Inside a materials recycling facility
WSN Environmental Solutions (a NSW government-owned corporation) operates two materials recycling facilities (MRFs) in Sydney; we visited the Chullora MRF, pictured, one of the largest in Australia. It accepts both “fully co-mingled” and “source separated” recyclables, from kerbside collections where households either put everything into one bin, or presort paper from containers. Here, all recyclables get sorted into different streams – glass, plastics, paper and aluminium – ready for reprocessing.
As the delivery trucks tip their contents on the floor, large front-end loaders push it onto conveyor belts, where sorters remove by hand hazardous substances such as medical waste or car batteries, food waste and cardboard. We also saw them pick out lots of plastic bags, which should never be included in household recycling.
The second step in separation is more automated. The recyclables move through screens with different-sized holes, so small pieces (such as glass shards) fall through at a different point from cans and containers. A strong magnet separates ferrous metals from the rest of the recyclables; an “eddy current” works similarly for aluminium cans. An “air classifier” blows the lighter items (paper) away from the heavier ones (glass). Predominantly mixed plastics now remain on the belt. The majority of the plastics received up to 80%, PET and HDPE, are then sorted out by hand; the rest are baled (compressed) into large blocks of mixed plastics, ready for transport to manufacturers for reprocessing.
Beyond the MRF
Reprocessing takes place either in Australia or overseas. According to the Plastics and Chemicals Industries Association (PACIA), 64% of all plastics recycled in 2007 were reprocessed in Australia. Of these, 61% was used for the manufacture of new products, 18% was exported (predominantly China) and 21% reused internally by the company that reprocessed it (for example, by a soft drink manufacturer in the production of PET bottles).
At the processing plant, the plastics are shredded, chopped or ground, washed, melted and pushed through an extruder, much like a spaghetti press. The mass is then cooled, pressed through a die and chopped or pelletised into granules, ready for manufacture into new products. Check out our video to get an idea of the process – and noise – that prevails on the floor.