When treating municipal wastewater, nitrogen removal is often limited due to low C/N, which needs to be compensated for by additional carbon source injections. This study investigated the feasibility of using industrial-waste polyglycolic acid (PGA) as a carbon source for denitrification in an SBR to obtain an economical carbon source. The results revealed that an optimal denitrification performance in a methanol-fed activated sludge system was achieved with a PGA dosage of 1.2 mL/L, a pH of 7–8, and a dissolved-oxygen (DO) concentration of 3 ± 0.5 mg/L. Under these conditions, all quality parameters for effluent water met the required criteria [COD < 50 mg/L; TN < 15 mg/L; NH₄⁺-N < 5(8) mg/L]. PGA enhanced the variety and richness of microbial communities, thereby markedly increasing the relative abundance of major phyla such as Proteobacteria and Bacteroidota and major genera such as Paracoccus and Dechloromonas. Furthermore, PGA upregulated the expression of nitrogen-metabolism-related genera, including amo, hao, nar, and nor, which improved the denitrification performance of the system. This study provides a reference for applying PGA as a carbon source for low-C/N-wastewater treatment and solid-waste utilization.

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.

This study systematically analyzed research trends in aquaculture wastewater treatment from 2000 to 2024 using bibliometric methods. Through knowledge mapping and keyword co-occurrence analysis conducted with Citespace6.1 software on the Web of Science Core Collection and the CNKI (China National Knowledge Infrastructure) Core Journal Database, we aimed to elucidate the distribution characteristics, evolution of research hotspots, and differences in technological pathways within the existing research landscape, while identifying gaps in integrated knowledge synthesis and cross-regional comparative analysis. The results indicate: (1) China’s publication output in this field over the past five years has significantly surpassed international levels, reflecting an imbalance in regional research activity; (2) antibiotics, nitrogen and phosphorus, organic pollutants, and heavy metals constitute the primary pollutant categories, with increasing attention focused on antibiotic and heavy metal pollution in recent years; (3) domestic research demonstrates a preference for natural ecological treatment technologies, whereas international research is predominantly oriented toward biological treatment technologies. By integrating Chinese- and English-language literature data with visual analytics, this study addresses the existing gap in systematic knowledge mapping and comparative analysis of regional technological pathways, and highlights the ongoing paradigm shift from pollution elimination toward resource recovery. The findings provide an empirical basis for formulating differentiated regional governance policies and guiding investments in low-carbon and environmentally friendly technology research and development, thereby promoting the transition of the aquaculture industry toward green and sustainable development.