung | Sugarcane |
| Bagasse | Manure |
| Okhla khad | Food wastes |
| Lead and cadmium | e-wastes |
| Column I | Column II |
|---|---|
| Cow dung | Manure |
| Bagasse | Sugarcane |
| Okhla khad | Food wastes |
| Lead and cadmium | e-wastes |
Define the terms:
(a) Waste
(b) Fly ash
(c) E-wastes
(d) Composting
(e) Mine tailing
(a) Waste is any substance which is discarded after primary use, or is worthless, defective and of no use.
(b) Fly ash is gaseous waste of cement industry which contains fine solid particles of non-combustible ash.
(c) e-Wastes are electronic wastes that consist of discarded appliances using electricity like computers, TVs, etc.
(d) Composting means putting the waste organic matter to decay so that it can be used for fertilizing the agricultural land.
(e) Mine tailing are the left-over material after the processing of the mined products like copper, silver, gold, etc.
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.
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:
List some of the common wastes produced in mining operation and mention how these can be reused.
Common wastes produced in mining operation are:
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.
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:
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:
Precautions:
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