The effectiveness of stage-matched interventions in changing waste source separation behaviour: Evidence from a consecutive quasi-experiment.

In many developing countries, inefficient waste source separation poses a significant challenge to sustainable waste management systems, hindering progress towards a circular economy. Previous research has shown mixed results regarding the effectiveness of informational interventions and has not thoroughly evaluated regulatory measures. This study innovatively employs a quasi-experimental design, enhanced by successive surveys, to assess the impact of targeted interventions on behavioural changes in waste separation practices. Utilizing the Health Action Process Approach, we introduced three interventions - posters, educational lectures and a supervision policy - over 8 weeks among university students. Our results indicate stepwise improvements in waste separation accuracy: posters modestly increased awareness without significantly altering behaviours; educational lectures led to a 40% increase in the food waste separation rate and supervision achieved over 90% separation purity, but with an increase in 'fly-dumping'. The interventions incurred costs of 36, 60 and 365 RMB per capita annually. This research underlines the importance of customized informational interventions and the costs and challenges of initial regulatory measures in waste management, offering crucial empirical evidence and insights for creating impactful environmental behaviour change interventions.