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SCIENCE ~ CHAPTER 12
ENERGY AND MATERIAL
RESOURCES
Miss Nelson
SECTION 5
Recycling Material Resources
ANTICIPATORY SET
What kind of things does your
family throw away?
How does your family get rid of
its trash?
STANDARDS
S 6.3.c – Students know the natural origin of the
materials used to make common objects
THE BIG IDEA
What are three methods
of handling solid waste?
What can people do to
help control the solid
waste problem?
KEY TERMS
 Municipal solid waste – waste produced
in homes, businesses, and schools
 Incineration – the burning of solid waste
 Leachate – polluted liquid produced by
water passing through buried wastes in a
landfill
 Sanitary landfill – a landfill that holds
nonhazardous waste such as municipal
solid waste and construction debris
KEY TERMS
 Recycling – the process of reclaiming
and reusing raw materials
 Biodegradable – capable of being
broken down by bacteria and other
decomposers
 Composting – the process of helping
biodegradable wastes to decompose
naturally
RECYCLING MATERIAL RESOURCES
Read Recycling Material Resources on page
506 of your textbook
THE PROBLEM OF WASTE DISPOSAL
 In our daily activities, we generate many types of
waste
 Used paper
 Empty packages
 Food scraps
 These materials are produced in homes, businesses,
schools, and other places in the community
 Called municipal solid waste
 Other sources of solid waste include
 Construction debris
 Certain agricultural/industrial wastes
THE PROBLEM OF WASTE DISPOSAL
Three methods of handling solid
waste:
Burning
Burying
Recycling
Each has its advantages and
disadvantages
INCINERATION
 The burning of solid waste
 Advantages
 Burning facilities do not take up much space
 Do not pose a risk of polluting ground water
 The heat produced can be used to generate electricity
 Disadvantages
 Even the best incinerators release some pollution into the air
 Reduce the volume of waste by 90% - some still remains
 This remaining waste needs to go somewhere
 Expensive to build
LANDFILLS
 Until fairly recently, people usually disposed of waste in open
holes in the ground
 Rainwater falling on a dump dissolved chemicals from the
wastes, forming a polluted liquid called leachate
 Could run off into streams and lakes, or trickle into groundwater
 In 1976 open dumps were banned
 Now much solid waste is buried in landfills that are
constructed to hold waste more safely
 However, even well-designed landfills still pose a risk of
polluting groundwater
THE PROBLEM OF WASTE DISPOSAL
Read The Problem of Waste Disposal on pages 507 508 of your textbook
RECYCLING
 The process of reclaiming raw materials and reusing
them to create new products
 Any material that can be broken down and recycled
by bacteria and other decomposers is biodegradable
 Unfortunately, many of the products people use
today are NOT biodegradable
 A wide range of materials can be recycled
RECYCLING
Most recycling focuses on four
major categories of products:
Metal
Plastic
Glass
Paper
METALS
Metals such as iron and aluminum can be
recycled
With recycling, no ore needs to be mined,
transported, or processed
Recycling metals helps conserve these
nonrenewable resources
PLASTIC
 When oil is refined to make gasoline and other
petroleum products, solid materials called resins are
left over
 Resins can be heated, stretched, and molded into
plastic products
 When these products are recycled, they take on very
different forms!
 Fleece jackets
 Carpeting
 Floor tiles
 Trash cans
GLASS
Glass is made from sand, soda ash, and
limestone mixed together and heated
Glass is one of the easiest products to recycle
because glass pieces can be melted down
over and over to make new glass containers
Recycling glass is less expensive than making
glass from raw materials
PAPER
It takes about 17 trees to make one
metric ton of paper
Most paper products can only be recycled
a few times
Each time paper is recycled, the new
paper is rougher, weaker, and darker
IS RECYCLING WORTHWHILE?
Besides conserving resources, recycling
also saves energy
Making aluminum products from recycled
aluminum rather than from raw materials
uses about 90 percent less energy overall
For certain materials, recycling is usually
worthwhile
IS RECYCLING WORTHWHILE?
Recycling is not a complete answer to the
solid waste problem
For some cities, recycling is not cost-effective
Scientists have not found good ways to recycle
some materials
The value of recycling must be judged on a
case by case basis
RECYCLING
Read Recycling on pages 509-510 of your
textbook
WHAT PEOPLE CAN DO
Reduce
Reuse
Recycle
WHAT PEOPLE CAN DO
Create less waste by reducing your use of
non-recyclable materials
You can also make an effort to buy
products made from recycled materials
Start a compost pile
CHECK FOR UNDERSTANDING
Name three ways of dealing with solid waste.
CHECK FOR UNDERSTANDING
Name three ways of dealing with solid waste.
Three ways of dealing with solid waste are
burning, burying, and recycling.
GUIDED PRACTICE
Describe an advantage and
disadvantage of each method.
GUIDED PRACTICE
Describe an advantage and disadvantage
of each method.
Incineration can be used to generate
electricity, but can pollute air. Burying
waste in a sanitary landfill can possibly
pollute groundwater, but the land later
can be used for other things. Recycling
conserves nonrenewable resources, but
it is not always cost effective.
INDEPENDENT PRACTICE
Complete Energy 12-5 Independent
Practice