Course: Science and Elementary Technology, Topic: UNIT 10: Sustainable waste management

General

UNIT 10: Sustainable waste management
1. Look at the picture below.

Fig 10.1
2. Is there a better way in which we can manage the wastes in the
picture?

10.1 Classification of wastes
Find out
1. How wastes are classified.
2. What should happen to the wastes.
Activity 10.1 Classifying wastes
1. Take a walk around the school compound.
2. Look out for any types of wastes.
3. Group the wastes as shown in the table below.
4. Discuss the advantages and disadvantages of each category of
wastes.
5. How should we dispose of each type of waste?
The two main categories of wastes are biodegradable and non-biodegradable
wastes.
a) Biodegradable wastes – these are wastes that can be
decomposed by microorganisms to form organic manure.
They include kitchen garbage, animal dung, vegetable remains
among others.
b) Non-biodegradable wastes – wastes that cannot be decomposed
by microorgarnism. They are recycleable. They remain in the
environment forever.
Examples: plastics, polythene bags and
glass.
Waste can also be grouped as follows:
a) Hazardous wastes – wastes that can
harm or cause diseases, fire etc. Examples
are biomedical wastes.
b) Toxic wastes – wastes that can cause death. Examples: chemicals
and gases such as carbon monoxide.
c) Flammable wastes – wastes that can easily catch fire and react
explosively with air. Examples : waste fuels and gas cylinders.
Remember!
We should form a habit of separating wastes into their various categories.
For example, hazardous, biodegradable and non-biogradable recyclable
wastes.
10.2 Sources of wastes
Find out
Different sources of wastes.
Activity 10.2 Discussion
1. Think about the activities that take place in the following places:
• Farms
• During general cleaning at home
• Industries
• Medical centres
(i) Which ones create wastes?
2. For each category, discuss some wastes that come about as a
result of the activities.
Sources of wastes in our environment include:
• Urban or municipal wastes
- these are wastes collected
from residential areas, markets,
streets and other places mostly
in town. Examples: plastics, old
clothes, pieces of glass, organic
matter and food remains from
households and wastes from
business premises establishments.

• Industrial wastes - these
originates from cement factories,
power stations, textile factories,
food processing industries and
many others.
Remember!
Some of these wastes especially those from chemical industries can
be hazardous, so we need to be careful when handling them.
• Agricultural wastes - Bio-degradable wastes, are associated
with agricultural activities.
Examples: crops remains, animal remains,e.t.c
• Construction wastes - these are wastes from construction sites.
Examples: unwanted materials produced at the construction sites,
empty cement bags, broken bricks, soil and packaging boxes .
• Biomedical wastes - generated from hospitals, clinics and other
medical institutions. Examples: expired drugs, surgical dressings,
plastic syringes and used gloves.
• Electronic sources of wastes - e-waste or e-scrap are old
electronic and electrical devices. Examples : old DVD, television
sets, telephones, computers, vacuum cleaners and their parts.
• Wastes from automobiles - are wastes that come from cars or
old vehicles. Also, oil and grease.
10.3 Waste management techniques
Find out
1. How garbage is collected.
2. How garbage is safely transported to a landfill.
3. How recycling, up cycling and re-using of waste is done.

Activity 10.3 Applying waste management techniques
1. Collect the garbage around the school surroundings.
2. Apply waste sorting techniques
3. Search in library, text book or search engine on waste
management.
4. Write a report on compositing of waste,up cycling and
recycling of waste and waste processing .
Wastes should be handled depending on their types:
• Hazardous wastes - These can cause harm. They should either be
buried or burnt in an incinerator. For example, hospital waste.

Note :The golden rule of environmental stewardship
Always remember the 3Rs - Recycle, Reuse and Reduce!

Waste management refers to the process of handling wastes after its
production. Some ways of handling wastes include:
• Collection of the wastes.
• Safe transportation of wastes.
• Waste processing to identify what wastes are to be re-used, recycled
or decomposed.

a) Professional garbage collection
Garbage or wastes can be collected in
two ways:
• The garbage is thrown into dust
bin.
• By depositing the wastes in a
compost pit.
b) Safe waste transportation
Collect and safe transport the garbage to dumpsites or landfills.
c) Proper waste processing
Biological , chemical and mechanical methods used are:
1. Changing chemical composition of waste.
2. Removing environmental pollutant from industries and municipal
wastes.
3. Treating sewage before discharging.

(d) Recycling and re-using
Recycling is the process of converting waste materials into same new
materials. Old plastic bottles can used to make new ones.
Re-using is making use of the waste product for another purpose from
the original one.
For example: old plastic tins can be used as flower pots.
e) Up cycling
Up cycling is changing the wastes into different utility items. For
example, plastic bottles can be used to make chairs, toys among
others things.
f) Compositing
This is making use of natural processes to decompose. These
wastes materials ( biodegradable)are dumped in a compost pit and
left to rot or decay. The manure formed is used in agriculture to
improve crop production.
UNIT TEST 10
1. What is waste management?
2. With examples, give the difference between biodegradable and
non-biodegradable wastes.
3. a) What are hazardous wastes?
b) Write down different types of hazardous wastes and their
potential danger.
4. Distinguish between recycling and re-using wastes?
5. Recently, Kigali was ranked as the cleanest city in Africa. How do
you think the government of Rwanda has managed to do this?
6. The golden rule of waste management is 3Rs. What does it stand
for?
7. Give the missing information in the table below.
8. What do you understand by the term ‘professional garbage
collection’?
9. Mungwana’s computer got spoil. He took it and dumped it in a
compost pit nearby his home. Comment on this.
10. What can you advise Gamka who doesn’t like collecting garbage
in her home compound?
11. Explain what landfill is and its importance in the society.
12. What should be done to hazardous wastes?
13. Wastes are a must! Discuss this statement.

Science and Elementary Technology

General

UNIT 10: Sustainable waste management

UNIT 10: Sustainable waste management

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