Funding Glass Recycling Research
The GPF encourages applications to fund research into finding alternative uses for glass in New Zealand and if appropriate may provide financial support for its introduction or development. See Grants for more information.
Download the Application for Funding PDF (14KB)
Alternative Uses for Waste Glass in New Zealand
Glass - the question of what to do with it when you're done with it.
Glass traditionally recycled into new containers needs to be transported to the only manufacturing plant in Auckland, While this can be a challenge for towns and communities in the South Island or at a distance from Auckland, some of these communities have very successful collection programmes. However not all of the material collected is of a standard suitable for new bottle manufacture and alternative uses are being developed to utilise this material.
Click on the following to see alternative uses for waste container glass being adopted in New Zealand:
Sporting Turf & Golf Bunkers
Base Course for Roading
Water Filtration
Agricultural Mulch
Erosion Protection
Sandblasting
Concrete Foundation
Sporting Turf and Golf Bunkers
Teeing up New Glass Solutions
NZ Sports Turf Institute has been conducting research into several options, and a very promising possibility is the use of crushed recycled glass in sporting turf and on golf courses.
The Forum has now received the final reports on the use of Glass sand in the construction of golf greens and topdressing. These comprehensive trials covered a two year period embracing eight seasons and concluded that glass sand is an acceptable alternative to conventional sand. This is an opportunity for the utilization of material not suitable for remanufacture into new containers.
Glass sand is perfectly safe to use and touch and, like sand, it raises and supports the pile of the turf.
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Three of Christchurch’s top golf clubs – Harewood, Windsor and Waitikiri - kindly agreed to participate in the trials. All three courses participated in the bunker sand trial. It was hoped that the glass won’t blow away as much as sand does, and will therefore provide a more consistent level of glass sand, for a longer period. Different combinations of glass and sand ratios were used in some bunkers at each club, and different weights of crushed glass (medium and light) were also used. The performance of the recycled glass was assessed monthly, and compared with the performance of standard sand bunkers. The effectiveness of crushed glass as a top dressing on greens was trialled on the chipping green at Windsor Golf Club. The glass sand was applied in the same ways sand is, and the results were measured monthly. |
The trials were based on similar experiments in the United Kingdom, and considered the effects of the glass sand on the grass roots, soil and surface temperature, player perceptions and – of course – how well it plays. Initial results showed that the glass has no adverse effects on the grass, with roots growing through undisturbed.
Roading - Getting it Right from the Base Up with Glass
Since 2006 the Palmerston North City Council in Partnership with Higgins Aggregates and Fullcircle have been recycling around 2,000 tonnes of glass into a 5% aggregate mix which has been used in cycle track and road construction in addition to building foundations.
The Awapuni Recycling Centre built on the closed Awapuni Landfill was built on a foundation that included the 5% aggregate mix.
Higgins Aggregates are able to produce a number of different aggregate materials with this process and Transit New Zealand has modified specifications to allow use of up to 5% glass cullet in the base course of roads.
Higgins Aggregates is paid $30/tonne to produce the 5% glass aggregate mix. This is significantly less than the local landfill costs of $55 to $100/tonne.
The trail blazing efforts of the Palmerston North City Council was recognized in an award from the New Zealand Packaging Council in August 2007
CONTACT: Cobus Van Vuuren
Manager - Higgins Aggregates
Palmerston North
Phone : 06 357 1025
Below - 5% crushed glass aggregate and crushing process.
Below are examples of projects being carried out in Palmerston North using the 5% aggregate mix:
Cycle Track Construction
Recent Sub Division Road
Transit New Zealand has given the green light to amend its specification for aggregates to allow recycled crushed glass to make up 5% of base aggregate used for road paving.
Contact: Bruce Taylor
Fulton Hogan - Nelson
Phone : 03 547 9789
Water Filtration - Crystal Clear Solutions from Glass
FilterCrystal is made from recycled crushed glass and is perfectly safe to handle with bare hands. Approximately 20% less crushed glass is required for filtration than in traditional sand filtration. This means a saving in purchase, shipping and disposal costs and savings in fuel. Because it's made of recycled glass it saves existing resources being wasted, and new ones being used.
FilterCrystal is the ideal option for swimming pool or spa pool filtration. FilterCrystal is superior to traditional sand filtration methods, providing cleaner water, more efficient operation and cheaper running costs.
Eco Consult report on Glass as Filtration Medium
 | The Glass Packaging Forum commissioned Eco Consult in Christchurch to report on glass as a very effective filtration Medium. If you wish to receive the report please email Donna at the Glass Packaging Forum – donna.glassforum@xtra.co.nz |
Glass as an Agricultural Mulch
Trial Underway - Crushed bottles assist in ripening grapes for a 'first glass' wine
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 | Hennie and Celia Bosman |
The application of crushed glass to vineyards is a first in New Zealand, and possibly the world. If results are successful the scheme could provide a viable solution to the growing problem of glass recycling in New Zealand.
The development of develop alternative uses for materials (such as glass) recovered from the waste stream has been sought to utilise this product viably and long term. Successful earlier trials for the use of crushed glass as a decorative mulch in gardens sparked the idea of using the reflective properties of glass to accelerate the ripening process in larger scale commercial horticultural applications. The glass is crushed to size of coffee sugar crystals, and is perfectly safe to touch or handle.
The trials will even compare wines produced from rows using glass and normal rows. Coincidentally, Senior Lecturer Glen Creasy from Lincoln University has been working on a similar trial with Neudorf Vineyard in Nelson using mussel shells instead of glass. Evaluation of the effectiveness of mussel shells has been underway since 2001, and has produced some promising preliminary results relating to grape microclimate and wine quality.
Glass recycling is becoming increasingly difficult in New Zealand. Although glass collected at kerbside in Christchurch and Waimakariri is recycled, glass recycling is become increasingly marginal in other areas. This is because of the high costs of transporting glass to Auckland where O-I, the only large scale bottle manufacturer and recycler of glass in New Zealand, is located, and the limited volume of glass the company can accept for recycling. This trial shows great promise and that, if successful, the use of glass in vineyards (and other horticultural enterprises) could provide a good local market for crushed glass.
Erosion Protection - Avoiding Slips by Being Boulder with Glass
Since childhood George Archer has been intrigued with the way moving water erodes earth and rock, initially washing away the softer materials forming slurry, slowly washing away granules of harder material, or undermining the harder substances such as rocks which in turn cause them to tumble and grind against each other. Even the small particles carried in the water continue to grind at anything they touch until the water movement stops and then the eroded particles fall and become a stream or seabed.
Erosion protection can be achieved in many ways; George has chosen to concentrate more on the emergency or urgent, rather than the long term more expensive.
George's Terrain Erosion Protector (TEP) concrete system is aimed at being as portable as possible, as cheap to manufacture as possible, and most importantly, be as effective as possible.
The small TEP is designed with a squat, thick body with six arms tapering away from the body. The TEP rests on some of the arms resisting forces that try to roll it, while the other arms can inter-lock with arms of other TEPs when two or more are brought together. When several TEPs are placed together in moving water the interstices formed between the interlocking arms slows the water movement, meaning the "fines" of sand and soil can drop out of suspension tending to build a beach thus further locking the concrete shapes.
The small TEP (above) weighs about 350kg to 375kg. When its mould paper is removed the concrete surface should be as smooth as the cardboard. This is important as a smooth concrete object placed in moving water takes far longer to be roughed up by passing water borne sand and soil particles. Because of its shape a TEP of about 350kgs resists rolling about as well as a rock weighing about 1000kgs. Some rocks can be expected to lose about one half of their weight when immersed in water!
Because of its shape and length of curing time and the fact that there is no need to remove and re-use the moild material, a TEP can be built with a quite wide range of concrete quality, and that realization meant that George could look for materials that may be considered "waste" for inclusion into manufacture.
Waste glass seemed to be a solution because: Firstly, glass particularly bottle glass, has a higher density than concrete. Secondly, although glass should be crushed, it does not demand too fine a "crush". There seems to be no need to remove labels. Because of the shape and mechanical strength of a TEP the possible ill effects of bottle residue affecting concrete strength is a small issue. A TEP does not require reinforcing steel so bottle content residue does not have any steel to re-act with.
George is still experimenting with the proportions of crushed glass used in the mix but his aim is to use 20-30% waste crushed glass. He's getting boulder by the day!
Contact George on aec.arch@xtra.co.nz
Sandblasting - Glass Blast
BlastGlass is cleaned-screened crushed, recycled container glass collected at kerbside.
Crushed glass is a proven and effective dry or slurry blasting media ranging in particle size.
Crushed glass has been proven to perform to standards equalling traditional silica sand.
Sandblasting is not colour sensitive, so there is no need to colour sort the glass. This means sandblasting may be a suitable higher-value application for stockpiles of mixed colour glass.
Cost effective. Finely crushed glass is very good for off-site and outdoor work, where the abrasive medium will not be collected for recycling e.g. bridges, storage tanks, farm equipment and machinery.
South Island Foundation - Waste Glass on Trial - Concrete Results
2007 trial using rolled glass in concrete foundation at the Ashburton Resource Recovery park
Waste Busters in Ashburton are evaluating the use of surplus glass in the construction of slabs for building bases. The glass was crushed in situ prior to the pouring of the concrete. The project was overseen by the Local Building Inspector. Project report as follows:
OBJECTIVE
To investigate the feasibility of using glass as filling material in concrete slabs and in so doing identify another use for this resource.
We acknowledge the help and support of NZ Glass Packaging Forum for funding us to investigate options for reusing glass.
INVESTIGATION
As to methodology and practicality of the project approaches were made initially to Bryan Ching at Fulton Hogan, Chris Roulston at Benchmark Homes and John Bruce (Building Inspector) at Ashburton District Council.
All supported the principal and a trial quantity of glass crushed using a vibrating roller supplied by Fulton Hogan. The consistency of the crushed product was deemed acceptable. Foundations were poured (9 m x 4 m) and while the weather delayed proceedings work commenced mid July.
METHODOLOGY
The top layer of loose soil was removed and a plastic liner was placed in accordance with standard building practice.
14 X 2 Cu M bags of glass was crushed that resulted in 7.2 cu metres of end product that was used as a basic fill on top of the plastic lining, this product was used to provide 200mm of fill over the whole slab.
The consistency of the glass was inspected by Council Inspectors and was deemed to be satisfactory and a comment made that the consistency was smaller than considered necessary but in no way detrimental to the considered end result. Given the inclement weather at the time there was a small amount of soil contamination but nothing that was considered adverse.
Following the glass fill 100mm of hard fill was used to contain the glass and 75 mm of concrete was poured on top of this material.
There was no compaction of any of these layers, as it was not considered necessary, the only work done on any of these layers was initial levelling of the material, no reinforcing was used in the concrete.
The slab was left for 6 days before being used and has had constant use since. This includes impact use with metal products being dropped, worked on with hammers and a constant heavy load as the primary function of the slab is a metal drop off point and at any one time there would be between one and two ton of metal on the slab. There are no signs of stress (cracking or sagging) evident and indications at this early stage is that the initiative is successful.
COST COMPARISONS
The cost of hard fill is $12.83 per ton and a ton is 1.7 cu metres. The total area of material used is 7.2 cu metres and equates to 12.3 ton of equivalent hard fill at a cost $157.80
Our only cost is the cost of crushing and handling and to be competitive a charge of $8 to $10.00 a cubic metre be applied.
INTEGRITY TESTING
In order to fully evaluate the integrity of the trial it has been identified that a hole be cut in the slab to determine if any subsidence has occurred.
This test was carried out on the 9th October 2007 and a 12 x 15 inch hole was cut in the slab. It was pleasing to note that no subsidence had occurred whatsoever plus the action of removing the cut portion required a certain amount of hammering to achieve the removal and there was no subsidence as a result of this. The results were pleasing and despite the hard use and constant vibration from passing heavy machinery no compaction of the glass had occurred at all.
For further information contact:
Tony Dawson - Business Manager
Wastebusters Trust Canterbury
www.wastebusters.net.nz
Ph (03) 308 9998
Fax (03) 308 9989
