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Bioplastics are alternatives of conventional petroleum-based plastics. Bioplastics are polymers processed from renewable sources and are biodegradable. This study aims at conducting an environmental impact assessment of the bioprocessing of agricultural wastes into bioplastics compared to petro-plastics using an LCA approach. Bioplastics were produced from potato peels in laboratory. In a biochemical reaction under heating, starch was extracted from peels and glycerin, vinegar and water were added with a range of different ratios, which resulted in producing different samples of bio-based plastics. Nevertheless, the environmental impact of the bioplastics production process was evaluated and compared to petro-plastics. A life cycle analysis of bioplastics produced in laboratory and petro-plastics was conducted. The results are presented in the form of global warming potential, and other environmental impacts including acidification potential, eutrophication potential, freshwater ecotoxicity potential, human toxicity potential, and ozone layer depletion of producing bioplastics are compared to petro-plastics. The results show that the greenhouse gases (GHG) emissions, through the different experiments to produce bioplastics, range between 0.354 and 0.623 kg CO2 eq. per kg bioplastic compared to 2.37 kg CO2 eq. per kg polypropylene as a petro-plastic. The results also showed that there are no significant potential effects for the bioplastics produced from potato peels on different environmental impacts in comparison with poly-β-hydroxybutyric acid and polypropylene. Thus, the bioplastics produced from agricultural wastes can be manufactured in industrial scale to reduce the dependence on petroleum-based plastics. This in turn will mitigate GHG emissions and reduce the negative environmental impacts on climate change.

SummaryThe German government has adopted a law that requires sewage plants to go beyond the recovery of phosphorus from wastewater and to promote recycling. We argue that there is no physical global short‐ or mid‐term phosphorus scarcity. However, we also argue that there are legitimate reasons for policies such as those of Germany, including: precaution as a way to ensure future generations’ long‐term supply security, promotion of technologies for closed‐loop economics in a promising stage of technology development, and decrease in the current supply risk with a new resource pool.

Abstract Rare earth permanent magnets are important components for modern (energy) technologies and are employed to reduce GHG emissions and combat climate change. The process of extracting these minerals from the ore has contentious economic, environmental and social implications. While the environmental impacts of their production have already been analyzed in several studies, the economic and the social perspective is still under-researched. The Social Life Cycle Assessment (S-LCA) approach employed in the present research explores whether there is a difference in social risks for rare earth permanent magnet production from three different rare earth ore production locations and the associated value chains. While one is located completely in China, another is composed of processes in Australia and Malaysia. The third process chain combines processes in the United States and Japan. The Product Social Impact Life Cycle Assessment (PSILCA) 2.0 database is used to assess the social implications. The analysis focuses on value chain actors, a stakeholder group of great interest to businesses but often underrepresented in S-LCA research. The impact categories describing this stakeholder group pertain to issues of social responsibility along the value chain, fair competition and corruption. Overall, the US value chain indicates the lowest level of social risk along the supply chain. However, in order to gain a deeper understanding of the social risks a sectoral and geographical analysis is conducted. Across all three cases, the mineral, fossil fuel and chemical sectors are shown to be problematic.

Abstract Waste disposal is a core issue worldwide. Different researches are being carried out in order to handle waste materials, generated in industrial production and application processes, e.g. paint residue from metal coating in the automobile industry. Often waste is disposed in landfills at substantial economic and environmental cost. Combustion is another way to get rid of possibly hazardous waste. Pulverized fuel combustion is one of the latest combustion technologies. However, pulverized fuel combustion faces severe problems if the waste (fuel) contains components with low melting point. Having a low melting point, it gets difficult to manage and convey the pulverized material to the hot combustion chamber. The melting of fuel causes clogging in the fuel transport nozzle used to convey the material into the combustion chamber. In this work, a new technology for combustion of materials with low melting points is proposed, focusing on apparatus and nozzle design to prevent clogging. For this purpose, different nozzle designs were evaluated by multi-phase CFD simulations. Two sets of nozzle air flow rates were used in four nozzles. Effect of different flow rates and fuel particle size on combustion temperatures are also discussed. It was noted that nozzle air flow rate has a strong influence on the temperature distributions. Small fuel particle sizes result in wider combustion zones while larger particles give longer combustion zones. The results come up with optimized nozzle design and nozzle air flow for transportation of pulverized material with low melting point.

Abstract The most pressing global challenges have been summarized in the UN Sustainable Development Goals. Given the complex feedbacks and interdependencies among them, fulfilling these goals requires a holistic approach leading to profound transitions. The food-energy-water nexus is often proposed to be one such holistic approach. However, to date no consistent definition of the nexus concept exists, while research interest in the nexus rapidly grows. Therefore, in this paper, the nexus is defined as a concept of systems thinking. A nexus systems thinking test is developed that can be used as a new way of categorizing nexus research. To examine the test's viability and suitability, it is applied to a sample data set of nexus-related research papers. By means of a multi- and mixed methods document analysis it is analyzed if the papers conceptualize the nexus approach as a systems thinking concept. The results show that all papers meet the four system criteria. Different emphasis, however, is put on certain aspects. The nexus systems thinking test proved to be a viable systematic method to investigate if and in which way nexus research incorporates a systems thinking perspective. It does not only offer a new way of categorizing nexus related research, but also allows assessing its quality from a comprehensive nexus perspective. The test thus provides valuable and systematic understanding of a rapidly developing, central research field within sustainability science.

Abstract This paper examines the impact of climate targets which have been adapted to individuals’ behavior based on global political events. As the global climate targets of the Paris Agreement are largely supported by society, we investigate the potential of these targets to lead to personal and social norms concerning individual contributions to the Paris Agreement´s climate goals. We assume that these norms mediate the influence of personal involvement in the Paris agreement and of environmental values on greenhouse gas avoiding decisions. Also, we expect that these norms predict greenhouse gas avoiding behavior, rather than norms related to climate change. The research is based on a laboratory study with students conducted in December 2017 in Germany (n = 226). The main results show for the students surveyed in the research that norms in favor of contribution to the Paris Agreement substantially influence objective carbon offsetting, as well as consumption of local food and green electricity; and these norms partially mediate the influence of personal involvement in the Paris Agreement and of environmental values on decision-making.

Abstract Despite the comparatively limited stock of vehicles, heavy-duty road transport is responsible for a major share of CO2 emissions from the European transport sector. Electric trucks powered by overhead lines, so-called trolley trucks or catenary hybrid trucks, have been proposed as a potential GHG mitigation option. However, from the perspective of the energy system, trolley trucks constitute an additional and inflexible electricity demand. Here, we analyse scenarios with an ambitious European market diffusion of trolley trucks and their impact on the electricity system and CO2 emissions. Our results show that trolley trucks can noteworthily reduce the CO2 emissions from heavy road transport even when the additional CO2 emissions from electricity generation are taken into account. Furthermore, the actual impact of the additional load from trolley trucks on the total energy system is limited. Compared to the anticipated electricity demand from passenger cars in 2030, trolley trucks require less energy and the load is more equally distributed over daytime. Our findings thus show that electric trucks are an interesting option for CO2 mitigation in heavy road transport.

The average antimony concentration in municipal solid waste is estimated to be about 10-60 ppm. Thermodynamical models predict a volatile behavior for antimony compounds, yet literature mass balances show that about 50% of the antimony input remains in the grate ashes. This fact can be explained by the formation of thermally stable antimonates in the fuel bed due to interactions with alkali or earth-alkali metals. Thermogravimetric experiments revealed an increased thermal stability for antimony oxide in presence of oxygen and calcium oxide. Spiking experiments on the test incinerator TAMARA showed that chlorination processes have a strong effect on antimony volatilization whereas high fuel-bed temperatures and addition of antimony oxide only have a moderate effect. In the grate ashes, antimony shows a pH-depending leaching property, which is typical for anionic species. This fact supports the thesis that antimony is present in the grate ashes in an anionic speciation.

Rapid population growth invokes the need for a vast amount of water conservation. Many centralized water treatment systems will reach their limits and face difficulties to provide clean industrial water to rural areas. The infrastructure for water distribution is dilapidated in many regions and only little of the wastewater is currently being recycled. One solution could be the expansion of decentralized membrane bioreactor (MBR) systems in peri-urban areas. MBR achieves excellent water qualities, whereas the comparatively high energy consumption is the main drawback. Therefore, MBR plants need to be optimized in their specific energy consumption to obtain a high degree of self-sufficiency for decentralized locations. There is a dire need for innovative controlling strategies and efficient coupling with energy supply systems through novel applications. This chapter will highlight the basic approaches to reduce the MBR's overall energy consumption and ways to establish sustainable, autonomous operations without sacrificing the process quality.