Biography

  • Education in clinical medicin (MD), medical microbiology and immunology (MSc) and microbial genetics (PhD)
  • Molecular biology and biotechnology
  • Microbial source tracking (MST) of water fecal contamination
  • Host-specific genetic markers
  • Clinical relevant pathogens present in water, soil and biogas digestate materials
  • Analyses of antibiotic resistance genes (ARGs) in environmental samples
  • Microbial pollution and water quality measures
  • Microbial diversity of water and biogas digestates with special focus on bacteria and archaea
  • High-throughput Next Generation DNA Sequencing (NGS) technology, e.g Illumnia MiSeq platform
  • Bioinformatics analyses on DNA/RNA molecules, quantitative real-time PCR (qPCR) and Illumina sequencing data analysis
  • Functional genetic markers of carbon and nitrogen cycles

 

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Abstract

Nature-based solutions (NBS) have been broadly adopted to strengthen water and wastewater sanitation by effectively removing microbial pollutants and limiting significant health risks to aquatic environments and humans. However, temporal variations of pathogen removal efficiencies in NBS and the specific link with faecal pollutants remain understudied. In this study, a Norwegian urban NBS operating as a nature-based treatment system (NBTS) for water purification was monitored on pathogen removal capacities and faecal source tracking through a 1-year study. Applying coupled molecular analyses, i.e., pathogen molecular detection and genetic microbial source tracking, enabled the systemic assessment of this NBTS’s remediation performance while unveiling the intrinsic link between pathogen prevalence and the faecal pollution sources. Notably, the system exhibited stronger pathogen attenuation activity on Enterococcus faecalis, Salmonella enterica serovar Typhimurium, Clostridium perfringens, and Legionella pneumophila (linked closely to human origin in the studied NBTS) than Shigella species and Giardia lamblia sourced mainly from animals. Moreover, the studied system displayed temporal dynamics of its functioning. As such, more fluctuations often occurred in cold months than in the warm period and under varying impacts of measured environmental conditions (i.e., water temperature, pH, electrical conductivity, dissolved oxygen, total dissolved solids, salinity, and oxidation reduction potential). Collectively, the findings of this study consolidate the functional potential of NBS in combating the microbial pollution that results specifically from waterborne enteric pathogens in a tight link with faecal contamination. The disclosed performance seasonality also calls for extra consideration for better-informed system management and remediation enhancement. Last but not least, the holistic study outcomes underscored the explicit value of applying complementary molecular approaches to achieve deeper insights into the functional status of a target NBS over time.

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Abstract

Purpose: Rice production in paddy soil is important for food security, and nitrogen fertilisation is important to achieve high yields. Digestate, the organic rest from biogas production can be a good fertilizer, but relatively little is known about its use in paddy soil, which is investigated here. Method: Nitrogen transformations and rice growth in soil waterlogged and at field capacity after application of digestate and digestate products were assessed in a pot experiment. Nitrogen transformations and nitrous oxide (N2O) emissions with the same digestates were also assessed in an incubation. Results: One of the tested digestates had as good fertilizer effect as urea. Nitrogen transformations went mostly as expected under given water status, but digestates were more affected by waterlogging than urea. Some instability appeared about 10 days after fertilizer application. Then nitrite levels were high, responsive microbial populations peaked and N2O emissions started. Whilst emissions after mineral fertilizer application (urea) were not affected by waterlogging, emission after application of one of the examined digestate was high at field capacity but almost zero under waterlogging. N2O emissions from all other digestate and water treatments were also low. Conclusion: Digestates have great potential as organic fertilizers in rice production, but N2O emissions under aerobic soil conditions are of concern and warrants further investigation and mitigation strategy.

Abstract

Nature-based solutions (NBS) have been broadly adopted to strengthen water and wastewater sanitation by effectively removing microbial pollutants and limiting significant health risks to aquatic environments and humans. However, temporal variations of pathogen removal efficiencies in NBS and the specific link with faecal pollutants remain understudied. In this study, a Norwegian urban NBS operating as a nature-based treatment system (NBTS) for water purification was monitored on pathogen removal capacities and faecal source tracking through a 1-year study. Applying coupled molecular analyses, i.e., pathogen molecular detection and genetic microbial source tracking, enabled the systemic assessment of this NBTS’s remediation performance while unveiling the intrinsic link between pathogen prevalence and the faecal pollution sources. Notably, the system exhibited stronger pathogen attenuation activity on Enterococcus faecalis, Salmonella enterica serovar Typhimurium, Clostridium perfringens, and Legionella pneumophila (linked closely to human origin in the studied NBTS) than Shigella species and Giardia lamblia sourced mainly from animals. Moreover, the studied system displayed temporal dynamics of its functioning. As such, more fluctuations often occurred in cold months than in the warm period and under varying impacts of measured environmental conditions (i.e., water temperature, pH, electrical conductivity, dissolved oxygen, total dissolved solids, salinity, and oxidation reduction potential). Collectively, the findings of this study consolidate the functional potential of NBS in combating the microbial pollution that results specifically from waterborne enteric pathogens in a tight link with faecal contamination. The disclosed performance seasonality also calls for extra consideration for better-informed system management and remediation enhancement. Last but not least, the holistic study outcomes underscored the explicit value of applying complementary molecular approaches to achieve deeper insights into the functional status of a target NBS over time.