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The comparison of the Ecological Footprint and its counterpart (i.e. biocapacity) allow for a classification of the world's countries as ecological creditors (Ecological Footprint lower than biocapacity) or debtors (Ecological Footprint higher than biocapacity). This classification is a national scale assessment on an annual time scale that provides a view of the ecological assets appropriated by the local population versus the natural ecological endowment of a country. We show that GDP per capita over a certain threshold is related with the worsening of the footprint balance in countries classified as ecological debtors. On the other hand, this correlation is lost when ecological creditor nations are considered. There is evidence that governments and investors from high GDP countries are playing a crucial role in impacting the environment at the global scale which is significantly affecting the geography of sustainability and preventing equal opportunities for development. In particular, international market dynamics and the concentration of economic power facilitate the transfer of biocapacity related to “land grabbing”, i.e. large scale acquisition of agricultural land. This transfer mainly occurs from low to high GDP countries, regardless of the actual need of foreign biocapacity, as expressed by the national footprint balance. A first estimation of the amount of biocapacity involved in this phenomenon is provided in this paper in order to better understand its implications on global sustainability and national and international land use policy.

The paper deals with effects of two different widespread extraction methods (conventional extraction and Soxhlet extraction) and four different pre-treatments (homogenization with pressure and with blades, sonication, and impact with glass spheres) on the extraction yields and properties of polyhydroxyalkanoate (PHA) extracted from biomass coming from an innovative process (short-cut enhanced phosphorus and PHA recovery) applied in a real wastewater treatment plant. The results show that the two different extraction processes affected the crystallization degree and the chemical composition of the polymer. On the other hand, the extractive yield was highly influenced by pre-treatments: homogenization provided a 15% more extractive yield than the others. Homogenization, especially at high pressure, proved to be the best pre-treatment also in terms of the purity, visual appearance (transparency and clearness), thermal stability, and mechanical performances of the obtained PHA films. All the PHA films begin to melt long before their degradation temperature (Td > 200 °C): this allows their use in the fields of extrusion or compression moulding. SYNOPSIS: Optimizing the extraction of PHAs from municipal wastewater gives a double beneficial environmental impact: wastewater treatment and circular bio-based carbon upgrade to biopolymers for the production of bioplastics and other intersectoral applications.

Abstract: In this study the Impact-Pathway Approach methodology was applied for monetary valuation of health impacts due to cadmium emitted to soil as a micro-pollutant present in phosphorus fertilizers. Due to the high persistency of cadmium in soil, and high soil-to-plant transfer rates, humans are exposed to cadmium through their diet causing potential adverse health impacts. Future scenarios for cadmium emissions to soil via agricultural applications of inorganic and organic fertilizers in Denmark were defined. A simplified fate and speciation model allowed the increase in soil cadmium concentration to be calculated for each scenario. Human exposure was determined based on soil-crop bioconcentration factors for cadmium and dietary intake rates of Danish food crops. Updated dose-response functions linking lifetime cadmium intake to the probability of developing cadmium-induced renal disease and osteoporosis were applied. These impacts were converted into monetary values by using the EU standard value of a life-year adjusted for quality of life experience. Annualized cost per unit of phosphorus and cadmium are presented, discounted and undiscounted, for comparison. Application of struvite (magnesium ammonium phosphate) and mineral fertilizer produced the lowest external health costs, followed by the fertilizer products wastewater sludge and pig manure. The external cost estimates produced in this study could be used to design economic policy instruments to encourage use of cleaner fertilizer products.

Wood biomass is turned into industrial fuel through chipping. The efficiency of chipping depends on many factors, including chipper knife wear. Chipper knife wear was determined through a long-term follow-up study, conducted at a waste wood recycling yard. Knife wear determined a sharp drop of productivity (>20%) and a severe decay in product quality. Dry sharpening with a grinder mitigated this effect, but it could not replace proper wet sharpening. Increasing the frequency of wet sharpening sessions determined a moderate increase of knife depreciation cost, but it could drastically enhance machine performance and reduce biomass processing cost. Since benefits largely exceed costs, increasing the frequency of wet sharpening sessions may be an effective measure for reducing overall chipping cost. If the main goal of a chipper operator is to increase productivity and/or decrease fuel consumption, then managing knife wear should be a primary target. (C) 2014 Elsevier Ltd. All rights reserved.

Hydrothermal carbonization (HTC) of sewage sludge reduces the waste volume and can be source of energy and valuable products. Furthermore, HTC offers several advantages over conventional dry-thermal pre-treatments, as no prior drying is requested, and the high quality of the char produced promotes applications as energy production and storage, wastewater remediation, and soil amendment. Relationships between char yields, physicochemical properties and process parameters are here analysed, with the aim to provide insight into the choice of the process severity required to fit the desired application. Moreover, presence and fate of heavy metals and organic contaminants are discussed. The highest reaction temperature is the main parameter affecting the physicochemical characteristics of the char produced, while the heating rate governs the heat mass transfer and the rate of intermediates formation. Depolymerization of the biomass results in a reduction of the oxygen to carbon ratio and, therefore, in augmented high heating values, further increased by deposition of 5-(hydroxymethyl)furfural. Recirculation of process water may enhance dehydration reactions and the deposition of degraded polymers, increasing dewaterability and yield, but field trials are recommended to assess the feasibility of this option. An overuse of chars for energy generation purposes would be deleterious for the environmental life cycle. Further research is encouraged to assess the pollutants abatement and their degradation pathways when incorporated in the carbonaceous product, to promote the application of hydrochars as soil amendment, as well as for environmental remediation purposes.

Abstract This study investigates the sustainable utilization of CO2 for energy extraction from geothermal reservoirs. Geothermal energy is a reliable and renewable source, but its efficiency can be enhanced through innovative approaches. The concept of utilizing CO2 as a working fluid in geothermal systems holds promise due to its favorable thermodynamic properties and potential for CO2 capture and storage. This research aims to explore the feasibility and benefits of using CO2 for energy extraction from geothermal reservoirs. The study combines theoretical modeling and numerical simulations to assess the performance of CO2-based geothermal systems. A conceptual framework is developed, considering the thermodynamic behavior of CO2 and its interactions with the subsurface reservoir. The simulations involve reservoir characterization, fluid flow analysis, and heat transfer calculations, taking into account various operational parameters and system configurations. The results demonstrate the potential of utilizing CO2 for energy extraction from geothermal reservoirs. The simulations reveal enhanced heat transfer efficiency and increased power generation when compared to traditional geothermal systems. The utilization of CO2 as a working fluid facilitates higher thermal efficiencies, lower greenhouse gas emissions, and improved overall system performance. The results also highlight the importance of proper reservoir characterization and operational optimization for maximizing energy extraction potential. The findings of this study emphasize the sustainable and efficient utilization of CO2 for energy extraction in geothermal systems. By employing CO2 as a working fluid, geothermal power generation can be significantly enhanced, contributing to a more sustainable and carbon-neutral energy sector. The outcomes of this research provide insights into the technical feasibility and environmental advantages of CO2-based geothermal systems, serving as a basis for further development and implementation of this innovative approach. The study contributes to the ongoing efforts in harnessing renewable energy sources and reducing carbon emissions, advancing the field of geothermal energy and promoting a sustainable energy transition.

The growth of global population continuously increases the demands for agroforestry-derived products, underpinning a sustainable growth of energy matrix in the sectors of food security, transportation, and industrial is momentous. The high demand for the sustainable energy sources has led to an increase in the application of pesticides associated with growing crops for the production of biofuel. In 2019, the global consumption of pesticides was 4.2 million tonnes. Case studies on life cycle assessment (LCA) of pesticides showed that toxicity is the major severe impact of pesticide usage, contributing to human toxicity (∼70%) and freshwater eco-toxicity (>50%). This alarming situation needs a solution as conventional pesticides pose various negative impacts to human and the environment, rendering the biofuel production process unsustainable. In this review, we focus on the interaction between pesticide use, biofuel production, food security for a sustainable balancing in between government benefits, environmental, and human health, aiming to track the implications and impact to the global efforts towards achieving the UN Sustainable Development Goals (SDGs). Even though, there are strict government regulations and legislations pertaining to pesticide use, and policies devised as guidelines for agroforestry sectors to implement and monitor these measures, the discrepancies still exist in between national and supranational entities. To cater the above issue, many efforts have been made to upscale the biofuel production, for example, the United States, Brazil, China and Indonesia have ventured into biofuels production from non-food-crops based feedstock while other developing nations are rapidly catching up. In this perspective, a sustainable nexus between Biofuels-Pesticides-Agroforestry (BPA) is essential to create a sustainable roadmap toward the UN SDGs, to fulfilling the energy, food, and land security. The contribution of technologies in BPA includes genetic modified crops, integrated pest and weed management with controlled release pesticides, use of nano-biopesticides is being reviewed. As a whole, the concept of biofuel processing complex (BPC) and farmers upskilling, together with the effective implementation of efficient policies and Internet of Things (IoT) would be the key to drive the BPA nexus towards fulfilment of SDGs.