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Separation
of Contamination from Ground PVC Window Material
Clean PVC regrind from recycling of PVC window profiles is a valuable raw material, that can be used again for the production of PVC windows. But contamination such as by rubber from seals, polyamide, plasticised PVC, etc are problematic. Such contamination can influence the possibilities of using PVC recyclate or even make the use of recyclate impossible. The rubber seals are therefore normally separated manually before shredding. This process is laborious however, only allows a low rate of throughput and is therefore not suitable for economic recycling of used windows.
(L-R) Input fraction, (1) PVC regrind with rubber;
(3) Reject,
from PVC regrind separated rubber; (4)Clean
PVC regrind for production of new window profiles
The
separation process used by hamos GmbH
in Penzberg works however entirely automatically, i.e. without manual
pre-sorting. The PVC window profiles are firstly shredded into regrind,
from which dust is then removed (Illustration 1). The material is then
largely freed of rubber and other contaminants by an EKS type of electrostatic
separation equipment (Illustration 2). Use is made here of the different
electrostatic charge of rigid PVC compared with rubber (Illustration 3)
and other substances. The PVC has purity of approx. 99.5% after this stage
of separation.
The subsequent type SEA optoelectric colour sorting equipment separates
the rubber and possible colour contamination from the material, so that
the PVC material (Illustration 4) is distinguished by now having purity
of more than 99.995%.
EKS
electrostatic separation equipment
The
combination of the hamos EKS and SEA has proved itself many times worldwide.
The process guarantees high throughput and optimum product purity, whereby
other contamination that arises in window recycling, such as metals, wood,
glass and minerals, are also separated out.
hamos GmbH will show this process at the fensterbau/frontale 2006 fair.
fensterbau/frontale 2006, 22-25.3.2006, Nuremberg, Hall 3, Stand 405.
Tel: +49 (0) 8856 9261 0
Email: hamos@hamos.com
Web: http://www.hamos.com
Recycled
Glass Delivers Clear Benefits for Water Treatment
Results
of commercial-scale trials into the use of recycled glass as a medium
for filtration of industrial and domestic wastewater have indicated it
could cut the costs of treatment, as well as being kinder to the environment.
Wakefield-based
water treatment specialists Aqua Enviro are conducting trials of recycled
glass filtration medium (RGFM) with a cross-section of end-users: Croda
Chemicals Europe, at its plant in Rawcliffe Bridge, Goole; frozen fruit
and vegetable processor JE Hartley, in Thorganby, York;
Yorkshire Water, at its sewage treatment plant in Malton, North Yorkshire;
and kitchen roll and tissue manufacturer Georgia Pacific UK, at Stubbins
Mill, Ramsbottom, Bury.
Interim results of the trials, which have been funded by WRAP (the Waste
& Resources Action Programme), have shown that using recycled glass
as a filtration medium could improve the quality of effluent, compared
to traditional sand. It could also help water companies and industry to
meet tough new environmental targets and avoid fines, without incurring
extra costs.
The Environment Agency regulates the amount of suspended solids that are
permissible in water discharged into watercourses. Organisations exceeding
their limits may face heavy penalties.
Reduction of suspended solids is important, as they have a negative effect
on the environment by de-oxygenating water, with a consequent detrimental
impact on fish habitat. Excessive growth of blanket weed brought about
by suspended solids can also affect river flow as silt and other particles
build up when they are caught in the weed.
Mark Lowe, consultant, Aqua Enviro, said: "The results of trials
of the RGFM trials have been positive and encouraging. Tests have shown
the medium is more effective than sand at removing suspended solids in
effluent and delivers better performance in backwashing. As a result,
less frequent backwashing is required, leading to cost savings.
'Unlike sand, the recycled glass has shown no tendency to clog up, or
'blind', when faced with high loadings of suspended material, leading
to fewer blockages.'
RGFM is set to reduce suspended solids in water discharged by Croda Chemicals
Europe into watercourses by up to 80 per cent, from 250mg/l to 50mg/l.
This will help Croda to meet the standards of the Integrated Pollution
Prevention and Control accreditation. The material has coped excellently
with major peaks in solids loading. It could also help Croda to cut operating
costs, through reduced cleaning and maintenance bills and lower capital
outlay in the future, as the company will need a smaller membrane system
to allow water reuse within the plant.
Tissue, pulp, paper and packaging manufacturer Georgia Pacific UK has
used RGFM to treat effluent water destined for reuse at its plant or discharge
into the sewage system. RGFM has reduced levels of suspended solids, which
can be as high as 280mg/l, by 80 per cent.
The trial has also shown that other significant benefits can be achieved
by recycling the cleaned water back into the mill. These include the fact
that the effluent, once removed of other impurities, is still hot and
would not require re-heating.
At JE Hartley's plant, which processes and distributes vegetables, RGFM
has also outperformed sand as a filtration medium. RGFM removed 80 per
cent of suspended solids from effluent compared to 32 per cent for sand.
Hartley's is now considering upgrading its filtration process to incorporate
RGFM in the future.
In addition, Yorkshire Water has trialled RGFM at its sewage treatment
plant in Brawby, Malton, which serves 10,000 households in the town. RGFM
has proved to be more effective than sand and it has helped the utility
to reduce suspended solids in the effluent, which is discharged into the
River Derwent, by 70 per cent.
Performance on backwashing also matched or bettered that of sand.
Mark Lowe said: 'If the interim findings are confirmed in the final report,
they will have implications for a wide range of industrial sectors treating
wastewater including heavy engineering, car manufacture, food and beverage
factories and paper and pulp mills. They could also highlight RGFM's potential
as a filtration medium for drinking water and in aquaculture applications,
including fish farming, as well as for water used in swimming pools and
spas.
'The results will be of particular interest to manufacturers of filtration
equipment and media, as well as managers responsible for effluent quality
requiring a more consistent and sustainable solution to their treatment
problems.'
Bronnie Allen, materials development manager at WRAP, said: 'We're delighted
with progress to date. So far, trials indicate RGFM, which is manufactured
to BSI PAS 102 specifications, is viable commercially and offers economic
and performance benefits compared to traditional filtration materials.
It is also a way for companies to demonstrate commitment to the environment.'
Companies interested in learning more about recycled glass applications
should contact Bronnie Allen at WRAP on 0808 100 2040.
Web: http://www.wrap.org.uk
US
Army Salutes UK Recycled Glass Initiative
The
US Army has completed a major manoeuvre by switching to environmentally
friendly grit blast media, made from recycled glass, at its Field Support
Battalion base near Southampton.
Glass
grit, sourced from reprocessor Krysteline, is being used to refurbish
military equipment - including land vehicles, generators and watercraft
- at the site in Hythe after the army switched from using traditional
copper slag.
Grit blasting involves abrasive particles being powered onto a surface
using high pressure air and is often the fastest and most thorough means
of cleaning, descaling, deburring and removing oxides or other surface
contaminants. The process is widely used in many industries, including
aerospace, construction and transport.
In addition to helping environmental sustainability, recycled glass grit's
main benefits are that it is non-toxic, inert and does not cause respiratory
or environmental problems. It contains negligible levels of chlorides
and salts that can corrode clean surfaces and its residue being classed
as a nuisance dust, rather than hazardous waste, means disposal costs
can be lower.
The introduction of US HAZMAT regulations, governing the use of hazardous
materials, was another factor in the unit reconsidering its choice of
abrasive.
Colin Buchanan, Paint Supervisor and HAZMAT Officer at the US Army Field
Battalion, said:
'The unit has been particularly impressed that glass grit creates significantly
less dust during the blasting process, which had been a problem for us
in the past, and any it does generate is easily controlled.
'Another benefit we have identified is that, in addition to complying
with HAZMAT regulations, the glass grit can be disposed of in a number
of ways, without presenting an environmental hazard. It has also proved
more cost-effective than many of the alternative materials we investigated.'
The eleven-acre army site offers facilities tailored for the maintenance,
overhaul and storage of forward deployed combat equipment. Many of the
vehicles have suffered significant war damage, making it necessary to
strip back all paint on the chassis and bodywork, to determine what metal
damage has been caused.
Once stripped to bare metal, the parts are blasted with TruGrit recycled
glass blast media in preparation for repairs and re-painting, in the appropriate
camouflage colours, ready for release back into service.
Mr Buchanan said:
'By sharing the results of the tests here, we hope to encourage other
army sites across the world to consider switching to glass grit. The benefits
it offers in terms of cleanliness, ease of control, cost effectiveness
and environmental performance all add up to make it an ideal product for
blasting.'
At Hythe, two types of equipment are used during the blasting process,
a standard shot blast system and a portable, lightweight blasting gun,
which enables paint to be stripped layer-by-layer. Currently the unit
uses four tonnes of medium grade (0.75 - 1.5mm) glass grit every week,
at a pressure of 200 PSI.
Bronnie Allen, Materials Development Manager (Glass) at WRAP, said:
'Recycled glass grit has been proved in the USA to achieve a suitable
surface profile on steel for paints and coatings. It has been used for
cleaning many different surfaces very successfully in this country but,
up to now, usually in environmentally sensitive locations, such as near
watercourses.
'We hope that trials such as this will prove the commercial and operational
benefits of glass grit and encourage specifiers and contractors to use
it more widely.
'We're delighted that the US Army has made the decision to switch to the
new medium and we hope others will sit up and take note of the benefits
it has to offer.'
Recycled glass is available manufactured to BSI PAS 102 specifications,
meaning buyers can procure material confident it is fit for use.
Any companies interested in setting up a trial or learning more about
recycled glass grit applications should contact Bronnie Allen at WRAP
on 0808 100 2040.
Web: http://www.wrap.org.uk