Towards a Sustainable Bioeconomy through Industrial Symbiosis: Current Situation and Perspectives

To burn or valorise bark from a pulp mill: Environmental sustainability analysis using prospective consequential life cycle assessment

Bark represents 10 % dry weight of spruce trees and is a major side stream from pulp production. Currently, pulp mills burn bark to produce energy with a low economic value, directly emitting biogenic carbon dioxide to the atmosphere. Biorefining bark using a continuous flow-through fractionation process generates high added-value compounds (tall oil, starch, phenol, and pulp) that allow for extended carbon storage durations. This study assesses the potential future environmental impacts of valorising bark instead of burning it. We conduct a LCA study combining a prospective consequential modelling perspective with an input-related functional unit and account for the effects of storing biogenic carbon in the bark-based products. Our findings show that biorefining bark maintains lower environmental impacts than combustion, reducing time-differentiated climate impacts by up to 30 %, but only when the carbon dioxide used for pulping is recirculated and the fractionation processes are integrated with a co-located pulp mill supplying surplus waste energy, considered to have no associated environmental impacts. Storing biogenic carbon for a longer period of time has a positive effect on mitigating short-term climate impacts. However, our analysis reveals that while time-dependent climate impacts decrease, there is an increase in human toxicity and ecotoxicity impacts, with combustion performing better in these categories. This highlights the importance of expanding the scope of LCA studies to include impacts beyond climate change. Overall, this work demonstrates that combining a prospective consequential modelling perspective with an input-related functional unit is a relevant approach to study potential future impacts of emerging biorefineries and thus supports the development of a sustainable circular bioeconomy.

Participatory modelling of scenarios to restore nitrogen cycles in a nutrient-saturated area

This paper aims to find socially acceptable solutions of circularity as measure to reduce nitrogen (N) losses and prevent environmental damage by combining participatory modelling and scenario Substance Flow Analyses (SFA). A local perspective was taken on the agro-food-waste system in the animal production-dominated German district Cleves. Three scenarios were programmed as Monte Carlo simulation of SFA with stakeholder input regarding crop allocation, livestock composition, livestock reduction, and manure allocation following the elimination of feed imports. The three scenarios either utilized the unaltered stakeholder input (PS), altered crop allocation to satisfy the demand for feed (CBS), or adjusted the livestock numbers to match the locally available feed (LBS). In the reference year (2020) agricultural losses amounted to 68 kg N year-1 ha-1 agricultural land and 116 kg N in feed was imported year-1 ha-1 agricultural land. In the PS feed import elimination led to deficits in feed availability. The LBS showed the biggest reduction of agricultural N losses and improved N use efficiency (+6 %), however agricultural losses were still high (50 kg N year-1 ha-1 agricultural land). The results show a limited effect of feed import elimination on N losses if no further measures are taken, such as reduced consumption of animal-based products. Further, the study shows that it is important to improve stakeholders' knowledge about approaches to circular agro-food-waste systems. The discrepancy between stakeholder visions and N circularity provide policy makers with the recommendation to improve stakeholders' visions of a circular agro-food-waste system.

Evaluating the Transition of the European Union Member States towards a Circular Economy

This paper presents the assessment of the European Union member states in terms of the circular economy (CE) targets, using a combination of the Data Envelopment Analysis (DEA) method and factor analysis. This approach fills in the existing knowledge gap by providing an innovative methodology of an objectivised comparative evaluation of the degree of implementation of the CE principles by the EU countries. Assessing countries’ performance in achieving the goals of the circular economy is a challenge due to the lack of a generally accepted methodology, the multitude of indicators, and the insufficient data. Countries may be compared in a narrow way, according to single indicators, but a more holistic synthetic assessment of countries is also needed to determine their position against each other. In such cases, DEA may be successfully used. The study resulted in the identification of two clusters of countries with similar profiles of relative efficiency in the CE goals’ implementation. It was concluded that the position of a particular country in achieving the CE aims was strongly correlated its GDP per capita. Moreover, factor analysis showed that many CE indicators are strongly correlated with each other and may be aggregated into five meta-indicators (factors): Recycling rate of general waste, Waste production, Jobs and investments, Recycling rate of special waste, and Circular material use rate. In addition to simple rankings and indication of benchmarks, the article offers a novel concept of technology competitors which was used to group units competing for positions in the ranking.