Chemical Processing - November 2007 - (Page 50)

>> END POINT Waste not, want not… Biodegradable plastics are a perfect fit with future recycling strategies Recycling waste, whetheR inside a plant oR further down the product chain, is something to be encouraged — as we all know from both a process engineering perspective and the wider environmental view. our recent reports on eU waste directives such as Rohs and weee (www. chemicalprocessing.com/articles/2006/157.html) have highlighted the increasingly international initiatives being made to impart a recycling mentality across industry and its customers. the difficulty is turning that mentality into sound practice — moving from perception to practicality, if you like — because the perception of recycling can differ significantly from the reality, as a recent nationwide online survey has shown. ronmental waste transfer station — to dispose of the general detritus that the curbside refuse collectors can’t cope with. But at least this is where you see recycling in action, or at least the beginnings of the process. instead of just three or four receptacles to put your segregated waste in, the number of large containers on offer runs well into double figures. there are ones for fluorescent light tubes, scrap metal, solvents and paints, timber, textiles, batteries and so on, not to mention those for weee-type products like consumer electronics. and yes, one for all things plastic, even though very little plastic is recycled anywhere in the true sense of the word. some can be ground up and remolded into lower cost products, but true recycling processes — such as ge plastics’ route to polybutylene terephthalate (pBt) based resins and polymers that uses pet plastic bottles for feedstock (www. chemicalprocessing.com/articles/2007/003.html) — remain few and far between. Biodegradable plastics that don’t really need recycling at all are more interesting in the long-term. By mid-2008, telles, for example, should be producing 50,000 ton/yr of such plastics at its currently under construction clinton, iowa, plant. taking starch from an adjacent adM wet corn mill as feedstock, the plant will produce polyhydroxylalkanoates (phas). Marketed under the trade name Mirel, these are high-performance biodegradable plastics that can be used in place of oilbased polymers in injection molding, paper coating, cast film and sheet, blown film and thermoforming. Metabolix says it already has more than 40 prospective customers working on more than 60 applications such as packaging, consumer products, agricultural products and single use disposables (www.chemicalprocessing.com/articles/2007/185.html). Biodegradable polylactic acid (pla) polymers, such as those produced by natureworks at its corn-based 140,000metric-ton/yr plant at Blair, neb., have already moved into the mainstream of consumerism following retail giant walMart’s 2005 decision to use pla packaging for fruit and herbs in its stores. another reason why so many people think more plastics are recycled than is actually the case? they may not free up much room in my garage — home to our own mini-recycling center with its five containers — but truly disposable biodegradable plastics could change people’s perceptions on recycling. and perhaps even confirm their belief that plastics don’t really come from oil at all. CP Mike Spear, editor at large, Hefordshire, U.K. MSpear@putman.net www.chemicalprocessing.com Truly disposable biodegradable plastics could change people’s perceptions on recycling. commissioned by “natural plastics” producer telles, a joint venture between Metabolix, cambridge, Mass., and archer daniels Midland, decatur, ill., the survey suggested that, on average, most people thought around 40% of plastic is recycled in the U.s. the actual figure is 5.7% nationally, according to the U.s. environmental protection agency. and, perhaps of more concern — although quite encouraging for telles and its biodegradable polymers made from corn sugar and other renewable sources — around 40% of the survey’s respondents thought conventional, oil-based plastics were already biodegradable. Most alarming, mind you, were the 72% who didn’t know conventional plastics were made from oil! such benign ignorance of the realities of plastics recycling is understandable in a way. when we are now coaxed, if not actually compelled, to separate all our household waste into an ever-increasing number of “recyclable” categories, people can perhaps be forgiven for assuming that “recycling” is what actually happens to all their waste. here in my U.K. neighborhood, for instance, every household is supplied with three recycling boxes (for paper, plastics and glass, respectively) and two mini-dumpster type bins, one for garden waste and similar compostable materials, the other for anything leftover. well, almost everything. such is the average household’s accumulation of waste that most people still have to make regular trips to the town dump — sorry, envi50 • november 2007 http://www.ChemicalProcessing.com/articles/2006/157.html http://www.ChemicalProcessing.com/articles/2006/157.html http://www.ChemicalProcessing.com/articles/2007/003.html http://www.ChemicalProcessing.com/articles/2007/003.html http://www.ChemicalProcessing.com/articles/2007/185.html http://www.chemicalprocessing.com

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Chemical Processing - November 2007 Contents From the Editor ChemicalProcessing.com Field Notes In Process Energy Saver Compliance Advisor PAT isn't Standing Pat Pursue the Perfect Plant Eliminate Exchanger Tubing Troubles Portable Conveyor Speeds Paint Production Process Puzzler Plant InSites Equipment & Services Product Spotlight/Classifieds Ad Index End Point

Chemical Processing - November 2007

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