Fig. 3.

Results of six LCA studies reporting the greenhouse gas emissions per tonne of food waste for different disposal options, including recycling food waste as swill. Negative emissions mean that the process has a net negative carbon balance, ie the emissions avoided are larger than emissions released. Swill, for example, avoids emissions associated with the production of conventional feed, and anaerobic digestion (AD) avoids emissions from the fossil fuels it replaces. Where a study reported emissions for multiple food waste types, the mean emissions are shown, and none of the studies shown include land use change, a major source of agricultural emissions, when calculating the emissions avoided from swill feeding. The swill data for Vandermeersch et al. (2014) are for a 10% swill, 90% anaerobic digestion scenario. Gaps are left where studies did not report particular food waste disposal options, and the country of study is listed under each reference. Two further LCA studies (Ogino et al., 2012, Tufvesson et al., 2013) use different units (reporting results per kg of animal feed and per MJ of fuel energy, rather than per tonne of food waste) and so cannot be displayed for comparison. (Eriksson et al., 2015, Kim et al., 2011, Lee et al., 2007)