Upload
others
View
2
Download
0
Embed Size (px)
Citation preview
1 of 28 © Boardworks Ltd 2016
Life Cycle Assessments
2 of 28 © Boardworks Ltd 2016
Life Cycle Assessments
3 of 28 © Boardworks Ltd 2016
What is a Life Cycle Assessment?
A Life Cycle Assessment (LCA) examines the
environmental and human impacts of a product across
its entire lifespan.
LCAs consider the use of resources (e.g. water, energy
input or output) and the environmental impact of each
stage in the life of a product.
The stages in the life of a product include:
making the material for the product
manufacturing the product
using the product
disposing or recycling the product.
4 of 28 © Boardworks Ltd 2016
Stages considered in an LCA
5 of 28 © Boardworks Ltd 2016
Sorting activity
6 of 28 © Boardworks Ltd 2016
Life Cycle Assessments
7 of 28 © Boardworks Ltd 2016
Comparing different materials
The ability of different materials to perform the same job can
be compared by carrying out a Life Cycle Assessment (LCA).
This allows companies to make the most
environmentally friendly decisions about
the items they produce.
The waste production and use of water,
resources and energy can easily
be measured.
Measuring the effect of pollution, however, is
not straightforward. It is a subjective process
that requires assigning numerical values to the
different effects of pollution.
8 of 28 © Boardworks Ltd 2016
LCA of a carrier bag
9 of 28 © Boardworks Ltd 2016
Plastic or paper?
starting
resources used
waste
production
global warming
one polyethene
plastic bag
one paper
bagassessment
factor
energy usage
water consumption
non-renewable renewable
8 g 50 g
4 kg CO2 eq
730 kJ 1680 kJ
1.80 litres
14 kg CO2 eq
4.60 litres
Compare the LCA’s of a paper bag and a plastic bag.
Which bag would you choose?
10 of 28 © Boardworks Ltd 2016
Interpreting LCA data
Which is more important:
using renewable resources
or reducing greenhouse
gas emission?
Which type of bag is more environmentally
friendly: polyethene plastic bags, or paper bags?
From the data given, it seems that
plastic bags win the argument– is this
what you expected?
It is important to remember that
both materials use up energy
and release CO2.
How could you improve the LCA of a paper bag?
11 of 28 © Boardworks Ltd 2016
Recycling products
PET is what everyday drinks
bottles are made out of.
As they consist purely of
PET, it is possible for
the used bottles to be
manufactured into a
new product.
Reusing recycled materials reduces energy consumption and
greenhouse gas emissions during manufacturing processes.
For example, reusing plastic
bottles reduces the need to
manufacture new polymers.
12 of 28 © Boardworks Ltd 2016
Recycling PET bottles
Collection - Through recycling schemes, such as your
local recycling collection.
Sorting - The PET plastic must then be separated from
other materials.
Recycling and reuse of PET bottles is a multi-step process
that involves:
Downsizing – The plastic is crushed into flakes and
cleaned to remove food particles and other impurities.
Manufacture of the new product.
New products that are made from recycled PET include:
soap bottles, soft drink bottles and plastic film.
13 of 28 © Boardworks Ltd 2016
Biodegradable plastics are increasingly being used in
carrier bags, bin bags and food packaging.
One of the problems with traditional plastics is that they do
not break down when thrown away.
Biodegradable plastics are
plastics that can be broken down.
They are converted into carbon
dioxide, water and minerals by
microorganisms.
Biodegradable plastics, such as polylactide, are plant-
based polymers. They are often made from starch that has
been modified to become more stable.
What are biodegradable plastics?
14 of 28 © Boardworks Ltd 2016
How is biodegradable plastic made?
15 of 28 © Boardworks Ltd 2016
Biodegradable or non-biodegradable?
starting resources
used
global warming
non-
biodegradablebiodegradable
assessment
factor
disposal
non-renewable renewable
moderate
incineration, landfill,
recycling
high
incineration, landfill,
recycling, composting
The table below compares data for non-biodegradable
plastic with biodegradable plastic.
Time is required to allow plants to grow for the production
of biodegradable products.
16 of 28 © Boardworks Ltd 2016
Trusting Life Cycle Assessments
How do you know a Life Cycle Assessment is accurate?
Increasing attention towards environmentally friendly products
puts a new demand on companies and manufacturers.
The subjective nature of LCA’s mean that companies can use abbreviated
assessments. These are selective
towards specific factors, in order to
reach the desired outcome.
LCA’s are used to justify the manufacture of products and support environmental
claims that are beneficial to sales.
17 of 28 © Boardworks Ltd 2016
Can life cycle assessments be biased?
Think about the following example:
Alternatively, if multiple hand
towels are used per person?
LCA’s for paper towels and an electric hand dryer were carried
out and compared.
What would be the outcome if the
company assumed only one paper
towel is used per person?
It would be more beneficial to the paper towel company if the
LCA assumed only one paper towel is used per person.
18 of 28 © Boardworks Ltd 2016
Life Cycle Assessments
19 of 28 © Boardworks Ltd 2016
What can businesses
and individuals do to
reduce the amount of
waste they produce?
Dealing with waste is
important, but there are
many issues involved:
If more products are made from biodegradable plastics,
how will the management of landfill sites change?
Dealing with waste
How many products could be made from recycled and
biodegradable plastic?
What will happen to closed landfill sites in the future?
20 of 28 © Boardworks Ltd 2016
How is waste plastic disposed?
21 of 28 © Boardworks Ltd 2016
Landfill – pros and cons
22 of 28 © Boardworks Ltd 2016
Incineration – pros and cons
23 of 28 © Boardworks Ltd 2016
Recycling – pros and cons
24 of 28 © Boardworks Ltd 2016
Disposing plastics
25 of 28 © Boardworks Ltd 2016
Electricity generation schemes
Some waste products can be used to generate electricity.
The methane can be captured and
burned to produce electricity.
An example is the biogas methane.
This is produced from organic
matter such as plant and animal
waste at farms and landfill sites.
The electricity produced is renewable, and improves the life
cycle assessment of a process by reducing the amount of
waste product.
26 of 28 © Boardworks Ltd 2016
Life Cycle Assessments
27 of 28 © Boardworks Ltd 2016
Glossary
28 of 28 © Boardworks Ltd 2016
Multiple-choice quiz