Suchergebnisse

Biofuels are likely to play an increasingly important role in the transportation sector in the coming decades. To ensure the sustainability of the biofuel chain, regulatory criteria and reduction targets for greenhouse gases (GHG) emissions have been defined in different legislative frameworks (e.g. the European Renewable Energy Directive, RED). The provided calculation methods, however, leave room for interpretation regarding methodological choices, which could significantly affect the resulting emission factors. In this study, GHG reduction factors for a range of biofuels produced in a Danish biorefinery system were determined using five different emission allocation principles. The results show that emission savings ranged from -34 % to 71 %, indicating the need for a better definition of regulatory calculation principles. The calculated emission factors differed significantly from default values provided in the literature, suggesting that case-specific local conditions should be taken into consideration. A more holistic LCA-based approach proved useful in overcoming some of the issues inherent in the regulatory allocation principles. On this basis, indirect land use change (ILUC) emissions were shown to have the same magnitude as the direct emissions, thus indicating that the overall system should be included when assessing biofuel sustainability criteria.

The need for biofuels is steadily increasing as a result of political strategies and the need for energy security. Biorefineries have the potential to improve the sustainability of biofuels through further recovery of valuable bioproducts and bioenergy. A life cycle assessment (LCA)-based environmental assessment of a Danish biorefinery system was carried out to thoroughly analyze and optimize the concept and address future research. The LCA study was based on case-specific mass and energy balances and inventory data, and was conducted using consequential LCA approach to take into account market mechanisms determining the fate of products, lost opportunities and marginal productions. The results show that introduction of enzymatic transesterification and improved oil extraction procedure result in environmental benefits compared to a traditional process. Utilization of rapeseed straw seems to have positive effects on the greenhouse gases (GHG) footprint of the biorefinery system, with improvements in the range of 9 % to 29 %, depending on the considered alternative. The mass and energy balances showed the potential for improvement of straw treatment processes (hydrothermal pre-treatment and dark fermentation) as well as minor issues related to enzymes utilization in different bio-processes.

Introduction The Extended Producer Responsibility (EPR) "is a policy approach under which producers are given a significant responsibility – financial and/or physical – for the treatment or disposal of post-consumer products" (OECD, 2018). For packaging, the importers/producers pay a certain environmental contribution in order to reach a certain recycling target independently from the market demand. Due to the importance of EPR, the European Commission is working on harmonising its application and the way the contributions are calculated (European Commission, 2018). This work focuses on plastic packaging due to the recent importance of this waste fraction. The specific objectives of this work are: to demonstrate that the reported quantity of recycled plastic are not actually recycled; to quantify which costs are covered by the environmental contribution and to propose an "extension" of the EPR for plastic packaging. This work will contribute to the discussion on how to implement effectively EPR in Europe. Material and Methods The EPR strategies for plastic packaging waste in Europe are analysed with the use of the Material Flow Analysis (MFA), system and market analyses with a special focus on export of waste. Lastly, we worked on modelling how the environmental contribution could be quantified in order to reach the recycling targets. Results and Conclusions The data on material officially recycled in European countries usually report only the quantity of material that is sold in the market as waste bales after sorting and not the material that will actually become a new product that is not tracked. Furthermore, the environmental contributions generally do not account for the design of the products a part for rare shy attempts to do so (e.g. France and Italy) even if the design can highly impact the market price of the waste bales (e.g. PET clear versus PET mixed) and of the applications of the secondary polymers. The conclusion of this study is that the current EPR is not leading to the wanted recycling targets. The environmental contributions paid by companies should be modelled based on the real recycling path and on the design of the packaging. Finally, EU should work on a better understanding of the fate of the plastic collected.

In recent years, the concept of circular economy has gained attention as a strategy to counter-act resource depletion and ensure sustainable development. A primary focus of the circular economy is to recirculate materials, thereby closing material loops, as opposed to losing them through incineration or landfilling. Consequently, recycling has been highlighted as a crucial measure in the transition towards circular economy, which has led to recycling targets for sev-eral waste material fractions in the EU. One of these materials is plastic for which specific strategies has been completed, emphasising the importance of quality of recycled plastic. The quality aspect is especially important regarding plastic from household waste (HHW), as this is a highly contaminated and heterogeneous waste stream. As a large share of the plastic products in the HHW is high-quality food packaging, recycling of plastic HHW to lower quality does therefore only contribute to partial closing of the plastic loop, because virgin plastic is still needed for the production of high quality plastic. This aspect needs to be taken into consideration, so the most circular waste management options can be identified. The aim of this presentation is to present a method for substitutability estimation that takes the aspect of quality and circularity of recycled plastic from HHW into account. The method focuses on waste plastic streams from HHW prepared for recycling and includes two steps: 1) quality assessment and 2) substitutability estimation. In step 1, the waste plastic stream in question is assigned either high, medium or low-quality, based on knowledge related to the degree of contamination. The quality levels are linked to the poten-tial applicability, in the sense that a waste plastic stream assigned high-quality has the poten-tial to be used in food packaging (complying with comprehensive legislation), whereas medi-um-quality at best can be used in toys, pharmaceuticals and electrical and electronics (applica-tions regulated to varying degrees), and low-quality streams can at best be used in building and construction, non-food packaging, automotive and others (applications not regulated). In step 2, the substitutability (also called substitution ratio or B-factor) is estimated based on the assigned quality and the European market share related to the applications in which the plastic has a potential to substitute virgin plastic. As an example, 57% of the Euro-pean PET is used to produce food packaging. If a PET stream from HHW is found to be me-dium-quality, meaning that it cannot be used for food-packaging (which requires high-quality), it does not have the potential to substitute virgin plastic in these 57% of the PET market and can therefore not close this part of the PET loop. Thus, such PET HHW streams are assigned a substitutability of 0.43 (=1-0.57). Consequently, due to the high level of food packaging in plastic HHW, only recycling where the plastic waste have the potential to be recycled into high-quality plastic contribute to the full circularity of plastic from HHW. This is especially important for PET and LDPE HHW streams, as more than 50 % of the European PET and LDPE markets are used for food packaging.

As a response to the growing pressure on the supply chains, developing a resource-efficient circular economy will be fundamental to satisfy the future demands for material resources. In this context, the Danish Government, in 2013, launched its Resource Strategy Plan, mandating that, by 2018 at least 60% of organic waste – that cannot be prevented or reduced –generated by service sector, should be source-segregated and collected separately. In order to establish the baseline of the current situation, and to allow for any evaluation of performance against target indicators, data on solid waste generation and composition are required. The overall aim of this study was to quantify the potential for source-segregated organic waste as well as mixed waste from institution. This study was carried at the Department of Environmental Engineering at Technical University of Denmark. In the course of this study, two plastic waste bins of 60 L each were placed in the kitchens: organic waste bins and mixed waste bins. Organic waste and mixed waste from these kitchens were collected and weighed separately, on a daily basis, during 133 working days (29 weeks). However, waste was not sampled during weekends and public holidays, when the offices were officially closed. Furthermore, the composition of source-segregated organic waste was analysed to investigate its purity. During the sampling period, the number of employees coming to work at the department was recorded. These data were used to investigate any relationship between mass of discarded waste (source-segregated organic and mixed waste) and the number of employee coming to work at the department. The result showed that 20 to 60 days (e.g. working days) should be considered to obtain reliable data when sampling waste from an institution. We found a significant correlation between mass of source-segregated organic waste and the number of employees coming to work at the department (0.70 with 95% HDI 0.6 and 0.78). Similarly, there was a significant correlation between mixed waste and number of employees (0.49 with 95% HDI 0.3 and 0.62). The generate rates of source-segregated organic waste amounted to 23 ± 5 kg/employee/year, of which 20 ± 5 kg/employee/year was source-segregated, with a considerably high purity of 99%. Mixed waste amounted to 10 ± 5 kg/employee/year. These results show that source-segregated organic waste from institutions offers promising potential. They also suggest that recycling target for source-segregated organic waste might be achievable with reasonable logistical ease in institution areas.