Suchergebnisse

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.

In an endeavor to make Europe carbon-neutral, and to foster a circular economy, improving food waste management has been identified by the European Union (EU) as a key factor. In this study, we consider 21 pathways, covering: (i) prevention; (ii) reuse for both human consumption and animal feed; (iii) material recycling as an input into the food and chemical industries; (iv) nutrient recycling; and (v) energy/fuel recovery. To include all types of impact, a sustainability assessment, encompassing environmental, economic, and social pillars, is performed and complemented with societal life cycle costing. The results indicate that after prevention, reuse for human consumption and animal feed is the most preferred option, and, in most cases, nutrient recycling and energy recovery are favored over material recycling for chemical production. While highlighting that the food waste management hierarchy should be supported with quantitative sustainability analyses, the findings also illustrate that biochemical pathways should be improved to be competitive despite the fact that food waste valorization has the potential to satisfy the EU demand for the chemicals investigated. Yet, the results clearly show that the potential benefits of improving emerging technologies would still not eclipse the benefits related to food waste prevention and its redistribution.

Recycling of plastic waste is promoted by the European Union as an important step toward a circular economy. Recovered plastic waste is a complex and heterogeneous material, and the impurities and/or untargeted polymers associated to plastic waste may affect the recycling process and potentially decrease the intended benefits. An environmental and financial assessment was conducted on one tonne of hard plastic waste collected at Danish recycling centres. Three management scenarios were considered: two mechanical recycling (a simpler and a more advanced configuration, namely sMR and aMR) and a feedstock recycling (FR) scenario based on conversion through pyrolysis. Scenario aMR provided the largest savings in the highest number of impact categories (including global warming potential) and total costs; scenarios sMR and FR provided smaller savings (or even burdens), depending on the environmental impact category considered. A scenario analysis evaluating the type of energy provision, location of recycling facilities and the application of the recycled material confirmed the ranking of results with respect to global warming potential and total costs. A global sensitivity assessment of model data inputs demonstrated that three to nine parameters were typically sufficient to achieve more than 90% of total variance of the results; critical parameters were mainly related to sorting efficiencies, technical yields and market substitution factors. The study demonstrates that if high quality of the recycled plastic is achieved, both environmental savings and financial revenues are possible.

The Bioeconomy Strategy was launched by the European Union (EU) in 2012 to promote the transition from a fossil- to a bio-based economy. To meet ambitious energy and climate mitigation targets, extensive use of first generation biomass has occurred in the last years incurring environmental, economic, and social concerns in relation to the actual sustainability of the supply and transformation processes. To circumvent these issues, second generation biomass has been often proposed as an alternative and, among the others, biowaste (e.g. from household or industry). According to the biomass pyramid, biomass should first be used to produce high-value products (e.g. pharmaceuticals), and only when the biomass is no longer suitable for the mentioned applications it should be used for fuel and energy purposes. Following policy reccomendations, life cycle thinking should be applied to document the sustainability of bioeconomy pathways. In this study, we focus on biowaste and evaluate sustainability of a variety of utilisation pathways by applying life cycle assessment and life cycle costing. Scenarios are assessed investigating both high- (e.g. animal feed production) and low-value products (e.g. energy recovery from incineration). The results obtained are expected to fill the research gap with respect to economic and social assessment of second generation biomass usage, and to assist decision makers in deciding the best application of the mentioned biomass.

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.

Energy, materials, and resource recovery from mixed household waste may contribute to reductions in fossil fuel and resource consumption. For this purpose, legislation has been enforced to promote energy recovery and recycling. Potential solutions for separating biogenic and recyclable materials are offered by waste refineries where a bioliquid is produced from enzymatic treatment of mixed waste. In this study, potential flows of materials, energy, and substances within a waste refinery were investigated by combining sampling, analyses, and modeling. Existing material, substance, and energy flow analysis was further advanced by development of a mathematical optimization model for determination of the theoretical recovery potential. The results highlighted that the waste refinery may recover ca. 56% of the dry matter input as bioliquid, yielding 6.2GJ biogas-energy. The potential for nitrogen, phosphorous, potassium, and biogenic carbon recovery was estimated to be between 81% and 89% of the input. Biogenic and fossil carbon in the mixed household waste input was determined to 63% and 37% of total carbon based on 14C analyses. Additional recovery of metals and plastic was possible based on further process optimization. A challenge for the process may be digestate quality, as digestate may represent an emission pathway when applied on land. Considering the potential variability of local revenues for energy outputs, the costs for the waste refinery solution appeared comparable with alternatives such as direct incineration. © 2014 Elsevier Ltd.

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.