Source-separation infrastructure and the reduction of residual household waste: Evidence from Iceland's 2023 waste...

This study evaluates whether Iceland's 2023 waste-management reform, which combined Extended Producer Responsibility (EPR) financing with mandatory four-bin kerbside collection, reduced targeted household waste remaining in the general bin. Using a decade-long dataset (2014-2025) derived from systematic waste characterisation studies, the analysis employs a panel Interrupted Time Series (ITS) design comprising 55 observations across five analytical areas in the Capital Region to quantify changes in residual biodegradable waste, paper, plastic, and non-targeted fractions. The results indicate a statistically significant structural break in household disposal behaviour, with total waste in the general bin declining by an average of 37 % following the reform. This shift is primarily driven by a pronounced "organic transition," as biodegradable waste remaining in the residual stream decreased by 54 %. By 2024, total apparent capture rates for paper and plastic reached peaks of 83 % and 44 %, respectively, before showing slight stabilisation in 2025. These findings suggest that the EPR framework provided an important financial and regulatory foundation, but the decisive behavioural mechanism was the rollout of accessible household-level source-separation infrastructure, especially for biodegradable kitchen waste. For paper and plastic, observed changes are more consistent with the continuation and reinforcement of pre-existing downward trends alongside improved post-reform apparent capture rates. However, the slight stabilisation in performance by 2025 is consistent with a tendency for initial participation gains to diminish over time, highlighting the importance of sustained behavioural engagement, contamination control, and complementary collection pathways for residual materials not targeted by the four-bin system.