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Sustainable development and reducing natural and energy resource consumption are the focus of the policies of many institutions. In this context, livestock farming is one of the major anthropogenic sources of GHG and acidifying gas emissions and requires comprehensive analysis to minimise its ecological footprint. For this reason, it is beneficial to analyse the various processes within this production sector to reduce the consumption of resources, particularly water and soil consumption; reduce energy consumption; and try to valorise the biowaste produced, especially manure, byproducts and wastewater. Reusing residual bioresource and organic waste offers the possibility of valorising a discarded product and, at the same time, reducing the consumption of natural resources. For this purpose, biorefinery processes allow bioresources to be transformed into bioproducts or bioenergy. Therefore, this study investigates the application of biorefinery processes to animal-derived waste, aiming to extract valuable resources while curbing resource consumption. This review analysed 293 scientific papers on biorefinery processes published in the last 11 years applied to livestock biomass to extract relevant information to understand the evolution of this topic and formulate hypotheses regarding future research directions. The analysis strongly emphasizes energy production and a growing interest in insect cultivation. In the coming years, one of the most significant challenges will be the successful transfer of technologies and processes from experimental research to the applied industry. To do this, it will be necessary to reduce costs, exploit economies of scale, improve process management, and develop synergies between different industrial sectors to implement smart circular economy systems. Overall, this review aims to clarify the hypothesis driving research in this area and emphasizes the tangible applications of findings within the broader context of sustainable resource management. [Display omitted] [ABSTRACT FROM AUTHOR]

The transformation of the energy systems encompasses technological, societal, cultural, economic, and environmental aspects and calls for a more important role for citizens and communities. Bioenergy systems are subjects to legal, technical, environmental, economic, and social settings. At the regional level, bioenergy can incorporate agricultural traditions and offer waste-management solutions. Many are the stakeholders, with different perceptions and sometimes, conflictual interests. This study is a multidisciplinary, comprehensive review of recently published papers, on legal, technical, economic, and environmental layers of the bioenergy. It highlights the role of bioenergy in the transition to a Circular waste-based Bioeconomy. Three dimensions of sustainability (environmental, economic, and social) were discussed and some thermodynamic (energy, exergy, emergy) and environmental indicators applied to bioenergy systems, were cited. Findings conclude that in the context of Circular Bioeconomy, global bioenergy sector may face challenges, due to the new demand for biomaterials from the same sources. Bioenergy sustainable pathways should be selected at the base of high efficiency, towards closing loops and in the concept of cascade and integrated biorefineries. At the regional level, bioenergy systems may be integrated with the cascade biorefinery models or can offer waste management solutions by stand-alone, tailor-made decentralized systems. In redesigning the bioenergy sector, local knowledge, public health, and community's resilience should not be neglected, while social-environmental benefits should be considered in addressing the viability of bioenergy plants. Social acceptance can be improved by a better understanding of the scientific and technical issues and by developing a broader consciousness of the planet and life. [ABSTRACT FROM AUTHOR]

Circular economy principles can lead to a series of opportunities to tackle climate change, particularly in cities of developing countries where the generation of waste, consumption and demand for energy is growing rapidly. This paper aims to advance the understanding of the expansion of circularity for tackling climate change using biomass for energy at the urban scale. In addition, little is known about how Circular Economy (CE) flows can be quantitatively integrated, what potential trade-offs exist in promoting Circular Economy using biomass, and how governance models can integrate these flows and contribute to a Circular Economy transition in cities. Based on an empirical study of a city in India, where the private sector participation through an innovative Public-Private Partnership (PPP) model enabled the use of urban wastewater in thermal power plants, the study presents the viability of Circular Economy models at the city scale. The feasibility of a further expansion of this circularity by co-firing biomass in local thermal power plants was analyzed, as a potential solution for reducing pollution and carbon emissions in a hard-to-abate sector. The result indicated an average 20.5 MJ kg−1 calorific value for torrefied mixed biomass pellets from crop residues, which, if applied to about 447 kt y−1 surplus biomass available in Nagpur would amount to 9.18 PJ of energy (per year). Overall, local power plants demanded about 19.85 Mt of coal in 2017–18, equivalent to 297.8 PJ in that fiscal year. Thus, the supply of torrefied pellets from peri-urban crop residues can meet between 2 and 3% of the demand from coal-fired power plants, resulting in a 0.3% decrease in the emissions from the power sector in India in 2017–18 (i.e., 922 MtCO 2), benefiting different sectors and levels of government. The analysis provides a framework for understanding the technical and institutional possibilities for strengthening the relationship between circular economy and climate change in the cities of developing countries by connecting flows and systems within and beyond urban centers. Therefore, the expansion of Circular Economy in cities can occur by integrating urban sectors and policy coordination at different levels of governance. Partnerships between local governments, utilities, and civil society for co-managing energy, water, and waste in cities can reduce the financial burden on national governments, including meeting national emission targets. [Display omitted] • Urban circular economy can be advanced using biomass in thermal power plants. • Our model estimates biomass contribution to national decarbonization targets. • Biomass pellets can meet between 2 and 3% of the demand from local coal-fired power plants. • Such replacement accounts for a 0.3% decrease (or 922 MtCO 2) in the emissions from India's power sector. • Results contribute to the design of CE models for cities and regions by including different levels of government and sectors. [ABSTRACT FROM AUTHOR]

The role of education and communication is crucial to achieving the transition toward a circular economy (CE). Achieving cognitive, attitude and behavioural changes in the consumer and general population is a very complex process which requires mature scientific knowledge created by specialists. The current study aims to evaluate the degree of maturity of research on CE and bioenergy carried out from the areas of education and communication which are published in scientific literature between 2009 and 2019. The object of study have been scarcely approached from epistemological and methodological point of view, which is the novelty value of this study. To achieve the goal a systematic literature review (SLR) has been carried out on 74 peer reviewed scientific articles and conference papers. The records have been subjected to a clustering process (qualitative analysis) and a subsequent univariable (frequencies and vertical percentages) and multivariable quantitative analysis (comparison of column proportions). The studies' theoretical approaches were identified and the levels of formalisation, the predominant objectives and the hypothesis were analysed. In addition, the analysis of the research areas of studies reveals the epistemological process and outcomes of the literature. Several conclusions are drawn such as the scientific literature in this field is limited in scope. Moreover, from an epistemological perspective, descriptive studies are predominant, mainly addressed from the field of engineering, as well as analytical studies, which are mainly undertaken from Social and Legal Sciences. There are two main groups of articles based on their purpose: those which seek to describe, detail or define; and those which are more innovative, which analyse, establish or deconstruct the phenomenon. The results also show that the level of methodological and theoretical formalisation is limited, which indicates that research is in an initial stage. The foregoing results lead authors to conclude that the object of study has a low level of maturity. • Circular Economy and bioenergy literature on Education or Communication is limited. • The level of maturity of the scientific literature in this field is low. • Descriptive studies are predominant in research whose field is engineering. • The degree of theoretical formalisation of analysed studies is low. • Circular Economy and bioenergy research on Education or Communication is needed. [ABSTRACT FROM AUTHOR]

The aim of this paper is twofold: (i) to build a model by combining an agglomerative hierarchical algorithm with multicriteria analysis and geographic information systems (GIS) in order to identify whether there are opportunities to create strategic partnerships based on geographic coordinates of raw material suppliers and the volume of raw material supply; and (ii) to apply the model in a case study in order to identify suitable locations for building a biodigester, thus establishing strategic partnerships and circular economy-based practices. The model involves four stages: (1) defining the study site, (2) building the set of cluster solutions, (3) defining the suitable locations for building a biodigester, and (4) conducting analyses of feasibility of strategic partnership and sensitivity. The model was applied in a small region and it was analyzed the possibility of creating two or three clusters. The use of the model allowed, from both quantitative and qualitative perspectives, to preliminarily identify the possibility of creating a strategic partnership, and also determine the location of a biodigester. The case study applied in southern Brazil took place in a region with high potential for generating biogas from agro-waste. A geographic map with roads, rivers, and constraints was built. Strategic partnerships, sensitivity analysis, and circular economy-based practices were discussed. The results of this work could provide useful information when using the model for other regions, and the model could easily incorporate further criteria and conditions, making it flexible and tailored to users' needs. • An important source of clean energy that has been gaining interest worldwide is biogas. • The study build a model by combining an agglomerative hierarchical algorithm with multicriteria GIS. • The work identify whether there are opportunities to create strategic partnerships based on geographical coordinates. • The model was applied in a case study in order to identify suitable locations for the installation of a biodigester. [ABSTRACT FROM AUTHOR]

This paper assesses the potential energy and environmental impacts of an anaerobic digester coupled with a combined heat and power plant powered with bio-wastes from the agri-food sector. The analysis is carried out through the Life Cycle Assessment methodology following a "cradle-to-grave" approach and is based mostly on primary data. The anaerobic digester - combined heat and power plant is analysed considering a twofold perspective: one more energy – oriented where the main function of the system is to generate renewable electricity and a waste – oriented one in which the main function is treating bio-wastes. In addition, the environmental indirect effects related to potential competitive uses of bio-wastes are evaluated. Biomass transport and the electricity consumed during the operation phase make the largest contribution (higher than 60%) to almost all the impact categories examined. The comparison with the electricity eco-profile from the national grid and with a composting facility highlights that the anaerobic digester - combined heat and power system may reach better energy and environmental performances for both the electricity generation and bio-waste management. Image 1 • A life cycle assessment of an anaerobic digester coupled with a combined heat and power plant is performed. • The plant is analysed through the perspectives of energy production and waste treatment. • Biomass transport and electricity consumed during the operation phase make the largest impact contribution. • The examined system can be a sustainable solution for both electricity generation and bio-waste management. • Indirect effects in competitive economic sectors can offset the environmental benefits of the examined system. [ABSTRACT FROM AUTHOR]