Collection and recycling of plastics pipes in
demolition and construction waste stream

A. J. Whittle*

1

and D. Pesudovs

2

A benefit of thermoplastic pipe materials is that scrap or damaged product can be reprocessed
and virtually all in-house waste material is reused in a modern plastics pipe factory. Also there are
schemes for recycling scrap generated during installation of new pipes or exhumation of old
ones. In the present study, a process of extracting scrap plastics pipes from demolition and
construction waste in a major city is described together with the proportion of the most common
plastics pipe materials (poly(vinyl chloride) and polyethylene) occurring in the waste. The
condition of the recovered pipes and the methods used to turn them into a reusable form is
described. While the overall proportion of plastics pipes in the waste stream was very small, the
condition of the recovered pipes was such that the pipes could be cleaned, comminuted and
reworked. The pilot trial has now been expanded to recycle pipes reclaimed on a regular basis
from the demolition and construction waste in the three largest cities in Australia.

Keywords: Recycling, Scrap pipes, Used pipes, Construction waste, Demolition scrap

Introduction

A particular benefit of thermoplastics pipe materials
such as poly(vinyl chloride) (PVC) and polyethylene
(PE) is that process scrap or damaged product can be
comminuted and reprocessed.

1,2

Thus there is essentially

no in-house waste of plastics materials in modern pipe
and fittings factories. The ability to reuse scrap material
into pipe products has been enhanced by the develop-
ment of sandwich construction pipes in which the
rework is used in the inner layer protected by an inner
and outer wall of virgin plastics.

3,4

Such products are

used for non-pressure applications such as drain, waste
and vent, a cross-section of which is shown in Fig. 1.
Figure 2 illustrates electrical conduit with colour coded
orange inner and outer wall and a non-coloured, foamed
inner layer.

Recycling of pipes that have been in service brings

additional problems to be overcome. These include
collection, sorting, identification and cleaning. It is
accepted that plastics pipes and conduits used in
infrastructure are often expected to have a service life
in excess of 100 years.

5

This is beyond the current age of

the plastics pipes industry and such pipes are not yet
available for recycling. Replacement today of infra-
structure pipes is likely to be due to unacceptable failure
rates (which might be due to operational, installation or
manufacturing issues) or a need to change the capacity
of the pipeline due to unforeseen demand. In such

instances the original pipeline might be left in position
and the replacement installed alongside. Alternatively
the original pipeline might be exhumed and recycled.
This is decided on a case by case basis and will be
affected by the quantity of pipe available and the
remoteness of the site.

Another potential source of pipes for recycling is

scrap and offcuts from the building industry. In cottage
construction (houses, town houses and similar) trades-
men invariably minimise waste for economic reasons
and in Australia it has been impractical to collect and
recycle the small amount of scrap generated. In larger
residential constructions, pilot schemes have been run
whereby plastics pipes offcuts have been collected in
dedicated waste bins and recycled. Again however the
ability of the tradesmen to efficiently cut and use the
pipes means the amount of product available for
recycling is minimal. For example, only

y200 kg of

scrap PVC pipe was generated when dedicated collection
bins were made available at a major residential
development in Sydney.

In the present study the authors have determined the

amount and condition of plastics pipes that occur in the
waste stream generated by construction and demolition
waste and implemented procedures for its isolation and
reuse. The material comes from major demolition sites
and construction sites. For geographical and demo-
graphic reasons the initial trial was carried out in Sydney
and the project has now been implemented on an
ongoing basis in Sydney, Melbourne and Brisbane.

Geography and demographics

Australia is the smallest continent, having an area of a
little under 8610

6

km

2

(or

y75% the size of Europe).

The population is only 20?5 million, most of which is

1

Iplex Pipelines Australia Pty Limited, 35 Alfred Road, Chipping Norton,

NSW 2170, Australia

2

Plastics Industry Pipe Association, Suite 246, 813 Pacific Highway,

Chatswood, NSW 2067, Australia

*

Corresponding author, email [e-mail]

190

ß

2007 Institute of Materials, Minerals and Mining

Published by Maney on behalf of the Institute
Received 13 February 2007; accepted 14 February 2007
DOI 10.1179/174328907X191260

Plastics, Rubber and Composites

2007

VOL

36

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concentrated on the eastern and south eastern seaboard.
In fact 47% of the population lives in the three cities of
Sydney, Melbourne and Brisbane. Brisbane is 1000 km
north of Sydney by road and Melbourne 900 km south
west. The fourth largest city, Perth has a population of
about one and a quarter million but is

y3000 km from

Sydney. Despite its large land mass, Australia’s major
cities have a dearth of convenient landfill sites. For
example, waste from Sydney is now transported some
250 km to a former open cut gold, copper, lead and zinc
mine. Any reduction in the amount of waste needed to
be sent to landfill is a benefit to the community.

The recycling program initiated by the Plastics

Industry Pipe Association has taken these demographics
into account. Sydney was chosen for the pilot scheme
which has now been adopted as a permanent arrange-
ment. The scheme has also been expanded to include the
next two populus cities, Melbourne and Brisbane, in
order to capture a substantial portion of the waste
plastics pipes available in Australia.

Construction and demolition waste

There are two Sydney recycling centres in Sydney
handling demolition and construction waste. Each site
processes

y2000 t of waste per week. Eighty five per

cent of the waste is recovered and processed into a
saleable form. The proportions, shown in Fig. 3, being

concrete aggregate 40%, soils 40%, timber 3% and
metals 2%. The remaining 15%, previously including any
plastics pipes, is sent to landfill. Note the recycling
centres in question only accept building and construc-
tion waste and do not handle toxic materials, asbestos,
industrial waste or chemicals. Neither are rotting or
putrefying materials such as vegetable or animal waste
accepted (Fig. 4).

Plastics Industry Pipe Association negotiated with the

operator of the Banksmeadow site to undertake a three
month trial collecting all plastics pipes pieces longer
than

y200 mm. Materials are brought to the recycling

centre in large waste bins and sorted using an excavator
fitted with modified jaws (Figs. 5 and 6). Reusable
materials are placed in specific bins for subsequent
despatch. The arrangement did not entail any additional
collection costs as the scrap pipe material passed
through the recycling centre anyway. Costs incurred
were related to the time spent extracting the pipes and
placing them in the bins plus the cost of hiring and
transporting the bins. It was decided the recycling centre
operators should merely collect all plastics pipes and not
try to identify or sort the different materials.

Trial

Arrangements were made for the operator of the
recycling centre to extract and isolate all plastics pipes
coming into the centre for a three month period. The

1

Drain, waste and vent sandwich pipe with foam core

2

Electrical

conduit,

sandwich

construction

pipe

with

white core and coloured inner and outer wall

3

Proportion of materials in construction and demolition
waste

4

Prohibited materials at recycling centres

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2007

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191

scrap pipes being placed in 20 m

3

waste bins which when

full, were despatched to the Iplex Pipelines PVC pipe
factory in Sydney. During the trial, a total of three bins
were filled at approximately monthly intervals.

The contents of each bin were sorted manually on

arrival at the factory into PVC, polyethylene and other
(Figs. 7–10). Any pipe pieces that were clearly unusable,
for example small pieces heavily contaminated with

metal fittings were put aside. After sorting, all of the
pipe was weighed and the amounts tabulated. The vast
majority of the scrap pipe was either PVC or PE with
only a very few odd pieces of polypropylene and
polybutylene. There was insufficient quantity of the
latter two polymers to warrant keeping them.

The pipe sections recovered varied in diameter from

25 to 350 mm and in length from full 6 m pipe lengths to
200 mm offcuts. There was very little foreign material
such as metal brackets and self tapping metal screws

5

Excavators sorting materials from pile of waste

6

Excavator

placing

plastics

pipe

samples

in

20 m

3

(700 ft

3

) bin

7

Bin 1 with PVC conduit and drainage pipe predominant

8

Bin 2 with mixture of PE and PVC

9

Manual sorting of pipes before weighing

10

Stillages of sorted PE and PVC

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mixed in the recovered plastics pipes. It was confirmed
that most of the PVC pipes would require very little
cleaning to allow them to be granulated, micronised and
blended into pipe feedstock, especially for the inner layer
of sandwich construction pipe. It was also confirmed
that the PE could be converted into saleable pellets
without difficulty, but not for reuse into pipes.

The amount of PVC and PE pipe collected over the

three months is shown in Table 1. This represents only
y0?014% of the material handled by the recycling
centre. An examination of the pipes together with the
print message details confirmed the majority of the
product was from construction rather than demolition
sites. That is, the pipes had been use to provide
temporary services

on construction

sites

such as

Sydney’s cross-city tunnel. The polyethylene pipes were
almost entirely made to a pressure pipe specification and
appeared to have been used primarily for water supply
together with some drainage applications. The PVC
pipes were electrical conduit, drainage plus some
pressure pipes.

Continuing collection of waste plastics
pipes

A contract has been entered into for the recycling centre
to continue to separate all plastics pipe pieces longer
than

y200 mm and place them in 20 or 40 m

3

bins. The

arrangements for sorting, cleaning and processing the
reclaimed pipes have been adapted to suit each
individual city. For example, in Sydney, the bins are,
when filled, transported to another site where the PE
and PVC are separated by a plastics recycler. The PE is
processed by the recycler into pellets suitable for non-
pipe applications. The PVC is sent to a PVC pipe factory
for granulation, micronising and blending into the inner
layer of sandwich construction drainage pipes or
electrical conduit. In Brisbane, the reclaimed PE is
blended into corrugated drainage pipes. The pipe
products that incorporate reclaimed material satisfy
the same performance requirements as products made
from all-virgin material.

Conclusions

The trial collection plastics pipes from the construction
and demolition waste stream demonstrated.

1. It is possible to extract plastics pipes from the

construction and demolition waste stream with no
additional infrastructure beyond the large waste bins
needed to hold the pipes after they have been sorted
from the other materials.

2. The amount of plastics pipe in the waste stream is

very small, being only of the order of 0?014% of the total
material passing through the recycling centres.

3. The majority of the plastics pipes in the waste

stream is either PVC or PE and is mostly suitable for
recycling.

4. The pipe in the waste stream is primarily of recent

manufacture, having been used for temporary services in
building and infrastructure construction sites.

5. The PVC is suitable for recycling into sandwich

construction drainage pipes and conduits.

6. The PE can be recycled into either non-pipe

products or into non-pressure, corrugated drainage pipe.

7. The PVC and PE pipes made using reclaimed

material meet the same specification as pipes made with
all-virgin polymer.

It has been shown there is an extremely small amount

of plastics pipe from the construction or demolition
industries going into landfill in Australia. It has been
further shown that the amount can be reduced even
more by extracting scrap pipes during the normal
sorting of reusable materials such as timber metals and
aggregates at the recycling centres. The extraction of
plastics pipes does not require any new equipment or
techniques. The PVC and PE pipes can be sorted
subsequently by hand and are being successfully reused
in both pipe and non-pipe applications.

Acknowledgements

The authors are grateful for the Plastics Industry Pipe
Association permitting the publication of this paper and
the Sydney Recycling Centre for participating in the
initial trial and permitting the photographs to be taken
at its facility. This paper is based on a presentation at
Plastics Pipes XIII held in Washington, DC in October
2006.

References

1. W. Ziebell: Proc. Plastics Pipes VIII, Einhoven, The Netherlands,

September 1992, The Plastics and Rubber Institute, Paper A2/6.

2. M. J. Bevis: Proc. Plastics Pipes VIII, Einhoven, The Netherlands,

September 1992, The Plastics and Rubber Institute, Paper A2/5.

3. G. Voituron: in ‘Recycling of PVC and mixed plastic waste’, (ed.

F. P. La Mantia), 57–58; 1996, Toronto-Scarborough, Chem. Tec.
Publishing.

4. G. Parisi and A. Neubauer: in ‘Recycling and recovery of plastics’,

(ed. J. Brandrup et al.), 331–333; 1996, Munich, Hanser Publishers.

5. A. J. Whittle and J. Tennakoon: Plast. Rubber. Compos., 2005, 34,

311–317.

Table 1

Quantities of pipe collected during trial

Bins

PVC, kg

PE, kg

Total, kg

Bin 1 on 3 June 2005

645

464

1109

Bin 2 on 6 July 2005

714

441

1155

Bin 3 on 15 August 2005

1156

183

1339

Total

2515

1088

3603

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2007

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