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Recycling

Making good use of discarded plastics Non-biodegradable plastic, which is becoming infamous in an eco-aware society, is redeeming itself for practical yet sustainable technology. Angelica Buan discovers how discarded PET bottles are being used to harness solar energy and build walls in Manila, while scientists in the US have developed a technology to remove arsenic from water, using discarded bottles, and a US company has successfully made bottles out of plastic waste from the sea! PET bottles light up homes and make walls in Manila The MyShelter Foundation, a Philippine-based nongovernment organisation spearheaded by social entrepreneur Illac Diaz, who is also the proponent of the A Litre of Light project, has introduced to the country a solar light bulb made using a discarded PET bottle. The bottle is filled with filtered water, diluted with bleach (to act as anti-algae agent) and then inserted vertically onto a piece of galvanised iron so that the top part is exposed to the sun and the bottom half juts indoors. The bulb only functions at daytime. Illac Diaz seen here with the PET bottle wall

This practical technology, which was first developed by students from US-based Massachusetts Institute of Technology, was actually invented in 2002 by Brazilian engineer Alfredo Moser, who found a nifty way to light up his workshop during the energy crisis in his hometown. He used a 2 l PET bottle with its cap covered with an empty camera film canister. An alternative to the day lighting method, the bulb harnesses natural light from the sun, giving off approximately 50-60 watt lighting in a 360-degree arc. A 1 l bottle gives off around 55-watt lighting. According to Diaz, “PET bottles are more ideal for this purpose (unlike a plastic sheet, for example, which refracts light in a columnar beam) because they refract light in 180 degrees, enough to light up a 40-sq m room.� The bulb is good for five years and serves to defray the high cost of electricity in the country. Meanwhile, the foundation has also erected the first of eight class rooms using PET bottles for walls. The project has been piloted on a 560-sq m land in Laguna Province, South of Manila. Diaz says that not only are the PET bottles

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durable but also three times stronger than conventional concrete material; not to mention that plastics take around 600 years to degrade! The bottles are filled with liquefied adobe (a combination of clay, sand, water and organic materials), stacked like regular bricks and reinforced with discarded materials like glass bottles, chicken feathers and human hair as well as the environment-friendly pozzolanic cement, making the structure sturdy and earthquake-proof. The structure is also inexpensive, with one wall panel costing around US$46. While this bottle-wall school is touted to be the first in Asia, a town in Guatemala built its own in 2009. With the help of volunteers from the US-based Hug It Forward organisation, the townsfolk of Granados gathered about 6,000 PET bottles for the school. The bottles are first filled with plastic bags and other common waste materials, these are then aligned by metal fencing and the gaps filled with trash materials. To finish off, three layers of cement are applied on both sides of the bottle wall panels. The NGO has since built 12 schools with this kind of bottle walls. Bottle solution for arsenic-contaminated water With almost 100 million people in developing countries exposed to dangerously high levels of arsenic in the drinking water and unable to afford complex purification technology, US scientists have found an inexpensive method for removing arsenic. It uses discarded PET bottles that are chopped up and coated with cysteine, a nutrient found in many foods and dietary supplements, according to a report by the American Chemical Society (ACS). Stirred in the arsenic-contaminated water, the cysteine binds the arsenic allowing for drinkable water to be produced. Laboratory tests of the method were conducted

PET bottle light bulbs that are lighting up homes in Manila

Profile for Plastics & Rubber Asia

Plastics and Rubber Asia October-November 2011 Issue  

Plastics and Rubber Asia October-November 2011 electronic issue

Plastics and Rubber Asia October-November 2011 Issue  

Plastics and Rubber Asia October-November 2011 electronic issue