Identifying the key policy drivers for behavioral improvement in waste source separation in the Yangtze Delta Region, China

Since 2019, Chinese authorities have actively attempted to improve the waste separation behavior of civilians with interventions such as publicity and supervision. Their focus was to study the residents' waste separation attitudes with questionnaires and not the actual separation behavior via objective investigation. Selecting Zhangjiagang in Yangtze Delta Region as study area, we focused to compare the effects of publicity and supervision on residents' actual separation performance before and after intervention implementation. Based on on-site collection of 810 waste bags, detailed composition analysis and physical properties observations in 3 communities (C1, C2, and C3), it was found that after 1-month supervision period in C2, the source separation rate of green and grey bins dramatically rose from 13% to 90%, 20%–72%, respectively, which led to marked differences in moisture content, bulk density, and lower heating value compared to before supervision. However, with 3-month publicity in C1 and C3, the source separation rates were still less than 30% in the 2 bins, almost no improvement. Furthermore, the multi-period supervision intervention demonstrated the source separation rates for 3-month supervision in green and grey bin (90% and 68% respectively) were actually identical with 1-month supervision (90% and 72%), which indicated that occasional residents’ misclassification might contribute to the existence of separation rate thresholds. To achieve waste source separation across society, on-site supervision via supervisors beside the drop-off containers is suggested to be implemented, not just applying publicity.