Water Science and Technology最新文献

The persistent contamination of aquatic ecosystems by recalcitrant organic pollutants, including industrial dyes and pharmaceuticals, necessitates the development of efficient and sustainable water treatment technologies. While semiconductor photocatalysis offers a promising route for mineralization, conventional materials such as TiO₂, ZnO, and g-C₃N₄ are severely hindered by their reliance on UV light and rapid electron-hole recombination. Polypyrrole (PPy)-based nanocomposites have emerged as a transformative solution, leveraging PPy's unique conductivity and visible-light absorption to enable highly efficient, solar-driven photocatalysis. Unlike prior surveys that often focus solely on performance, this review systematically connects rational nanocomposite design with fundamental mechanistic insights and, critically, operational stability. The architecture of the catalyst - encompassing core-shell, ternary, and advanced Z-scheme heterojunction systems - constitutes a critical factor governing overall performance. Notably, optimized configurations have demonstrated degradation rates up to fivefold greater than those achieved by more basic designs. However, the literature reveals a crucial trade-off: the most kinetically rapid catalysts often suffer from poor long-term stability, posing a significant barrier to practical deployment. This review explores the intricate relationships between structure, performance, and stability, highlighting evidence-based design principles with direct relevance to the development of scalable water treatment technologies.

This laboratory-scale study investigates the effects of pulsed electric fields on electrochemical water softening using a strategy combining low-frequency pulse co-regulation, grey relational analysis, and neural network optimization. Results indicate that initial hardness, duty cycle, and frequency significantly influence hardness removal efficiency in descending order. Optimized pulse parameters enhance softening efficiency by balancing ion reaction and mass transfer rates, reducing energy consumption and concentration polarization. Under low hardness (≤600 mg L^-1), pulsed operation increases descaling per unit energy by 28.23-43.59% compared with direct current. High-speed imaging revealed that pulse intervals optimize bubble dynamics, promoting detachment with higher density and larger specific surface area, which weakens crystal-electrode adhesion and reduces ion diffusion resistance. The GA-MLP model, combined with grey correlation analysis, optimized softening under high hardness, determining ideal parameters for different hardness levels. Experimental verification confirmed these parameter combinations. The study provides new recommendations for optimizing electrochemical water softening parameters across varying hardness conditions based on laboratory-scale data.

Heavy metals are emerging pollutants that originate largely from anthropogenic activities. Their remediation in the free ion state was successfully achieved by simple alkali precipitation. However, the presence of organic compounds in aqueous media from diverse sources coexisting with heavy metals leads to the formation of stable, soluble, and recalcitrant complexes that challenge conventional treatment methods. Therefore, the remediation of heavy metal complexes (HMCs) has been extensively studied by researchers, resulting in the development of methods and techniques such as the use of chelating agents, bioadsorbents, and advanced oxidation processes for their treatment. In this review, the route to the environment, concentration level, and associated potential harm or damage caused by HMCs were covered. A detailed and comprehensive bibliometric analysis of publications dealing with the methods and mechanisms for the removal of various metal complexes was conducted. This review introduces the chemical interaction within the heavy metal complex (metal + organic ligands), summarises and discusses the newly developed methods, as well as their treatment performance and limitations for such newly formed pollutant compounds. To the best of our knowledge, this is the first article to provide a systematic summary of common and attractive methods employed for the remediation of HMCs.

The pursuit of sustainable livestock farming and environmentally responsible agricultural practices has spurred the development of innovative and affordable wastewater treatment technologies. This study investigates new biological treatment approaches that integrate the complementary processes of filtration, biosorption, and biodegradation to enhance eco-friendly wastewater management. A novel treatment concept was developed, representing a modern modification of the biosorption method that combines the oxidation of organic pollutants with ammonium reduction by an immobilized biocenosis, achieved through controlled aeration zones within a single bioreactor. An experimental facility was constructed and implemented at Feldman EcoPark (Kharkiv region, Ukraine) to serve the wastewater treatment needs of a contact zoo and animal rehabilitation center. The installation consists of a drainage treatment column with filter materials and a bioreactor - rotating biological contactor (RBC) containing microbial communities immobilized on inert carriers. Operational testing demonstrated high treatment efficiency, achieving up to 97.1% reduction in chemical oxygen demand (COD) and 85.6% removal of nitrogen compounds. Among the tested methods, biosorption proved particularly advantageous due to its cost-effectiveness, operational simplicity, and adaptability. The study also evaluated recycled polymers, including post-consumer PET, polycarbonate, and LDPE, as sustainable functional materials supporting filtration and microbial growth in wastewater treatment systems.

Nutrient contamination is a major contributor to eutrophication and water quality degradation worldwide. Conventional treatment technologies often lack selectivity and efficiency in complex aquatic environments, highlighting the need for advanced materials with tailored recognition capabilities. Molecularly imprinted polymers (MIPs) have emerged as promising adsorbents for nutrient remediation due to their high selectivity, stability and reusability. This review synthesizes recent progress on the synthesis strategies of MIPs. Applications of MIPs in removing phosphate, nitrate and ammonia from water are critically examined, with particular attention to adsorption performance under varying environmental conditions. The limitations of current systems, including modest adsorption capacities, incomplete template removal, matrix interferences and scalability challenges, are discussed alongside concerns about the fate and transport of MIPs in natural waters. Finally, the review highlights future opportunities in green synthesis and hybrid MIP composites to overcome current barriers. Collectively, this work positions MIPs as promising next-generation materials for selective nutrient removal and sustainable water remediation.

Coal gangue, a solid waste from coal mining, contains sulfide minerals that oxidize with oxygen and water to produce sulfuric acid, leading to acidic leachate. This leachate, rich in acidic substances and heavy metals, contaminates water sources through runoff or precipitation. To address this, a treatment system combining electrocoagulation and sulfate-reducing bacteria (SRB) was developed. Pine needles, used as a slow-release carbon source, replaced traditional carbon sources for microbial growth and metabolism. The system's key parameters included an electrode spacing of 6.5 mm, a current density of 25.0 mA/cm², a reaction time of 29.5 min, 500 g of pine needles, 260 mL of SRB inoculum, and a daily water intake of 1,300 mL. Over 60 days, water samples were analyzed every 2 days for efficiency and microbial structure. Pine needles effectively released carbon, sustaining microbial activity. Removal rates for total iron (TFe), Mn²⁺, Zn²⁺, and SO₄^2- were 99.5, 95.22, 99.60, and 79.59%, respectively, with effluent pH stabilized between 7.0 and 8.0. Key microbial taxa, including Clostridium, Lutispora, and Citrobacter, decomposed organic matter and reduced sulfate, enhancing treatment efficiency. This system effectively treated acidic coal gangue leachate, complied with standards, reduced environmental impact, and delivered significant benefits.

The intensifying global freshwater crisis has amplified the strategic importance of non-conventional water resources (NCWRs), particularly desalinated seawater (DSW) and potable reclaimed water (PRW). Effectively allocating these diverse NCWRs requires balancing ecological protection with economic development. However, the lack of a systematic method for quantifying their multicriteria value across economic-ecological nexuses hinders sound decision-making. Based on emergy theory, this study improves the comprehensive value assessment framework by adding ecological cost value, which is used to assess the multicriteria value of DSW and PRW. The results show that the ecological costs of DSW and PRW were 5.86 × 10¹⁰ and 2.44 × 10¹¹ sej/m³, respectively, which indicates that the impact of emissions on the environment cannot be ignored. The environmental-economic values of DSW and PRW were 4.137 × 10¹² and 4.80 × 10¹³ sej/m³, with cost-effectiveness ratios of 1:0.001 and 1:4.92, respectively. The assessment framework proposed in this study offers a comprehensive approach to water resource valuation, demonstrating the pronounced advantages of PRW over DSW. Additionally, the active promotion of NCWRs utilization and the continued refinement of the management system are crucial for advancing their development. These findings provide policymakers with a scientifically grounded tool to optimize water allocation strategies that balance economic and environmental objectives.

Bangladesh's textile industry, a cornerstone of the national economy, faces persistent challenges in achieving effluent compliance, particularly for salinity-driven total dissolved solids. A synoptic survey of eight facilities in Dhaka EPZ-2 (n = 24 grab samples) revealed near-universal TDS non-compliance (seven of eight facilities), with outlet concentrations of 1,800-2,950 mg L^-1 exceeding the ECR-2023 limit of 2,100 mg L^-1; one facility (Paddocks Jeans) maintained TDS ≈ 980 mg L^-1. The ecological risk assessment indicated that maximum TDS levels (2,950 mg L^-1) exceeded the LC₅₀ for local aquatic species, aligning with elevated ecological and public health risks. Compliance was evaluated using a normalized Z-score framework, and ecological risks were screened via a locally adjusted risk-quotient approach. Modular reverse osmosis and sludge pyrolysis performance is presented from documented pilots and literature (e.g., RO 85-92% TDS rejection; pyrolysis yielding metal-rich char). Integrating these findings, we propose a staged, SME-feasible pathway: Phase 1 - digital dosing and solar aeration with continuous monitoring; Phase 2 - piloting modular RO or electrodialysis reversal for salinity control and water reuse; and Phase 3 - shared sludge valorization facilities to offset costs and promote circularity. This study provides an actionable roadmap and advanced resource recovery, directly contributing to SDGs 6, 9, and 12 in Bangladesh's textile sector.

During floods, debris accumulates around the pier in the channel. The depth of debris accumulation beneath the water surface significantly influences on local scouring around the pier, and affecting its flood-fighting capacity. Flume experiments were carried out to investigate local scour around the pier when debris accumulations occurred at three distinct levels: on the water surface (H_a/H = 0), in the middle of the water body (H_a/H = 0.5), and near the riverbed (H_a/H = 0.8). Through numerical simulation verified by experiments, the flow characteristics were obtained, and the impact of the subaqueous debris position on the flow field was analyzed. The results show that the debris accumulations significantly aggravate the local scouring around the piers. Longitudinal and transverse maximum scour depths around the pier increase progressively as the debris accumulates from the water surface toward the riverbed. The maximum scour depth is directly proportional to the extent of debris penetration beneath the water surface. Specifically, when the debris is near the riverbed (H_a/H = 0.8), the scour depth reaches its maximum. Compared to without debris, the maximum longitudinal scour depth increases by 28.3%, while the maximum transverse scour depth increases by 53.8%.

Wastewater management challenges can be addressed through source separation strategies, such as urine or grey water separation. To quantify advantages and avoid operational issues, an understanding of the impact of source separation on municipal wastewater treatment plant (WWTP) operation and effluent discharge is necessary. This can be achieved using activated sludge models. A key question is whether detailed chemical oxygen demand (COD) fractionation of domestic wastewater sub-streams is needed or if a load-based approach suffices for simulations. Determining COD fractions of wastewater sub-streams is effort-intensive and uncertain, with unclear effects on simulation improvement. Therefore, a simulation study was conducted, in which urine, grey water, black water, and brown water were subsequently separated from the inflow of a WWTP model. Two distinct fractionation scenarios were investigated: (i) purely load-related separation and (ii) load-related separation with individual COD fractionation. The results indicate that most trends in all source separation scenarios are comparable between both fractionation scenarios for most parameters. Only the COD effluent concentrations for grey water separation showed opposing trends. Differentiated fractionation impacts precipitant consumption in grey and brown water scenarios. Thus, a purely load-related approach suffices to identify the main benefits or operational challenges of source separation on WWTPs.