A polymer can be called a bio-polymer if it consists (partly) of bio-based renewable materials and/or is in some way biodegradable. Paper contains cellulose which is a polymer (a linear chain of hundreds of linked organic compounds) of glucose. Cellulose is a renewable bio-based material that can be found in cell walls of plants, many forms of algae and oomycetes (fungus-like micro-organisms) and is biodegradable under the right conditions.
Paper is well known for its recycling potential. There are three categories of feedstock that can be used for making conventional recycled paper: -mill broke (paper trimmings and other paper scrap from the manufacture of paper), pre-consumer paper (material which was discarded before use) and post-consumer paper (material discarded after consumer use). However, although seen as the recycling industry’s biggest success story, the paper recycling process itself brings along several unsolved problems. One of the biggest issues is the need to remove the ink from recovered paper (called de-inking) because the paper has already been used for printing. To remove the ink additional chemicals have to be used that can be damaging to human and environmental health. In some cases, the paper is also bleached with e.g. hydrogen peroxide or even chlorine (known to form toxic pollutants in combination with organic matter). De-inking and bleaching products can end up as toxic sludge. In addition, paper cannot be recycled endlessly: a sheet of paper is made of cellulose pulp (e.g. from wood fibers) suspended in water, formed and dried in a specific shape. As the pulp dries, the fibers stick together and form an interlocking pattern. During the recycling process, paper is mixed with water and ground into new pulp, but with a loss of quality: the grinding shortens and weakens the fibers. Theoretically, you could recycle the same fibers for 6 to 7 times before fiber properties have diminished to such extend that they cannot be used for paper anymore. In many cases, new cellulose fibers are added to the recycled fibers so that the paper will maintain its desired quality.
From a Cradle to Cradle® perspective, the use scenario of a material is crucial: in the conventional paper making process paper fibers cannot be recycled endlessly and can therefore not be considered as technical nutrients. Thus, the paper making process has to be optimized in such a way that fibers can be re-used as often as possible until they become unsuitable for paper, carton or tissue, and then serve as valuable biological nutrients for soil application or energy generation. The by-products from the paper recycling process (e.g. from de-inking) should be safe for humans and the environment and should be suitable for the use scenario. Cradle to Cradle® thinking goes even further: why use wood logs in the paper making industries or even as biomass in incineration plants for energy when they can be used to make furniture first? From a Cradle to Cradle® perspective wood should be used in a cascade: starting with the applications that make use of the full potential of the material (furniture) and over time and use towards the lower end of the spectrum (burning for energy, and recovering ashes). As an example see the following graphic on the Cradle to Cradle paper cascade (see Figure 1 for an example of a paper cascade from a Cradle to Cradle® perspective).
Figure 1. Example of Cradle to Cradle® paper cascade (from: Usability of Life Cycle Assessment for Cradle to Cradle purposes)
Gugler* is the first printing company worldwide that has succeeded in developing a printing product that has passed the strict criteria of Cradle to Cradle® certification and has received a silver certificate. All off-set printing product-components within this Cradle to Cradle Certified® product group have been assessed by the Environmental Protection Encouragement Agency (EPEA) and are optimized for their suitability in the biological or technical cycle. Environmental and human health-related aspects have been evaluated as well as other criteria such as solar income, social standards and the responsible use of water. The ashes of the burned printed products are intended to be beneficial in future as safe biological nutrients and can be returned to the soil to feed organisms, grow biomass and restore soil organic matter. This complies with the first principle of Cradle to Cradle®: Waste = Food (Nutrients are nutrients, or everything is a resource for something else) in which nutrient can remain part of continuous biological or technical cycles.
Van Gansewinkel, material flow manager, was known as a waste manager before they started working together with EPEA on applying the principles of Cradle to Cradle® to their company structure. Their credo today is “Waste no more” or “Afval bestaat niet” (waste does not exist in Dutch). Van Gansewinkel is working together with different partners to form continuous cycles and is an appreciated member in the design process of a product. Van Gansewinkel Office Paper has received the Cradle to Cradle® silver certificate and is a clear example of a collaboration between three different partners: Van Gansewinkel, Océ and Steinbeis who work together toward accomplishing a continuous cycle for paper cellulose fibers. Confidential office paper is collected by Van Gansewinkel under the name Destra Totaal and brought to Steinbeis in Germany, where the paper is de-inked and shredded into pulp for new paper in a process that is friendly for both environmental and human health. Steinbeis has developed a method in which the paper fibers can be re-used more than the conventional 6-7 times so that in the future the cellulose fibers can be viewed as a technical nutrient in this specific scenario. The paper is then sold by Océ to companies that use and discard of the paper and picked up by Van Gansewinkel, and so the story continues.
Photo: Van Gansewinkel
However, paper does not necessarily need to be produced from cellulose fibers (such as wood) but can be produced from other materials as well. Taiwan Lung Meng Technology Co Ltd and TerraSkin, producers of a special kind of paper, have rethought the service and pathway of their paper products. What if paper could be tear-resistant, water-resistant, easily recyclable and safe for degradation and burning? Lung Meng and TerraSkin paper products are made from Calcium Carbonate (CaCO3, >75%) and a small quantity of non-toxic resin of biodegradable Polyethylene (PE, <25%) that has been certified silver by the Cradle to Cradle® certification program. Preferably this PE is bio-based from a Cradle to Cradle® point of view so it can be produced from renewable sources, for non bio-based PE a technical cycle is preferred so the material can stay in continuous loops and no non-renewable sources are lost.
Sometimes a scenario for a product from paper is clear: toilet paper is an example of a product where a material (e.g. cellulose fibers) can find an application in the last steps of a cascade as biological nutrient. Toilet paper should be designed in such a way that it is safe for humans and leaves no harmful residues behind in the environment. Van Houtum developed Satino Black, a hygienic paper and soap range that are Cradle to Cradle® silver certified. All ingredients have been analyzed in collaboration with EPEA and had to meet strict requirements to be suitable for the biological cycle. Once flushed, the toilet paper will biodegrade and is safe for burning and recovering of nutrients.
Photo: Van Houtum
There is still a great potential to optimize our paper making industries, starting at re-thinking what the exact use scenario of our paper products is. How can we make sure that valuable materials such as cellulose fibers are used in such a way that they are re-used until further use is not possible so they can be converted into biological nutrients to contribute to soil organic matter and plant growth. How can we optimize the process in such a way that by-products do no harm human and environmental health, but can be beneficial as either biological or technical nutrients. Paper does not necessarily needs to be made from cellulose fibers from wood: a large range of materials is suitable. Looking closely at the proposed use scenario and end of use will help choosing the best materials for producing paper.