Drivers in current and future municipal solid waste management systems: cases in Yokohama and Boston.

Despite some progress, municipal solid waste (MSW) still poses pressure on cities and remains one of the major challenges in environmental management. There is no single solution to the problem since the drivers behind MSW systems may vary significantly from city to city. In this context, the development of a common strategy to attain a sustainable management has been increasingly difficult. This paper presents an issue-driven analytical framework to evaluate the past, present and future MSW management strategy for the cities of Yokohama and Boston considering four driver categories while evaluating if the relevance of these drivers has changed over time. These categories represent: (i) legal drivers (e.g. laws and regulations); (ii) technology development and institutional drivers (e.g. available technologies); (iii) regional and international drivers (e.g. solid waste flow as recyclable resources); and (iv) socio-economic drivers (e.g. population trends and public awareness). The analysis indicated that solid waste management capacity for both cases was under stress due to different reasons. In the case of Boston, the moratorium for disposal facilities played an important role while increasing population was a key driver for the city of Yokohama. The future management scenario suggests that various waste-to-energy alternatives and strong solid waste reduction policies will play a key role for Boston. In Yokohama, a shift on waste composition and generation triggered by a demographic change may open the path for new technologies while also considering the international demand of solid waste as a recyclable resource.