Life-Cycle Assessment Harmonization and Soil Science Ranking Results on Food-Waste Management Methods

Area of Science:

• Environmental Science
• Life Cycle Assessment
• Soil Science

Background:

• Food waste management significantly impacts climate and soil health.
• Life cycle assessments (LCAs) and soil productivity studies offer complementary data but require harmonization.
• Previous assessments of food waste management methods lacked standardized impact metrics.

Purpose of the Study:

• To harmonize climate and energy impacts of various food waste management methods.
• To rank soil benefits of these methods using scientific soil productivity data.
• To compare harmonized impacts against non-harmonized averages and identify research gaps.

Main Methods:

• Reviewed 147 life cycle studies, selecting 28 for climate and energy impact harmonization.
• Assessed 80 soil productivity studies to rank soil benefits.
• Calculated harmonized climate impacts (kg CO2e/kg food waste) and energy impacts (MJ/kg food waste).

Main Results:

• Harmonized climate impacts ranged from -0.20 kg CO2e/kg (anaerobic digestion) to 0.38 kg CO2e/kg (landfill gas-to-energy).
• Harmonized energy impacts ranged from -0.32 MJ/kg (in-sink grinding) to 1.14 MJ/kg (aerobic composting).
• Aerobic composting and anaerobic digestion ranked highest for soil benefits, while in-sink grinding and landfill gas-to-energy ranked lowest.

Conclusions:

• Harmonization reduced reported climate emissions compared to non-harmonized averages.
• Aerobic composting and anaerobic digestion demonstrate superior environmental and soil benefits for food waste management.
• Further research is needed to refine soil benefit measurement and reconcile LCA and soil science data.