In Japan, mechanical plastic recycling has been widely practiced. In recent years, the chemical recycling method has been gaining interest, especially due to its high-quality products similar to virgin materials. Understanding the environmental impact of both methods from the energy consumption standpoint is crucial so that attempts to preserve plastic resources can be based in the most energy-sustainable way. This research aims to determine the environmental impact of mechanical recycling and two types of chemical recycling technologies (coke oven and gasification) by analyzing their energy usage and environmental loads. The results relating to the electricity consumption and water usage show that mechanical recycling results in a 17% share of global warming potential (GWP), coke oven 51%, and gasification 32%. Although mechanical recycling results in a lower GWP, chemical recycling yields highly valuable products and byproducts that can be reused in its processes, such as steam and industrial water, reducing the overall environmental load. These recovered materials are also potentially useful for other industrial processes in an industrial symbiosis ecosystem.

Smart bins can increase transparency and accuracy in monitoring waste characteristics such as weight, volume, and disposal times. This information can aid in enforcing waste reduction policies, including the pay-as-you-throw (PAYT) system. However, the public's response to this technology remains uncertain. Despite Japan's reputation for high waste separation compliance and collection rates, it has one of the world's highest per capita rates of plastic and packaging waste generation. This study surveyed 1000 Japanese individuals regarding their perception of smart bin features and their potential to encourage waste reductions. Multiple correspondence analysis (MCA) was used to explore the relationships between respondents' social attributes and their responses. The findings indicate a slightly higher responses from younger respondents (above 85 % of those age 10-29 compared to around 75 % of those aged 60 and older) who were in favour of smart bin technology functions such as unscheduled waste pick up and automatized waste separation. On the other hand, there was a strong unwillingness (0.57 count ratio) to reduce plastic waste even if a smart bin assisted PAYT is introduced from those who did not engage in waste separation and cleaning in the first place. Finally, an open-ended question about strategies to reduce plastic waste resulted in a large portion of mindset change ideas (24.8 % of the female respondents) and technology innovations proposals (24 % of male respondents). Although development of a smart-bin prototype is taking place, behavioral change strategies to foster a willingness to reduce waste must take place along with technological interventions.

Due to aging and depopulation, cities in Japan struggle to maintain their municipal waste collection services. These challenges were exacerbated by the pandemic. To overcome these challenges, a prototype of collective and contactless waste collection technology has been developed. However, its acceptance by society is unknown. In this study, we surveyed Japanese people’s preferences regarding household waste disposal. The results showed that older adults (older than 60) are willing to walk longer (more than 2 min) to carry their waste to the disposal site than younger adults. They are also less concerned about the risk of disease infection from touching other people’s garbage than younger respondents (at a 0.24 count ratio). Other significant findings are that people who live alone prefer the temporary disposal site to be placed more than one minute away from their house (at a 0.19 count ratio). People living alone also produce less plastic and packaging waste than larger households. With more Japanese older adults living alone because of the scarcity of older-adult care facilities, we proposed two waste collection strategies that can allow for the implementation of more collective and automatized contactless waste pickup technology. Each design poses different challenges, such as the need for residents’ cooperation and a higher energy supply. However, they also open new opportunities, such as encouraging active aging and using renewable energy.