Glass Recycling FAQ
- Q?What are the alternative uses for glass?
- Q?What sort of glass can be recycled?
If you have kerbside recycling, you can put out your glass containers for recycling. There are also some landfills and transfer stations that have bins for recycling glass.
Remember, you can only recycle food and beverage containers, for example:
Clear glass jars and bottles
Brown glass (beer bottles)
Green glass (wine bottles)
The above types of glass can be fully recycled WITHOUT loss of purity when making a new bottle.
- Q?What sort of glass cannot be recycled?
You can’t recycle light bulbs and fluorescent tubes, pyrex dishes and ovenware, china and crockery – cups, saucers, plates, decorated drinking glasses, window glass, opal glass, glass bricks, medical and laboratory glass containers, TV tubes and computer screens.
Why? Because if the recycled glass is being used to make new glass it must be pure and this means you can only use glass and beverage containers. Other types of glass can have a damaging or harmful effect on the quality of the new glass.
- Q?Why do you have to separate the containers by colour?
Glass needs to be separated by colour if it is going to be used to make new glass containers.
O-I New Zealand, New Zealand’s only glass manufacturer, makes bottles and jars in seven colours. These are flint or clear glass, amber glass, blue glass and four varieties of green. The reason for sorting the glass is to maintain the green, brown and clear colours which consumers want and which are an important part of a product’s branding and also to ensure that the glass furnaces can be run as energy efficiently as possible.
When the raw materials are mixed in the furnace, other minor ingredients are added (some of which will determine the colour of the glass).
When recycled glass (cullet) is added to the mix, it already contains these minor ingredients and can have an impact on the colour of the glass made.
It is really important that the bottles and jars are consistent in their colour, so they only add clear to clear glass in the furnace and green to green and so on.
- Q?Some areas of New Zealand you can throw your bottles in with paper, plastics and cans – when the truck comes along it all goes in the one big bin on the back. Does this mean you can’t use this glass to make new glass?
If glass is mixed or co-mingled with cans, paper and plastics and is not separated by colour on the back of the recycling collection truck, it has to be separated when it gets to the sorting plant if it is going to make new glass containers.
If it is not going to make new glass it is not so important to have it colour separated but it still needs to be separated from other packaging.
Currently if glass is being collected with other packaging in large wheelie bins, this has to be sorted by either mechanically or by hand picking. However if glass is mixed in by colour and compacted with other cans, plastic and paper on the collection truck, this does reduce the amount of glass which can be recycled into new glass.
Some councils including Palmerston North, Wellington and Dunedin have elected to keep their glass separate at the point of collection. Keeping glass separate results in better quality glass which can be made into new glass containers here in New Zealand.
- Q?What happens to bottle tops and paper labels?
It is really important to remove bottle tops and jar lids and other metals from your recycled glass, before it goes in the recycling bin. Metal can contaminate the glass recycling process. Of particular concern are the aluminium ring tabs and neck rings.
Paper Labels and Sleeves
Paper is also a contaminant in the glass recycling process. As much as possible paper sleeves and labels are removed from the bottles and jars when they are received at the sorting plant. Any small amount of paper left is burnt up in the furnace.
- Q?Where do you recycle your glass?
97% of New Zealanders have access to facilities to household recycling facilities, either at kerbside or at drop-off centres.
77% of New Zealand councils offer households a kerbside recycling service.
At kerbside (outside your house) or at a bottle collection point.
Check with your local council to find your nearest recycling facilities.
- Q?Who organises the recycling trucks?
Your local council is responsible for waste management and will select a company or companies to collect your recycling and to process it.
- Q?What happens to the glass collected?
A lot goes to make new glass containers and the glass manufacturer in Auckland has the capacity to take much more colour sorted glass.
For glass which is not of furnace quality, there are a variety of different applications, see FAQ about Alternative Uses and our Applications page for research that has been done into using glass in an alternative way.
- Q?Does recycled glass have a dollar / economic value?
73% of all glass containers used in New Zealand were recycled in 2014/2015.
Using recycled glass requires less energy to melt than using virgin materials (silica sand, soda ash etc).
Less raw material is needed when recycled glass is used in a batch of new glass.
With commingling affecting local supplies to the furnace, there are benefits in using glass from the south of the South Island based on current costs (e.g. NZ dollar value for imported raw materials).
Over the last year 66% of glass recovered for recycling was utilized in the manufacture of new bottles and jars. The remaining 34% was used for alternative purposes.
- Q?What are the environmental benefits of recycling glass?
Lower energy usage leads to lower greenhouse gas emissions (pollution)
- Diverts glass from going into landfills
- Using glass as an aggregate for roads or concrete reduces quarrying