The Future of Sustainability at Pulp and Paper Mills

Located in Espoo, Finland, Aalto University’s Department of Bioproducts and Biosystems (Bio2) is at the forefront of forest products technologies and cutting-edge biotechnology. The school’s research activities target innovative products and solutions for applications ranging from construction and textiles to biomaterials, energy, and biomedicine.

Metsä Fibre’s Kemi bioproducts mill, set for start-up in late 2023, is a classic example of a modern pulp mill ready for the future. Metsä Group plans its mills around the company’s unique bioproduct mill concept, the core of which is the resource-wise use of the wood raw material and side streams of production. No fossil fuels will be needed in production, and renewable energy in the form of electricity, wood-based fuels, and heat will be sold from the mill to external customers. (Photo courtesy: Metsä Fibre)

Paper360° Senior Editor Mark Rushton spoke to Professor Olli Dahl, chair of Environmental Technology within Process Industries, about sustainability at pulp and paper mills, opportunities and challenges, and what the future might look like.

P360°: Looking at the pulp and paper industries as a whole, how do they rank in terms of sustainability as they are right now when compared to other industries?

DAHL: The pulp and paper industries are doing very well today. The raw materials used are renewable, the environmental issues are well controlled, and most of the mills are profitable. In this way, they can also create economic and social well-being in their local area. Other industries are struggling mainly with non-renewable raw materials, whose acceptability is declining all the time. In addition, these other industries’ raw material quality has deteriorated, and the quantities have also decreased.

What challenges are the pulp and paper industries facing when it comes to increasing and maintaining their ability to be environmentally sustainable? 

In the pulp industry, the sizes of production units have increased a lot over the last five to 10 years. This development will lead to a high environmental impact locally and regionally. The wood procurement area is growing while CO2 emissions from transport are also increasing. The ability of forests to sequester carbon must also be taken into account regionally. However, suitably sized pulp mills are excellent platforms for producing bio-based products in a sustainable way, now and in the future.

Paper mills are still of moderate size and direct environmental impacts will not be the issue. In addition, paper mills are switching to producing packaging for consumers and replacing fossil-derived plastic packaging, so environmental performance could not be better. It is also positive that the fibers in packaging can be recycled many times.

What opportunities do you see for these industries going forward to improve their sustainability factors? Is there any ‘low-hanging fruit’ they can already be taking advantage of?

Regarding the pulp industry, in addition to the “normal” products produced at pulp mills, such as pulp for packaging and tissue, higher value cellulose grades should also be considered—for instance, fibers for textile production, or fiber products for food and animal feed. From the forest to clothing and food on dinner tables is a big opportunity for the future of the pulp industry.

These new products will improve the profitability of pulp mills and create more new jobs. This will improve the well-being of regions and people, so the social dimension will be improved.

The opportunities for the paper industry lie in plastic-free board grades, packaging boards, and biodegradable single use products. With efficient R&D development we can create new sustainable products for our society.

There is a lot of talk about opportunities for other bioproducts to be produced from side streams at both pulp and paper mills. Can you comment on what these product possibilities are, and how realistic it is to see them adding significant value to mill revenue?   

Unfortunately, side streams can do little to improve the economy of a pulp mill. Still, they can create the conditions for new companies to become part of the ecosystem and thus create jobs locally. Pulp mills provide a lot of extra heat, but this opportunity has not yet been sufficiently exploited. The ashes from wood burning or gasification have already been processed into fertilizers. Sulfuric flue gases can be used to produce sulfuric acid and methanol can be produced from condensates. So, there are many opportunities for new business where the pulp mill acts as a center and source of raw materials for small and medium enterprises.

In the paper industry, side streams from paper mills can be turned into small specialty products like cat litter and all organics can be used for biogas production. Unfortunately, I don’t see any significant new business coming from them because the volumes are quite small locally. However, co-operation with local communities and a combination of side streams could create a business of sufficient size and thus improve the profitability of exploiting side streams.

What do you see as the most easily achievable bioproducts that can come from mills? What are you favorites?

In addition to traditional products, the processing of paper pulp and wastepaper into dissolving pulp grades and further into textile fibers offers a very high potential for pulp and even paper mills. Decomposing biomass into sugars could also provide an opportunity to produce chemicals. However, this requires a CO2 tax on similar fossil products to make the business profitable. Also, the processing of wood bark and lignin into new chemicals and materials will provide an opportunity for the production of new bioproducts.

Can you talk about some of the R&D that is being carried out on future products that may emerge from pulp and paper mills?

There are a lot of R&D projects ongoing around the world to develop new bioproducts. The challenge is always that we must compete with fossil products that are already on the market. I see the best opportunities for a variety of fiber products—from packaging to individual fibers ranging in size from nanoscale to micro-sized and used for completely new uses such as construction, as part of asphalt road structures, as part of human food, and for animal feed.

In your opinion, which technologies are making the greatest advances when it comes to improving sustainability, or allowing the production of new bioproducts at mills? 

This is difficult to answer because companies do not reveal their own secrets beforehand. The greatest progress will be made in the processing of cellulose into new textile fiber products and in the processing of lignin for the battery industry. However, the development of new products requires a combination of various technologies and a lot of research to achieve the goals. It seems that the development of new products is at its most advanced in the Nordic countries.

What will modern mills look like 50 years from now?  And what products will they be making other than pulp and paper?

The pulp and paper mills of the future will be waste-free, appropriately sized, more numerous than now, and evenly distributed around the world. Very big mills will be vulnerable due to the challenge of obtaining raw material in all sustainable aspects.

Pulp mills will produce totally new fiber products from nano- to micro-sized; these products will have uses we do not even know yet. In addition, some of the sugars released from fibers, extracts from bark, and lignin separated from black liquor will be processed using novel technologies into chemicals and materials to replace products made from crude oil. Excess electricity will be converted to hydrogen and stored as hydrogen paste and the extra heat will be used in greenhouses, which will be used to grow high-quality medicinal plants.

Paper mills will still make consumer packaging, but they will be energy-positive production facilities where all wastewater organic materials and other organic residues are converted to biogas by anaerobic technology and further to hydrogen paste. Hydrogen and hydrogen paste will evolve into a fuel for all modes of transport. One third of the profitability of paper mills will come from non-packaging products.