Shaping the future of sustainable wood fiber insulation production

Reviving Swiss wood fiber boards while reducing freshwater use to the minimum 

Wood fiber has been continuously gaining traction over plain wood in the world of construction and isolation, thanks to its versatility and its many attractive qualities. For starters, its nature is very sustainable since it is made from the leftovers of the timber industry: materials like sawdust, chips and off-cuts that would otherwise be considered waste. Other features boosting wood fiber’s rising-star status are its major insulation and thermal capabilities that help keep temperatures stable and save energy costs, its moisture management properties that keep mold at bay and its 100% recyclability rate.

It’s no surprise then, that the wood fiber market is not only stable but booming with healthy growth projections in the coming years. This has stimulated a revival in local production of wood fiber in Europe, especially in Switzerland, where this industry stopped decades ago and left a major gap in the Swiss wood processing chain. Swiss company Lignatherm AG ⁠– part of Schilliger Holz AG ⁠– has decided to recommence production of Swiss-made insulation boards out of domestic raw materials with the smallest environmental impact possible.

Lignatherm’s challenge

To restart production, Lignatherm is building a new wood fiber insulation boards factory projected to be finished in the summer of 2025. Once up and running, it will process around 50,000 tons of wood chips into wood fiber insulation boards every year in a building just shy of 40 meters high and an area of 6,000 m2. The surrounding scenery is nothing short of idyllic: The factory is being built in Küssnacht – not only the birthplace of Switzerland as an independent nation, as per Swiss folklore – but also a town righteously considered a natural wonder with a privileged position on the northwestern shore of Lake Lucerne.

With such a treasure to protect, Lignatherm set off looking for a partner to mirror their appreciation toward the environment and effectively deal with both the elevated water usage and the wastewater generation inherent in wood fiber board production. These are coincidentally two of the most significant environmental considerations related to the industry.

GEA’s innovative 3-stage solution

There are several strategies to optimize freshwater use and recycle wastewater. Methods like dispersive flotation or wastewater biotreatments have long been helping fiber board producers reduce their wastewater volume or mitigate the amount of waste in the water. However, none of the available options represents a one-stop solution; and this leads to shortfalls on other savings (such as in energy) that could otherwise be achieved.

“We will manufacture a sustainable product,” says Tobias Osterwalder, Head of Processing and Managing Director of Lignatherm. “So, a sustainable and resource efficient manufacturing process is very important to us. We needed a partner that could help us orient the whole production process towards using the entire amount of wastewater from the process, not only to optimize our energy efficiency, but to keep the use of freshwater requirement as low as possible. In GEA we found the right partner to support us with such a challenging process.” Lignatherm started with strong criteria that made them trust in GEA’s expertise to provide the answer to their efficiency and sustainability specifications and parameters.

And so, GEA engineers set to design a tailor-made three-stage solution for a water treatment process that will allow Lignatherm to recycle nearly 100% of their effluent water. This will significantly reduce freshwater consumption and, thus, environmental impact.

Designing this one-stop solution required not only a depth of technical skills but also solid knowledge of the wood fiber board industry, since even the seasons or the level of moisture in the wood has a significant influence on the kind and number of particles, organic acids and other hydrocarbons that must be treated before discharging the generated wastewater.

The result is a powerful synergy of some of GEA’s core technologies tailored to the specific needs of Lignatherm. The process acts in three different crucial parts of the production process to ensure maximized water savings and energy efficiency: 

• The first stage comprises mechanical separation with GEA decanter centrifuges. Here, suspended solids are effectively removed from the wastewater stream.
• The second stage is the thermal separation with the Falling Film Evaporator. Here, dissolved solids are concentrated for their later disposal, while clear condensate is produced to feed the third stage. This stage is especially sustainable thanks to the mechanical vapor recompression (MVR) system that powers the evaporator without fossil fuels at the maximum energetical efficiency. This system reaches a coefficient of performance (COP) – a value of the the energy-saving potential of a thermal separation plant – of more than 25. This is at least five times higher than that reached with other heating options such as heat pumps or gas boilers.
• The third stage consists of our steam reformer. This stage gives full circularity to the water recycling system. It catches wastewater in a loop where it transforms into process steam so steam does not otherwise need to be generated. This way, more than 95% of the wastewater can be reused as steam – equally reducing the need for freshwater by over 95%.

It has been a challenging but rewarding project. “I am excited about how the smart combination of different GEA technologies enables us to provide our customers with a perfect-fit process solution,” says Roland Moser, Evaporation Sales & Process Manager and one of the engineers behind the development and tailoring of the solution for Lignatherm. “It is a cornerstone for reducing effluent and water consumption in [medium-density fiberboard] production and an example of energy efficiency.”

GEA's solution to close the water treatment loop

Experience and innovation: A win for sustainability.

The weight of GEA’s 100-plus years of experience in thermal separation plants and the chemical industry – including in fiber board wastewater treatment – combined with passionate and skilled engineers capable of adapting the process to Lignatherm’s exact needs were the “key elements in achieving outstanding results,” says Rafael Piña, Project Manager Evaporation. “Thanks to this synergy, the Lignatherm project has not only exceeded its initial goals but has also resulted in improvements to our technology, establishing a new superior standard.” The project's success impacts not only the industry but also redefines what can be achieved in terms of water protection and overall sustainability.

Such important milestones are always backed on strong teamwork and communication – values that both GEA and Lignatherm share as “the constant dialogue was fundamental in adjusting processes and technologies, ensuring that each solution aligned perfectly with Lignatherm’s expectations” adds Piña. 

Osterwalder noted that Lignatherm felt open and direct communication right from the start and in every aspect of the project in “GEA’s expert advice and joint work to develop the ideal solution for the project.” That successful collaboration and exchange are the key factor behind the sustainable comeback of wood fiber production in Switzerland while keeping Lake Lucerne pristine.