Paper is one of the world’s most recycled and recyclable materials. It’s produced from a marvellous renewable resource: tiny wood fibres that are grown on trees that are sustainably farmed using a circular approach.
In fact, around 50% of all fibres used for paper making worldwide are recycled fibres. This is a very positive aspect of the paper industry and there are few, if any, other global industries that have a better record of using recycled raw materials.
Using recycled fibres widely in the paper industry is positive for the environment – but the scientific reality is that old paper cannot be recycled forever because the cellulose fibres eventually break down into dust, or fines, as they are called. Papermakers’ experience over many decades shows that for most quality grades of paper, after they are recycled about 3-4 times the fibres are then too short to make quality paper. In Europe, the fibres were used 3.8 times on average in 2020, whereas the world average was 2.4 times, according to the European Paper Recycling Council, EPRC Report.
Papermaking fibres are tiny cellulose filaments that are very thin, having a thickness of only about 40 micrometres (µm), much thinner than a human hair. They are also very short in length, between 1 and 3 mm, around the diameter of a pin head. Each time paper is recycled, the sheet must first be torn up again into the tiny individual fibres, using mechanical energy, water and chemicals in a giant blender to “repulp” it. This often causes the fibres to be cut in half or even shorter segments. It also causes them to lose their stiff shape and become softer and more flexible, which is not great for paper properties.
The image shows termo-mechanical processed pulp through a microscope, with a close-up of the longer cellulose filament called a papermaking fibre. After being processed and reused several times, the fibre becomes too worn out to function well.
In the recycling process, the shorter, weaker and non-useful parts of the incoming paper which can’t be recycled – like fines, clays, inks, coatings, staples, plastics, etc – are filtered out in what is called the screening process and rejected as sludge to be landfilled. In an average recycling plant, up to 30% of the incoming material may be unsuitable for paper making and is lost as sludge and not part of the new paper. Therefore, without new fibres coming into the circuit, the paper cycle cannot be maintained.
So, we now know that fibres degrade each time they are recycled, meaning that there are physical limits on why recycled fibres can’t be used to a greater extent than they are today. Fresh fibres are always needed in the circular process.
In addition to this fact, it is also good to know that there are some clear quality and functionality advantages and reasons for using fresh fibre in certain grades of paper. Some grades can easily use 100% recycled paper, if the incoming quality of old paper is high enough. Other grades can use perhaps 50% recycled. But some grades must have all fresh fibres to meet the quality demands in terms of performance and market requirements.
Because RCF (recycled fibre) degrades after several uses, for some paper grades RCF simply can’t give the paper the required properties it needs – or the properties could be achieved but with too high economical or environmental costs.
These properties might include strength, brightness, bulk, opacity, printability, and many other technical characteristics that are commonly known as quality specifications.
Fresh-fibre paper produced with Holmen’s TMP (thermo-mechanical pulp) process is lighter and more porous than RCF paper, with a naturally high opacity and brightness. Fresh-fibre papers made with TMP are comparatively thick, but light, which provides advantages regarding cost and environmental impact.
The lighter paper also means lower weight for distribution and reduced CO2 emission for transport. The high opacity is good for readability and makes it possible to use a lighter, thinner paper, without contents being visible from the other side of the page.
Although it seems intuitive to think that RCF must be better than fresh fibre in environmental terms, the comparison is not entirely black and white. There are some grey areas, and all pulp production methods have their advantages and disadvantages. So although paper recycling is a wonderful use of natural resources, it is incorrect to say that it is always better. It depends on the specific process, location, products being made and conditions that are being compared.
In fact, a major, independent, peer-reviewed study done by Environmental Resources Management concluded already in 2007 that when it comes to RCF and fresh fibre: “Overall the results indicate that neither fibre type can be considered environmentally preferable. /.../ Intelligent and sustainable use of available fibre sources requires understanding the challenges associated with each fibre type and effectively managing the life cycle to minimise impacts and maximise benefits.”
A life cycle assessment study made by the Swedish Environmental Research Institute, IVL, in 2017 indicates that fresh fibre-based paper actually has a lower environmental impact than its recycled counterparts. The study concluded that fresh fibre-based paper, produced in Sweden, had significantly lower emissions compared with recycled fibres produced in Germany.
Similar findings were made in a recent, independent third-party study by the publisher Penguin Random House, 2020. The publisher wanted to find out how large a carbon footprint the paper from their main suppliers had, and they also included manufacturers of recycled paper. Holmen’s fresh-fibre book paper from Hallsta paper mill in Sweden had the lowest CO2 footprint in the study.
The reality is that both recycled paper and fresh fibre paper are needed to cover the world’s demand for paper, and their production and usage complement each other.
Paper production and usage is a system of circularity – but it can be even better. When sourcing paper, buyers should demand transparency about environmental impact from the producer and use only products where it’s possible to fully trace the origins and the environmental impact.
In every step, a no-waste approach can guide both producers and consumers to better solutions that are also better for the Earth.
Author: Hugh O'Brian, pulp and paper industry technical writer
1. European Paper Recycling Council (EPRC) Report 2020. Report available for download.
2. Life Cycle Assessment of Tissue Products Final Report December 2007, Kimberly-Clark. Report available for download.
3. A life-cycle assessment of specialty paper, Swedish Environmental Research Institute, IVL. Whitepaper available for download.