The environmental performance of different end-of-life options for compostable diapers in a UK system

This study employs Life Cycle Assessment (LCA) to evaluate the environmental impact of compostable diapers in the UK across four disposal scenarios: (1) landfill and incineration (L&I); (2) composting with food and garden waste, with landfilling of the resulting compost (C-FGW); (3) separate composting and landfilling of the compost (C-NCC); and (4) separate composting with compost application as a soil amendment (C-CC). The environmental impacts were assessed with EF 3.0 method. The results indicate that diaper manufacture is the primary environmental impact contributor across all scenarios. C-CC emerges as the most environmentally favourable scenario, offsetting L&I with a reduction in mineral resource use (28 %), water use (19 %), and freshwater ecotoxicity (15 %). However, the contribution to climate change, eutrophication, acidification and human toxicity only shows marginal improvements. Hybrid scenarios combining composting and landfilling (C-FGW and C-NCC) yield the least favourable outcomes due to loss of composting benefits and potential emissions from landfill. Potential biogenic carbon sequestration for diaper disposal was estimated, with L&I generating higher emissions than C-CC, and compost landfilling resulting in potential carbon storage. This study highlights the need to consider infrastructure challenges and soil health risks before widespread adoption of diaper composting in UK. Overall, this research provides insights into the environmental performance of compostable diapers, identifies key limitations and informs policy decisions regarding sustainable diaper disposal.