We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Material and energy flows of industrial biogas plants in Switzerland in the context of the circular economy
Summary
Researchers modeled material and energy flows through industrial biogas plants in Switzerland, finding that anaerobic digestion (breaking down organic waste without oxygen) could replace up to 14,000 tonnes of chemical fertilizers annually — but currently allows about 70 tonnes of plastic per year to end up in farm fields. Addressing that plastic contamination is essential if biogas expansion is to support a true circular economy.
Today, biomass is one of many countries most important renewable energy sources. Anaerobic digestion (AD) is a promising alternative to treating organic wastes from both energy and nutrient perspectives. Here, we develop a material flow model to assess the current utilization of wet biomass in industrial AD installations from mass, energy, and nutrient perspectives in Switzerland. We then identify how the current situation fits into the circular economy concept and develop quantitative scenarios for the future of industrial AD. The nutrient transfer coefficients through AD are >74 %. In the future, this could replace up to 14,000 t/a of chemical fertilizers, saving up to 40,000 t/a of CO2-eq. Today, however, 70 t/a plastic ends up in the fields after AD, which should be improved if AD is to increase in the future. Thus, increased AD of organic wastes could reduce dependence on fossil fuels while promoting a circular economy.
Sign in to start a discussion.
More Papers Like This
Digestate from Biowaste and Sewage Sludge as Carriers of Microplastic into the Environment: Case Study of a Thermophilic Biogas Plant in Ostrobothnia, Finland
This Finnish study found microplastics in every waste fraction sampled from a thermophilic biogas plant — including reject water and digestate from both biowaste and sewage sludge digestion. Because digestate is commonly spread on agricultural land as a fertilizer, biogas plants represent an underappreciated pathway for microplastics to enter soil ecosystems at scale. The findings highlight a critical gap in microplastic regulation: current wastewater treatment frameworks do not adequately address plastic contamination in biogas waste streams.
Fate of microplastics in a centralized biogas plant treating mainly sewage sludge
Researchers tracked the fate of microplastics through a centralized biogas plant treating sewage sludge, examining how anaerobic digestion and subsequent dewatering partition microplastics between solid and liquid digestate fractions. The study informs efforts to develop safer digestate-based recycled fertilizers that minimize microplastic introduction to agricultural soils, where 20-55% of microplastics entering wastewater treatment plants are estimated to end up in sludge.
Baseline levels of microplastics in agricultural soils obscure the effects of additional microplastics from recycled fertilizers
Researchers investigated whether liquid or solid digestate fertilizer from a Swiss biogas plant adds detectable microplastic loads to agricultural soils above natural background levels. Despite finding microplastics in digestate, treated soil concentrations were not significantly different from the unfertilized control, suggesting high baseline soil microplastic levels obscure the signal from digestate inputs.
Unmasking microplastics in anaerobic digestion: Hidden threats, synergistic pollutants, and biodegradation Frontiers — A comprehensive hotspot review
Researchers reviewed how microplastics disrupt anaerobic digestion — the process used to convert organic waste into biogas — finding that microplastics suppress methane production, harm microbial communities, and carry along other pollutants like antibiotics and heavy metals into the system.
Characteristics, limitations and global regulations in the use of biogas digestate as fertilizer: A comprehensive overview
This review examines the use of biogas digestate, the leftover material from biogas production, as agricultural fertilizer, highlighting both its benefits and risks. While digestate is rich in nutrients, it can contain contaminants including heavy metals, pathogens, and microplastics that may enter the food chain through treated crops. The authors review global regulations and call for stricter quality controls to prevent microplastic and other contaminant transfer to agricultural soils.