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A considerable amount of wet biogenic residues and waste has no resource-efficient use in several European countries yet. Hydrothermal processes (HTP) seem to be promising for treating such biomass as they best work with substrates with 70% to 90% water content. However, thus far the suitability of HTP for this purpose has not been sufficiently evaluated, for which this work aims to identify suitable multi-criteria analysis (MCA) methods that can be used to identify promising ways for the hydrothermal treatment of wet bio-waste. A review on 31 recent MCA studies in bio-waste management was conducted with the aim of comparing them to methodological requirements for evaluating HTP. Furthermore, an MCA approach for HTP based on the review findings is proposed. Results show that no observed MCA method is directly transferable for assessing HTP, for which a customized approach combining the analytical hierarchy process and the technique for order preference by similarity to ideal solutions is proposed and preliminarily validated with literature data. These preliminary calculations indicate that hydrothermal gasification seems most promising under consideration of multiple criteria using the available average and exemplary data. However, needless to say there is still a long way to go to obtain the sufficient adequate data to validate and use the model appropriately, for which further studies are necessary to acquire more reliable data and to assess also future technology developments of HTP.

The energy system in the Region of Aysén, Chile, is characterized by a strong dependence on fossil fuels, which account for up to 51% of the installed capacity. Although the implementation of waste-to-energy concepts in municipal waste management systems could support the establishment of a more fossil-independent energy system for the region, previous studies have concluded that energy recovery systems are not suitable from an economic perspective in Chile. Therefore, this work intends to evaluate these technical options from an environmental perspective, using life cycle assessment as a tool for a comparative analysis, considering Coyhaique city as a case study. Three technical alternatives were evaluated: (i) landfill gas recovery and flaring without energy recovery; (ii) landfill gas recovery and energy use; and (iii) the implementation of an anaerobic digestion system for the organic waste fraction coupled with energy recovery from the biogas produced. Mass and energy balances of the three analyzed alternatives have been modeled. The comparative LCA considered global warming potential, abiotic depletion and ozone layer depletion as impact categories, as well as required raw energy and produced energy as comparative regional-specific indicators. According to the results, the use of the recovered landfill gas as an energy source can be identified as the most environmentally appropriate solution for Coyhaique, especially when taking into consideration the global impact categories.

The new "Hazardous Waste Management Regulation" was published in the Official Newspaper of the Chilean Republic on 12 June 2003, being in force 365 days after its publication (i.e., 12 June 2004). During the next 180 days after its publication (i.e., until 12 December 2004), each industrial facility was obligated to present a "Hazardous Waste Management Plan" if the facility generates more than 12 ton/year hazardous wastes or more than 12 kg/year acute toxic wastes. Based on the Chilean industrial figures and this new regulation, hazardous waste management plans were carried out in three facilities of the most important sectors of Chilean industrial activity: a paper production plant, a Zn and Pb mine and a sawmill and wood remanufacturing facility. Hazardous wastes were identified, classified and quantified in all facilities. Used oil and oil-contaminated materials were determined to be the most important hazardous wastes generated. Minimization measures were implemented and re-use and recycling options were analyzed. The use of used oil as alternative fuel in high energy demanding facilities (i.e., cement facilities) and the re-refining of the used oil were found to be the most suitable options. In the Zn and Pb mine facility, the most important measure was the beginning of the study for using spent oils as raw material for the production of the explosives used for metals recovery from the rock. In Chile, there are three facilities producing alternative fuels from used oil, while two plants are nowadays re-refining oil to recycle it as hydraulic fluid in industry. In this sense, a proper and sustainable management of the used oil appears to be promissory.

This work introduces the outcomes of the first process for the identification and evaluation of sites potentially contaminated in the Region of the Bio Bio, Chile. The methodology combined qualitative and quantitative elements from Austrian and German risk assessment procedures, calibrated and adapted to the Chilean reality. The developed process consists of collecting historical and current registers on soil use, effects of materials handling on the population's health, and the description of the site conditions. The first analytical step corresponds to an image algebra analysis, through which the most vulnerable areas of the region are established. The sites identified inside the most vulnerable areas are classified into five priority classes, giving an approximate degree of endangerment from these sites. Through the experience, from a total of 507 sites identified as suspicious of contamination, five sites were classified under the highest priority. The results of this analysis have allowed Chilean authorities to focus their resources on the detailed investigations to be carried out in the five priority locations, whilst planning the future strategy to follow for the practical management of all sites found as currently posing a risk to the environment and to the society.

The present paper describes the development, performance and conclusions derived from three know-how and technology transfer projects to South American countries. The first project comprised a collaborative study by European and South American universities to find sustainable solutions for Chilean and Ecuadorian leather tanneries which had underachieving process performances. The second project consisted of investigations carried out in a Brazilian municipality to enhance its municipal solid waste management system. The final collaborative programme dealt with the initial identification, evaluation and registration of suspected contaminated sites in an industrial region of Chile. The detailed objectives, methods and procedures applied as well as the results and conclusions obtained in each of the three mentioned projects are presented, giving special attention to the organizational aspects and to the practical approach of each programme, concluding with their main advantages and disadvantages for identifying a set of qualitative and quantitative suggestions, and to establish transferable methods for future applications.

When surveying the trends and criteria for the design for recycling (DfR) of bio-based polymers, priorities appear to lie in energy recovery at the end of the product life of durable products, such as bio-based thermosets. Non-durable products made of thermoplastic polymers exhibit good properties for material recycling. The latter commonly enjoy growing material recycling quotas in countries that enforce a landfill ban. Quantitative and qualitative indicators are needed for characterizing progress in the development towards more recycling friendly bio-based polymers. This would enable the deficits in recycling bio-based plastics to be tracked and improved. The aim of this paper is to analyse the trends in the DfR of bio-based polymers and the constraints posed by the recycling infrastructure on plastic polymers from a systems perspective. This analysis produces recommendations on how life cycle assessment indicators can be introduced into the dialogue between designers and recyclers in order to promote DfR principles to enhance the cascading use of bio-based polymers within the bioeconomy, and to meet circular economy goals. [ABSTRACT FROM AUTHOR]

Abstract: This work presents an analysis on the suitability of mechanical biological treatment of municipal solid waste in South America, based on two previous experimental investigations carried out in two different countries. The first experiment was performed for determining the mass and volume reduction of MSW in the province of Concepción (Chile). The implemented bench-scale process consisted of a manual classification and separation stage, followed by an in-vessel biological degradation process. The second experiment consisted of a full-scale experiment performed in the city of Estrela (Brazil), where the existing municipal waste management facility was adapted to enhance the materials sorting and separation. Expressed in wet weight composition, 85.5% of the material input in the first experiment was separated for biological degradation. After 27 days of processing, 60% of the initial mass was reduced through degradation and water evaporation. The final fraction destined for landfilling equals 59% of the total input mass, corresponding to about 50% of the initial volume. In the second experiment, the fraction destined to landfill reaches 46.6% of the total input waste mass, whilst also significantly reducing the total volume to be disposed. These results, and the possible recovery of material streams suitable for recycling or for preparing solid recovered fuels, are the main advantages of the studied process. [Copyright &y& Elsevier]

• Using the World Café with La Prospective enhances acknowledgement of complexity. • Future studies fit as relevant science for sustainability of complex systems. • Biogas systems from an holistic perspective can be understood with future studies. • Biogas is strategic for waste and residue management in the circular bioeconomy. Biogas currently plays an important role in the German energy mix - mainly as a way to produce electricity; but will this still be the case in 2050? This paper addresses this question by studying the system's future to better understand the next actions it should take in the present. It aims to determine the key influential factors in the evolution of the biogas system with the goal of understanding its integration in the wider energy systems of 2050. A sequential, mixed and multidisciplinary system method was used based on the methodology of la prospective : a common methodology for future research and scenario planning. These key influential factors have the most links within the biogas system and are both highly dependent and highly influential. Thus they can be strategically managed to influence the system as a whole. The primary finding of the study is that biogas should be more strategically employed in waste and residue management, playing a stronger role in the circular bioeconomy, as opposed to its current role as an electricity generator. Furthermore, the paper identified the factors green jobs creation , flexible small biogas technology innovations and carbon capture and utilization technologies as possible indicators of the evolution of the system. Finally, this study shows that the applied methodology is a sound way of determining how a complex system may be assessed and identifies the factors that can influence its development towards more complex solutions. [ABSTRACT FROM AUTHOR]