Glass is one of the least potentially toxic waste products that we produce. The raw materials it is composed of are cheap and relatively available, although they do need to be quarried, which has environmental implications.
Glass will not decompose in a landfill site, but it will not leach toxic chemicals. The chief issue with glass production, and the benefit of recycling it, is the energy needed to run and maintain the huge furnaces, and to a lesser degree, the energy of transporting the raw materials and the product.
Why is it Important to Recycle Glass?
Unlike other materials we examine on this site, glass can be melted down and reformed again continually with little or no loss to its quality. There are no waste or by-products from this process, and as the furnaces are in place, it is just the collection and breaking down process that is necessary. Crushed glass is known as cullet.
This is passed through a magnet, which removes any traces of metal, at several stages of the process, from recycling collection point, through crushing, and before the heating point, the glass will be screened for metals or other waste products. A pure glass product must be collected, otherwise impurities will be captured within the new recycled glass – and manufacturers then wouldn't use the product!
Glass is only 2% of the total volume of the average household, but it does account for about 8% of the weight of the total solid waste annually across the world. Recycling glass saves approximately 50% of the energy required to produce new glass. This is because recycled glass, in the form of cullet, needs a slightly lower temperature to melt it.
This lower temperature has the added benefit of prolonging the life of the furnaces – perhaps by up to 20 years. Each ton of recycled glass reduces mining waste by 230 kilograms, thus preserving the environment and saving energy