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The highly-efficient treatment of coal mine water with low energy consumption contributes to much safer and more efficient coal mining. At present, mine water processing at underground is still limited for its small treatment water yield, large land coverage and high operation cost in ground treatment, high drainage costs when mine water is discharged into the surface water system. In this light, this study puts forward the "deep ground-underground-surface ground" linkage system for mine water treatment and utilization. The treated mine water is partially used for mining production and residential usage, while the rest is subject to deep reinjection or drainage. This paper first introduces the operational mechanism behind this system, and then evaluates its validity in terms of water quality, water quantity, hydrogeology, underground structure, and feasibility of recharge engineering. This study then reviews existing mine water treatment methods for varying water qualities and the "underground-surface" joint treatment system; Also, a summary is drawn regarding the selection of aquifer for reinjection purposes, reinjection construction operations, reinjection tests, simulation of reinjection water quality, and analysis of reinjection safety.

Sludge disintegration is an environmental and industrial challenge that requires intensive research and technological development. Sludge has a complex structure with a high yield of various chemical and biological compounds. Anaerobic digestion is the most commonly used process for sludge disintegration to produce biogas, detoxify sludge, and generate biosolids that can be used in agriculture. Biological cell lysis is the rate‐limiting cell lysis. This review discusses the application of sonolysis as a sludge pretreatment for enhanced anaerobic digestion via three combined processes: thermal destruction, hydrochemical shear forces, and radical oxidation. The mechanistic pathways of sono‐pretreatment to enhance biogas, sludge‐enhanced dewatering, activation of filamentous bacteria, oxidation of organic pollutants, release of heavy metals, reduction of bulking and foaming sludge, and boosting ammonia‐oxidizing bacterial activity are discussed in this review. This article also discusses the use of ultrasound in sludge disintegration, highlighting its potential in conjunction with Fenton and cation‐binding agents, and reviews common large‐scale sonoreactors available on the market.. [ABSTRACT FROM AUTHOR]

This review examines the technological bottlenecks, potential solutions, and future development directions in the treatment and resource utilization of semi-coking wastewater (SCOW) in China. By comprehensively investigating the semi-coking industry and analyzing wastewater treatment research hotspots and existing projects, this study systematically explores the current status and challenges of each treatment unit, emphasizing the necessity for innovative wastewater treatment technologies that offer high efficiency, engineering feasibility, environmental friendliness, and effective resource recovery. This review highlights prospects and recommendations, including the development of novel extractants for phenol and ammonia recovery, a deeper understanding of biological enhancement mechanisms, exogenous bio-enhancement materials, and the creation of cost-effective advanced oxidation process (AOP)-based combined processes. Additionally, it underscores the potential for repurposing SCOW as a valuable resource through appropriate treatment, whether recycling for production or other applications. [ABSTRACT FROM AUTHOR]

Fluoride has become a globally concerning pollutant due to its potential toxicity and negative health impacts. Adsorption has been regarded as the most promising approach for the elimination of fluoride contamination owing to its cost-effectiveness and high efficiency. Nanomaterials are excellent adsorbents for defluoridation due to their high specific surface area, high adsorption properties, and ease of self-assembly. However, there are still some challenges in the application of nanoadsorbents for wastewater treatment. Therefore, this review summarizes the research progress of nanoadsorbents for fluoride removal and develops a fundamental understanding of the structure and adsorption properties of nanoadsorbents in different dimensions. It studies the synergistic effects of different nano- components in adsorption capabilities. In addition, challenges related to the engineering applications of nanoadsorbents and some suggestions to address these issues are presented to promote their practical application prospects. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFASs) are bioaccumulative and widely distributed persistent organic pollutants (POPs). Understanding the distribution of and ecological risks posed by PFASs is critical, particularly for PFAS emissions and accumulation from a common urban pollution source. The transformation characteristics and ecological risks of PFASs from a typical aging municipal landfill leachate were systematically monitored and assessed over five years in this study. The results showed that the total PFAS concentrations (ΣPFASs) in the rivers were between 26.4 and 464.3 ng/L, whereas in sediment, ΣPFASs ranged from 9.5 to 58.5 ng/g (w/w). The presence of perfluorooctanoic acid (PFOA) was the most prominent PFAS in both water (39.4–152.3 ng/L) and sediment (1.1–56.1 ng/g). In a five-year monitoring study, the concentration of PFASs in the aging landfill decreased by 23.3%, with higher mean concentrations observed during summer (307.6 ng/L) compared to winter (250.4 ng/L). As for the pollution distribution, the suspended particulate matter–water partition coefficient (log Kd) of carboxylic acid (PFCAs) and perfluoroalkane sulfonic acids (PFSAs) ranged from 1.53 to 2.65, and from 1.77 to 2.82, respectively. PFSAs and long-chain PFCAs exhibited a greater propensity for sediment association compared to short-chain PFCAs. An ecological risk assessment of four typical PFASs, PFOA, perfluorooctane sulfonate (PFOS), perfluorobutanoic acid (PFBA), and perfluorobutane sulfonic acid (PFBS), utilizing the hazard quotient method revealed that the rivers surrounding the typical aging landfill exhibited a low contamination risk for PFOA, while no ecological risks were associated with the other three FPASs. This study contributes to an enhanced comprehension of the occurrence, distribution, and risk of PFASs in the rivers in rivers and sediment surrounding a typical aging landfill site in China, thereby providing crucial reference information for ensuring water quality safety. [ABSTRACT FROM AUTHOR]

Aair quality issues and respiratory diseases have become issues of particular concern since the outbreak of the COVID-19 pandemic. The indoor air quality of crowded places such as underground metro stations has received growing attention from passengers and staff, thus requiring both qualitative and quantitative assessment. However, the traditional fuzzy comprehensive evaluation is ineffective in this respect. Therefore, this paper proposed the method of optimal combination weight and improved fuzzy comprehensive evaluation to assess the air quality. First, subjective weights were calculated with the multiple-input weighted precedence chart and analytic hierarchy process; objective weights were computed using the entropy weight and exceedance multiple methods. Second, the moment estimation theory was introduced for the optimal combination of these weights. Results show that the optimal combination weighting method achieves the minimum relative deviation. Moreover, in the traditional fuzzy comprehensive evaluation, the air quality is generally classified based on the maximum membership, and the evaluation is inapplicable when the validity (K0) is less than 0.5. Therefore, the concept of confidence was introduced herein for improvement. Finally, the optimal combination weight and improved fuzzy comprehensive evaluation is proved to be the most reasonable in comparison with the traditional fuzzy comprehensive evaluation and indoor air quality index. This study not only suggests a good method to assess the indoor air quality of metro stations but also provides references for decision makers. [ABSTRACT FROM AUTHOR]