What happens to Glass – The Recycling Journey

So what happens to the glass you have consumed? You could “dump it” in landfill. But that is wasteful, irresponsible and even anti-social. Glass is too valuable a commodity, and it should be recycled, for all the reasons given in the section “Benefits of Glass Recycling”. So what happens on the recycling journey?

You can take it to a bottle bank (a system know as bring), or it might be collected on your doorstep (known as kerbside collection). It speeds up the process if glass is already roughly sorted into brown, clear and green, as it is at bottle banks, but with many methods of collection, including domestic recycling boxes, that isn’t always possible.

Once it is collected, the glass is transported to a MRF (Materials Recycling Facility) or a glass recycling and treatment plant, such as the ones operated by Berryman Glass, the country’s leading glass recycler.

The most popular and environmentally favorable approach is to glass recycling is to remelt it to produce more bottles and jars. Every 1,000 tonnes of recycled glass that is used in this ways saves 345,000 kWh of energy, 314 tonnes of CO2, 1,200 tonnes of raw material and 1,000 tonnes of landfill.

Put simply, the energy saved from recycling one bottle will power a 100 watt light bulb for almost an hour or a computer for 20 minutes. In 2008, the UK recycled 1,650,000 tonnes of used bottles and jars. That means though that 1,000,000 tonnes still went through the residual waste stream and was lost in landfill.

Once in the treatment plant, the bottles and jars are placed on a conveyor belt and sorted to remove the metal and plastic caps and collars that dress bottles from the neck up. This is done both manually and by using powerful vacuums to suck up the waste from the belts.

The glass, or cullet as it is known, then goes through machines that use laser, X-ray and digital technology to remove critical contaminants such as ceramic and stone. It can also distinguish between colours and types of glass. As it falls, each fragment is scanned and identified and the information fed into a computer which activates air jets lower down.

These jets are fired at the specified piece of contamination or glass with pinpoint accuracy, blasting them onto separate conveyor belts. In this way the green, brown and clear glass can be separated out.

Once sorted, the furnace-ready cullet , if it is of sufficient quality, is supplied to the bottle and jar manufacturer, who make new bottles and jars from the finished, high quality cullet. This is known as a closed loop system, where waste material is turned back into its original form and sent back to be consumed. In the case of bottles and jars, the loop can repeat itself over and over again, forever!

For manufacturing green bottles up to 90% cullet can be used, with the rest made up of raw materials including sand, soda ash and limestone. The ingredients are melted in a furnace that can reach 1600 degrees C from which toffee-like strands of glass will be cut into ‘gobs’ and placed into moulds.

From there, they are reheated to 550C to allow for a controlled period of cooling that will ensure a strong, non-brittle final product. Following stringent safety and inspection tests, the finished bottles and jars are put into pallets and distributed to customers and retailers to end up back on your table.

Other uses for low grades of  recycled glass which do not meet the specification for new bottle and jar manufacture include a coarse aggregate substitute for use in road construction, concrete product manufacture or as trench backfill. When crushed to a finer size, it may be used as a replacement aggregate. Other applications include sports turf sub base,  golf course bunkers,  grit blasting, glass bead manufacture or as a fluxing agent in brick manufacture.

Another popular use for recycled glass is in fibreglass insulation manufacture where either mixed colour bottles and jars or flat glass cullet is used offering numerous benefits over virgin materials.