Rubbish and recycling
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The Materials Recovery Facility (MRF)
Background
The facility is scheduled to be completed and ready for when the new Auckland isthmus recycling service starts on 30 June 2008. This facility
is the southern hemisphere's most advanced recycling sorting facility - capable of sorting up to 120,000 tonnes of recyclable waste yearly from
Auckland and Manukau households and converting more than 95 per cent into reusable product.
The contract is a "build, own, operate and transfer" contract where the building and operating costs lie with the MRF operator, Visy Recycling New Zealand. After 14 years, the facility will be transferred back to both councils.
How the sorting process works
The recyclable materials from Auckland and Manukau cities arrive at the MRF and are emptied on to the tipping floor. From here, the materials
are moved into the facility via a conveyor belt. The conveyor belt leads to a pre-sort station. This is where sorting is done by hand to separate
any contaminants such as food and vegetation waste, plastic bags and textiles and heavy non-recyclable items like gas bottles, car batteries and
concrete blocks.
The mixed materials then pass through a series of automated sorting technologies including:
- Primary Trommels - to remove stringy items and separate between large paper and containers and glass
- Secondary Trommels - to remove glass from containers and paper
- Disc Screens - to remove fine materials and differentiate between containers, paper and cardboard and between sizes of paper and cardboard
items
- Magnets - to recover metals
- Eddy Current Separators - to recover aluminium
- Near-Infra-Red Sorting (NIRS) Devices - to separate paper from plastics and to sort between different types and colours of plastics
- Glass, once separated, will be sorted for colour and contamination to merchant standard using optical sorting technology.
The entire process consists of eight basic elements:
| Step one - receiving the materials |
| |
The materials are transported to the facility in the recycling collection trucks and are emptied on to the tipping floor. From here, the
materials are moved into the facility via a conveyor belt. |
| Step two - primary sorting of materials |
| |
The conveyor belt leads to a pre-sort station. This is where sorting is done by hand to separate any contaminants. |
| Step three - steel removal |
| |
After the hand sorting, the conveyor belt carries the recyclable material to a large magnet to separate the steel from the other materials. |
| Step four - trommel sorting |
| |
The remaining materials are then carried (via conveyor) to a machine called the trommel. The trommel is a large rotating cylinder that
separates materials based on their size. As the trommel rotates, the materials tumble around inside. The smaller recyclables (glass, plastic and
aluminium) fall through the holes in the trommel and down on to other conveyor belts. The bulk of the paper travels through the trommel and onto
a conveyor belt at the end of the cylinder. |
| Step five - screen sorting |
| |
Materials that fall though the trommel holes then pass over a vibrating screen. The screen works like a sieve and removes fine pieces of glass. |
| Step six - air separation |
| |
The remaining materials move over an air classifier, which separates the lightweight materials like aluminium cans and plastic containers from
heavier glass materials. |
| Step seven - glass storage |
| |
Glass bottles are carried to storage hoppers for transportation. |
| Step eight - final storage |
| |
Plastic containers, cartons and aluminium are then sorted into separate streams and conveyed into storage bays to be baled. These bales are then
ready for delivery to reprocessing plants. |
At the reprocessing plants, items such as glass, plastics, paper and aluminium will each be treated differently in order to be sold back to
manufacturers for reuse.
You can view more about the sorting process on the
Visy Recycling website
(www.visy.com.au/recycling/?id=27).
Plastic containers:
At the reprocessing plant, the bales are broken apart and the plastics are separated by type (based on what kind of polymer they are made from eg
High Density Polyethylene (HDPE), Polyethylene terephthalate (PET) or Polyvinyl chloride (PVC)).
The containers are then cut up into small flakes and washed so that any labels and dirt are removed. The clean - but still wet - plastic flakes
are then put into giant industrial dryers.
The finished product is sold on to companies in New Zealand, Australia and China who will use the plastic flakes to make new items such as
soft drink bottles, pillow and sleeping bag filling, recycling bins and speed bumps.
Interesting fact: recycling just one plastic bottle can save the same amount of energy needed to power a 60-watt light bulb for six hours!
Paper:
Paper from Auckland's recycling is transported to paper mills. Locally, some of the paper is recycled at the Penrose Mill while the remainder is
exported overseas to various markets such as Malaysia.
The paper and cardboard is then sorted into types and washed, bleached and rolled to make recycled board. It can then be used to make a huge range
of items for the printing and packaging industry.
Interesting facts:
- Modern techniques mean paper can be recycled up to 15 times before it starts to break down.
- Recycled paper saves 50 per cent of the energy and natural resources that would be needed to make paper from virgin pulp.
Glass:
Glass is recycled at the O-I New Zealand plant in Auckland where it is further sorted into individual groups - clear glass, amber glass and
green glass.
The glass can then have future uses such as new glass bottles and jars and as a sand substitute in road construction.
Interesting facts:
- Recycling one glass bottle saves enough energy to light a 100-watt light bulb for four hours; power a television for 20 minutes; or a computer
for 25 minutes.
- Making new glass from old bottles and jars uses 75 per cent less energy than using natural raw materials.
- We save over a tonne of natural resources for every tonne of glass recycled.
- Using recycled glass to make new glass cuts related air pollution by up to 20 per cent.
- Recycling one tonne of glass saves the equivalent in energy of 10 gallons of oil.
- Most bottles and jars contain at least 25 per cent recycled glass. Glass never wears out - it can be recycled forever.
Steel and aluminium cans:
Aluminium and steel cans are shredded and melted into liquid form.
For aluminium cans, a process is undertaken to separate the aluminium from the oxygen. Once the aluminium is separated, it can then be used to
make new aluminium cans and other aluminium-based products.
Recycling steel cans follows almost the same process as aluminium. Steel cans are melted in a furnace and then poured into casters that continuously
roll and flatten the steel into sheets. The steel sheets can be used to make new food cans and steel products such as car parts.
Most steel is recycled in New Zealand and made into more steel products. Aluminium is sent to Australia or Japan for recycling.
Like aluminium, steel can also be recycled again and again. It does not lose any of its strength or quality in the recycling process. It also takes
much less energy to recycle steel and aluminium than it does to make new cans from raw materials.
Interesting facts:
- One recycled aluminium can saves enough energy to run a television for three hours.
- Recycled steel that is de-tinned, melted down, rolled and re-moulded into new steel products, saves about 75 per cent of the energy needed to make
cans from virgin ore.
- Aluminium can recycling saves even more energy - up to 95 per cent.
As we have shown above, the beauty of recycling is that the story doesn't end when the materials are taken away from your kerbside. These materials
make their way back into our lives in many ways. By recycling, we are giving used products a new lease on life rather than having them buried away in
landfill.
The trucks
The vehicles used to collect the new recycling bins are typically single operator dual control vehicles with a driver-operated side-lifting bin
collection arm. The driver uses left-hand drive while the vehicle is emptying bins and reverts to right-hand drive while travelling from the collection
area to the Materials Recycling Facility (MRF) or travelling to a different collection area.
Recyclables are emptied from each recycling bin into the body of the collection vehicle. Paddle or blade compactors are used to efficiently pack
recyclable materials into the body.
Visy Recycling NZ
Visy Recycling NZ is a fully owned subsidiary of an Australian company that has been trading in New Zealand for 10 years. Visy Recycling has been
operating MRFs in Australia for over 20 years and bring with them state-of-the-art technology and years of experience.
Visy already employs over a thousand people in New Zealand, and this project will generate at least 24 new jobs in the Auckland area.
Education centre
You can book a visit to Visy's new 'state of the art' recycling facility.
This is an in-class education programme where students can learn about the
benefits of recycling. Groups of up to 30 students are able to book a one hour
visit to the onsite education centre. Experts will be on hand to answer all your
questions.
For further information or to book a tour, please contact VISY on 0800 VISY
NZ (0800 847 969) or visit their website (www.visy.co.nz).
Updated October 2008
