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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. • Dynamics model was developed to analyze the contribution of secondary sorting of WPs. • MSW generation and disposal as well as social economic benefits in Tianjin were simulated. • WPs reduce the social economic cost 422.45 million yuan per year in Tianjin's MSW. • Even with rising labor costs, the social economic benefits of WPs are significant. [ABSTRACT FROM AUTHOR]

In the context of addressing climate change and promoting high-quality development, it is necessary to evaluate the impact of carbon emissions trading scheme (ETS) on China's total factor productivity (TFP). Based on a quasi-experimental design, we provide firm-level evidence of TFP improvement from China's pilot ETSs. Using panel data of Chinese listed firms during 2009–2018, the difference-in-differences method is adopted to evaluate the impact of ETS on the firm-level TFP. The results show that the ETS significantly improves the firm-level TFP, increasing it in pilot regions by approximately 14% when compared with non-pilot regions. Further analysis shows that this improvement is not affected by the heterogeneity of firms' ownership, but by industrial heterogeneity. Moreover, this improvement is realized by promoting firms' operating and profitability capacity. We also find that the impact of ETS on firm-level TFP is stable and exhibits no time lag. Our findings not only improve the effectiveness evaluation framework of the Chinese ETS, but also have some implications for how to promote the construction of a national carbon emissions trading market in the context of high-quality development. [Display omitted] • We evaluate the impact of China's ETS on firm-level TFP with the DID method. • ETS significantly improve the firm-level TFP in the pilot regions. • The policy effects are affected by the heterogeneity across industries. • The impact of the ETS on firm-level TFP is stable and exhibits no time lag. • The promotion of firm-level TFP by the ETS does not stem from innovation capacity. [ABSTRACT FROM AUTHOR]

In recent years, there have been a number of studies on bioretention during hot summer, with only few studies reported during low-temperature winters. The application of bioretention in cold areas still lacks effective guidance. In this study, runoff simulation experiments were conducted to explore the influence of wood chips filler and water treatment residue on the removal of runoff pollutants under different packing gradations and low temperature conditions. Under low temperature, nitrate nitrogen removal rate of wood chips filler decreased from 70% to 90% in autumn to −23%- 35% in winter, the total nitrogen removal rate decreased from 75 to 90% in autumn to 20%–50% in winter, the removal rate of ammonia nitrogen and total phosphorus exceeded 70% during the entire experiment. Water treatment residue filler maintained a high ammonia nitrogen and total phosphorus removal rate during the experiment, with the total phosphorus removal rate above 90% and ammonia nitrogen removal rate above 80%. The bioretention effluent concentration of nitrate and total nitrogen was higher than 7.3 mg/L and 8.5 mg/L, respectively, most of the time. However, at low temperature, the COD removal rate of the two fillers was 25%–50%, which was very poor. Therefore, wood chips filler was observed to be better suited for the removal of nitrate and total nitrogen from the runoff, while water treatment residue had a better effect on the removal of ammonia nitrogen and total phosphorus in winter. Thus, for the application of bioretention in northern China, appropriate fillers should be selected considering the water quality characteristics of the area. [Display omitted] • The removal rate of NH 4 +-N and TP remained high at low temperature. • In winter the solid carbon can't enhance the removal of NO 3 −-N and TN. • The effect of packing gradation on water purification is not obvious. • At low temperature, bioretention could not effectively remove COD. [ABSTRACT FROM AUTHOR]