Linn Solli
Research Scientist
Biography
Education: Doctoral degree (PhD) (2017) in microbiology at the University of Life Sciences, NMBU.
Area of research:
- Blue / green bio economy (agriculture / aquaculture)
- Climate and environmentally friendly management of organic residual fractions (animal manure, fish sludge, slaughterhouse waste etc)
- Anaerobic degradation of organic fractions
- Biogas process and methane production
- Dynamics in anaerobic microbiological communities
- Tolerance for nitrogen (ammonia) and fatty acids (LCFA / VFA) in anaerobic microbiological communities
- Syntrophic relations between different groups of bacteria and methanogenic Archaea
At Ås we have Norway's largest biogas laboratory, with equipment and instruments for various types of biogas experiments (e.g. potential tests, long-term continuous biogas experiments, analysis of gas and organic material). The laboratory also has facilities for micro-algae experiments, composting experiments and a number of different analyzes.
Abstract
No abstract has been registered
Abstract
Marine aquaculture sludge is a significant side stream from the aquaculture industry and represents a promising substrate for biogas production. In this study, the performance of two lab-scale continuous biogas reactors was investigated when feeding increased amounts of marine aquaculture sludge (MAS) in mix with cow manure (CM) over a period of 340 days. The MAS volume was gradually increased from 20% to 100%, increasing the biogas yield from approx. 200 to 400 mL/g COD/d. The content of NaCl in the feedstock was 25 g/L when feeding 100% MAS. Microbial community analysis (16S rRNA gene amplicon sequencing) revealed that most archaeal OTUs detected at high MAS loading were associated with acetoclastic Methanothrix and Methanosarcina genera. Increasing the MAS load was associated with reduced microbial diversity, yet no distinct MAS-specific species emerged as key drivers in the recovered microbial community. Our results highlight the great potential of MAS as a substrate for biogas production and the possibility to establish biogas systems with salinity conditions corresponding to sea water.
Authors
Abdullah Bugra Senol Linn Solli John Morken Wietske Annechien Stel Nazli Pelin Kocatürk SchumacherAbstract
Aquaculture sludge from recirculating aquaculture systems (RAS) represents a growing waste stream with potential for biogas recovery; however, elevated salinity can inhibit anaerobic digestion (AD). This study evaluated the biochemical methane potential (BMP) of RAS sludge under freshwater (0%), brackish (1.2%), and marine (3.3%) conditions and assessed the effectiveness of biochar and zeolite. Batch BMP assays were conducted under mesophilic conditions at an inoculum-to-substrate ratio of 2:1, with additives applied at 0.8 g/g VS. Increasing salinity significantly reduced methane yields (p < 0.05), from 533.6 ± 3.4 NmL CH4/g VS in freshwater to 478.1 ± 10.2 and 341.3 ± 0.6 NmL CH4/g VS in brackish and marine conditions, respectively. Biochar enhanced methane production by 5.9–11.3% across all salinities, while zeolite increased yields by 7.7% and 15.7% under brackish and marine conditions, respectively, but had no effect in freshwater. Methane production kinetics were well described by the modified Gompertz model (R2 = 0.983–0.999). Overall, biochar was more effective at low salinity levels, whereas zeolite mitigated salinity-induced inhibition, indicating that targeted additive application can enhance methane recovery from saline aquaculture sludge and support sustainable RAS waste management.
