Glass recycling nz

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Glass photo.jpg



The multiple shapes and forms of glass containers

Glass is a material that has been used by people for almost 5000 years, with early signs of its usage dating back to the times of the Ancient Egyptians in the 3rd century BCE (Lehmann, 2006). The first signs of widely manufactured bottles comparative to those in use today date back to 1632 in England (Dungworth 2012). It was not until the late 19th century when the glass producing process was truly mechanized. This was with the creation of a machine by Michael Owens that could produce 10,000 bottles over an eight hour work day (Dungworth 2012).

The Owens Bottle Company, created in 1903, followed the radical shift in the manufacturing process which resulted in the 1929 merger with the Illinois Glass Company to create Owens-Illinois (O-I) (Owens-Illinois, 2013). O-I is now the largest glass bottle and glass container manufacturer in the world (Glass Packaging Institute, 2013). At the moment the major glass bottler in New Zealand is O-I, who have a factory in Auckland. This factory is able to produce 50000 bottles an hour, 24 hours a day, seven days a week. O-I uses both collected glass and raw material to meet our demand for bottled goods. As a recyclable material, glass is ideal. According to O-I, glass can be fully recycled without the risk of losing purity, almost indefinitely. Not only that, but it takes less energy to melt recycled glass, than it takes to melt raw materials. If glass isn’t recycled it can end up in a landfill, taking up valuble space. If left there, it will almost never complete decompose because of its nature. There are also other uses for reusing glass; an aggregate in landscaping, roading, as bedding for the laying of pipes, as a resource for sandblasting in the place of sand, as a filter in drainage systems, and many more (Zero Waste New Zealand Trust, 2005)[5].

At the moment 97% of New Zealanders have access to some form of Glass recovery service. This is by either a curb side collection service or via council run refuge centres (Zerowaste New Zealand, 2013). Currently 2/3 of the glass that is being used in new Zealand is recycled each year, a proportion that is expected to grow(Glass Packaging Forum Inc, 2011). The service provided varies from council to council, with some councils offering a mixed bin for all recyclables, as is done in Christchurch (CCC, 2013), some councils offering a two bin solution (one for glass, and one for everything else) such is done in Dunedin (DCC, 2013), down to smaller councils offering a service provided by the private market, to save the rise in rates, as is the case in the Kapiti Coast District (KCDC, 2013). There are a number of reasons for these different approaches. People are more likely to take part in a mixed bin plan, while a two bin plan is less likely to result in damaged or contaminated bottles. A two bin plan is often met with a lower public participation rates and some smaller councils simply cannot afford to collect everything as it is only viable for them to receive glass goods(Glass Packaging Forum, 2007) . As with the multiple methods of collecting glass, councils have a variety of plans for dealing with the collected materials. Some councils such as the Mackenzie District Council, collect glass and when enough has been collected it is moved to Christchurch for further processing. While larger councils find solutions for themselves.

The Glass Recycling Process:

Glass bottles cooling after being manufactured at the New Zealand O-I plant[1]

Only crushed glass bottles and jars, known as cullet, is widely accepted in the recycling process, as other items such as light bulbs, ovenware and mirrors contain materials that could contaminate the recycled glass (Baeyens et al., 2010). Container glass is so easily recycled because the container has the benefit of being completely recyclable with no waste created during the recycling process (Baeyens et al., 2010). Recycling of container glass can occur over and over again without a drop in quality, but it cannot occur indefinitely as a small amount of mass is lost during each melting process, as a result from the release of gases(Larsen et al., 2009).

Manufacturing from raw materials requires huge amounts of energy to be expended in the melting of the three main ingredients of glass; silica, calcium oxide and sodium oxide (Larsen et al., 2009; Baeyens et al., 2010). Other chemical compounds can be included for the desired hardness or colouring of the container (Baeyens et al., 2010). 75% of the energy used to produce a glass container is used for the melting of the raw materials in the furnace (Larsen et al., 2009). Recycling glass is more energy efficient as it can be melted at lower temperatures. This is because the cullet is in the non-crystalline stage whereas the raw materials are not(Baeyens et al., 2010).

Cullet is not used by itself when making new glass containers, but is added to the raw materials during the manufacturing process (Baeyens et al., 2010). A 10% increase in the amount of cullet being melted with the raw materials will reduce the energy consumption of the furnace by 2-3% (Larsen et al., 2009). It is also more resource efficient, as when glass is being made from raw materials it loses approximately 20% of its content due to the release of gases such as CO2 (Larsen et al., 2009). Before the cullet is melted it must be sorted by colour, as the permanent dyes used in coloured glass will cause impurities in the new containers (Baeyens et al., 2010).

After this, the sorted cullet is smashed to pieces of less than 60mm and washed. Metal and plastic cap rings, corks and other such non-glass items are then removed from the processed cullet (Larsen et al., 2009). Any paper labels that are still attached to the glass containers after they have been washed will burn up in the furnace and does not affect the end result (O-I New Zealand, 2006). The processed cullet is then added as a supplement for the raw materials, with some cullet proportions being as high as 90% (Larsen et al., 2009).

Kerbside Recycling within New Zealand:

Single bin for all forms of recyclable waste:


Auckland city were the first to use the one bin system. The waste in Auckland is transported to two different refuse centres one in Witford and the other at Redvale, the two locations handle the huge output of waste from the larger population of the mega city. Once the glass is separated it is then transported to the glass recycling specialists, O-I, in Penrose. Auckland generates 32,000 tones of glass per year with a large 94% of the glass coming in from kerbside collection. However, only 50% of the collected glass is re-manufactured into glass jars and bottles again. The rest of the glass that is obtained is mainly used for the production of fibreglass mixtures that are made in Auckland (Auckland Council, 2012).

Figure 1. Christchurch's kerbside recycling has increased in recent years [2]


Christchurch adopted the one bin method of recycling collection in 2009, using a single bin for all recyclable waste. The waste collected from the city streets is transported to the Parkhouse Road Refuse Centre. Here, the trucks unload the materials into a sorting shed where front-loaders place the waste into a high-tech machine that passes the rubbish through different levels of processing for separation. This is to ensure that all of the glass ends up at the same place, away from any plastic, paper or metal. Once the glass has been separated it is then taken away to re-manufacturing companies across the nation and abroad. The glass is crushed, then the glass is used for other glass based products such as; grit blasting, in the place of sand, roading or filtering swimming pools. There are many other uses for glass across the region of Canterbury. The detailed picture in Figure 1, shows that there has been an increasing amount of kerbside collection annually for the city, until 2011, where there was a significant depletion. This was due to the events of the earthquake which effected the kerbside collection as residents had been evacuated (Christchurch City Council, 2013).

The change in the method of collection has been described as a change for the better by the residents, with one saying it makes the recycling much more simple when knowing what bin goes out each week. Another, who is an elderly woman, said that the new method makes the chore of taking the rubbish to the kerbside a much more pleasant experience for her, using a wheelie bin rather than the recycling crate.

A simple video showing the process in the Christchurch recycling method: [6]

A Schematic of the Recycling Plant process can be found here: [7]

Separate bin collections in cities across New Zealand ( separate bins for recycled waste)


Wellington has separate bins, one just for glass and one for cardboard, plastics and other recyclables, which are collected weekly. The waste that is collected in Wellington suburbs go out to different landfills, depending on the area involved, and the proximity of nearby sites; there is the Poriura Refuse Station to the north of the city, Wainuiomata station east of the city, Hutt Valley station to the north east and finally the southern refuse centre called Owhiro Bay. Wellington asks for their residents to have their glass pre-separated from their cardboard and plastics between each of the 40L bins (Wellington City Council, 2013).


Dunedin has a somewhat of a mixed method for recycling their waste. There is the large 140L yellow bin that has the dry recyclable waste, and a smaller 40L blue bin for glass, although each residence is entitled to, up to three of these, to compensate for the small capacity available for the collection of glass bottles and jars. These bins are collected on alternating weeks. There is also the ability to add handles, like those of a supermarket basket, to the bins, these can help the owner carry their bins to the kerbside in a simpler fashion, this handle cost $7 extra for the public, unless physical disabilities are a factor, where they are then free. Glass from Dunedin gets separated in the trucks during the day while being transported, then go to a holding site, from where they are then sent up to Auckland for re-manufacturing or to be put to use in another area (Dunedin City Council, 2010).

Regional Council methods of collection

Mackenzie District

The Mackenzie District is made up of 3 towns; Twizel, Tekapo and Fairlie, each with a refuse station. Waste is collected from the kerbside by truck, on a weekly basis and is deposited at the refuse station for sorting, which is done on site. The waste is delivered to Christchurch when the stations are at a high capacity. 71% of homes in the district use kerbside collection, with an average of 104Kg of recyclable waste per person being produced each year (Mackenzie District Council, 2012)

Timaru (South Canterbury)

South Canterbury uses a similar one bin system to Christchurch, all sources of recyclable waste are collected in the one bin. This is for central Timaru and the surrounding rural areas. Transpacific Industries Ltd are the sole collectors for the district, collecting all the recyclable waste, which is then transported to Auckland for re-manufacturing (Timaru District Council, 2012).

Private Collectors

Kapiti Coast and Tauranga

These two areas depend solely on the residents to organize their own waste collection, rather than being covered by their rates for the council. The councils offer the residents numbers and information for the local companies that operate in the area, but it is down to the home owners to decide who they choose. This process can be somewhat problematic with the demand put on companies fluctuating, and the slackness of home owners not deciding their waste disposal company at a fashionable time or opting out completely (Kapiti Coast District Council, 2010; Tauranga City Council, 2010).

Problems with the Current System:

Costs and Market Force Economics

The only glass manufacturing/recycling plant in New Zealand is a privately owned facility found in Penrose, Auckland. The geographic location of the plant has led to the situation of significant costs being involved in transporting cullet to the North Island from all over New Zealand. Unfortunately these costs are usually borne by the community rate payers, with the economics of the market dictating the affordability of shipping this product to Auckland. This creates a situation in which any opportunity the recycling of glass market has of being sustainable revolves around both council and business budgeting money for the collection, transport, marketing and recycling of glass.

The following are the quoted costs to transport a container to ACI in Auckland. This includes pickup, delivery and container return.

Place of origin Container Price Cost per tonne

Christchurch $1,600.00 $80 - $100

Timaru $2,000.00 $100 - $125

Invercargill $3,840.00 $192 - $240

(Zero Waste New Zealand Trust, Market Study, 2005)

Stockpiled cullet in Central Otago. [3]

In 2005 New Zealanders recycled nearly 110,000 tonnes of glass and with so many more containers in circulation, the country's only glass smelter and manufacturer, could not use all the glass being collected. The glass plant manager ACI -OI (Owens Illinois International) payments for recovered clear glass was cut from $75 a tonne to just $10, as the company's Auckland plant could not process all the glass available. This led to councils with an earlier best case scenario of breaking even after transport costs to suffer stiff financial losses in order to have glass recycled. This emphasis on “economic viability” led many councils adopting the system known as “stockpiling” in order to accommodate glass until the market dictates it is at least possible to again break even financially.


Councils and recycling operators had to find alternative ways to deal with the surplus. This lead to some councils sending the product back to landfill but many regarded this as too costly and an ineffective use of landfill space. Hence the term stockpiling came into being, which referred to the creation of giant glass storage areas, usually above ground and often in the open where glass picked up for recycling was stored until the economics of the situation changed.

The situation was eventually widely regarded as unviable as mountains of glass grew across the south island and an initiative by the New Zealand Glass Packaging Accord (NZPA) saw a temporary voluntary levy on importers of glass containers. The temporary levy which expired at the end of November 2005 raised $1.5 million. These funds were used to pay recyclers $65 per tonne for clear glass sent to ACI - the difference between the original price of $75 per tonne received and the new price of $10 per tonne. It was also to fund research into new uses for recycled glass (NZPA, 2005). However from the point of view of many communities (including Otago), the levy had no benefit. Glass recycling was at very best, a breakeven prospect before that due to transport costs. The levy simply restored the situation to a point where councils lost less money if the cullet was transported to Auckland. As the years have passed market forces dictating the situation have not improved with glass still heading to both stockpiles and landfill instead of the recycling plant (Zero Waste, 2005).

Contaminated and Broken Glass

Broken glass can also be an issue, with the quality of the cullet being important for remanufacture. Increasing contamination of glass from increased uptake of fully compacted co-mingled kerbside collection in some centres, along with breakages by consumers or in pickups or stockpiling, or in a later transport phase has seen much cullet deemed unsuitable to recycle (NZPA, 2009). Many stockpiling operators simply did not understand the decrease in quality either from breakage or contamination by dirt, which came about from moving large piles with machinery, would render the cullet unsuitable for recycling. Decreasing net quality glass cullet has occurred previously leading to even more being put in landfill. In one local example Central Otago Wastebusters estimates that between 483 tonnes to possibly 2000 tonnes of cullet has been rendered unusable and marked for landfill (Otago Daily Times, Sat, 6 Aug 2011). This situation can also be exasperated by council pick up methods for recycling. If the “mixed stream” method is used the glass mixed with other items can break and contaminate paper, plastics and other recyclables making them more difficult, costly or impossible to recycle. In addition, broken glass can damage recycling equipment at the associated products mill later on. If a “single stream” method is used, where recyclable glass (container glass) is picked up separately then the glass need only be separated by colour at the point of pick up in “split stream” trucks or at the recycling center. This is necessary as the three types green, amber and flint (clear) then need to be made back into green, amber and flint containers ( NZPA, 2009).

Other Uses

The large “mountains” of stockpiled glass and glass heading for landfill is correctly regarded as inefficient, wasteful and detrimental to the environment despite shorter term economics dictating these actions. An increasing amount of research, development and trial and error has gone into finding more long term economically viable and environmentally sustainable methods of reusing glass containers (NZPA, 2009). Engineering and construction companies in partnership with councils have started to use non-recyclable quality material for aggregate in roads and footpaths. Glass can be used as a replacement aggregate in a number of construction applications including concrete, asphalt and roading. There has been extensive research overseas in road applications for this materialas an aggregate due to the high volumes that could be consumed at a reasonable cost given the material has already been processed prior to making glass. The cost of transporting anddisposing of a tonne of waste in a modern landfill in New Zealand varies between $NZ 50 to $NZ 90, which is approximately two to four times the cost of crushing and blending the glass into an aggregate currently used for road material (Fulton, Bob. 2008). This excess recycled glass has been used in a 5% crushed aggregate mix since 2006 and initial monitoring of road performance responses have been positive, leading to the possibility of an increase in glass percentage (NZPA, 2009).Other uses of reusing cullet have been investigated and tested, including the material as filtration systems, glass and ceramic tiles, agriculture, an abrasive in sandblasting, landscaping and also potentially has numerous uses in golf courses. In many cases it is unlikely that recycled glass could be collected, processed, blended and delivered to a construction site or factory and compete with the cost of natural aggregate or sand given the prior investment in efficiency and development of the products being made. However, if the right kinds of economic incentives are in place, glass aggregate could be a “relief valve” forexcess collected material (Zero Waste, 2005).

Indicators & Trends:

In the last decade New Zealand has experienced an increase in overall recycling. Over a five year period between 2004 and 2009 there is a recorded 26% rise in the recycling or recovery of packaging that prevented it from entering landfills. This equated to 430,000 tonnes of packaging that included glass, paper, plastics, aluminium and steel (Packaging Council of New Zealand, 2009). The Packaging Council of New Zealand (2009) has produced a number of graphs outlining the status of the recyclable materials in New Zealand. Figure 2 shows the various forms of recoverable recycling between 1994 and 2010.

Figure 2. Percentage trend of all recoverable packaging (Figure extracted from the Packaging Council of New Zealand, 2009).

Figure 2. Percentage trend of all recoverable packaging (Figure extracted from the Packaging Council of New Zealand, 2009).

The indicators used to assess how much glass New Zealand is recycling compared to how much is entering landfills is the proportion of packaging waste recycled which is acquired from consumption and recovery data. The consumption data is recorded from how many containers are sold by producers and the recovery data is acquired from how much glass is recycled. These indicators work well as they inform what progress (or lack thereof) that has been made in closing the gap between the consumption of glass containers and their recovery for recycling or other purposes. The space between the consumption and recovery data lines are what is going into landfills annually in New Zealand (Figure 3). Figure 3 shows that there has been little progress in closing that gap even though recycling of glass containers has improved dramatically since 1994.

Figure 3. Trends of glass recovery and consumption over time (Figure extracted from the Packaging Council of New Zealand, 2009).

Figure 3. Trends of glass recovery and consumption over time (Figure extracted from the Packaging Council of New Zealand, 2009).

The data for the proportion of kerbside recycling available to New Zealand homes has not been recorded annually each year. Only since the passing of the Waste Minimisation Act (2008) has data been consistently reported each year since 2010 (Figure 4). This time series graph shows a peaking of available kerbside recycling at 84% as of 2012. The data that has been collected by surveys prior to 2010 was carried out by the Ministry for the Environment and is based on one off surveys of territorial local authorities. This patchy data set prior to 2010 only gives a rough indication of the availability of kerbside recycling (Figure 4).

Figure 4. The proportion of kerbside recycling available to New Zealand homes (Data extracted from the Glass Packaging Forum, 2012).

Figure 4. The proportion of kerbside recycling available to New Zealand homes (Data extracted from the Glass Packaging Forum, 2012; Statistics New Zealand, 2013a).

A survey by the Glass Packaging Forum (2012) shows that the majority of recycling occurs at home (84.4%). Work place, communities and schools have much lower instances of recycling which is where the gains must be made if glass container recycling is to be increased nationwide.

Figure 5. Survey results of where New Zealanders recycle glass containers the most(Data extracted from the Glass Packaging Forum, 2012).

Figure 5. Survey results of where New Zealanders recycle glass containers the most (Data extracted from the Glass Packaging Forum, 2012).

As population has increased in New Zealand so has the consumption and recovery of glass containers. In 1994 New Zealand’s population was 3,620,060 which rose to 4,367,810 in 2010 with the glass consumption and recovery keeping pace (Statistics New Zealand, 2013b). In 2007, 97% of New Zealand households had access to either domestic kerbside recycling or to recycling drop off stations with 77% of councils providing a kerbside weekly or fortnightly pickup service. (Glass Packaging Forum, 2007).

Glass Recycling Initiatives:

Waste Minimisation Act (2008)

The Love NZ logo is becoming an iconic New Zealand recycling brand.[4]

This Act replaced The New Zealand Packaging Accord (2004) which was a voluntary agreement between industry and government to reduce packaging waste and encourage recycling of used packaging. The difference between the New Zealand Packaging Accord and and the Waste Minimisation Act is that the Act is a legally binding document which requires businesses (producers, brand owners, importers and retailers) and consumers to become responsible for packaging that they produce and consume. The Accord was based on voluntary participation with no legislation backing it (Ministry for the Environment, 2009; Ministry for the Environment, 2004).

The Waste Minimisation Act has 5 main roles:

  • It funds local government, communities and businesses by placing a levy on all waste that enters landfills.
  • It requires businesses, consumers and other involved parties to take responsibility for their used packaging through product stewardship schemes.[8]
  • Provides a legal framework for mandatory data collection of landfill waste and recycling to increase information so that more effective waste minimisation methods and procedures can be implemented.
  • Sets out the role that Territorial Local Authorities (TLA’s) play in waste minimisation.
  • Creates a Waste Advisory Board to inform the Minister for the Environment on waste minimisation issues.

The changes in data recording has not influenced the data recording methods behind the consumption and recovery of glass containers (Figure 2) but has influenced the methods of data collection regarding aluminium, steel and paper (Figure 1)(Ministry for the Environment, 2009).

Love NZ

Love NZ is a recycling initiative aimed at reducing the amount of rubbish that we put into our landfills. They are backed by local governments, TLA’s and big industry so that they may produce a reliable recycling infrastructure for the public places of New Zealand (Love NZ, 2011). Their 2012-2015 aims are to install over 1,000 public place recycle bins and provide over 2,000 recycle bins for events such as concerts, fairs and markets (Love NZ, 2011). They also target areas of high human congregation such as city centres to advertise and create awareness of the need to recycle (Love NZ, 2011).