Chapter 5 Models for Technology Creation
Tutorial 14 Recycling: Finding uses for non-usable materials
Overview of Main Concepts
 One secondary result of economic growth is the general problem
of too much trash in the landfills.
 Some solutions that are already being implemented include:
reduction of packaging used, market incentives, reuse materials
for other purposes and separation of recyclables before collection.
 Sometimes solutions are dependent on previous technological
paths taken.
 Even solutions, which are innovations, many times bring with
them additional unexpected secondary effects.
14.1 Introduction
One secondary result of economic growth is the general problem of too much trash in
the landfills. The innovations that have begun to contribute some solutions or
improvements have come from the non-linear model and have been examples of
learning by doing.
14.2 What Has Already Been Done
What has already been done to reduce the amount of municipal solid waste (MSW) in
landfille? Some solutions that are already being implemented include:
1. Source reduction - or reduction of packaging used
It was estimated that reduction of packaging material by only 7% in a city like Hong
Kong could reduce the cost of collection by approximately $7 Billion HKD over the
next 20 years.
2. Market incentives - such as subsidizing recycling.
Many things that may make the recycling more profitable or make waste less
attractive could be considered market incentives.
3. Reuse materials for other purposes.
Examples in the following section 14.5 regarding reuse of used tires
4. Separation of recyclables at the source - before collection.
Some items that are separated in many communities include paper, aluminum, glass
and plastic. Since recycling for these items is more common, the separated materials
can be directed straight to the facility for processing rather than trying to pull it out of
landfills.
It has been found that aluminum recycling has been much more successful than
recycling of materials such as paper.
Why?
It could certainly be that the quality of recycled paper is sometimes inferior to new.
But from an economic standpoint, new paper is relatively inexpensive to make.
Whereas the cost of processing used paper when de-inking and other processes are
required are more expensive. Aluminum is more successful because the cost of
making new aluminum is expensive compared to recycling.
How might we increase the amount of paper recycled?
Recycling paper can be increased with anything that makes it more attractive to
recycle or less attractive to throw it away. Such things could include market
incentives for recycling paper, subsidizing processing equipment such as de-inking
machines, government processing of the paper, or government paying for used paper.
Taxing paper to account for the additional collection fee might persuade people not to
waste.
14.3 Complimentary Technologies
What about complimentary technologies? Are there any technologies that can exist
by themselves but when used together can improve paper recycling? Another way to
think about it is whether or not there is a machine/technology that if available from,
let’s say, the Hong Kong Government for $1 would improve paper recycling. Likely
machines for processing used paper and de-inking used paper or paper shredding can
exist without one another, but paper recycling is more effective when these are used
together or when they are more easily accessible.
14.4 Path Dependence
Sometimes solutions are dependent on previous technological paths taken. For
example, materials which are biodegradable they may be treated differently than those
that are non-biodegradable. Tires and plastics will not break down in the landfill.
Solutions for reducing the contribution of these items or those such as disposable
diapers to landfills will be influenced by the fact that they are not biodegradable.
14.4 Categorizing Solutions
If the solution to the problem of tires in landfills included changing the tires materials
to some type of biodegradable material, you might characterize the change as
embodied. However, if the change was along the lines of cutting the tire into pieces
and using the pieces for a new purpose then the change could be considered an
disembodied technological change or innovation.
14.5 Unexpected Results
Even solutions, which are innovations, many times bring with them additional
unexpected secondary effects.
Example
Recall the problem about tires in the landfill. Billions of tires are just sitting in
landfills and millions were being added to the piles every year. The tires take up too
much space in the landfill, they become rodent infested and breed mosquitoes. There
is danger to the community from fires because the fumes that are be poisonous.
Some solutions in recent years have included cutting up the tires and using the pieces
beneath a road surface to provide insulation for the road so it does not freeze as easily
in cold weather. It is also found to reduce the frost penetration and the ‘heaving’ or
the pushing upward of road subsurfaces causing cracking in the roads. This uses
approximately 100,000 tires per kilometer of road.
In one city a 6 foot high dam was constructed from discarded tires. It reduces the
number of tires in the landfill and prevents soil erosion. One company has begun to
use the tires as sound reduction material in barriers located along the sides of roads.
Typically they are use about 15,000 scrap tires for a 1 kilometer wall about 10-28 feet
high. These walls are able to reduce the sound on the other side by 20-40 decibels.
This is very significant when considering that a reduction of 10 decibels is
approximately 50% reduction in sound.
However, even innovations which are solutions to problems sometimes bring on
additional unexpected side effects. An unexpected result of the use of these tires was
found in Washington State in the U.S. During the implementation of this promising
solution a problem was discovered.
In Fall of 1995 steam began rising from the cracks in the roadway and fires began to
emerge After 8.5 million tires had been disposed of through these methods this was
discovered. Similar projects were put on hold until ways were established to
eliminate the likelihood of igniting surfaces.
14.6 Further Study
Mike May, “Making the Sound Barrier”, Technology Review, November/December,
Vol. 98, No.8, 1995.
J. Glynn Henry and Gary W. Heinke, Environmental Science and Engineering, 2nd
edition, Prentice Hall International Editions: New Jersey, 1996, p.578-579, 586.
Peggy Chalmers, “Tire Chips Reduce Road ‘Heaving’ in Winter”, American City &
County, 1995, v110n1, Jan., p.46.
“Innovative Scrap-tire Dam Prevents Soil Erosion in Arizona”, World Wastes, 1996,
vol.39, no.11, Nov. p. 51.
“Scrap Tire Plan Goes Flat”, ENR, 1996, vol.236, no.7, February 19, p.17.