Last week was national clean up and recycle week. Gabi Falanga took a deeper look at paper recycling.
The Mpact paper recycling mill in Springs is a vast maze of heavy machinery, spinning pulpers and fiery hot rollers.
From above, a massive 17-ton roll of board swings from a crane.
This is where paper and cardboard products come to be reincarnated into new, clean pieces of paper board, which can then be turned into one of the many products we use every day.
The mill receives both pre- and post-consumer materials to process.
The pre-consumer products consist of offcuts or rejects that packaging companies could not or did not want to use.
Post-consumer products are those which have already been used, such as empty cereal boxes, old cardboard boxes or pieces of paper which have served their purpose.
As we walk through a large outside area filled with bales of materials ready to be used, Paper Recycling Association of South Africa communications officer Samantha Choles explained why paper recycling is important.
“Recycling is about saving landfill space, creating jobs and recovering valuable paper fibre for use as a raw material. It’s not about ‘saving trees’. The trees used in paper-making are planted and harvested to make paper, just like other crops,” she said.
The Mpact facility has two board machines which take care of the recycling. One is BM3, which produces industrial board, and the newer one is BM6, which is more modern, fully automated and produces coated folding boxboard products for variable types of packaging.
Within these two machines, the recycling process takes place in five stages in what is known in the industry as stock preparation, forming, pressing, drying and finishing.
In the stock preparation section, the raw material is fed into massive pulpers, along with water and steam, and are spun around at high speed to separate the fibres and produce pulp.
In one of BM6’s four pulpers, a long rope hangs into the churning watery pulp mixture. Stuck to the rope are pieces of plastic, bottles and other rubbish, a strange sight to behold. This rope system, called a ragger, was installed two months ago to make it easier to remove rubbish from the pulp before it continues through the stock preparation system, explained Mpact’s Leondo Alexander.
He said all kinds of rubbish comes through with paper recycling, including bricks, paper clips, plastic, glass, stones and staples. The pulp is processed further by screening and cleaning equipment which separates the pulp, leaving behind impurities, such as sand and plastics, to be disposed of.
Then it’s off to the refiners.
In these round, silver machines, the pulp fibre is rubbed together in a process which results in fibrillation of the fibre.
“It’s like teasing hair,” said Alexander.
“It gives the fibre split ends, so that it bonds together better. It’s very important in paper making.”
But each time the pulp fibres go through a refiner, they get shorter.
Alexander explained that new or virgin fibres, which are long fibres, sometimes need to be added to the mixture in the recycling process.
“You can only recycle fibre six to seven times,” he noted.
The next section is the wet end of the process, also known as the forming side. In BM3, the pulp goes through seven vat formers. As the layers exit each vat, rollers squeeze the excess water out.
These layers are combined into seven layers, which are then transported to the press section via felt conveyors.
The board needs support because it is not yet strong enough to move through the sections by itself.
If there are any breakages, the sheet falls, along with the water, into huge pulpers in the floor below the machines and will be fed back into the system to be used.
BM6 works slightly differently, and pulp is sprayed onto drainage wires and transferred to felt, seven times over, to gain the seven-ply layers.
A wave of sticky heat and a strong sour smell welcome one to the drying section.
The wet sheets are fed over and under massive rollers or cylinders to be dried. Steam, which is produced by boilers in the facility, is pumped into these cylinders to provide the heat to dry the sheet. Steam can be seen rising off the sheets as they dry rapidly.
It is in the finishing section that the board is processed to meet the specifications of specific customers.
Paper is run over special rollers, called calenders, ironing it to the required smoothness and thickness.
In both machines, scanners monitor each piece of board for signs of defects. Staff keep an eye on the machine and its scanners from a control room. Another thing that sets BM6 apart from BM3 is that it has a coating plant which coats the board with certain barriers, depending on where the end product will be used.
“Is it going to be used in a fridge, or a freezer or a cupboard, and are you going to eat from it?” Alexander said, explaining some of the criteria which determine how the board is coated.
This particular mill produces only board, which is sent to customers in reel or sheet form.
A fitting machine cuts the board to the correct sizes. Massive 17-ton rolls of board, called jumbos, hang suspended from cranes, and large computer screens display graphs with the details of each product including their bond (strength) and calliper (thickness).
The moisture level of the board is also monitored towards the end of the process, to ensure that it's at the right levels.
Operators cut strips off each jumbo to send to the laboratory for quality testing. The strips get put into a chute, where they are sucked at lightning-fast speed to the lab at the opposite end of the factory.
At the listing station, each product gets a label which details the type product and reel size, when it was made, the time and weight, and who the operator was – this ensures full traceability.
Once the board has gone through the finishing section, it gets sent either straight to the customers or is stored in a warehouse for later dispatch.
According to Alexander, the plant uses about 140 000 tons of recycled fibre a year.
Nothing is wasted here, and any board with defects gets put back into the system to be recycled again. The water used in the system is cleaned on site and re-used.
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Quality by-products taken from cartons
Milk and juice cartons have become a staple in many households, but not everyone is aware that these can be recycled with their normal paper recycling.
The cartons, commonly known as Tetra Pak, come in all shapes and sizes and are filled with a variety of foods and beverages.
Cartons are made up of 75 percent paper. On the inside, they comprise thin layers of polyethylene and aluminium foil to keep food safe, seal in liquids and protect the contents from external moisture, oxygen and light without refrigeration.
Mpact’s Leondo Alexander said the liquid carton recycling plant was an exciting development at its Springs mill “because now we have the capability to recycle cartons for use in new paper products”.
The most important part of the process is to clean the pulp properly.
“Otherwise we can’t make proper paper or board from it,” he said.
Bales of Tetra Pak move along a conveyor and into a massive hydropulper, which looks like an oversized blender. Paper pulp sinks to the bottom, while the lighter plastic and aluminium composites float to the top.
The materials are fed into a compactor before being bailed and shipped to customers who use them to make a variety of goods, including plastic moulded models and furniture.
The paper pulp or fibres get spun at high velocity to clean it further, before going to the thickeners, where water is squeezed out by rollers.
Paper fibres from recycling cartons are valuable because they are virgin fibres, which can be added to recycling pulps to strengthen the mixture.
“Recycling cartons is worth the investment because we can extract quality virgin pulp on our own premises,” Alexander said.
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Much greener South Africa on the cards
Sixty-six percent – or 1.2 million tons – of the country’s recoverable paper and cardboard was recycled last year, the Paper Recycling Association of South Africa (Prasa) says.
This volume of material would’ve taken up 3.6 million cubic metres of landfill space, or the equivalent of 1 435 Olympic-sized pools.
Paper packaging including corrugated cardboard, boxes, cartons and kraft material accounted for 67 percent of the total. Newspapers and magazines made up 12 percent and graphic papers 13 percent.
“There is little or no difference between the effort needed to simply discard paper into a rubbish bin versus putting it into a recycling bin, but the rewards for recycling are boundless,” said operations director Ursula Henneberry.
“You reduce your waste footprint by ensuring that paper packaging and products are reprocessed into new items instead of ending up in landfill. Recycling creates jobs, from the people who walk the streets collecting recyclables to bigger companies which employ individuals to collect and sort recyclables.”
About 100 000 people earn a living from recycling.
Communications officer Samantha Choles suggested that households get a box or container to keep paper recycling separate from wet waste and other recyclables.
“There are a number of programmes available to support your paper recycling efforts, from free kerbside collections in many residential areas to large paper banks at schools and community organisations," Choles said.
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What works and what doesn't
Paper items that can be recycled:
* Magazines and brochures, including the glossy varieties.
* Milk, juice and food cartons (rinsed and flattened).
* Newspapers.
* Office materials, including shredded papers and envelopes.
* Cardboard boxes of any kind, including cereal boxes, medicine and cosmetic boxes, toilet and kitchen paper roll cores and flattened packing cartons.
* Telephone directories, and discarded hardcover and paperback books.
* Paper gift-wrapping materials.
Materials that should NOT be included in paper recycling:
* Wet or dirty paper and cardboard. “If it is clean and dry it fetches a better price and makes better fibre,” explains Prasa's Samantha Choles. “As soon as it gets wet it starts to rot.”
* Sticky notes.
* Wax-coated, foil-lined and laminated products.
* Used paper plates, disposable nappies, tissues and toilet paper.
* Cement and dog food bags.
* Foil gift wrapping and carbon paper.