Scientists at the City University of Hong Kong can turn coffee grounds and stale bakery goods into a sugary solution that can be applied to manufacture plastic. Photograph: Alamy
We frequently talk about the
recycling on these pages, with an eye toward the developing awareness that the concept is no longer limited to inorganic, static materials. This recent article in the Guardian indicates that plant cellulose based plastic is just the tip of the iceberg in the possible ways to convert the mountains of food waste in many parts of the world into materials with environmental benifits.
Scientists at the
City University of Hong Kong have found that they can turn coffee grounds and stale bakery goods – collected from a local Starbucks – into a sugary solution that can be used to manufacture plastic. The food waste was mixed with bacteria and fermented to produce succinic acid, a substance usually made from petrochemicals, that can be found in a range of fibres, fabrics and plastics.
Meanwhile, engineers at the Colorado School of Mines have discovered a way to turn banana peels, eggshells and rice husks
. By blending, drying and pounding it into a fine powder, and with a little help from the magic of science, they found the mixture could provide some of the metal oxides required in the composition of glass. Ivan Cornejo, a professor at the university,
told the Denver Post
at the time that such an innovation could reduce the need to mine for silica, one of glass’s primary components.
Food into graphene
Now, a new EU project,
, is researching a way to fashion food waste into graphene. It’s perfectly timed, given the recent buzz surrounding the material and its potential to revolutionise the green industry. The material,
discovered in 2004
, is so super, Bill Gates is even investing in it to develop an
ultra safe condom
.The project uses a process known as anaerobic digestion (AD), where waste is converted into biogas. Finding a new lease of life for food waste using AD isn’t anything out of the ordinary. Businesses have been using the process to make energy for some time. Most notably, early last year, Harvest Power, a Brooklyn-based waste treatment plant, built a digester to deal with
waste coming from Disney World
. More recently, Sainsbury’s partnered with recycling specialists Biffa to launch their first
shop powered by food waste
collected from the chain’s stores. But PlasCarb takes the process one ambitious step further.“Together with an innovative low-energy plasma reactor we convert the biogas from AD, which is mainly methane and carbon dioxide, to graphitic carbon [from which comes graphene] and renewable hydrogen,” explains project manager Neville Slack, from the
Centre for Process Innovation.
Beyond the science and technicalities of the process, PlasCarb offers a possible dual advantage over how traditional materials and gases are produced: a happier environment and a commercial use for food waste from a range of industries including retail and hospitality.
“The obvious benefit is taking waste destined for landfills and transforming it into raw materials in a sustainable way,” adds Slack. “Graphene is the latest wonder material. Hydrogen has also been identified as a future transport fuel for a low carbon economy.”
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