In the United Kingdom, Closed Loop Recycling Ltd. recycles used plastic bottles back into food-grade quality material in a process chain that involves several technologies in three key stages: sorting, granulating and washing, and decontamination.The plastic bottles arrive at the plant, squashed and compacted together into square bales, which typically weigh about 500 kg. The bales that contain both PET and HDPE bottles are fed into the bale breaker – six large rotating cork screws that loosen and open up the bale. The crushed bottles then pass through the trommel, which removes small bits of rubbish, such as stones and dirt, as well as any lids and caps that have come off the bottles.

Metal contaminants such as food and drink cans, screws and wire are then removed. A powerful electromagnet extracts steel objects and then an eddy current separator is used to remove any aluminium objects. Paper, carrier bags and films are then separated from the bottles by a row of air jets that blow light objects off the conveyor belt. With the majority of unwanted waste removed, the bottles are sorted by type of plastic and colour employing optical sorting machines into: clear PET bottles, light blue PET bottles, HDPE bottles, coloured PET and other plastics. Clear and light blue PET bottles and uncoloured HDPE bottles are granulated into flakes. The flakes are cleaned first by a dry cleaner and then a hot wash (80ºC). A sink-float separator is used to separate PET flakes (which sink in water) from HDPE flakes (which float and are skimmed off). Both flakes are then decontaminated.

To return the PET flakes back into a food-grade product, a process developed by United Resource Recovery Corporation of the United States is used. The pure PET flakes are bagged and sold to plastic packaging manufacturers, to be made into new bottles or other food packaging. HDPE flakes are processed into food-grade material employing a Vacurema, which treats the flake under low pressure and high temperature. Heating the flakes to over 200ºC melts them, eliminating any contamination. The molten plastic is extruded, filtered, cut into small pellets and cooled for use in making new milk bottles. Contact: Closed Loop Recycling Ltd., 16 Choats Road, Dagenham, Essex RM9 6LF, United Kingdom. Tel: +44 (20) 8593 6040; Fax: +44 (20) 8593 6511; E-mail: info@closedlooprecycling.co.uk.

Source: www.closedlooprecycling.co.uk

In the United States, Tyco Healthcare Group LP, together with Mr. Piyush Reshamwala and Mr. John Japuntich, has patented a process for reclaiming and recycling plastic from discarded plastic articles. The process includes breaking down waste materials into pieces using mechanical force, removing non-magnetic pieces, separating out relatively heavy pieces from the non-magnetic pieces, segregating relatively non-conductive pieces from the heavier pieces, and reclaiming plastic pieces from the relatively non-conductive pieces.

The system includes a crusher for breaking down the discarded materials, a magnetic separator for the removal of relatively non-magnetic pieces, an air classifier for separating out relatively heavy pieces from the non-magnetic pieces, an electrostatic separator for segregating non-conductive pieces from the relatively heavy pieces, and a metal detector for separating out plastic pieces from non-conductive pieces. The recovered plastic is moulded in an injection moulding machine. Contact: Tyco Healthcare Group LP, 15 Hampshire Street, Mansfield, MA 02048, United States of America.

Source: www.wipo.int

A team of scientists from University College of Dublin and Trinity College, both in Ireland, and Institute for Technical and Macromolecular Chemistry, Germany, has studied the conversion of the polymer polyethylene terephthalate (PET) to a biodegradable plastic polyhydroxyalkanoate (PHA).

PET was pyrolysed at 450ºC resulting in the production of solid, liquid and gaseous fractions. The liquid and gaseous fractions were burnt for energy recovery, while the solid fraction terephthalic acid (TA) was used as the feedstock for bacterial production of PHA. Strains previously reported to grow on TA were unable to accumulate PHA. The bacteria were therefore isolated from soil exposed to PET granules at a PET bottle processing plant. From the 32 strains isolated, three strains capable of accumulation of medium chain length PHA from TA as a sole source of carbon and energy were selected for further study.

These bacterial isolates were identified using 16S rDNA techniques as Pseudomonas putida (GO16), P. putida (GO19), and P. frederiksbergensis (GO23). Strains GO16 and GO19 accumulate PHA composed predominantly of a 3-hydroxydecanoic acid monomer while the strain GO23 accumulates a PHA with 3-hydroxydecanoic acid as the predominant monomer with increased amounts of 3-hydroxydodecanoic acid, compared with the other two strains. PHA was detected in all three strains when nitrogen depleted below detectable levels in the growth medium.

Strains GO16 and GO19 accumulate PHA at a maximal rate of about 8.4 mg PHA/l/h for 12 h before the rate of PHA accumulation fell dramatically. Strain GO23 accumulates PHA at a lower maximal rate of 4.4 mg PHA/l/h but there was no slow down in the rate of PHA accumulation over time. Contact: Dr. Kevin O’Connor, School of Biomolecular & Biomedical Sciences, University College Dublin, Belfield, Dublin 4, Republic of Ireland. Tel: +353 (1) 716 1307; Fax: +353 (1) 716 1183; E-mail: kevin.oconnor@ucd.ie.


Source: pubs.acs.org

IoSys, Germany, developed Mobile Infra-Red optic (mIRo) device for identifying plastics, as plastic recycling demands that plastic materials be sorted according to their type. This plastic distinction technology, which involves Near Infra-Red (NIR) spectroscopic analysis, can easily distinguish the waste plastic at the touch of a screen. Data processing is carried out by the PC unit built into by the system. Its operation is easy, without the need for any special facilities. These features make mIRo suitable for fieldwork. Other key features include:

• Non-destructive measurement;
• Less than 1 sec measuring time;
• Analysis of non-dark-coloured plastic possible;
• Possibility of calibration and editing of up to 8 individual plastics or mixtures by customer; and
• A wide range of polymer types can be identified.

The equipment measures 364 mm (W) × 316 mm (L) × 195 mm (H), and weighs about 8 kg. Contact: IoSys - Dr. Timur Seidel e.K., Steinhauser Str. 14, D-40882 Ratingen, Germany. Tel: +49 (2102) 895 001; Fax: +49 (2102) 895 002; E-mail: office@iosys-seidel.de.

Source Website: www.iosys-seidel.de

China’s Suzhou Yaoshi Machinery Co. offers equipment for crushing, washing and drying waste polypropylene (PP) and polyethylene (PE) film products. Waste agricultural films, packing material and hard plastics can be treated step by step by this machine. This processing line can be linked to a granulating system for reducing waste PE and PP films into granular material to produce new PE/PP films. The PE/PP granules may then be injection-moulded to finished products.

The company supplies all these machinery that integrates into a complete system that includes belt conveyors, film/sheet processing tanks, scrubbing/washing equipment, crushers, screw conveyors, dewatering and drying systems, injection moulders, etc. Contact: Suzhou Yaoshi Machinery Co., West of Fourth Bridge, Sanxing Town, Zhangjiagang, Jiangsu, 215624 China. Tel: +86 (512) 5853 8148; Fax: +86 (512) 5853 0618; Website: www.ysmachine.com.

Source: yaoshi.en.alibaba.com

Plastinum Polymer Technologies, the United States, has developed a process to recycle more types of plastic than just milk jugs and soda bottles. Formerly non-recyclable household plastics, scrap automobile and electronic plastics, and post-production waste plastics can now be made into new items to be used in various different settings. The proprietary process, called Blendymer Technology, allows mixed plastics to be processed without sorting to create new high-quality plastic.

The recycled plastics created by the Blendymer process are Infinymer SSL and Infinymer SML. Infinymer SSL is like polyolefin and Infinymer SML is like polystyrene. Contact: Plastinum Polymer Technologies Corp., 10100 Santa Monica Boulevard, Suite 300, Los Angeles, CA 90067, United States of America. Tel: +1 (310) 651 9972; Fax: +1 (310) 861 1502.

Website: tech.blorge.co