The report provides a baseline understanding of the current management approaches identified in previous research undertaken by REFRESH with respect to the policy concept of a Waste Hierarchy. It categorises management approaches that have been identified for 20 selected food production residues.
The categorisation relates each management approach to preferential tiers of waste management outlined in the EU waste policy’s ‘Waste Hierarchy’. These tiers are intended to promote measures to encourage waste prevention and resource efficiency over waste recovery and disposal.
Seventy-six possible management approaches have been identified from the twenty food production residues selected by previous REFRESH research. However, several of the twenty residues are in fact broader groupings of by-products from different animal sources, so the number of residues considered has been increased to thirty.
Two thirds of the management approaches fall under the Waste Hierarchy category of waste prevention by re-use. This is influenced by many of the food production residues being classed as by-products, and not wastes, when applying EU Directive definitions. This status is defined in EU waste policy typically where further use for food production residues is certain and where additional processing of those residues is considered normal industry practice.
This can be open to interpretation, however, since certainty of further use (for ascribing ‘non-waste’, (by-product) status) for many of the food residues is subject to wider and changeable forces. For example, by-products used as animal feed may be subject to a market context which may vary seasonally and yearly. Animal by-products that are consistently rendered into raw materials for further uses could be considered normal industry practice, but this could also be interpreted as a waste recovery process, for non-integrated plants.
Few (6 in total) of the approaches identified for management of food chain residues were categorised as the least preferred tier of the Waste Hierarchy: waste recovery (other). This typically means conversion of food waste residues into energy or fuels.
Partly this is because anaerobic digestion, the most common valorisation approach identified with energy recovery, has been promoted to the preferred tier of recycling, above composting, following lifecycle evidence (DEFRA, 2011b).
Key observations from this work relate to
1) The challenges of identifying true wastes, the volumes which are actually discarded for waste recovery or disposal, from the majority of food by-products that industry currently valorises, to prioritise areas which will support the EU’s food waste targets. This reflects the paucity of available data on both waste disposal and commercial processing and use of these materials across the EU.
2) Using this waste hierarchy categorisation, alone, is not a useful sustainability metric for evaluating the status of available valorisation approaches. The purpose of the waste hierarchy, is a first basis for communicating a general policy preference. In many cases the relative environmental merit is likely to be very case specific.
3) For any generalised waste hierarchy conclusions, the relative merits of valorisation approaches would rely on a systematic review of evidence. This would rely on a mature body of comparable studies (consistent LCA’s or similar) looking at various management contexts to provide a reasonable consensus on best environmental options for valorising food waste.
With respect to the findings of this report the next steps will be an investigation of a subset of valorisation opportunities that relate to the approaches identified. This is followed by generic models of valorisation process steps for high level lifecycle assessment and lifecycle cost comparisons to indicate the relative merits of current, market relevant, valorisation approaches.
Metcalfe, P., Moates, G., Waldron, K., 2017: Detailed hierarchy of approaches categorised within waste pyramid. REFRESH Deliverable 6.3