Sludge - the stinky mud that is the left over product from for example municipal wastewater treatment, fish farming etc. - is a global challenge. It is everywhere and is difficult to get rid of. It is active, fermented and contains a lot of water, and it can also be hazardous to health. Therefore, a group of Danish water procurers lead by DANVA joined forces in 2016 and launched a pre-commercial procurement to find a way to recycle and reuse valuable resources in wastewater.
During the PCP, the cleantech startup AquaGreen perfected an innovative solution that removes all forms of disease germ in the sludge, makes it inactive and odor-free and at the same time removes the water, which is otherwise expensive and difficult to get rid of. Even before the PCP was finished in 2019, customers were already in line with AquaGreen.
AquaGreen's innovative idea was to use the organic material in the sludge to drive a drying and combustion process based on pyrolysis (cleavage of organic compounds by heating without oxygen). The solution consists of a process plant with a combined steam dryer and pyrolysis unit that extracts thermal energy for the heat supply and natural fertilizer for agriculture (purified bio-coke) from the sludge. Re-circulating phosphorus and carbon as a soil improver enables a more responsible use of natural resources and reduces CO2 emissions. The solution contributes to energy efficiency goals by reusing the calorific value of the organic components of the sludge as thermal energy to drive the process and excess thermal energy, for district-or local heating. Removing all dangerous pathogens, xenobiotics, heavy metals and pollutants from the sludge improves health and sanitation impacts on society.
The market for wastewater and biogasification is ramping up with increasing legislation emerging around Europe not to throw polluted wastewater sludge directly on farmers’ fields in order to avoid residues of plastic, endocrine disrupting substances and heavy metals ending up in the food chain. In 2016, Aquagreen received a EUROSTARS grant from the EU Horizon 2020 program to address in particular the fish farming market. The aquaculture industry, in particular from Norway, has become a key driver for the company’s business. In principle, Aquagreen’s technology can be used anywhere where sludge is generated, such as cruise ships, festivals, refugee camps and military camps. But the entrepreneurs also get calls from interested people who ask if they can steam dry slurry, shrimp, salmon lice, seaweed, brewer's mask and apple hull.
The startup is located on the campus of the technical university of Denmark, in cooperation with whom it developed its patent pending solution. To address markets in other countries Aquagreen has established joint ventures in Norway, Germany and one in Canada is on the way.
“Our startup business has grown a little the other way around compared to typical startups. Normally, you start developing a technique that you then try to sell it. In our situation, we have contact with the market from the beginning and the solution was developed for a client from the beginning. We know that there is a great need. Customers are in line. It gives a completely different drive.”
Ulrik Birk Henriksen, senior researcher at DTU Chemical Engineering
Claus Thulstrup, owner/CEO Aquagreen
More information on the Aquagreen website
Presentation about the company, its solution and business proposition