ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
Introduction
Solid waste management refers to the method of collecting and treating solid waste. In this
module, the sources of solid waste will be identified as well as the impacts, treatment and
prevention of solid waste will be discussed.
Learning Outcomes
Intended Learning Outcomes


Identify the various effects of environmental pollution and describe the engineer's role in
the manipulation of materials and resources.
Select appropriate design treatment schemes and efficient safety measures for waste
disposal and explain their effect if implemented in the community and in the workplace.
Topic Outcomes
 Define solid waste and determine its impacts and treatment, prevention and protection
related to solid waste pollution.
 Recommend treatment, prevention, and protection ways related to solid waste based on
existing rules and standards."
 Identify the sources of solid waste and discuss how to control them
SOLID WASTE
• these are the discarded solid substances generated from human activities and having no
more value with respect to its economic, physiological or technological process
• solid waste in a broader sense corresponds to any domestic, industrial and agricultural
resources that are considered already useless.
Source: http://mizenvis.nic.in/KidsCentre/SolidWastes_2971.aspx?format=Print
Fig. 1. Pile of solid wastes
Page | 1
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
Classifications of Solid Waste
Solid wastes can be classified as follows:

Organic waste- These are the wastes generated during the preparation of food like
vegetables, flowers, leaves, fruits, and other wastes from market places.

Biodegradable wastes –Wastes that come from plants or animals that can be degraded by
other living organisms, often used for composting, If processed, this can be a source of
heat, electricity and fuel. These include human waste, manure, sewage, slaughterhouse
waste.

Non-biodegradable wastes - Waste that cannot be broken down by other living organisms

Combustibles – These are usually organic waste having low moisture content. Examples
are paper, wood, dried leaves, etc.

Non-combustibles – These includes metals, tins, cans, bottles, stones, etc.

Toxic wastes – Examples are old medicines, paints, chemicals, bulbs, spray cans,
fertilizer and pesticide containers, batteries, shoe polish.

Recyclables – These wastes can be recycled or used again for the same or different
purpose. These includes paper, glass, metals, plastics, etc.

Construction wastes - These wastes consist of unwanted materials that are produced
directly or indirectly from the manufacturing, assembly and other construction processes.
Examples of these are rubble, roofing, broken concrete, nails, electrical wiring, etc.

Hazardous wastes - These waste are considered harmful and dangerous and can consist
of medical waste, industrial waste and hospital waste.

Bulky wastes - Examples of these are tree branches, tires etc.
Sources of Solid Waste
Several tons of solid wastes are generated every day. These wastes are disposed of at
various landfill sites that creates foul odor and if not treated properly can become harmful to the
environment as well as to the human beings. The major sources of solid wastes are the following:
Page | 2
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
A. Residential
One of the main sources of solid waste come from households. These places generate huge
amount of solid waste that includes food wastes, plastics, paper, glass, leather, cardboard, metals,
yard wastes, ashes and special wastes such as electronics, tires, batteries, old mattresses and used
oil.
B. Industrial
One of the leading contributors to solid waste are the manufacturing industries,
construction sites, fabrication and power plants. The solid waste are generated from housekeeping,
food and packaging, construction and demolition materials, medical and hazardous wastes.
C. Commercial
Existence of many commercial facilities and buildings are significant factors considered in
the generation of solid waste particularly the hotels, restaurants, stores and office buildings. These
facilities produce lots of solid wastes ranging from plastics, food wastes, metals, paper, glass,
wood, cardboard materials, and other hazardous wastes.
D. Institutional
Institutions such as schools, prisons, military barracks and other government centers can
also generate solid wastes. Example of wastes produced in these places consist of glass, plastics,
food wastes, wood, paper, metals, cardboard materials, electronics as well as various hazardous
wastes.
E. Construction and Demolition Areas
Many solid wastes generated can also be attributed to the construction and demolition sites.
The solid wastes produced in these sites usually consist of steel materials, concrete, wood, plastics,
rubber, copper wires, dirt and glass.
F. Municipal Services
Urban centers also greatly contribute to the generation of solid waste. Among the solid
waste brought about by the municipal services are those from street cleaning, wastes from parks
and beaches, wastewater treatment plants, landscaping wastes and wastes from recreational areas,
including sludge.
G. Agriculture
Agricultural wastes like pesticides, spoiled foods and some hazardous materials are
produced from farms, orchards, dairies and vineyards.
Page | 3
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
H. Biomedical
Biomedical wastes refer to the wastes generated by hospitals and biomedical equipment
and chemical manufacturing firms. These include syringes, bandages, used gloves, drugs, paper,
plastics, food wastes and chemicals. Biomedical wastes should be disposed of properly to avoid
environmental and human problems as well
Effects of Solid Waste Pollution






Leachates from garbage dumps seep into the soil can pollute underground water.
Scavengers, stray animals and insects can invade the garbage and clutter the waste that
can damage the atmosphere and can spread various diseases
Food and water supply, if gets contaminated with pathogens present in solid wastes, may
result in cholera, jaundice, hepatitis, gastro enteric diseases etc.
Waste plastics and rubber pollute the atmosphere with toxic fumes while organic solid
wastes emit obnoxious odor upon decomposition that make the environment polluted.
Hospital and clinic wastes if not properly handled can cause transmission of diseases.
Solid wastes can result in water logging that facilitates breeding of mosquitoes resulting
to the spread of diseases like malaria and plague.
SOLID WASTE MANAGEMENT
Solid waste management can be attributed to the collection and treatment of solid wastes.
This is imperative because waste that are collected but are not treated can result to some
environmental and human problems. It is also related to the control of generation, collection,
handling and dumping of solid waste in the best way to address some environmental considerations
like public health, conservation, etc. To solve the problems in solid waste management, there must
be careful planning with the help of the administrative, financial and engineering department.
Legal aspects should also be taken into considerations knowing that there are differences when it
comes to the waste generated by the residential, industrial, urban and rural areas.
The main goal, therefore, of solid waste management is to reduce and eradicate the adverse
effect of solid waste to individual’s health and to the environment as well so that economy will be
developed and the quality of life will be improved. It also aims to convert solid waste into
something valuable and as a beneficial resource.
The 5 R's of Waste Management
As good citizens, it is our responsibility to manage our waste sustainably. In doing so, we
have to follow the five R’s of waste management, that is, refuse, reduce, reuse, repurpose and
recycle. If these methodologies will be incorporated in one’s business, wastes can be reduced,
Page | 4
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
landfill problems can be minimized and the negative impacts on the environment will be lessened.
Below is the hierarchy of 5R’s. It can be seen that recycling is the last recourse after trying to
refuse, reduce, reuse, or repurpose.
REFUSE
REDUCE
REUSE
REPURPOSE
E
RECYCLE
Fig.2. Hierarchy of 5R’s
1. Refuse
The first in the hierarchy of 5R’s is refuse and this is the best way to minimize waste.
Every business should learn how to refuse waste; they should not buy non- recyclable products
and should be clever in their purchasing decisions and setting standards as early as possible so
that in the process, the organization will become used to refuse waste. When buying products,
refusing unnecessary product packaging is also advised.
2. Reduce
Reducing the amount of waste is one of the best things that all of us can do. Avoiding too
much use of resources can help reduce the waste and therefore, there is less waste to manage.
Listed below are some tips on how to reduce the waste.



To reduce packaging, buy in bulk
Always bring a reusable shopping bag instead of paper or plastic bag every time
you go to a grocery store
Buy products that use less packaging
Page | 5
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment


Instead of buying/using disposable items, buy/use reusable items instead
In your letter box, put signage like "no junk mail"
3. Reuse
One important thing that an individual can do is to reuse waste materials. Start by
focusing in one area of your business or home. You can replace all of the single-used items
with reusable materials and in so doing, the waste material will not end up in landfill but can
be used up again. As a consequence, you will not be prompt to buy a new product. This can
also save money, energy and resources. Listed below are some tips on how to reuse waste.
 Unwanted toys, books and clothes can be given to hospitals, schools or care centers
 Plastic containers, wrapping papers and boxes can be saved and can be used again
 Old jars can be reused for storage
 Buy second hand items in stores or online trading websites
 Bring used household stuffs to a resource recovery center
Fig. 3. Reuse shopping bags to reduce waste.
Source: LEARNZ
Fig. 4. Be creative and find ways to reuse waste
material.
4. Repurpose
If an item cannot be refused, reduced or reused, the option will be to repurpose. This
method is also referred to as upcycling. Repurposing requires creativity because you have to
think of all possibilities on how each product will serve more than one purpose. Example of
this is the binder clip, you have to think of different ways on how the binder clip can be used
aside from its own purpose like for holding power cords and charger in place; tin cans can be
used for keeping pencil, ball pens and other office supplies in place and can also be used as
decorative vase, etc. Everyone should be encouraged to repurpose items which they think they
Page | 6
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
no longer need and once you have done this, a brighter tomorrow is coming on our way. So let
us start to repurpose!
5. Recycle
Another form of reprocessing waste materials is through recycling. In this way, new
product is formed. Common example of this is the recycling of plastic bottles to make plastic
chairs, plastic buckets, etc. Most commonly, paper, cardboard, aluminum, glass, tin and
plastics are example of wastes that can be recycled. Organic wastes can also undergo recycling
like composting and worm plants.
Source: LEARNZ
Fig. 5. Wastes that can be recycled.
Challenge: What reusable products can be used to replace the following items in order to
reduce wastes? plastic containers, paper towels, disposable diapers, disposable batteries, plastic
cups
Essential Components of the Waste Management System
The essential components of the waste management system are defined.:
1. Waste generation
This pertains to some actions that focused on distinguishing materials that are not
functioning anymore or valueless to the owner and are subjected for disposal
2. Onsite handling, storage, and processing
Storage corresponds to a system for keeping the waste generated that has been
discarded prior to collection and disposal. For easier collection, disposal or storage
Page | 7
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
facilities like waste bins can be located at places that generate plenty of waste. To determine
the size and quantity of storage facilities, several factors like the number of users, type and
quantity of waste as well as the frequency of emptying must be considered and should
make sure that the facilities are safe.
3. Waste collection, transfer and transport
This concerns collecting waste from garbage bins by the collection vehicles and
bringing the garbage in the collection site where the waste conveyance trucks unload the
waste. Planning with respect to the collection of wastes should be overseen to avoid
overloading of the collection site.
.
4. Waste processing and recovery
This pertains to the services, tools, and methods used to make materials become
ecofriendly to be used again and to efficiently develop other essential features of waste
management.
5. Disposal
This is the final phase of waste management that involves activities with the
purpose of disposing waste materials in locations such as landfills or in places that converts
waste-to-usable materials facilities.
recognize
Steps for Effective Solid Waste Management System
To have effective solid waste management system, the following processes should be followed.
Categorize the solid waste
Determine the source of waste
Define the probable health risks from
waste
Determine the bulk of waste
Identify safe collection method
Introduce safe transportation
Establish safe disposal
Fig.6. Steps for effective solid waste management
Page | 8
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
Solid Waste Management Techniques
Growing population and climate change problems are potentially threatening many areas
around the world because these are associated with the levels of consumption and pollution that
damage the environment. One of the significant factors as regards to these issues is the technique
or methods on how the wastes can be disposed. Several approaches on solid waste management
are listed and discussed below.
I. Thermal Processes
A. Solid Waste Incineration
B. Pyrolysis
C. Pyrolysis / Gasification
D. Conventional Gasification
E. Plasma Arc Gasification
II. Biological Processes
A. Composting/ Aerobic Digestion
B. Anaerobic Digestion
III. Other Processes
A. Recycling
B. Landfill
Discussion of the Different Solid Waste Management Processes
I. Thermal Processes
A. Solid Waste Incineration
 Process that converts waste material into gas, ash and heat
 The amount of the waste is reduced by 75% by weight and up to 90% by volume
 Poisonous gases are released into the atmosphere.
 Noxious particles is accumulated in the ash being disposed
 An expensive alternative because several resources are needed to incinerate
waste.
Page | 9
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
Fig. 7. A Typical Solid Waste Incinerator
 Volume Reduction
 The volume of solid wastes is reduced by an average of 90% depending on
its composition, likewise, the weight of the solid is lessened by 70- 75%.
 Stabilization of wastes
 The organic components of the waste stream undergo oxidation that
makes the output(ash) more inert than the input(solid waste)
 Recovery of Energy from Waste
 Burning of waste produces energy that can be used to generate stream that
can provide on site electricity generation.
 Sterilization of waste
 Incineration of solid wastes can destroy the pathogens before it is disposed
particularly the clinical or biomedical waste.
B. Pyrolysis
 Thermal decomposition of carbon-based materials that produce syngas.
Page | 10
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
 Direct burning does not take place so no air or oxygen is present.
 Thermal decomposition takes place at 400-900 °C.
Source: https://www.slideshare.net/tanviralam31337/municipal-solid-waste-msw-to-energy
Fig. 8. Schematic Diagram for MSW to Energy via Pyrolysis
C. Pyrolysis / Gasification
 Pyrolysis/gasification is a variation of the pyrolysis process.
 In this process, there is an additional reactor added to promote gasification of the
carbon char or pyrolysis liquids that is formed from the initial pyrolysis step
 For gasification reaction, air, oxygen or steam is used
 For pyrolysis zone, the temperature ranges from 400-900 °C while in the
gasification zone it ranges from 700-1500 °C
D. Conventional Gasification
 A thermal method where carbonaceous materials are converted into syngas using a
limited amount of air or oxygen.
 The gasification condition ranges from 800-1600 °C
 In this process, the conventional gasification reactor is injected with steam to
produce CO and H2
Page | 11
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
Source:https://www.slideshare.net/tanviralam31337/municipal-solid-waste-msw-to-energy
Fig. 9. Schematic Diagram for MSW to Energy via Pyrolysis/Gasification
E. Plasma Arc Gasification
 A high temperature pyrolysis process that coverts carbon-based materials into
syngas
 Vitrified slag is produced as by product from inorganic materials and minerals of
the waste
 An electric arc in a torch generates high temperature that converts gas into plasma
 The operating temperature ranges from 4000-7000 °C
Source:https://www.slideshare.net/tanviralam31337/municipal-solid-waste-msw-to-energy
Fig. 10. Schematic Diagram for MSW to Energy via Plasma Arc Gasifiation
Page | 12
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
II. Biological Processes
A. Aerobic Digestion/Composting
 Involves the conversion of organic materials such as yard trimmings, food scraps,
coffee grounds and filters, tea leaves, herbs, spices, nuts and egg shells as well as
cut flowers or plant trimmings, as long as they aren't diseased to prevent the
emission of harmful greenhouse gasses.
 Meat, fish, butter, yogurt, cheese, milk, or animal fat is not allowed for
composting because these will keep the compost oily or greasy
 An alternative process to lessen methane emissions
 When used as a fertilizer, the need for chemical options which are not good to the
environment is minimized
 Compost can eliminate 99.6 percent of volatile organic compounds (VOCs) from
the air that are unsafe for humans.
 This can benefit the farmers and gardeners because compost increases the
retention of water in soil, so there is no need for irrigation
 It enables bigger crop yields, that gives farmers a better harvest and of course
more income.
Important Factors to be Considered During Composting

Feedstock and Nutrient Balance
 There must be proper balance of “green” organic materials and “brown” organic
materials.
 “Green” organic materials are those that contain large amounts of nitrogen like
grass clippings, food scraps, and manure.
 “Brown” organic materials are those having large amounts of carbon but little
nitrogen such as includes dry leaves, wood chips, and branches.

Particle Size
 Materials should undergo either grinding, chipping, and shredding to increase the
surface area on which microorganisms can feed.
 A compost mixture that is more homogeneous increases pile insulation that helps
sustain optimum temperatures
 Mixtures having very small particles is not also advisable because they might
prevent the air from flowing freely through the pile.

Moisture Content
 Compost pile must have sufficient moistness for microorganisms to survive
Page | 13
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment

Water carries the substances within the compost pile so that the nutrients in organic
material can be accessible to the microbes

Oxygen Flow
 Decomposition can occur faster by aerating the pile
 Aerating the pile can be done by using series of pipes, or bulking agents like wood
chips or shredded newspaper
 Too much oxygen is not recommended because it can lessen the moisture content
the pile that can delay the composting process

Temperature
 For microorganisms to have optimal activity, a temperature of at least 140° F is
needed
 To promote a speedy composting and to destroy pathogens and weed seeds,
accurate temperatures must be used, if not, rooting might occur.
Source: ISTOCK
Fig. 11. Food Waste for Composting
Source: ISTOCK
Fig. 12. Compost from Food Waste
B. Anaerobic digestion of Organic Waste
 An alternative way of composting food waste
 Produces renewable energy that avoids carbon emissions
 A process that is dependent on the micro-organisms that digest organic waste
and takes place in the absence of oxygen in a sealed tank
 Food waste is pre-treated to remove the contaminants before heating to 70°C
for one hour to kill all pathogens in the food
 After heating, the mixture is fed to the anaerobic digester where the bacteria
break down the waste that converts it into biogas and a residue called digestate
 The gas produced in anaerobic digestion can generate electricity and heat
Page | 14
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment

Another product produced is the nutrient rich bio-fertilizer that undergoes
pasteurization to kill any pathogens before farmers can use it on farmlands.
Source: https://ohioline.osu.edu/factsheet/fabe-6611
Fig. 13. Anaerobic digestion of Organic Waste
III. Other Processes
A. Recycling
Recycling is a simple way in which everyone can contribute to make the world a better
place to live. The benefit of recycling is not just reducing the amount of trash but also in terms
of the time and effort to collect, separate and send away the trash. There are still several
benefits that recycling can offer for a brighter future for our environment.
Source:https://www.metropolitantransferstation.com.au/blog/modern
-waste-management-techniques
Fig. 14. Examples of waste segregation for recycling process
Page | 15
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
Benefits of Recycling







Lesser amount of waste is accumulated in landfills and incinerators
Prevents pollution by reducing the need to collect new raw materials
Saves energy
Prevents depletion of natural resources
Creation of more employment opportunities
Encourage the use of greener technologies
Maintains ground water quality
Recycling Symbols and Materials
More cities are employing recycling programs but many people have no idea as to what
type of plastic can be recycled and which of them cannot be recycled. Each type of plastic has a
symbol that indicates if it can be recycled or not. These symbols can help to determine what can
and can’t be recycle in the future.
 Recycling Symbol #1
 One of the most common recyclable plastics is PET or PETE (polyethylene
terephthalate)
 Examples of these are the plastic bottles like soft drinks, beer bottles, mouthwash
bottles, salad dressing, and vegetable oil bottles but their caps cannot be recycled
 Recycling Symbol #2
 High-density polyethylene (HDPE) is another highly recyclable material.
 This in the form of milk jugs, household cleaners, detergent, shampoo, conditioner,
and cereal box liners. Just empty and clean them but caps cannot be recycled.

Recycling Symbol #3
 Polyvinyl chloride (PVC) or vinyl (V) is slightly more toxic than PET and HDPE
 When recycling them, you need to be extra careful
 Examples of these can be found in blister packaging, wire jacketing, and siding
windows.
 Recycling Symbol #4
 Plastics like the low-density polyethylene (LDPE) has many applications but
unfortunately, is not accepted in most recycling programs
 Examples of these plastic come in squeezable bottles, frozen food, dry cleaning,
shopping bags, and some furniture.
Page | 16
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
 Recycling Symbol #5
 Yogurt containers, syrup and medicine bottles, caps, and straws belong this kind of
material
 These are polypropylene (PP) which are more accepted by recycling programs
although not yet widely accepted
 To dispose, check if your curbside pick will take it, and if not, take it to a
community center or throw them in the designated trash bin
 Recycling Symbol #6
 This is the typical Styrofoam or the polystyrene (PS)
 This is classified as a probable carcinogen and therefore not accepted for recycling
by most state programs.
 Most materials that contain PS are egg cartons, meat trays, carry-out containers and
compact disc cases
Fig. 15. Recycling symbols
B. Sanitary Landfill
The most common solid waste disposal method is the sanitary landfill. The refuse collected
is basically spread out in thin layers and compressed. In the design of modern landfills, the
lowermost part of the landfill is enclosed with several water resistant liner like thick plastic and
sand. This is done to safeguard the groundwater from contamination due to leaching and
percolation. To prevent seepage of water, it is shielded with sand, clay, topsoil and gravel. In
addition, sanitary landfill should be well managed to ensure that it will not damage the environment
Page | 17
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
Source: Geosciences 2019, 9(10), 431; https://doi.org/10.3390/geosciences9100431
Fig. 16. Design of modern landfill
On the contrary, dumps are open hole in the ground where wastes are thrown and
buried and rats and insects thrive and is not environmentally regulated so it becomes health
hazard.
Source: https://wasteaid.org/closing-worlds-dumpsites/
Fig, 17. Picture of dumpsite
Page | 18
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
Essential Requirements for Solid Waste Disposal Site
The following are the essential requirements to be considered for a sanitary landfill disposal
site:
 Technical requirements:
 Better planning
 Proper design and construction
 Continuous maintenance during and after waste filling.
 Environmental requirements:
 Environmental aspects are the most important aspects in any appropriate
Solid Waste Management system.
 Environmental protection must be considered for all phases of SWM.
 Social requirements:
 This is the most challenging of all requirements considering that it is very
difficult to motivate the communities and other stakeholders, especially
people living in the vicinity at shorter distances from disposal sites
 Economic requirements:
 The minimum possible overall cost should be ensured and the benefits
through proper solid waste management should be maximized.
 Institutional requirements:
 There must be a responsible institution capable of managing the overall
planning, operation, and maintenance of solid waste landfill sites
Factors to be Considered in the Selection of Landfills Site
 It should be above the water table to prevent its interaction with groundwater.
 It should preferably be located in clay or silt.
 It should not be placed in a rock quarry because water can pass through the
cracks into the water fracture system
 It should not be put up in sand or gravel pits due to high leeching.
 It should not be located in flood plains because most of the trash is less dense
than water so during rainy days, garbage might float on top and wash away
downstream.
Page | 19
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
Adverse Impacts from Landfill Operations
According to an article shared by Puja Mondal entitled “Solid Waste Management:
Types, Sources, Effects and Methods of Solid Waste Management”, adverse effects can
take place from the operations of landfill but these effects may differ. These include:
 Fatal accidents
 Examples are scavengers buried under waste piles
 Infrastructure damage
 Example of this is the damage to access roads by heavy vehicles
 Pollution of the local environment
 Landfill can contaminate ground water or aquifers by leakage and residual
soil contamination during landfill usage and even after landfill closure.
 Production of methane gas generated by decaying organic wastes
 Methane is more potent than carbon dioxide so it poses danger to residents
of the area.
 Harboring of disease vectors
 Landfills if not properly maintained can become a hiding place for vectors
like rats and flies that can cause diseases
Page | 20
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
REFERENCES (Online Resources)
A Step-by-Step Guide to Recycling Symbols and Materials. Available:
https://helpsavenature.com/a-step-by-step-guide-to-recycling-symbols-and-materials (Accessed:
July 20, 2020)
15+ Awesome Reasons Why We Should Recycle More. Available: https://www.conserve-energyfuture.com/why_should_we_recycle.php (Accessed: July 20, 2020)
Are Benefits of Recycling Worth All The Effort? Available: https://www.conserve-energyfuture.com/benefits-of-recycling.php ((Accessed: July 20, 2020)
Bell, Shelby (2020, Jan 21), The 5R’s: Refuse, Reduce, Reuse, Repurpose, Recycle. Available:
https://www.roadrunnerwm.com/blog/the-5-rs-of-waste-recycling. ((Accessed: July 18, 2020)
Composting. Available:https://www.suez.co.uk/en-gb/our-offering/communities-andindividuals/what-happens-to-waste/food-and-garden-waste/composting (Accessed: July 20,
2020)
Difference Between Sanitary Landfills and Open Dumps You Must Know. Available:
https://helpsavenature.com/about. ((Accessed: July 27, 2020)
Hunt, Kristin (2019) What Is Composting? Available:
https://www.greenmatters.com/food/2018/12/07/ZboPlt/what-is-composting (Accessed: July 27,
2020)
Jamal, Haseeb. (2020, March 01), Requirements of Solid Waste Disposal Sites.
Available:https://www.aboutcivil.org/Requirements-Solid-Waste-Disposal-Sites ((Accessed: July
27, 2020)
Jamal, Haseeb. (2020, March 01), Sanitary Landfills Vs. Dump Sites. Available:
https://www.aboutcivil.org/Sanitary-Landfills-vs-Dump-Sites((Accessed: July 27, 2020)
Leblanc. Rick (2019, Oct. 11). An Introduction to Solid Waste Management. Available:
https://www.thebalancesmb.com/reduce-reuse-and-recycle-the-waste-management-hierarchy2878202 (Accessed: July 17, 2020)
Leblanc. Rick (2019, Nov. 20) The Waste Management Hierarchy. Available:
https://www.thebalancesmb.com/an-introduction-to-solid-waste-management2878102(Accessed: July 17, 2020)
Page | 21
ENGG 413- Environmental Science and Engineering
Main Topic 2: Natural Resources and Pollution in the Environment
Recycling Basics. Available: https://www.epa.gov/recycle/recycling-basics. ( Accessed: July 18,
2020)
Solid Wastes (2020, Aug. 5) Available:
http://mizenvis.nic.in/KidsCentre/SolidWastes_2971.aspx?format=Print (Accessed: 18, 2020)
Solid Waste Management: Types, Sources, Effects and Methods of Solid Waste Management.
Available:
https://www.yourarticlelibrary.com/waste-management/solid-waste-management-types-sourceseffects-and-methods-of-solid-waste-management/9949. (Accessed: July 17, 2020)
Solid Waste Management Manual
Available:https://ec.europa.eu/echo/files/evaluation/watsan2005/annex_files/WEDC/es/ES07CD.
pdf (Accessed: July 17, 2020)
The 5 R's of Waste Management. Available: http://www.learnz.org.nz/redvale181/bg-standardf/the-5-r%27s-of-wastemanagement#:~:text=As%20citizens%20of%20a%20society,recycle%2C%20recover%20and%2
0residual%20management. (Accessed: July 18, 2020)
Types of Composting and Understanding the Process. Available:
https://www.epa.gov/sustainable-management-food/types-composting-and-understandingprocess (Accessed: July 18, 2020)
Waste Management Waste Disposal(2018, Oct. 17) Modern Waste Management Techniques:
Available:
https://www.metropolitantransferstation.com.au/blog/modern-waste-management-techniques
What is Anaerobic Digestion? Available: http://www.biogen.co.uk/Anaerobic-Digestion/Whatis-Anaerobic-Digestion (Accessed: July 18, 2020)
Page | 22