7. GLASS RECYCLING Did you know? 125,000 tonnes of glass was returned for recycling in Victoria in 2000/01. (EcoRecycle 2001) 3.4% of household garbage in Victoria was made up of glass that could have been recycled in 1998/99. (Environment Protection Authority Victoria [EPA Victoria] 1999) 124,000 tonnes of glass was recycled in Victoria in 1997/98. (EPA Victoria 1999) In 1998, the recycling rate for glass for Australia was 44% (ACI Glass Packaging, 2000) Recycling glass saves 74% of the energy it takes to make glass from raw materials. (Grant T et al 1999)* History of glass Glass is one of the most ancient and useful materials known to human societies. The discovery of glass dates back to the Phoenicians more than 5,000 years ago. It is believed that the Egyptians invented the technique of hand blowing glass bottles in the first century BC. For 2,000 years, hand blowing continued to be the principal way of making glass bottles. However, during the last hundred years or so, mechanised glass blowing techniques have revolutionised the production of glass containers, allowing bottles to be produced quickly and cheaply. Today, glass containers are widely used to package a huge array of foods and drinks. Manufacture from virgin materials The three main raw materials used to make glass containers were sand (to provide silica), soda ash (to reduce the melting point) and limestone (to increase hardness). Now, crushed glass, called cullet, is the major raw material for glass manufacturing in Australia. Other ingredients are used in small amounts, the proportions of each depending on the type of glass required. To make glass containers the mix of ingredients, known as a batch, is fed continuously into furnaces and melted at about 1,500 C. The molten glass from the furnaces is then conveyed to moulding machines where globules of glass are o dropped into moulds. Air is blown into the hot globules to form bottles, which are cooled slowly and then dispatched to bottling plants for filling. Manufacture from recycled materials Bottles and jars collected in recycling schemes are sorted manually at recycling depots into clear, amber and green glass. Containers of different coloured glass are then taken to a beneficiation plant to upgrade the quality of the waste glass before reprocessing. At these plants, contaminants such as metals, plastic, china, ceramics and stones are removed, and the glass is crushed. The cullet is transported to the glassmaking factory where it is used with the other batch materials to make new glass containers. According to ACI Glass Packaging, new glass bottles may be made with up to 100% cullet. However, 'the actual percentage depends on the quality and quantity of cullet available'. (ACI Glass Packaging 2000) Using cullet has real environmental and economic benefits, offering energy savings and helping to save resources. Each tonne of cullet saves 1.1 tonnes of raw materials. Lightweighting Glass manufacturers today make glass bottles that are much lighter than bottles made in previous years. This process, called ‘lightweighting’, saves considerable amounts of energy and raw materials. ACI Glass Packaging state that a ‘stubby’ beer bottle made in 1986 weighed 260 g, but by 1997, the same size ‘stubby’ weighed only 180 g, which is a reduction of 31%. Recycling tips Household glass can be returned for recycling in kerbside recycling collections or to bottle bins in public places, such as shopping centres. Check the Recycle What & Where section of EcoRecycle Victoria's website (www.ecorecycle.vic.gov.au) for details of the waste and recycling services provided by your local council. What types of glass can be recycled? All clear, green and amber glass bottles, e.g. soft drink, mineral water, wine, beer All glass jars Clear glass sauce bottles What types of glass cannot be recycled in kerbside collections? Broken window glass and broken windscreen glass. Heat-treated glass, e.g. Corning Ware, Pyrex or Vision Ware Light globes White opaque bottles Laboratory and medical glass Do not include china, ceramic bottles or stones with glass bottles and jars in your recycling because it can lead to the rejection of thousands of bottles and jars collected for recycling. How to prepare glass for recycling 1. Remove lids or caps 2. Rinse bottles and jars. To conserve water, wash bottles and jars in used dishwater or in a bucket with other recyclables. References ACI Glass Packaging 1997, poster and brochure Beverage Industry Environment Council 1998,Recycling Audit and Garbage Bin Analysis BIEC see Beverage Industry Environment Council Grant T, James K, Dimova C, Sonnefield K & Lundies S 1999, Stage 1 Report for the Life Cycle Assessment of Packaging Waste Management in Victoria, Research report by the Centre for Design at RMIT, the Centre for Packaging, Transport and storage at Victoria University and the CRC for Waste Management and Pollution Control, November 1999. * Study limited to metropolitan areas, when modelled for rural locations energy savings decrease due to an increase in transport requirements, however, the rural results are still positive.
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