Social-economic assessment of integrated waste pickers in municipal solid waste management system: A case of Tianjin in China

Currently, China's municipal solid waste (MSW) management system has been changing from mixed collection and treatment system into separated collection and treatment system. Therefore, the source separated ability of MSW, the relevant policies of MSW classification and the MSW management system are still in the stage of exploration and improvement. This study chooses to integrate waste pickers (WPs) from the informal sector into the MSW management system, so that they can conduct secondary sorting of waste as a supplement to source separation. However, the existing research does not provide a method that allows the evaluation of integrated WPs from a dynamic and long-term perspective. In this paper, the system dynamics model of MSW management is improved to provide the ability to analyze the long-term evolution of social economic benefits of integrating WPs for secondary sorting. Taking Tianjin as an example, the scenario analysis is carried out. The results show that, on the basis of the existing mixed management mode, integrating WPs for secondary sorting (80% separated rate) can reduce the waste management cost per ton by 55 yuan in 2030. Under the current situation in Tianjin where the source separation rate of food waste is 20% and the source separation rate of recyclable waste is 60%, integrating WPs can reduce the social economic cost of Tianjin's urban MSW management system by 422.45 million yuan per year from 2022 to 2030. In addition, the results show that even if the source separated rate of food and recyclable waste increases, there is still room for 20%–80% increase in wages based on giving WPs a salary higher than the national per capita disposable income in 2022. This study provides a basis for integrating WPs into Tianjin MSW management system, as well as methods and quantitative tools to integrate WPs for cities in developing countries.