Straits Times 20 Dec 08;
Singapore produces 71 million kg of waste glass each year, but only 9 per cent is recycled. The rest is incinerated with other waste. To boost recycling rates, Singapore Polytechnic's Centre for Applications in Environmental Technology has teamed up with glass collection facility P&R Resource Management to find ways of making recycling safer, quieter and more convenient.
Grace Chua takes a look at the current process.
1 Glass bottles, mainly from restaurants, coffee shops and other F&B establishments in Singapore are sent to collection facilities such as P&R Resource Management in Sungei Kadut, which handles about 500,000kg of glass each month. Most are beer bottles, and a faint smell of the brew lingers in the air. At the company's collection yard, a forklift breaks the bottles by lifting a trough of glass up and pouring it from a height. The crash and clang can reach an ear-splitting 130 decibels, louder than a jet engine.
2 P&R's parent company, silicate-sand mining firm PUM Group, has a recycling facility at Pasir Gudang in Johor, Malaysia. Bottles and glass chunks are trucked and shipped there from as far away as Thailand, Indonesia and New Zealand. They will eventually be crushed into smaller, finger-length glass shards and recycled into new bottles. Part of the process involves workers separating impurities such as paper and metal from the crushed glass chips.
3 Different coloured chips - green, amber and flint (colourless) - are separated by machine. At glass-bottle factory Malaya Glass, this machine, called the 'dog-house', sends the raw material - a mixture of recycled glass chips, soda ash, limestone and other ingredients - into the furnace to be heated at temperatures of up to 1,600 deg C for 24 hours.
4 After heating and mixing, gobs of molten glass are moulded into bottles and containers. New bottles, which contain up to 70 per cent recycled glass come off the line to begin life again as beer and drink containers.
