Jane Powerson recycling plastic
Back by popular demand: Planet Mattersrevisits the mysterious world of plastic containers. What are those enigmatic triangles on the bottom? What do the numbers inside them mean? Why are they so tiny? And do we really have to know?
To answer the last first: it's true, we can recycle fairly efficiently without heeding the resin-identification codes (for that is what they are) on containers, but those little numbers help put at rest any doubts about what goes where. (And, if there's something I've learned about readers of this column over the past year, it's that you like to know exactly what's what - and where it goes.) All plastics are not equal. Some are relatively easy to refashion into more plastic, and are desirable fodder for the recycling industry, but others are more expensive to reprocess, and receive a limited welcome.
Two kinds of polymer (which, in this case, is just a fancy word for plastic) are accepted at almost all plastic-recycling facilities and in domestic green bins. The first, denoted by a number 1, is polyethylene terephthalate (PET or PETE), most commonly seen in clear plastic drink or water bottles. The second, number 2, is high-density polyethylene (HDPE), used in semi-rigid (that is, squeezable) bottles for shampoos, lotions and cleaning products, and in plastic milk containers. Screw caps for PET bottles (that is, plastic number 1) are made from HDPE (number 2), and are easier to process if you take them off the bottles before you recycle them.
As for the other kinds of plastics, number 3 is polyvinyl chloride (PVC), found in some detergent bottles. This is accepted by Oxigen recycling but not by Greenstar. The latter company, however, does accept number 4 plastics; that is, low-density polyethylene (LDPE), which means grocery bags, cling film and six-pack rings. The least favourite polymer of the five most common plastics is number 5, polypropylene (PP), used in food tubs and trays and in yogurt pots (but not in those little yogurt drink bottles, which are usually number 2/HDPE). Panda, which operates a domestic collection service in Dún Laoghaire-Rathdown, accepts all plastics, no matter what the number, as long as they are clean and uncontaminated.
All recyclable plastics collected in Ireland are baled and sent to the UK or Holland as "mixed plastics". There they are separated by polymer and moved on for further processing. Drink bottles, for instance, may end up as fleece clothing or carpets; milk cartons may be born again as agricultural pipes or artificial timber.
It is gratifying to think of our plastic debris having another life, but let's not get too carried away with this idea. It's best not to buy the stuff in the first place. Second best is to reuse it for something else. Trailing in third-best place is recycling.