Measuring, modeling and economic examination of biodegradation for organic fraction of municipal solid waste from the municipal waste management - Supporting Circular Economy and Ecosystem Services

Magnus Kristian Skøt & Andreas Dyreborg Martin

Student thesis: Master thesis


This thesis examines the effect of biodegradation on organic fraction of municipal solid waste (OFMSW) in the waste management in Lejre municipality and for the economy of a biogas plant and how the handling of the OFMSW can support circular use of resources and Ecosystem Services.
To measure the biodegradation of the OFMSW a standardized OFMSW-sample was designed and stored for 0, 4, 7, 11 and 14 days. The difference in biomethanepotential between the 0-day stored OFMSW-sample (reference) and other storage times was compared. The difference was an expression for the loss of carbon due to biodegradation. The loss from the biodegradation was used in a developed model for biodegradation of the OFMSW for Lejre Municipality. The calculated biomethanepotential from the OFMSW-samples is used in relation to a biogas plants contribution margin to investigate the consequences of biodegradation of the OFMSW for the economy of a biogas plant. This is seen in relation to future subsidies and prices of the Danish energy market.
The thesis concludes that Lejre Municipality has a total greenhouse gas emission in relation to biodegradation of the OFMSW of 91 tons CO2-e during the summer. This is based on a total amount of OFMSW (789 tonnes), which corresponds to 10563 DKK calculated from the socioeconomic price of CO2-e. Most of the OFMSW in Lejre Municipality comes from single-family households (97.1%) where it is measured to 88 tonnes CO2e of the total greenhouse gas emissions in the municipality. Waste containers from storey apartments are generally better to empty more frequently as the waste containers only contain OFMSW and therefore not shared with other fraction (residual waste). This means that more OFMSW is removed each time the container is emptied, and thus more greenhouse gas emissions is mitigated. A 180-liter one-room waste container can potentially discharge 2,4 kg of CO2-e and a two-part waste container can discharge 0,9 kg of CO2-e, at an average of 5 days of storage where the costs of emptying the container is 9,3 DKK for both types of waste containers.
In the reference sample (0 days of storage) the OFMSW has a contribution margin of 226.73 DKK/tonne in 2018 for a biogas plant. The contribution margin is lowered with 51,14 DKK/tons for each ten-percentage point loss due to biodegradation of OFMSW.
The use of the OFMSW as a biomass for biogas plants supports several Ecosystem Services since OFMSW is used for biogas production and recycling of nutrients.
The focus of Lejre Municipality in relation to OFMSW is generally on mis-sorted materials and percentage of recycled material, which are based on political objectives and the EU Waste Frame Directive.
There is a gap in the production chain between the municipal waste management system and the biogas plants use of biomass from the waste management system. This is especially seen in the cost for disposal (495 DKK/tonne) for the OFMSW in comparison to the actual value of the OFMSW (176 DKK/tonne OFMSW 10 % biodegradated).
Therefore, there must be created regulations or other measures that connects the biogas plants and the municipal waste management of the OFMSW.

EducationsTekSam - Technological and Socio-Economic Planning, (Bachelor/Graduate Programme) Graduate
Publication dateJun 2019
Number of pages76
SupervisorsTyge Kjær