Coal burning is a major contributor to air pollution. Selecting the optimal coal alternative path with economic feasibility and maximum environmental benefits is an important policy choice to mitigate air pollution. It could provide a basis for the design of energy transition policies and the green development of coal resource-based cities. This study designed a coal substitution policy based on the multi-objective optimization model, explored the optimal coal substitution path in coal resource-based cities with the goal of minimizing the costs and maximizing the benefits of coal substitution, and assessed the maximum emission reduction potential of air pollutants. The results show that: (1) by 2025, coal consumption in the study area must be reduced to 85%. The optimal coal substitution path is 90.00% coal-to-electricity and 10.00% coal-to-gas for civil emission sources and 83.94% coal-to-electricity and 16.06% coal-to-gas for industrial boiler emission sources. (2) by 2030, coal consumption must be reduced to 75%. The optimal coal substitution path is 90.00% coal-to-electricity and 10.00% coal-to-gas for civil sources and 78.80% coal-to-electricity and 21.20% coal-to-gas for industrial boiler sources. (3) by implementing the coal substitution policy, emissions of six key air pollutants such as SO₂, NO_X, CO, VOCs, PM₁₀, and PM_2.5 could decrease significantly.

As a linchpin of global energy conversion systems, the coking industry faces an imperative sustainable transition driven by tightening environmental regulations. The green development of coking enterprises is constrained by persistent heterogeneity across firms, exacerbated by the lack of a standardized enterprise-level evaluation framework—collectively impeding the industry’s green transition. This study established a comprehensive evaluation model for Green Coking Enterprises comprising 124 indicators, drawing on existing research, standards, and regulatory frameworks, and proposed the green coking concept. It covers seven core dimensions: infrastructure, management system, energy and resource inputs, environmental protection, products, by-products, and performance. Through a 2023 case analysis of the Ordos Etuoke Economic Development Zone—a strategic coking cluster positioned along China’s energy transition corridor—the applied framework revealed critical performance gaps. These gaps primarily manifested in three core dimensions: comparative disadvantages in resource consumption efficiency, deficiencies in environmental management systems, and lagging capabilities in deep processing of by-products. Accordingly, four improvement strategies closely aligned with these identified gaps are discussed. The development assessment model for coking enterprises constructed in this study provides a systematic methodology for evaluating the level of green transformation in such enterprises. It holds significant practical value for accurately identifying technical shortcomings, supporting management decision-making, and promoting the green upgrading of the coking industry.

This study explored the utilization of coal gangue with high iron content to synthesize poly-ferric-alum-sulfate (PAFS) and coal gangue leaching residue-PAFS (CG@PAFS) coagulants, which were subsequently applied to treat landfill leachate and its concentrate. The results demonstrated that the PAFS coagulant exhibited notable removal efficiency for key pollutants, including chemical oxygen demand (COD) and total phosphorus (TP), with removal rates of 23.8% and 77.5%, respectively. Its performance was comparable to polyferric sulfate (PFS) and superior to aluminum polysulfate (PAS). Mechanistic investigations revealed that Fe³⁺ in the PAFS coagulant reacted chemically with phosphate ions, forming insoluble precipitates and facilitating phosphate removal through flocculation. Furthermore, PAFS also exhibited moderate removal efficiency for COD and ammonia nitrogen (NH₃-N) via flocculation processes. From a sustainability perspective, this study advances a circular economy model by simultaneously addressing two pressing environmental challenges: the valorization of coal gangue (a massive industrial solid waste) and the treatment of landfill leachate (a hazardous wastewater). Importantly, the post-treatment sludge, rich in available phosphorus and silicon, demonstrates promising potential for beneficial reuse as a soil conditioner, thereby closing the material loop and reducing reliance on virgin chemical resources. This integrated waste-to-resource approach aligns with multiple Sustainable Development Goals (SDGs), particularly SDG 6 (Clean Water and Sanitation), SDG 11 (Sustainable Cities and Communities), and SDG 12 (Responsible Consumption and Production). Overall, this study provides valuable insights into the resource-efficient utilization of coal gangue and presents an effective, low-carbon, and sustainable approach for landfill leachate management.

Water environment management in industrial parks within river basins faces dual pressures from advancing industrialization and the protection of basin ecological environments, necessitating a shift from traditional management models toward more efficient, intelligent, and risk-coordinated approaches. Industrial parks in the Yellow River Basin contribute over 60% of the region’s economic output, yet they commonly suffer from low water use efficiency, low wastewater recycling rates, and high water environment risks, creating a structural contradiction between economic growth and ecological protection. To address this challenge, this study systematically reviews domestic and international practices, identifies development trends, and constructs a theoretical model for industrial park water environment management based on the “Three Waters and One Risk” (water use, pollution control, recycling, and risk prevention) framework, driven by organizational and technical management with smart empowerment as an integrative link. This forms a closed-loop feedback mechanism aimed at the synergistic goals of water conservation, pollution reduction, carbon reduction, and risk mitigation. Unlike existing studies that tend to focus on a single dimension, the model adopts a dual “park-basin” perspective. Furthermore, in contrast to purely theoretical models or single-park case studies, this study conducts an empirical analysis of the Baotou Industrial Park in the Yellow River Basin. It identifies key problems in management systems, policy instruments, and technical pathways, and proposes integrated, context-specific solutions covering organizational optimization, policy improvement, and technical systems for water conservation, treatment, and reuse. The model’s validity is examined through field data validation and comparative validation against the park’s existing management practices, confirming its accuracy in capturing actual conditions and its practical applicability. In conclusion, this study provides both theoretical references and practical guidance for enhancing integrated water environment governance in industrial parks within river basins, with the Baotou case offering a transferable framework for similar parks across the Yellow River Basin. Future research should further validate and refine the model through comparative studies across multiple parks and diverse policy contexts.