Cambi thermal hydrolysis: Presence and Future in the Nordics

Thermal hydrolysis is a sludge treatment technology that began in the Nordics. How is the region faring in adopting the process technology decades later, after its steady growth in other parts of the world.  

Thermal hydrolysis projects in the Nordics 

Cambi, the leading provider of thermal hydrolysis process (THP) technology worldwide, counts 15 references across Norway, Denmark, Sweden, and Finland as of 2024. As the technology was developed in Norway, it comes as no surprise that this country leads the pack with ten projects, three of which are expected to be commissioned in the coming two years. The third project for Denmark, is also nearly operational at Damhusåen in Copenhagen.  

The range of these Scandinavian references is quite broad in terms of the type of feedstock chosen for THP. Some use the technology only on secondary solids or waste activated sludge, others use it on sludge mixed with food waste (co-digestion), and some references treat food waste solely. One of the most recent projects, servicing Oslo and nearby municipalities for the utility Veas, will have THP treating digested solids by 2026. Set against the whole portfolio of projects by Cambi, the projects in the Nordics also have the highest density of systems used for codigestion of sludge with food waste. This speaks to the region's mindset, proving it places importance on utilising the inherent energy in food waste.  

Taking a closer look at some of these projects will highlight the variety of needs THP is addressing in the Nordics industry and the possibilities for similar plants:  

• The Copenhagen project for utility BIOFOS will treat only activated sludge before being mixed with primary sludge and digested. This approach is particularly effective when full hygienisation of all sludge is unnecessary, especially if the sludge is destined for incineration. The investment in THP will also be optimised as the unit will be smaller.  
• Norway’s largest treatment plant located west of Oslo, VEAS, is adopting the THP process downstream of digestion to maximise biogas output and dryness after dewatering. This set up, with THP after digestion, also has a great potential for biogas facilities utilising food waste and other organic waste streams. 
• We are building a THP system for NRVA in a new sludge treatment centre outside Lillestrøm in Norway. The system will feature a new design, which includes an additional energy-saving step that reduces steam consumption by approximately 30%. 

These exciting developments in the region solidify the value placed on THP technology. But where is the technology headed in this region's coming decades? 

Net-zero targets in the Nordics 

The future of thermal hydrolysis in this part of the world may be affected by the sustainability goals of the countries in question, especially if the countries place value on resource recovery and methane reduction. 

Sweden's climate act sets long-term, ambitious GHG targets for 2030 and 2045. The country has already greatly invested in biogas upgrading facilities and primarily uses sewage sludge to produce this energy source.

Thermal hydrolysis has space to grow in this market as treatment plants may increase their contributions to Sweden’s climate goal of net-zero emissions by 2045, which has legally binding targets in place. It also has intermediate goals set, such as reducing emissions by 63% by 2030 and 75% by 2040, compared to 1990 levels. 

With targets also tied to legislation, Denmark’s net-zero emissions target is also 2045. Like Sweden, it has set a midway goal of a 70% reduction in greenhouse gas emissions by 2030 compared to 1990 levels. 

Norway aims for emissions neutrality by 2050, with a 55% reduction target by 2030 compared to 1990 levels. However, the Norwegian climate plan is not a strict mandate, as the country has instead focused on policies that incentivise emissions reduction, like carbon taxes.  

Finland has the most ambitious plans in the group, with the plan also made into law. Finland’s 2035 carbon neutrality goal and 2040 net zero target year place it as a leader not just in the region but globally​. 

Lastly, Iceland’s climate plan also has an impressive 2040 emissions neutrality goal. Though its targets are not legally binding, it has implemented carbon pricing mechanisms and renewable energy subsidies.

Challenges in the continued growth of THP in the region 

While the potential of thermal hydrolysis is immense in the region due to the ambitions of each country towards more circular economies, several challenges must be addressed if it is to be fully realised.   

• The inclusion of climate and environmental considerations in biogas tender evaluations has yielded many positive experiences for Cambi. As an environmental technology company, we see these factors as central to our competitive advantage, alongside the economical total life-cycle cost of THP. It sometimes becomes challenging when utilities or contractors do not weigh these criteria sensibly and only focus on investment costs.  
• Effective communication between the parties during public procurement is crucial to meet the targets. Current public procurement processes tend to have highly formal communication requirements. At times, this can be counterproductive due to mistakes or misunderstandings that lead to unnecessary disqualifications. Slightly less formal communication with technology providers in the tender phase can solve this problem.

 “Samspillsfase,” a method in Norwegian public procurement, is a collaborative model that Cambi finds quite effective. At the beginning of a project, a “cooperation” contract is signed with all stakeholders—such as the client, the client’s consultant, and the chosen contractor. They work together in this phase to optimise the project's design, cost, and efficiency. Participants share information, align their expectations, and make collective decisions, which helps to identify potential issues and innovative solutions before the final execution contract is awarded. 

Cambi has noted that this collaborative approach enhances project outcomes by improving teamwork and ensuring that all parties are on the same page from the outset. One example is the project for the Norwegian utility FREVAR. The initial cooperation contract was signed in July 2022, and the work yielded design and cost optimisations that eventually led to a construction contract in March 2023.

The road ahead: Stricter regulations, biogas in the energy mix 

Alongside the stricter implications of the revised EU Industrial Emissions Directive, the revised EU Wastewater Directive will result in more demanding requirements for water purification in the coming years. This will result in more sludge available for biogas production and demands for energy neutrality throughout the treatment process. Producing biogas from sludge will be essential to achieving an energy-neutral system, aligning with EU goals for increased biogas production in the coming years. 

Biogas has also gained significant attention in recent years as part of the future energy mix. Many projects are under development in Norway, for example, for various organic substrates, primarily waste streams. However, securing long-term profitability in all these projects may be challenging.  

Denmark has set a positive example by supporting biogas projects with operational support related to the amount of renewable energy produced. This approach has allowed the country to advance significantly in this area, even utilising agricultural substrates with positive value, such as straw and energy crops.  

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Cambi’s thermal hydrolysis technology allows for better energy balance, hygienisation without pathogen regrowth and a high-quality biofertiliser product that can be used in agriculture. In cases where agricultural use becomes challenging, THP with biogas production remains a cost-effective pre-treatment that demands minimal energy use for drying and provides advantages for incineration. 

As the Nordic countries strive to meet stringent environmental regulations and reduce their carbon footprints, the thermal hydrolysis of sludge represents a transformative opportunity for the Nordic region's resource recovery and waste management strategies.  

Do you want to schedule a site visit to one of our Nordic sites or learn more about projects in this region? Get in touch with our region lead on our contact page.