Asker, Norway: A peer-reviewed study demonstrates that the N2-process satisfies the current requirements for deactivation of the indicator organisms Salmonella, E. coli and A.suum in both digestate and cow dung.
N2 Applied plasma-based nitrogen enrichment process is a technology targeting local fertiliser production only using air and electricity as single inputs. The produced NOx is absorbed into organic waste, producing a manure enriched with nitrogen made available for plants. The product, Nitrogen Enriched Organic fertiliser (NEO), has an increased content of mineral nitrogen and a lower pH.
– Additionally, biological activity is inhibited in produced NEO. This observation gave rise to the idea of determining critical operating conditions to inactivate the three indicator organisms Salmonella Senftenberg (S.Senftenberg), Escherichia coli (E. coli) and Ascaris suum (A.suum), Åsne Daling Nannestad (McS) Process engineer in N2 Applied.
The indicators tested are described in the Fertiliser Regulations and the Regulations on Animal By-Products.
During a period of two years (Q2 2021 – Q1 2023) the test organisms were added to freshly produced nitrogen enriched cow manure (NEO) processed to specific pH-levels. After different exposure times ranging from 0 to 48 hours, viable cells were counted to determine degree of inactivation.
The results show that all indicator organisms are reduced to below limits set in legislations at tested pH-levels (≤ pH 5.0). Critical exposure time varies for different substrates, pH-levels and indicator organisms, ranging from 1 to 26 hours.
– The aim of the treatment is to prevent the spread of disease. Important for many situations where livestock manure and digestate are sources of harmful pathogens. This study shows that our plasma technology is an effective sanitiser and therefore opens up a huge potential in turning organic slurries into fertiliser says Åsne Daling Nannestad (McS) Process engineer in N2 Applied.
The full peer-reviewed article can be found here.
Read the article published at Vannforeningen (2/24, page 141).
Aquateam Cowi has carried out the practicalities of handling microorganisms (cultivation and analysis). N2 Applied has been leading the project and in charge of operating machinery. It is funded by Regionale forskningsfond (RFF) Oslo. The collaboration with Aquateam COWI started in 2020 (a pre-project) and ran until Q1 2023.