Chemistry

LEARNING OBJECTIVES

After reading this unit, you will be able to:

•describe the steps involved in effective waste management

•explain the importance and benefits of waste recycling

•discuss the various effects of waste materials and poor waste disposal.

KNOWLEDGE GAIN

Segregate the waste as biodegradable and non-biodegradable.

4.1 STEPS TO EFFECTIVE WASTE MANAGEMENT

ACTIVITY 4.1: Steps to Waste Management

You must have seen an overflowing dustbin and held your breath when you crossed it on the street. What made you hold your breath? Have you ever thought that you are also involved in creation of this foul smell? Discuss this with your friends. Also think how you may contribute in reduction of this foul smell.

Waste materials (or rubbish) especially household wastes, are called garbage. Every time you throw something, you produce garbage. The peels of fruit and vegetables, left over cooked food and fallen leaves of plants are thrown away as garbage.

Unwanted, unused objects are thrown as garbage. Can you list out some waste materials you contribute to garbage? The garbage we add to the dustbin rots to produce foul smell. You can help in lessening the foul smell and making the dustbin look more attractive by adopting effective ways of waste management.

Many countries in Africa are facing significant challenges in relation to waste management. Waste generation is increasing. Only a sizeable portion of it is disposed on improperly located and operated dumpsites. It is having adverse impacts on environment and health.

ACTIVITY 4.2: Illustrating Waste Hierarchy

Observe the diagram. Sit in groups and discuss the terms given in waste hierarchy to manage waste.Make presentation with your group on the same. Give your views and suggestions in presentation.

Waste management includes all the processes of handling waste and reducing it. There are six steps to achieve effective waste management. These steps are studied as waste hierarchy. Waste hierarchy focuses more on waste minimization. All the steps revolve around the same motive. These steps are:

4.1.1 Prevention

ACTIVITY 4.3: Illustrating Prevention of Waste

At the end of the day, after you have taken your dinner and the kitchen has been cleaned, investigate the dustbin of your house. Look at the waste generated in your house. Make a list of the type of items in the waste. Which of the items do you think could have been avoided? Discuss with your family members and try to avoid the waste you could.

Prevention or avoidance means preventing or avoiding of the waste completely. It seeks to prevent waste from being generated. Waste prevention strategies include using less packaging, designing products to last longer. For example, we can stop using plastic carrier bags, and instead long-life bags, such as canvas bags.This is less practical and very expensive. It requires research to completely avoid or replace a substance or process. It is like, completely stopping vehicles like car in the dream to stop pollution. It is the most environmentally preferred strategy.

4.1.2 Minimization

The easiest method of waste management is to reduce creation of waste materials. It is done by reducing the amount of waste going to dustbins. It is a very cost-effective method. Reducing waste is self-explanatory. Waste minimization involves redesigning products and/or changing societal patterns, concerning consumption and production. It can be achieved in homes using more efficient appliances or using their electric supply more effectively. The following are some ways by which you can contribute to minimize waste

•By not leaving heating on constantly

.•By closing water running too long

.•By boiling a kettle with the right amount of water in it

.•By switching off the lights whenever not in use.

Figure 4.2: Close the running tap and switch off electricity when not in use.

4.1.3 Reuse

ACTIVITY 4.4: Showing Reuse of Waste

Students will take a nature walk, make observations, and collect natural objects for an art activity. Also collect some waste products which you can see. Now make some useful products from the materials you have collected. Showcase them in an art exhibition. Following are some things you may use.

This is simple; reduce waste by not wasting something, but reusing it. We should reuse items we normally throw away.For example, we should use sacks or clothed bags for multiple times instead of throwing them away after just one use. It is a cost-effective method as it can reduce on our purchases. It includes refilling. Ink cartridges are an example, in which the only bit replaced is the stuff

that is used up (i.e., the ink). Glass milk bottles are also often collected, washed, refilled and delivered many times in their life. Can you name some other items that you may reuse? Reuse is often seen along with the value which is retained of the product.

4.1.4. Recycling

ACTIVITY 4.5: Illustrating Recycling of Waste

Making a Model

To make your own recycled paper

•Take waste paper from old newspapers and magazines, and tear them into small pieces.

•Take warm water in a bucket and add a little starch to it

.•Soak the paper in the water for 5–6 hours.

•Take the paper out of the water and pound it with a mortar and pestle till it becomes soft and fluffy

.•Add more starch to it to thicken it

.•Spread this pulp on a fine wire mesh, and press it to squeeze out the excess water

.•Carefully turn the wire mesh upside down on a smooth surface, and put some weights on it

.•Let the pulp dry for several hours.

Once it dries up, your hand-made recycled paper is ready! You may not be able to write on the recycled paper, but you can draw on it.

We should remember to recycle items that are recyclable. Recycling is a series of activities that includes collecting used, reused, or unused items that would otherwise be considered waste. It includes sorting and processing the recyclable products into raw materials. Further, re-manufacturing the recycled raw materials into new products. Recycling involves putting energy into a waste item to convert it to something else entirely, sometimes with lower grade and value. Consumers provide the last link in recycling by purchasing products made from recycled content. It is the preferred option when reuse is not an option, if an item is broken, or in a poor condition that means it cannot be reused. In the milk bottle example, reusing involves washing and refilling, while recycling would involve grinding the glass and melting it again, turning the raw material into a different grade of glass.W bulb for

Do you Know

EXERCISE 4.1

1. What are the effective ways of waste management?

2. Prevention means preventing or avoiding of the ______ completely.

3. The easiest method of waste management is to reduce creation of waste materials.

                                                                                                           (True or False)

4. Name four items that you can reuse.

5. What are the components of garbage?

4.1.5 Energy Recovery

ACTIVITY 4.6: To Make a Biogas Generator

Materials

•1-litre clear plastic bottle (sports drink bottles and other wide-mouthed receptacles work particularly well for this activity, but you can use whatever is in your recycling bin)

•A few balloons

•Duct tape

•1/3 cup of raw vegetable scraps and grass

•1/3 cup of soil from the outdoors (not bagged potting soil)

•Permanent marker

●Scoop or large spoon

●Funnel

•Ruler

●String

How to make it

•Mix the vegetable scraps, grass, and soil

.•Using the funnel, pour it into the bottle

.•Stretch a balloon carefully over the opening of the bottle, and duct tape around the balloon’s base to seal it to the bottle and keep outside air out.

•Over the next few days, the microbes in the soil will digest the mixture and create methane gas, which will fill the balloon

.•Every other day, measure the amount of mixture in the bottle, and measure the circumference of the balloon by wrapping the string around it, marking it, and measuring the string.

Energy recovery from waste is the conversion of non-recyclable waste materials into usable heat, electricity, or fuel through a variety of processes, including heating. This process is often called waste-to-energy (WTE). It converts non-recyclable waste materials into electricity and heat. After energy is recovered, approximately ten per cent of the volume remains as ash, which is generally sent to disposal.

Energy recovery can also be achieved with bio-mass waste. We can either burn it directly, or compost it to capture methane, which can be burned to produce energy (bio gas).

How to find out the valuable “wastes” from daily wastes and convert the “wastes” into treasure?

As for high calorific solid wastes, briquetting is one of the ways to turn the wastes into treasure. Briquetting technology is used to density the loose combustible materials into solid composites. It can be made of different shapes and sizes with the presence of pressure and binding agents. Generally, there are a wide range of materials that can be used to make briquettes, such as waste paper, cardboard, water hyacinth, agricultural residues, charcoal dust, and wood wastes like sawdust, etc.

Try to find on internet and in library and research how briquetting is done.

4.1.6 Disposal

ACTIVITY 4.7: Showing Waste Disposal System

Visit a landfill and an incinerator site. Ask the people working there about description and details of the processes. Prepare a report and present in the class.

“Disposal” is also known as “burying it”. Mostly, it is least favored because we don’t get anything back from what we put in the ground. Once something is in disposal and buried, there is no real harm the waste can do as it degrades naturally – although this can take thousands of years. Some CO2 or other greenhouse gases may be released, however. Overall, sending something to disposal should be the last resort when the above five options have been tried.

Landfills are the most common form of waste disposal and are an important component of an integrated waste management system. In this method, the non-useful garbage is burned at a high temperature in a special kind of furnace called “incinerator”.

Composting is also a kind of disposal system. It is the process of converting plant and animal waste materials into manure. The biodegradable domestic garbage includes fruit and vegetable peels, left-over food and fallen leaves, etc. Compost is a natural fertilizer.

ACTIVITY 4.8: Preparing Compost

Dig a pit in the ground about 30 centimeters deep in a corner of the garden. Dump the plant wastes such as fruit and vegetable peels, left-over cooked food and fallen leaves into the pit on daily basis. The animal wastes like cow dung may also be added to the pit (see Figure below).

When the pit gets filled to the top with plant and animal wastes, a few buckets of water are added to the pit. The pit is then covered with a paste of soil and left undisturbed for about 3 months. The micro-organisms present in soil decompose the plant and animal waste materials buried in the pit to form compost. The compost formed can be dug up from the pit and used as a manure in the garden to grow plants. Please note that we should not dump plastics, glass pieces or metal objects in the compost pit because these are non-biodegradable waste materials which cannot be converted into compost by the micro-organisms present in the soil.

ACTIVITY 4.9: Game of Waste Management

Collect different pictures/images of waste items. Make cards by pasting them on cardboard. Mix them all. Sort the items (game pieces) into the category on the game board that you think is best for the earth.

ACTIVITY 4.10: Importance of 3Rs

Make a table showing wastes which can be reduced, recycled and reused. Discuss the importance of 3Rs in the class.

EXERCISE 4.2

1. Energy recovery can also be achieved with bio-mass waste.

              (True or False)

2. Disposal is also known as _____________.

3. What is the most common form of waste disposal?

4. Give one importance of waste disposal.

5. Compost is a natural __________ .

4.2 IMPORTANCE AND BENEFITS OF WASTE RECYCLING

ACTIVITY 4.11: Practicing Recycling Week

Practice recycling week in your routine. Discuss the benefits of recycling in your class during the week. At the end of the week, present your findings as report.

Effective Ways of Waste Management83If your approach is not towards disposing materials and other wastes, this recycling method will be a good approach for you. This is a process aimed to make undesirable objects into useful ones. By understanding what you can recycle and how you can recover valuable resources, you can be a very best part of helping the country to attain a positive environmental future.

The idea behind recycling is to reduce energy usage, reduce volume of landfills, reduce air and water pollution, reduce greenhouse gas emissions and preserve natural resources for future use. Some of its benefits are:

4.2.1 Environmental Protection

•Recycling includes reducing deforestation: Recycling reduces the need for raw materials, so that our forests can be preserved.

•Recycling helps reduce pollution: The manufacturing process (including the extraction of raw materials from the earth) for many products releases waste that pollutes the environment. For example, the power plants that provide the energy needed in the manufacturing process produce gases that pollute the air.The more we buy (as opposed to reducing), and the more we throw away (instead of reusing and recycling them), the more waste we create. This waste releases poisonous gases and chemicals into the environment during the disposal process.For example, when the non-biodegradable products in our waste are burned, they often emit gases that deplete the ozone layer in the atmosphere. These gases allow more ultraviolet radiation to reach our living atmosphere, giving rise to global warming and rising sea levels.

•Recycling also aids in reducing land pollution: Imagine if the various materials (especially the non-biodegradable ones) in our waste could be sent for recycling, the amount of waste that needs to be incinerated or buried in landfills would be reduced. With less waste, there would also be less need for landfills and incinerators. These lands could then be freed up for other uses.

4.2.2 Conservation of Natural Resources

By recycling, there is less need for raw materials. Less need for the resources that have to be planted, grown and harvested or extracted from ground (ores and minerals) and less need for space. Using recovered steel materials (through recycling) in place of raw ones, there is less demand for mining practices, which are environmentally devastating.

Recycling also helps us make full use of the precious materials that we have spent much resources, energy and effort to extract from the earth.

4.2.3 Energy Saving

It takes much less energy to make products using recycled materials as compared to making products from raw materials. This is because when products are made from raw materials, energy is not only required in the production process, but also in the extraction of the raw materials from the earth and the transportation of these materials to the manufacturing plants. Whereas for production, using recycled materials, the raw materials are already available. The recyclables are hardly broken down into their basic components for use in manufacturing

4.2.4 Job Creation

Recycling is more labor-intensive than land filling or incineration. This means that building the recycling industry is a way to create more jobs. More people will be engaged while you recycle. This will also help in improving the economy of the country. The various recycling industries include paper recycling units, steel recycling plants, plastic recycling plants and glass recycling units

EXERCISE 4.3

1. What are the benefits of waste recycling?

2. Recycle does not help reduce pollution. (True or False)

3. How do wastes pollute our environment?

4. Recycle waste materials into ______ .

5. Recycling industry is a way to create jobs. How?

4.3 EFFECTS OF WASTE AND POOR DISPOSAL

ACTIVITY 4.12: Group Discussion on Poor Disposal of Garbage

Imagine we all throw garbage, junk and rubbish away anyhow. Imagine there was no authority to supervise waste management activities from all the sources mentioned earlier. Imagine we all just sent our rubbish to the landfill, or just dumped them in a nearby river. What do you think will happen? A disaster! Engage in a group discussion to talk about the same.

 Modernization and progress has had its share of disadvantages and one of the main aspects of concern is the pollution it is causing to the earth – be it land, air, and water. With increase in the global population and the rising demand for food and other essentials, there has been a rise in the amount of waste being generated daily by each household. Solid wastes, when improperly disposed off can be an environmental hazard because, the surrounding environment and the fish in the nearby ponds get affected. This improper disposal can lead to death of fish as well as diseases to man, e.g., dysentery, cholera and some other fatal diseases.

Some of these wastes can also be very harmful to the atmosphere. These wastes when improperly dumped into the atmosphere can lead to the destruction of the ozone layer and may cause diseases such as cancer. As a result, of late a problem has cropped up, i.e., global warming. Air pollution can also lead to formation of acidic rain which is dangerous to crop life since it leads to the removal of soil fertility from the surface of the ground.   

It also affects drainage. When solid wastes are dumped in drainage channels and gutters, they block the flow of the sewage. This may cause flood. At the same time, solid wastes also affect soil drainage which hinders the growing of crops. Since some of the waste materials are waterproof, they can be dangerous to the aeration system of the soil and binder agriculture. It also leads to the reduction of fertile cultivatable land in the form of dumping sites. This in turn affects the country since Rwanda depends on agriculture for exports. It also pollutes the underground water which we use for various activities.

Waste materials like toxic if consumed by animals can be very dangerous to life and worse still if these wastes are dumped in water bodies. They are dangerous to aquatic life. Poor solid waste also leads to the death of animals (especially domestic animals). Death of animals like cattle leads to poverty and the death of animals like dogs, leads to insecurity in homes.

Poor Domestic Waste management also displays an ugly scenario of the environment. This can affect the tourism industry, as the tourists may not get attracted to visit the country. It also leads to the spread of diseases in such a way that when wastes like broken bottles are dumped anywhere, they collect water in them (when it rains) and this may become a breeding ground for mosquitoes. Wastes like human stool causes diseases when poorly dumped, as the flies will carry the germ from the stool. It can also lead to human injury. For example, when a person walks and steps on the broken bottles or nails or even pins (sharp objects), he can get injured which may lead to bleeding.

Uncontrolled dumping of solid waste can lead to wastage of land where we find lots of land being used as dumping sites for wastes. These same pieces of land are later on neglected by the inhabitants of the area.

ACTIVITY 4.13

Go out on field trips and study tours with your teacher to different industrial sites. Visit garbage pits or biogas plants. Understand and know the prevalent problem of waste and its proper utilization. Now submit a poster to your teacher showing techniques of waste management.

EXERCISE 4.4

1. Improper disposal of waste can lead to death of ______ as well as _______ .

2. Name two diseases caused by poor disposal of wastes.

3. Poor domestic waste management shows an ugly scenario of environment.

(True or False)

4. What are the effects of poor waste disposal?

5. How does poor disposal of wastes cause flood?

4.4 SUMMARY

•Waste material, especially household wastes are called garbage. It is very important to manage this waste material in a proper way. Waste management includes all the processes of handling waste and reducing it. There are six steps to follow:

♦Prevention: It means avoiding the waste completely. It is less practical and expensive

.♦Minimization: It means reducing the creation of waste material. It is very cost-effective.

♦Reuse: It means reducing waste by not wasting it but reusing it. It is also an effective method.

♦Recycling: It means collecting used, reused or unused items and processing them to form new products. It is used when reuse is not an option. It helps in environmental protection, conservation of natural resources, energy saving and job creation.

♦Energy Recovery: It means converting waste into usable heat, electricity or fuel. It is an effective method to produce energy.

♦Disposal: It means burying. It can take two forms—landfill and composting.

•Waste can cause deleterious effects not only to living beings but also to the environment. It causes diseases like cholera, dysentery and also pollutes air, land and water. The pollution created by waste also affects the tourism industry by affecting the scenic beauty of the country.

4.5 GLOSSARY

•Biodegradable waste: waste which can be broken down, by micro-organisms.

•Breeding ground: an area where birds, fish, or other animals habitually breed.

•Composting: the process of converting plant and animal waste materials into manure.

•Energy recovery:the conversion of non-recyclable waste materials into usable heat, electricity, or fuel through a variety of processes.

•Garbage:waste materials (or rubbish), especially household wastes, are called garbage.

•Global warming:the increase of Earth’s average surface temperature due to effect of greenhouse gases.

•Incinerator: a vessel where incineration occurs. Incineration is a waste treatment process that involves the combustion of organic substances contained in waste materials.

•Landfill: a site for the disposal of waste materials by burial.

•Non-biodegradable waste:waste that cannot be broken down. It remains in the environment as such.

•Ores: the ores are extracted from the earth through mining; they are then refined to extract the valuable element, or elements.

•Waste management: activities and action required to manage the waste.

•Waste recycling: the processing used materials (waste) into new, useful products.

4.6 UNIT ASSESSMENT

I. Multiple Choice Questions

1. Landfill is an effective way of

(a) Disposal   (b) Recycle    (c) Reuse (d) Reduce

2. Waste which can be broken down by micro-organisms

(a) Toxic (b) Biodegradable (c) Non-biodegradable (d) Deleterious

3. The most favored option of waste hierarchy is

(a) Minimization (b) Energy recovery (c) Prevention (d) Disposal

4. Glass bottles can be

(a) Reused (b) Recycled (c) Reduced (d) All of these

5. Recovering the waste can produce

(a) Fuel (b) Water (c) Heat (d) Both (a) and (c)

6. Generation of fertilizers from waste is

(a) Briquetting (b) Composting (c) Landfill (d) None of these 

7. Recycling benefits in .................

(a) protection of environment       (b) developing better quality product

(c) both (a) and (b)                       (d) none of these

8. Waste disposal affects

(a) Government (b) Electricity (c) Rain (d) None of these

9. Using canvas bags instead of plastic is an example of

(a) Prevention (b) Minimization (c) Disposal (d) Energy recovery

10. .................. is more labor intensive.

(a) Incineration (b) Landfill (c) Recycling (d) ReuseII.

Open Ended Questions

1. Add the following waste to the appropriate bin.

2. What is briquetting?

3. State the benefits of waste recycling.

4. What is waste management?

5. Name the six steps of effective waste management.

6. How can you contribute to minimize the waste?

7. What is waste to energy?

8. How does poor waste handling cause diseases?

9. How does poor disposal technique affect tourism sector?

10. State two examples on how energy is recovered from recycling.

PROJECT

Make a presentation showing benefits of waste recycling.