In the last years, Singapore has set clear targets to transition towards a circular economy. To advance on those targets, the country has introduced policies and strategies to encourage businesses and society to adopt sustainable practices. In 2019, Singapore launched a Zero Waste Master Plan, which lays out strategies for waste and resource management within the context of the circular economy. With this plan, Singapore aims to reduce the amount of waste sent to landfills by 30% by 2030. And it targets food, electronics, and packaging, including plastics, as priority waste streams. This report provides an overview of Singapore’s food waste management with special emphasis on food waste valorization strategies. Through an exploratory study and conducting interviews with different stakeholders, i.e., individuals, government, businesses, research institutes, key drivers and constraints to increasing food waste valorization were identified. The report also includes the view of food waste experts on valorization strategies that can be applied in the Singaporean context.

The increase in world population and the resulting demand for food, water, and energy are exerting increasing pressure on soil, water resources, and ecosystems. Identification of approaches to reduce the related cross-sectoral environmental impacts for the water–energy–food nexus is, therefore, crucial. The purpose of the review was to discuss the circular economy approaches devoted to understand the interdependencies among these three sectors. In particular, the review focuses on the importance of the application of life cycle thinking and life cycle assessment for understanding the interconnections in the nexus along the whole supply chains. Moreover, researches related to water and energy use in the agrifood sector are presented, addressing food waste management alternatives in a circular economy perspective.

By 2050, the global Earth population will reach 10 billion, leading to increased water, food, and energy needs. Availability of water in sufficient quantities and appropriate quality is a prerequisite for human societies and natural ecosystems. In many parts of the world, excessive water consumption and pollution by human activities put enormous pressure on this availability as well as on food and energy security, environmental quality, economic development, and social well-being. Water, food/materials, and energy are strongly interlinked, and the choices made in one area often have consequences on the others. This is commonly referred to as the “water-food-energy” nexus. These interconnections intensify as the demand for resources increases with population growth and changing consumption patterns, and Humanity continues using a linear economy model of ‘take-make-dispose’. The nexus makes it difficult for governments, public and private organizations, and the public, to set and follow a clear path towards a sustainable economy i.e., “meeting the needs of the present without compromising the ability of future generations to meet their own needs”. Humanity best chance at mitigating climate change, and shortage of resources is to harness the value of water as much as possible.This paper reviews the latest publications about the water-food-energy nexus and climate change, putting numbers into perspective, attempting to explain why water circularity is part of the key factors to accelerate the transition from a linear economy to a circular economy, and to meet the UN Sustainable Development Goals, and how circularity can be implemented in the water sector.

By 2050, the global Earth population will reach 10 billion, leading to increased water, food, and energy needs. Availability of water in sufficient quantities and appropriate quality is a prerequisite for human societies and natural ecosystems. In many parts of the world, excessive water consumption and pollution by human activities put enormous pressure on this availability as well as on food and energy security, environmental quality, economic development, and social well-being. Water, food/materials, and energy are strongly interlinked, and the choices made in one area often have consequences on the others. This is commonly referred to as the “water-food-energy” nexus. These interconnections intensify as the demand for resources increases with population growth and changing consumption patterns, and Humanity continues using a linear economy model of ‘take-make-dispose’. The nexus makes it difficult for governments, public and private organizations, and the public, to set and follow a clear path towards a sustainable economy i.e., “meeting the needs of the present without compromising the ability of future generations to meet their own needs”. Humanity best chance at mitigating climate change, and shortage of resources is to harness the value of water as much as possible. This paper reviews the latest publications about the water-food-energy nexus and climate change, putting numbers into perspective, attempting to explain why water circularity is part of the key factors to accelerate the transition from a linear economy to a circular economy, and to meet the UN Sustainable Development Goals, and how circularity can be implemented in the water sector.

The recovery of resources from waste streams including food production plants can improve the overall sustainability of such processes from both economic and environmental points of view. This is because resource recovery solutions will be instrumental in overcoming the grand societal challenges in relation to the Water-Energy-Food (WEF) nexus in one of many aspects. Identification, development and implementation of resource recovery solutions in an industrial setting is a challenge that requires careful assessment of environmental impacts, technology readiness level (TRL), economics as well as other implementation aspects. This manuscript will first introduce these multi-disciplinary concepts followed by four case studies that are each at a different level of technological maturity and have a unique economic value proposition. The technologies demonstrated in these case studies directly convert either food waste, waste energy or wastewater into valuable raw materials. Using the case study experience as a basis, a roadmap to commercialisation is discussed where the focus is on understanding industrial needs, the role of industrial symbiosis and the current challenges that must be overcome. To this end, the objective of this manuscript is to go beyond the purely single-faceted technical discussion and provide an insight into the multi-faceted aspects of commercialising resource recovery technology development, which would be a key pillar in realising the future circular economy in line with UN’s sustainable development goals.

Current studies on the food-energy-water nexus do not capture effects on human health. This study presents a new methodology for assessing the environmental sustainability in the food-energy-water-health nexus on a life cycle basis. The environmental impacts, estimated through life cycle assessment, are used to determine a total impact on the nexus by assigning each life cycle impact to one of the four nexus aspects. These are then normalised, weighted and aggregated to rank the options for each aspect and determine an overall nexus impact. The outputs of the assessment are visualised in a “nexus quadrilateral” to enable structured and transparent interpretation of results. The methodology is illustrated by considering resource recovery from household food waste within the context of a circular economy. The impact on the nexus of four treatment options is quantified: anaerobic digestion, in-vessel composting, incineration and landfilling. Anaerobic digestion is environmentally the most sustainable option with the lowest overall impact on the nexus. Incineration is the second best option but has a greater impact on the health aspect than landfilling. Landfilling has the greatest influence on the water aspect and the second highest overall impact on the nexus. In-vessel composting is the worst option overall, despite being favoured over incineration and landfilling in circular-economy waste hierarchies. This demonstrates that “circular” does not necessarily mean “environmentally sustainable.” The proposed methodology can be used to guide businesses and policy makers in interpreting a wide range of environmental impacts of products, technologies and human activities within the food-energy-water-health nexus.

Singapore is a city-island-state in the transition towards a circular economy. The country has already implemented policies and adopted several approaches that contribute to closing loops for e-waste, packaging waste, and food waste. However, other areas that also contribute to a circular economy have not been fully explored in Singapore. One of these areas is resource recovery from wastewater streams. In this report, we review state-of-the-art technologies to recover valuable components from domestic wastewater and sludge. These technologies are analyzed based on technological maturity and applicability for the recovery of phosphate, and organic compounds such as volatile fatty acids, bioplastics, and biomass. The report covers the current status of the recovery of these compounds in the Singaporean context and identifies factors that can promote or prevent the application of the recovery processes.

In this work we demonstrate that the synergistic combination of organic molecules extracted from food waste can empower different types of carboxylated gold nanoparticles (Au NPs) in removal of Cr(VI) species from both milliQ and real water solutions. In particular, chitosan extracted from shrimp’s shell and dissolved in an acidic active medium based on a 1:3 M mixture of ascorbic and citric acid allows citrate-capped Au NPs to improve their abatment efficiency from 18.4 to > 99% in milliQ and 80.6% in drinking water. When citrates are exchanged with 3-mercaptopropionic or 11-mercaptoundecanoic acids, the efficiency reaches 100% in both milliQ and drinking water. 11-mercaptoundecanoic acid is found to be the best capping agent in terms of efficiency and stability. Crossing of cyclic voltammetry and UV–Vis data enabled to define the main role of each individual component in abatment of Cr(VI). This study further advances research on the rational design of hybrid nanoparticle/polymer systems for environmental remediation, inspired by criteria of circular economy and environmental sustainability.

The water-food nexus in the Middle East and Northern African (MENA) region is characterized by resource depletion, import dependence and environmental degradation. This contribution proposes that consumption awareness and resource circularity can be seen as a pathway to alleviate environmental problems and achieve long-term supply security in the water and food sectors. The chapter introduces wastewater recycling as a salient and highly relevant development in the MENA region. Current directions in using treated wastewater are analyzed. Furthermore, forerunner countries from different MENA sub-regions are briefly introduced with the focus on the particular characteristics and policy challenges in each of presented cases of wastewater reuse. Furthermore, crosscutting issues are presented. These include the need for addressing the large consumption footprints in MENA countries, the existence of distorting subsidies for agricultural water, the lack of communities' participation, the inadequacy of existing strategies and the suboptimal coordination mechanisms between water and food sectors. We suggest at the end of the paper some recommendations to policy makers in the region. | Scopus