Synergistic control potential of flue gas pollutants under Ultra-Low emission standards in waste incineration plants.

As the dominant waste disposal process, incineration is regarded as the main incentive for the "not-in-my-backyard" syndrome, and faces an inescapable pressures of ultra-low emissions (ULE). Establishing precise response relationships between emission factors (EFs) and full-process influencing factors can provide guidance for the synergistic mitigation of flue gas pollutants (FGPs). In this work, the multi-dimensional EFs of FGPs were identified by initially integrating FGPs concentration monitoring data of existing 1,226 processing lines in China, technologies applied and operational experience (OE), local economic and political characteristics. Significant regional imbalance performance was observed, which EFs in the coastal regions were 3.55-92.39 % lower than those of the inland areas. NOx, SO2, HCl were identified as critical components requiring further reduction under the ULE standards, with exceedance rates recorded at 73.07 %, 38.90 %, and 56.69 %, respectively. An indicative value of 20 mg/m3 for PM is recommended for the control of heavy metals of Cd + Tl and Sb + As + Pb + Cr + Co + Cu + Mn + Ni based on the correlation coefficients of r = 0.28 (p < 0.001) and r = 0.20 (p = 0.002), respectively. Waste composition and OE were quantified as the main contributors of EFs' disparities by the tree-branching controlled variable approach established in this study. Predictive models for FGPs control process and corresponding EFs were constructed. EFs of nine FGPs in 2030 would decrease by 0.97-65.42 %, due to more complex purification processes employed to meet ULE's limitations, such as the application of five-stage processes growing from 45.60 % to 58.28 %. While regional imbalance in EFs-SO2 and EFs-HCl were extended with increases from 25.83 % to 33.07 % and 9.91 % to 32.32 %, respectively, due to the consistent disparities of OE and growing heterogeneity of control policies. Enhancing interregional empirical exchanges, reducing the regional market monopolies, and formulating technical guidelines would be beneficial to synergize the reduction of FGPs emissions and alleviate regional imbalance.

Inhalation health risk assessment of incineration and landfill in the Bohai Rim, China.

An inhalation health risks assessment of 96 waste to energy (WtE) plants and 178 landfills in the Bohai Rim, located in northeast China, has been conducted. Based on the latest emission inventories in 2020, WRF/CALPUFF was used to simulate the diffusion of pollutants. Population-weighted hazard index (HI) and carcinogenic risk (CR) of incineration and landfill for each pollutant and each target organ impacted were calculated. The health risks of incineration and landfill were correlated with per capita municipal solid waste (MSW) disposal quantity, emission factors, pollutant toxic effects and local migration and diffusion conditions. The HI of incineration and landfill in the Bohai Rim were 4.07 × 10-3 and 4.79 × 10-3, respectively, which was lower than the acceptable level (HI < 1), while the CR of incineration and landfill were 4.72 × 10-7 and 2.58 × 10-7, respectively, which was also lower than the acceptable level (CR < 1 × 10-6). The non-carcinogenic risks of incineration mainly targeted respiratory system and development system, while the non-carcinogenic risks of landfill mainly targeted nervous system and respiratory system. The carcinogenic risks of incineration mainly targeted respiratory system and digestive system, while the carcinogenic risks of landfill mainly targeted hepatic system and respiratory system. With the trend that incineration phase in, while landfill phase out, the number of patients for 15 target organ diseases caused by the disposal of unit mass MSW would decrease in the Bohai Rim, ranging from 1.8 × 10-8 - 1.8 × 10-2 (pop/t)，especially in developed provinces, such as Beijing and Tianjin. However, the number of patients for 4 target organ diseases caused by the disposal of unit mass MSW would increase, ranging from 1.18 × 10-6 - 5.28 × 10-3 (pop/t). Based on pollutants' pathogenic mechanisms, this study innovatively accessed and compared incineration and landfill's health risks of target organs, and provide technical and policy suggestions based on the changing trend of MSW disposal methods in the future.

Air Pollutant Emission Inventory of Waste-to-Energy Plants in China and Prediction by the Artificial Neural Network Approach.

The waste-to-energy (WTE) plant has been deployed in 205 cities in China. However, it always faces public resistance to be built because of the great concerns on flue gas pollutants (FGPs). There are limited studies on the socioeconomic heterogeneity analysis and prediction models of WTE capacity/ FGP emission inventories (EIs) based on big data. In this study, the incinerator level emission factors (EFs) in 2020 of PM, SO2, NOx, CO, HCl, dioxins, Hg, Cd + Tl, and Sb + As+ Pb + Cr + Co + Cu + Mn + Ni were calculated based on 322,926 monitoring values of all the 481 WTE plants (1140 processing lines) operating in China, with uncertainties in the range of ±34.70%. The EFs were significantly 45-96% lower than the national standard (GB18485-2014) and had negative relationships with local socioeconomic elements, while WTE capacity and FGP EIs had significantly positive correlations. Gross domestic product, area of built district, and municipal solid waste generation were the main driving forces of WTE capacity. The WTE capacity increased by 150% from 2015 to 2020, while the total emission of PM, SO2, CO, dioxins, Hg, and Sb + As + Pb + Cr + Co + Cu + Mn + Ni decreased by 42.46-88.24%. The artificial neural network models were established to predict WTE capacity and FGP EIs in the city level, with the mean square errors ranging from 0.003 to 0.19 within the model validation limits. This study provides data and model support for the formulation of appropriate WTE plans and a pollutant emission control scheme in different economic regions.