Glass is known to have been recycled since ancient times, in the city of Sagalassos, which used to be located in modern day Turkey. Throughout history it has been used to manufacture anything from small glasses and ornaments to windows and mirrors, with a long tradition in manufacturing jars and bottles. It is increasingly being used in the construction industry as modern architecture usually encompasses glass panels.
Because it is so easily breakable, glass products normally have a short lifespan. In the manufacture of bottles and jars, it has largely been replaced by plastic, as plastic is lighter and safer to handle, yet that is not necessarily beneficial to the environment.
Nonetheless, it remains among the most favoured materials for packaging, for a number of reasons. First of all, it is fairly cheap to produce and raw materials are usually inexpensive as well as readily available in many parts of the country. Because it is not mixed with other materials, it can be recycled repeatedly with no subsequent residue.
For the same reason, it is highly hygienic, which is why it is preferred within the food and drinks industry, as it does not contaminate the products in any way.
Reusing glass bottles became popular in the UK in 1971, when thousands of consumers returned their bottles to the popular soft drink company Schweppes. Later that decade, in 1977, the first bottle banks (glass collection centres) were created.
Today, people are no longer limited to returning bottles and can recycle any kind of glass by placing it in a specially designed bin, with a circular or rectangular aperture which is used for throwing the items inside. There are two different types of containers, one for clear glass and another one for brown and green glass. Moreover, removing glass from normal waste bags and placing it in special containers is also a safety issue, as such bags can be dangerous to remove during waste collection. Nowadays, recycling it instead of producing new glass also saves energy as well as carbon dioxide.
When depositing glass at a collection point, most people will find separate bins for the three differently coloured sorts of glass (transparent, green and brown), or a segmented larger container which holds all three. This is because glass maintains its colour after undergoing the recycling process. Aside from that, due to their chemical composition, it is unsuitable to mix two or tree colours before melting. It is also important not to mix heat resistant glass with the normal recyclable one as it has a very different consistence when melted and can damage the whole process.
However, mixed waste glass is not completely useless. Instead of melting it, some companies recycle it by grinding it, after which it is used in road fillers, driveways, parking lots etc. or construction materials such as flooring, counter tops or tiles.
The sorted glass is first placed onto a bottle supply hopper and from there passes into the crusher and then the cullet mill. From the cullet mill it goes through a powder sifter, onto a powder conveyor and into a mixing machine. The final step is melting the powder with the aid of a baking machine.
Glass products can easily be recycled into similar items, over and over again, saving both raw materials and energy. Recycled glass is widely used in thee food and drinks industry, ceramic industry and more recently, in constructions. A niche was created by certain beer producing companies, which recycle their glass bottles by turning them into goblets and tumblers, through a technique which allows using the whole amount of glass the bottle comprises. Such companies include Grolsch, Carlsberg and Corona.
The constructions industry employs recycled glass aggregates in order to obtain a higher quality type of concrete, which provides better visual effects than the regular one, and also for making bricks. The ceramic industry uses it for manufacturing tiles, sanitary ware (bathroom suites), ceramic plates and so forth. Recycled glass can also be used for decorative purposes, when in the form of rock or gravel, which is utilised by professionals in combination with other features for the creation of landscape applications.
Recycled glass is also dexterously used for making jewellery. Coloured glass in particular is melted by skilled artisans, particularly in certain African countries such as Ghana, to obtain beads of many shapes, which are then bound into aesthetically pleasing original products and successfully sold on western markets.
Akin to other recyclable materials, glass is of more use when recycled than when landfilled, which should be avoided as it is not biodegradable and will simply pile up where it is placed, wasting the raw materials and processing it has already undergone. Energy saving is an important factor in deciding the feasibility of glass recycling, as manufacturing new products through this method uses up to 40% less energy than using raw materials. As shown above, it can be integrated into a variety of materials, which makes it versatile. Furnace emissions are greatly reduced as well.
Did You Know?
According to Defra, each person in England produced an average of 457 Kilograms of waste in 2009-10. Of this, an average of about 181 Kilograms per person was recycled. That left 60% of un-recycled waste, at an average of 276 kilograms per person.