GHG emissions of food waste management options
Historically, in GHG emission accounting of food waste, fixed emission factors were assumed per food waste management and feed application option. More recent approaches account for the chemical composition of the waste stream, most notably its carbon content, with average values at the product-category level. The presented approach further increases the level of detail by incorporating detailed material-specific compositional data, enabling more accurate estimation of parameters that are critical in the destinations, such as nutritional value in feed application, biomethane potential and induced nitrous oxide emissions.
Calculations of consequential GHG emission effect for different products - provided in first link below - confirm that landfilling has, by a considerable margin, the highest climate impact among common waste management options. Results furthermore substantiate that the net climate impact in a destination pathway depends on material-specific characteristics, leading either to net GHG emissions or to GHG emission mitigation.
Remark: For destinations involving recycling or recovery processes the Consequential GHG emission effect result cannot be directly used as a waste management GHG emission factor for losses in product carbon footprint assessments.
For destinations involving recycling or recovery processes - such as composting, energy recovery, or feed applications - the CAT-BREVIA-derived consequential GHG emission effect includes environmental benefits arising from the substitution of primary materials, energy, or feed inputs. In product carbon footprint accounting, these benefits are allocated to the subsequent user of the recovered product rather than to the generator of the waste stream. Consequently, in product carbon footprinting the consequential GHG emission effect should not be used directly as a waste-management emission factor, as this would result in double counting of the recovery or recycling benefits at system level.
At the end of below document, for one food waste stream GHG emission effect values excluding effects of recovery or recycling are presented, calculated with the CAT-BREVIA’s heuristics. Values calculated in this way are considered more appropriate as material-specific waste-destination emission factors for product carbon footprinting.