Sustainability Assessment of Food Waste Management

As the world’s population is expected to increase from 7.7 to 9.7 billion by 2050 (United Nations, 2019), food production needs to increase by 30-70% in the next three decades (World Bank, 2020). In order to meet such a demand,the current food production system requires dramatic transformations to become sustainable (World Bank, 2020). About 30% of global food production is wasted every year, incurring environmental (e.g. greenhouse gases emissions), economic (e.g. increased price volatility) and societal (e.g. social inequalities) impacts (Stenmark et al., 2016; World Bank, 2020). A reduction in the amount of food wasted is identified as a key factor, not only in lowering the impact of the food supply chain on the environment (contributing 8% to global greenhouse gases emissions), but also combating hunger and providing a more sustainable economy (World Bank, 2020).

To tackle food waste, actions have been taken at both the global and the European level. At the European level, the Farm-to-Fork Strategy was implemented, aiming at making the food supply chain more sustainable and reducing food waste (European Commission, 2020). Yet, if food waste generation cannot be prevented, the European Commission supports utilising food waste as a resource to exploit the valuable components of such a feedstock, rather than its direct disposal (Sánchez López et al., 2020). To identify how best to utilise food waste, a food waste hierarchy has been suggested at the European level (Sánchez López et al., 2020). The most preferred strategy for the hierarchy is the prevention of food waste, followed by reuse for human consumption and as animal feed, material recycling, nutrient recycling, energy recovery and, finally, disposal (Teigiserova et al.,2020). In order to select which strategies to implement, it is necessary to support decisions with quantitative sustainability assessments encompassing the three pillars of sustainability, namely the environment, the economy and society.

The goal of this PhD thesis was to compare strategies for different levels of the food waste hierarchy and to suggest a clear prioritisation of these strategies to guide policy-makers. To support the transition to a greener economy, a framework was employed to assess all three sustainability pillars. The framework is based on life cycle assessment and life cycle costing to evaluate environmental and economic impacts, while the societal sphere is assessed by quantifying local impacts, such as employment, land occupation, landscape disamenities, accidents, noise and odour. The sustainability framework allows for aggregating the results into five areas of protection, of which two relate to the environment, two to the society, and one focuses on the economy. The aggregated results can be ranked by means of a multi-criteria decision analysis to enable the prioritisation of one strategy over another while considering trade-offs between the three pillars of sustainability.

The results supported the food waste hierarchy only at the higher levels,namely prevention and reuse for human consumption and as animal feed.Prevention was the best strategy by far, having the largest benefits from an environmental, economic, and societal perspective. However, when preventing food waste, households may save money on food, leading to the increased consumption of other products and/or services; consequently, such rebound effects may counterbalance the environmental benefits of prevention (global warming resulted in a net saving of -3,800 kg CO₂-eq t^-1 food waste). Nevertheless, it was observed that even when accounting for rebound effects,the benefits from a global warming perspective in terms of preventing food waste in Europe (-12 Mt CO₂-eq year^-1) outweighed the impacts related to increased consumption (6 Mt CO₂-eq year^-1). After prevention, reuse for human consumption implemented through food donations was the preferred strategy (global warming resulted in a net saving of -1,600 kg CO₂-eq t^-1 food waste). The analysis demonstrated that assumptions about which food products are substituted on the market when donating food highly affected the results, thereby highlighting that care should be taken in this regard. To support food donations it is recommended at the European level to implement clear regulatory frameworks that include economic incentives, which were found to be key to the success of such initiatives. Reuse for human consumption was followed by reuse as animal feed (global warming results ranged from -210 to 20 kg CO₂-eq t^-1 food waste) despite not performing among the top strategies across all three sustainability pillars.

The results did not indicate significant differences between the remaining lower levels of the food waste hierarchy: material recycling, nutrient recycling and energy recovery. Material recycling strategies were not found significantly more beneficial than nutrient recycling and energy recovery. Indeed, from a global warming perspective, the results obtained for material recycling (ranging from -50 kg CO₂-eq t^-1 food waste to 1,110 kg CO₂-eq t^-1 food waste) overlapped and exceeded those obtained for nutrient recycling (ranging from -130 to 270 kg CO₂-eq t^-1 food waste) and energy recovery (varying between -140 and 90 kg CO₂-eq t^-1 food waste). A main shortcoming of current material recycling strategies (in particular biochemical production) is the low technology readiness levels characterised by high energy and ancillary material consumption. These technologies require further optimisation with respect to not only environmental performance, but also socio-economic impacts, as they have high capital and operational costs. While further research and economic support for these technologies may change the ranking at these lower levels of the hierarchy, the results of this thesis clearly demonstrate that concrete emphasis should be placed on prevention and reuse initiatives as the most robust and overall sustainable alternatives in the food waste hierarchy.