Ramy Salemdeeb

•The circular economy requires a shift from weight-based targets to impact-driven targets.•A new environmental LCA tool is introduced to aid comprehensive policy development.•Whole life cycle thinking is applied to account for the environmental impacts of waste.•A holistic view of the environmental cost of waste is presented which promotes prevention and the circular economy ethos.
Resources and waste strategies have recently seen a shift in focus from weight-based recycling targets to impact-driven policies. To support this transition, numerous decision-support tools were developed to help identify waste streams with the highest impacts. However, the majority of these tools focus solely on greenhouse gas emissions and show a narrow picture of the overall environmental impacts. Furthermore, they cover burdens associated with direct waste management activities and hence fall short when it comes to highlighting the substantial benefits that can be achieved by preventing waste in the first place. This paper quantitatively demonstrates the necessity to adopt impact-based targets that go beyond estimating the greenhouse gas emissions of waste and highlights the substantial benefits of waste reduction and prevention. Using a state-of-the-art waste environmental footprint tool, the paper quantifies the overall environmental impacts of Scotland's household waste and shows how targeting ‘heavy’ materials does not necessarily have the highest overall environmental benefit. Results show that embodied environmental impacts of household waste dominate the total environmental burdens, contributing more than 90% to the whole life cycle impacts, and hence policymakers should prioritise interventions that aim at waste reduction and prevention. Moreover, our analysis shows that food and textile wastes are high-priority materials in Scotland, with the largest contribution to overall environmental burdens; up to 42% and 30%, respectively. Considering the overall environmental impacts of specific waste materials will enable policymakers to develop more granular and targeted interventions to accelerate our transition to a sustainable circular economy.

The environmental evaluation of food waste prevention is considered a challenging task due to the globalised nature of the food supply chain and the limitations of existing evaluation tools. The most significant of these is the rebound effect: the associated environmental burdens of substitutive consumption that arises as a result of economic savings made from food waste prevention. This study introduces a holistic approach to addressing these challenges, with a focus on greenhouse gas (GHG) emissions from household food waste in the UK. It uses a hybrid life-cycle assessment model coupled with a highly detailed multi-regional environmentally extended input output analysis to capture environmental impacts across the global food supply chain. The study also takes into consideration the rebound effect, which was modelled using a linear specification of an almost ideal demand system.
The study finds that food waste prevention could lead to substantial reductions in GHG emissions in the order of 706-896 kg CO2-eq. per tonne of food waste, with most of these savings (78%) occurring as a result of avoided food production overseas. The rebound effect may however reduce such GHG savings by up to 60%. These findings provide a deeper insight into our understanding of the environmental impacts of food waste prevention: the study demonstrates the need to adopt a holistic approach when developing food waste prevention policies in order to mitigate the rebound effect and highlight the importance of increasing efficiency across the global food supply chain, particularly in developing countries. (C) 2016 Elsevier Ltd. All rights reserved.

The disposal of food waste is a large environmental problem. In the United Kingdom (UK), approximately 15 million tonnes of food are wasted each year, mostly disposed of in landfill, via composting, or anaerobic digestion (AD). European Union (EU) guidelines state that food waste should preferentially be used as animal feed though for most food waste this practice is currently illegal, because of disease control concerns. Interest in the potential diversion of food waste for animal feed is however growing, with a number of East Asian states offering working examples of safe food waste recycling – based on tight regulation and rendering food waste safe through heat treatment. This study investigates the potential benefits of diverting food waste for pig feed in the UK. A hybrid, consequential life cycle assessment (LCA) was conducted to compare the environmental and health impacts of four technologies for food waste processing: two technologies of South Korean style-animal feed production (as a wet pig feed and a dry pig feed) were compared with two widespread UK disposal technologies: AD and composting. Results of 14 mid-point impact categories show that the processing of food waste as a wet pig feed and a dry pig feed have the best and second-best scores, respectively, for 13/14 and 12/14 environmental and health impacts. The low impact of food waste feed stems in large part from its substitution of conventional feed, the production of which has substantial environmental and health impacts. While the re-legalisation of the use of food waste as pig feed could offer environmental and public health benefits, this will require support from policy makers, the public, and the pig industry, as well as investment in separated food waste collection which currently occurs in only a minority of regions.