Daniel Frank
Dr., Communication Officer
EasyMining Services Sweden AB
Sweden
Daniel.Frank@easymining.com
Yariv Cohen
Ph.D., Head of Research and Development
EasyMining Services Sweden AB
Sweden
Yariv.Cohen@easymining.com
The Baltic Sea is a unique water body and has been an area of economic interest for centuries. And while countries developed and their general wealth increased, the environmental condition of the Baltic Sea worsened in an alarming way. And although in the last decade some measures were installed to prevent a further worsening some key environmental issues remain, such as eutrophication caused by high levels of nitrogen and phosphorus from agriculture, wastewater, and industry. Despite efforts to reduce nutrient input, the recovery process is slow due to legacy nutrients already present in the ecosystem. Algal blooms have increased, leading to dead zones (hypoxia) where oxygen is too low for marine life to survive.
Between the reference period of 1997-2003 and the year 2020, the total input of nitrogen decreased by 12%. Despite these reductions, eutrophication remains a significant issue. The Baltic Sea continues to experience severe oxygen depletion, with over 80,000 km² of its bottom areas affected by hypoxia or anoxia as of 2019.
Efforts to reduce nitrogen effluent in the Baltic Sea include improving agricultural practices, better wastewater treatment, and implementing regulations to reduce nitrogen emissions. There are several strategies in place aimed at reducing nitrogen pollution and recovering ecosystems affected by nitrogen in the Baltic Sea. For instance, there’s the Baltic Sea Action Plan (BSAP): It includes specific goals to reduce nutrient inputs (including nitrogen) from agriculture, wastewater, and atmospheric deposition. The BSAP emphasizes reducing nitrogen inputs by 20% by 2027 compared to 2007 levels and achieving a healthier marine ecosystem.
Additional to Improved Agricultural Practices, such as regional Nutrient Management Plans and Sustainable Farming Incentives a lot has been done towards Wastewater Treatment Improvements. Many countries bordering the Baltic have upgraded their wastewater treatment infrastructure to better remove nitrogen and other nutrients before they are discharged into the sea.
Nitrogen removal can be done by biological, chemical, and physical methods, with biological processes being the most used, namely nitrification and denitrification. However, they have certain drawbacks such as a high energy demand and a reduced efficiency in colder temperatures. Furthermore, state of the art nitrogen removal has two major issues: Nitrogen removal is the largest source of greenhouse gas emissions from a wastewater treatment plant, with up to 6% of the total nitrogen released as N2O. Also, in most of the processes, the nitrogen is only removed but not recovered. Since the production of nitrogen-based fertilisers is responsible for about 1% of all human-made carbon dioxide emissions via the Haber-Bosch process, one should start acting more circular by recovering nitrogen, when possible.
The Urban Wastewater Treatment Directive (UWWTD) introduces new requirements for wastewater treatment plants. Since plants in the EU with a size above 150.000 person equivalents must remove more nitrogen from the wastewater by 2039, as well as become energy neutral, e.g. via increased biogas production leading to a higher nitrogen load, it is clear that new innovative wastewater treatment solutions are needed.
The actual production of nitrogen based-fertilisers, the loss of nitrogen in wastewater treatment plants and the new regulation is a driving force for the implementation of innovative processes that both remove and recover nitrogen. One example for this can be the Aqua2N process.
Technologies to recover nitrogen loads can be beneficial in both reducing the load of water streams but also help reducing airborne emissions. EasyMining’s Aqua2N acts on liquid waste streams with high concentrations of ammonium nitrogen, such as sludge liquor. Although this comprises only 0.5 - 1.5 % of a plant’s total liquid flow, it contains 15 - 30 % of the total nitrogen load. By removing 95 % of the ammonium nitrogen in that stream, Aqua2N reduces both the nitrogen load and the carbon footprint of traditional plants. Furthermore, no nitrous oxide, a greenhouse gas 300fold more harmful than carbon dioxide, is emitted in the process. With the upcoming EU UWWTD the technology can help operators live up to the coming need to reduce nitrogen emissions.
While efforts to restore the Baltic Sea continue, recovery is slow, and climate change adds new uncertainties. Further reductions in nutrient pollution among others will be crucial. And although our very own Aqua2N technology can play its part in that development, technologies alone will not solve the problem: International cooperation among Baltic Sea nations is essential to tackle cross-border environmental issues effectively. Strong communication even with neighbouring countries that are not upkeeping the set agreements is crucial to ensure the future of the Baltic Sea and its vital role, it played for so long and for so many countries.