Ground glass solution for cleaner water

British science has led to a use for waste glass that cannot be recycled that could help clean up polluted waterways by acting as an ion-exchange filter to remove lead, cadmium and other toxic metals. Details are published in a forthcoming issue of the International Journal of Environment and Waste Management.

Only a fraction of waste glass bottles and jars can be recycled, partly because much of the glass is coloured, brown or green, and partly because the market sustains only a limited weight of recyclable glass. Millions of tonnes of waste container glass is generated across Europe. As such, large amounts of waste glass, purportedly for recycling, are shipped to China and elsewhere to be ground up and used as hardcore filling materials for road building.

Now, Nichola Coleman of the University of Greenwich, London, has developed a simple processing method for converting waste container glass, or cullet, into the mineral tobermorite. Tobermorite is hydrated calcium silicate, silicate being the main material that can be extracted from glass. In the form produced, the phase-pure 11-angstrom form – the mineral can be used as an ion-exchange material that can extract toxic lead and cadmium ions from industrial effluent, waste water streams or contaminated groundwater.

To make the tobermorite, Coleman simply heats a mixture of ground cullet, lime (as a calcium source) and caustic soda (sodium hydroxide solution) to 100 Celsius in a sealed Teflon container. Initial tests show that uptake of lead and cadmium from solution are rather slow, so Coleman suggests that, at this stage of development, the synthetic mineral might best be used in the in situ remediation of groundwater rather than in industrial ex situ effluent filtration processes. The concept is now being extended to create other classes of ion exchange filter from unrecyclable and low-quality waste glass.

“The cullet-derived sorbent could be used in reactive barriers to prevent the lateral migration of pollutants in groundwater, rather than as a remediation material for waterways,” says Coleman. “Heavy metal-contaminated land and groundwater are global problems, arising from industrial and military activities and also from the natural leaching of heavy metal-bearing minerals,” she adds.

Nichola Coleman (2011). 11 Å tobermorite ion exchanger from recycled container glass Int. J. Environment and Waste Management, 8 (3/4), 366-382

The opposite of built-in obsolescence

Manufacturers should be encouraged to make products that last longer, retain their retail value and are more readily recyclable after use, according to green consultant Peter Lang. Lang is co-founder of the charity Green and Away and a former Adviser to the Green Deputy Mayor of London. Writing in the International Journal of Green Economics, he suggests sustainability will only be achieved by promoting growth in high-quality goods and the phasing out of “shoddy” products.

“Society should be seeking growth in the quality of goods and services,” he says, “This change from quantity to quality is necessary because Western industrialised economies are already consuming beyond the planet’s carrying capacity.”

Lang explains that without changes in taxation and regulation, there will not be a cultural shift towards such high-quality goods that last longer, are more easily repaired and maintain their value on the second-hand market. Eradicating the manufacturing culture that leads to stickers proclaiming “No user serviceable parts” on electrical goods and plastic cases that either have no screws or cannot easily be opened for do-it-yourself repair, under the guise of “health and safety” represents an important part of this. Without this and other changes, we will continue to dispose of electrical goods, furniture, kitchenware, household goods and other products prematurely.

“The suspicion is that manufacturers are confident that their goods will be reliable for a year, but not much longer,” says Lang. “The cost of the product when new seems to make little difference: a £50 video recorder has a one year warranty, as does a £15,000 car,” he adds. “A cynic might be grateful that our planet takes all of 12 months to circle the sun: if it was less then warranties might be shorter too.” Longer warranties and guarantees seem only to apply to things like cutlery, which tend to lack moving parts or any likelihood of falling into disrepair without particularly severe handling and use.

He suggests that changes that are both financially and also culturally attractive will encourage consumers to opt for better-quality products and so nudge the manufacturers to improving their goods. Essential to such endeavours is strengthening existing “fit for purpose” legislation that protects consumers. He believes that products should either be designed “for life” or at the very least come with a label indicating life expectancy so that consumers can make a more informed decision as to which product to buy.

“To some these changes may seem harsh, but the crises of climate change, water and air pollution, and waste from manufacturing are already becoming huge,” says Lang. If we can change the manufacturing and consumer culture to choose high-quality over shoddy, longer lasting and more easily repaired, then we might again achieve a society that appreciates this quality and reduces dramatically our demands on raw materials, energy and waste facilities. Who knows, we might one day see a market in antique kettles and televisions that still function when plugged in!

Peter Lang (2011). Promoting the growth of high quality goods and the phasing out of shoddy products International Journal of Green Economics, 5, 126-132