Regional and temporal simulation of a smart recycling system for municipal organic solid wastes

• We structured a framework for a robust recycling and waste treatment system.
• The proposed smart recycling system is an example of robust system.
• We employed a model to simulate the smart recycling in a study area in Tokyo.
• The smart recycling results in greater CO2 emission reductions and lowers costs.
• The unit cost of the system is stable to changes in the amount of waste generated.

A cost-effective and robust waste treatment and recycling system is a requisite of a sustainable society. In our previous study, we proposed a “smart recycling system” that utilizes existing industrial facilities with higher energy efficiency so that a cost-effective and robust recycling system for treating municipal wastes can be established. In this study, we further develop the concept of smart recycling and propose a framework for facilitating the implementation of such a system. By making use of existing facilities and adopting both closed-loop and semi-closed-loop recycling processes, this system allows flexible adaptations on the changes of external factors. A spatially optimal scale is necessary to meet the requirements for such a smart recycling system. Thus, we develop an integrated model that combines both geographical information system based collection model and a process model for a smart recycling center. In order to test its applicability, we employ a case study approach to simulate the implementation of smart recycling in the three satellite cities of Tokyo Metropolitan Area and evaluate its effects under three different scenarios. Our simulation results show that smart recycling cannot only reduce carbon dioxide emission but also lower the overall costs. Also, by comparing with conventional waste incineration, we find that the unit cost of smart recycling is relatively stable to changes of the waste amounts due to its lower fixed costs for facilities.