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.
Authors
Getachew Birhanu Abera Aryan Bhusal Nabin Aryal Thea Os Andersen Linn Solli Svein Jarle Horn Lu Feng Begum BilgicAbstract
No abstract has been registered
Authors
Linn SolliAbstract
No abstract has been registered
Abstract
Since the 1950s, the use of plastics in agriculture has helped solving many challenges related to food production, while its persistence and mismanagement has led to the plastic pollution we face today. Soils are no exception and concentrations of polyethylene mulch debris up to 380 kg/ha have been reported in Chinese agricultural soils. A variety of biodegradable plastic products have thus been developed and marketed, with the aim to solve plastic pollution through complete degradation after use. But the environmental conditions for rapid and complete degradation are not always fulfilled, and the risk that biodegradable plastics could also contribute to plastic pollution must be evaluated. In this presentation, we want to share the knowledge gained through research projects on biodegradable plastics in agricultural soil, where we both studied the degradation of biodegradable mulch under Nordic soil conditions, and the fate of other biodegradable plastics in soil amendments such as compost and biogas digestate. A two-year field experiment with biodegradable mulch (PBAT-starch and PBAT-PLA) buried in soil in mesh bags showed that also under colder climatic conditions does degradation occur, involving fragmentation already after 2 months, but that complete degradation may take 3 to 9 years, depending on soil temperature and soil organic matter content (both correlate positively with degradation rate). Accumulation is therefore likely to happen when biodegradable mulch is repeatedly used every year. A full-scale experiment with compostable plastic cups (PLA) at an industrial composting plant, where we followed their fate and conducted metagenomic analysis over 13 weeks, demonstrated the major role played by fungi for a successful degradation of PLA. However, the successful management of biodegradable plastic products largely depends on existing waste management infrastructure. Most biodegradable plastic bags, labelled as compostable and used for food waste collection do not end up in industrial composting plants in Norway, but in biogas production plants. Here, we showed that these plastic bags (Mater-Bi®) are only marginally degraded (maximum 21-33 % mass loss) during biogas production, and likely to end up in biogas digestate and then in agricultural soils, unless digestate is treated to remove plastic residues.