Environmental Science: Water Research & Technology最新文献

The Philippines, one of the most typhoon-prone countries worldwide, faces serious risks to rural sanitation systems. However, limited empirical evidence exists on how typhoons impact household sanitation access. This study examined the effects of typhoons on household sanitation infrastructure and access in three rural municipalities. We carried out a cross-sectional study involving 994 households, in collaboration with community partners. One barangay (village) from each rural district was purposively chosen, and all households were invited to participate. We used bivariate and multivariate logistic regression to identify factors linked to typhoon damage (p < 0.05), and Cox proportional hazards model to assess facility downtime. Before the typhoon event, 29% of households reported using basic sanitation, 42% limited, 22% unimproved, and 7% practiced open defecation. Post-typhoon, basic sanitation coverage dropped to 16%, while unimproved sanitation and open defecation increased to 30% and 15%, respectively. Nearly half of the households using basic sanitation shifted to unimproved services. Typhoon-affected households were more likely to practice open defecation (aOR = 1.60, 95% CI: 1.11–2.29, p = 0.012) and more than twice as likely to report diarrheal disease (aOR = 2.24, 95% CI: 1.22–4.11, p = 0.009). Facilities located further from dwelling areas were more vulnerable to damage (aOR = 3.32, 95% CI: 2.27–4.86). Conversely, facilities with dedicated cleaning staff (aOR = 0.23, 95% CI: 0.15–0.36), repair and maintenance staff (aOR = 0.19, 95% CI: 0.12–0.30), or climate-adaptive measures (aOR = 0.08, 95% CI: 0.05–0.13) showed greater resilience. Median downtime for damaged facilities was two days, though recovery was slower among lower-income households and those with older facilities. These findings demonstrate how typhoons can undo sanitation gains, forcing households to fall back to lower service levels and worsening inequalities. Post-disaster responses should aim to prevent slipping from basic to unsafe sanitation practices. Long-term strategies must incorporate climate-resilient technologies, strengthen community capacity for repairs, and target vulnerable households with support. While current data on the role of community groups in resilience is limited, this study underscores the need for further research into how social support systems can improve sanitation outcomes.

The widespread contamination of industrial wastewater with lead (Pb²⁺) ions poses serious environmental and public health risks due to their toxic, teratogenic, carcinogenic, and mutagenic effects. In this study, an efficient electrocoagulation process (ECP) was explored for the treatment of real textile industrial effluent containing both organic and inorganic pollutants, including Pb²⁺ ions. An aluminium electrode-based electrocoagulation system (Al-ECP) was developed and identified as the most effective configuration for pollutant removal compared to other metal electrode (Fe, Cu, and Zn) based ECPs. The electrochemical processes occurring at the liquid–electrode interface were systematically examined along with long-term cycling stability to ensure electrode durability. Among the investigated electrodes, the Al-ECP exhibited superior performance, achieving 98.5% colour removal, 82.8% Pb²⁺ ion removal, and 90.1% total organic carbon (TOC) reduction within 60 min at a current density of 50 mA cm⁻². Importantly, the TOC concentration decreased significantly from 307.8 mg L⁻¹ to 30.29 mg L⁻¹, while the Pb²⁺ ion concentration was reduced from 520.0 mg L⁻¹ to 89.0 mg L⁻¹. Besides, UV-vis spectroscopic analysis has confirmed efficient colour removal, attributed to the complexation and adsorption of pollutants with the in situ generated amorphous Al(OH)₃ flocs. The successful capture of Pb²⁺ ions in the precipitated sludge was studied by X-ray photoelectron spectroscopy (XPS). Further, a techno-economic analysis has demonstrated the feasibility of the ECP system for industrial wastewater treatment and disinfection. Importantly, the study highlights its superior efficiency, stability, and practical applicability, and that sludge generation was minimal in the Al-ECP system at low operating current densities. Furthermore, the Al electrode dissolution analysis based on Faraday's law showed a faradaic efficiency of 82.24% in effluent treatment. Overall, the findings demonstrate that the Al electrode based ECP is a promising, cost-effective, and scalable approach for sustainable industrial wastewater treatment.

Precise extraction of strategic resources such as lithium and rare earth elements from complex aqueous systems like salt lake brines and industrial effluents presents a major challenge for sustainable water utilization and the circular economy. The core solution lies in developing separation technologies with ultimate ion selectivity. Traditional nanofiltration membranes rely on the Donnan exclusion effect generated by homogeneous surface charges. However, when facing ion pairs with similar hydration radii but different valences (e.g., Li⁺/Mg²⁺), their selectivity falls short of practical resource recovery requirements. The key to overcoming this bottleneck is to reconstruct the charge distribution of the membrane from a static, uniform background to a spatially specific arrangement tailored for the separation target. This article explains the principle of charge-mosaic membranes, which are characterized by the formation of ordered positive and negative charge microdomains on their surface or interior (known as charge-mosaic structures). These microdomains are designed to match the characteristics of target ions, creating electrostatic recognition sites and distinct transport pathways for specific ions. Microscopic physical mechanisms, key fabrication routes, and advanced characterization methods for realizing this paradigm are reviewed. By integrating multiscale simulations and materials informatics, this review aims to provide a clear framework for the rational design and engineered application of electrostatic microenvironments at membrane interfaces, driving a paradigm shift in water treatment and strategic resource recovery technologies.

Heterojunction photocatalysts enable oxidation under exposure to sunlight and eliminate recalcitrant dyes and immobilize microbial pathogens during decentralized wastewater treatment. Harnessing internal electric fields and H₂O₂ autocatalytic cycles within S-scheme, Z-scheme, and photo-Fenton hybrid systems suppresses charge recombination and enhances ·OH flux, representing key technical advancements reported in 2025. Such systems include the needle-like structures of ZrO/NiFe₂O₄ used to remove bisphenol A and 4-nitrophenol, ternary systems such as MoS₂/Bi₂O₃/CdS used to remove nitrophenols, ZnO-hydroxyapatite used to remove ciprofloxacin and methylene blue in domestic sewage, and Ti/graphite photoelectrodes used to remove reactive blue 19 in textile wastewater. Targeted applications include chloride-tolerant fixed-bed reactors for arid Middle Eastern dye effluents and floating platforms for tropical agro-industrial wastewaters to enhance rural and coastal resilience. The obstacles like scattering of light caused by turbidity and humic acid poisoning are neutralized via pre-coagulation, filtration, and mild annealing. This review highlights the dual-target kinetic models that combine H₂O₂ production and consumption cycles under AM 1.5G illumination to achieve performances over 95%. Such innovations align with WHO guidelines for pathogen removal, providing additive-free and scalable decentralized sanitation solutions for underserved areas.

The increasing presence of emerging pollutants (EPs), including chemical and resilient microbial contaminants, in aquatic environments demands multifunctional, sustainable treatment solutions. In this study, a green-synthesized, multifunctional, and multilayered carbon quantum dots (CQDs)-embedded chitosan-doped nZVI nanocomposite (nZVI–Chitosan–CQDs) was developed using waste-derived precursors to achieve synergistic microbial inhibition and chemical adsorption. Response surface methodology (RSM) was employed to optimize synthesis parameters, thereby achieving the maximum yield. Comprehensive characterization using FTIR and XRD for surface functionalization and crystallinity, SEM-TEM imaging for uniform multilayer encapsulation, BET analysis for high mesoporosity, XPS for Fe⁰/Fe²⁺/Fe³⁺ chemical states and strong interfacial bonding, and Tauc analysis demonstrating reduced bandgap and enhanced reactivity confirmed the successful integration of CQDs, chitosan, and nZVI to form a stable core–shell–shell structure. The developed nanocomposite completely inhibited the growth of Escherichia coli, Staphylococcus aureus, and Enterobacter sp., and disrupted the structure and EPS matrix of natural multispecies marine biofilms at 250–500 μg mL⁻¹. High removal efficiencies of 92% for Cr(VI), 89% for drugs, and 94% for dyes were demonstrated by the nanocomposite, which followed Langmuir isotherm behaviour and pseudo-second-order kinetics. The removal mechanism involved Langmuir-type monolayer chemisorption, electrostatic interactions, π–π stacking, surface complexation, and reductive reduction of Cr(VI) by the nZVI core. The antibacterial action was attributed to ROS production, which caused membrane damage and disruption of the EPS matrix, leading to biofilm destabilisation. The adsorption reaction was endothermic (ΔH° > 0) and spontaneous (ΔG° < 0), according to thermodynamic analysis. After multiple regeneration cycles, the nanocomposite maintained over 85% of its efficiency and was biocompatible. Overall, this green engineered nanocomposite presents an efficient, eco-friendly, and sustainable platform for simultaneously removing chemical and microbiological pollutants from contaminated water.

Disinfection is a necessary process during drinking water treatment; however, there is potential risks due to the formation of disinfection by-products (DBPs). Besides the regulated DBPs (THMs and HAAs), there is a growing concern about emerging DBPs (eDBPs), which appear to be much more toxic than the regulated ones. Climate-driven conditions can affect the concentrations and profiles of DBPs and enhance the formation of eDBPs. Since eDBPs are not included in the current monitoring programs, there is a need to predict their concentrations in drinking water using modeling techniques. The aim of this study is the development and application of a predictive modeling framework for the formation of selected eDBPs (haloacetonitriles, haloacetamides, halonitromethanes and haloketones) under chlorination or chloramination conditions in drinking water treatment systems. Through multiple regression analysis, linear and logarithmic models are used based on a dataset that describes the formation of eDBPs under various climatic conditions (seawater intrusion, flooding events, algal blooming and enrichment by humic acid) that could impact water sources. The dataset includes information on the concentrations of eDBPs, water quality parameters and disinfection conditions. Besides DOC and UV₂₅₄, different forms of nitrogen appear to be a significant predicting parameters on the formation of eDBPs, as well as the dose and contact time of disinfection. The proposed relationships can be useful tools for the identification and control of eDBPs in drinking water.

Enhanced biological phosphorus removal (EBPR) enriches polyphosphate-accumulating organisms (PAOs) via alternating anaerobic/aerobic feast–famine cycles to remove phosphorus from wastewater. EBPR can be prone to instability, although the causes are often unclear. Genome-centric metatranscriptomics was used to investigate an EBPR instability event at a full-scale facility that typically experiences a winter instability event to identify changes in microbial community composition and gene expression characteristic of reduced EBPR performance. The facility sampled operates an anaerobic/anoxic/oxic (A2O) EBPR process. Notably, the process monitoring data indicated few process changes beyond increased effluent phosphorus (>3 mg L⁻¹ compared to typical concentrations <0.5 mg L⁻¹) and lower water temperatures during the instability event. Microbial community composition remained consistent before, during, and after the instability event. Two PAO MAGs, Ca. Accumulibacter phosphatis and Ca. Accumulibacter propinquus, were the most abundant and transcriptionally active PAOs. DESeq2 analyses of significantly (adjusted p-value < 0.01) and differentially (|log₂(FoldChange)| >1) expressed genes revealed that the expression of key carbon metabolism, energy metabolism, and denitrification genes that typically peak in the anaerobic zone under anaerobic, high carbon conditions shifted to peak in the anoxic zone during the instability. These results demonstrate a shift in PAO activity, and not community composition, associated with a full-scale EBPR instability event.

The catalytic wet air oxidation (cWAO) technique is applied to treat industrial wastewater with a chemical oxygen demand (COD) value of ∼120 000 mg L⁻¹ in a trickle bed reactor packed with the Fe–Ag bimetal-synthesized carbon nanofiber (CNF) catalyst supported on activated carbon beads (Fe-Ag-CNF/ACB). The catalyst is synthesized using a multi-step thermochemical method involving the suspension polymerization of phenol–formaldehyde co-polymers doped in situ with Fe and Ag salts, followed by carbonization (900 °C, 2 h), steam activation (900 °C, 1 h), hydrogen reduction (650 °C, 2 h), and acetylene-based chemical vapor deposition (650 °C, 1 h). The catalyst is characterized using SEM, EDS, XPS, Raman spectroscopy, and XRD. The cWAO of the wastewater performed under continuous-flow conditions in a packed-bed tubular reactor shows ∼99% COD reduction at 244 °C and 27 bar oxygen pressure. A 25 g catalyst dose showed consistent performance for 12 h, with the COD in the treated water maintained below 2000 mg L⁻¹ at a flow rate of 1 cc min⁻¹ during the continuous operation of the packed-bed reactor. The spent catalyst was successfully regenerated in situ through a well-defined seven-step sequential protocol involving washing with deionized water at 25 °C, dilute acid treatment, washing with acetone, washing with deionized water at 80 °C, steam regeneration, H₂ reduction, and KMnO₄ impregnation, enabling four such regeneration cycles. Upon scale-up, a fourfold increase in the flow rate (4 cc min⁻¹) is possible in the same reactor by increasing the catalyst loading to 100 g. A linear relationship between the catalyst dosage and the treatment capacity confirms that 9.77 g of the catalyst is required for treating 1 L of wastewater. The overall cost, including catalyst synthesis and four in situ regeneration cycles, is determined to be ∼45 336 INR or 495 USD per kg of the catalyst. These findings highlight the potential of Fe-Ag-CNF/ACB as an efficient, regenerable, cost-effective, and scalable oxidation catalyst for the treatment of industrial organics-laden wastewater through the continuous operation of a packed-bed reactor.

Due to their energy efficiency, compactness, and versatility, membrane technologies represent a viable alternative for water purification, replacing more expensive methods such as coagulation and adsorption. Membrane processes commonly used in water treatment include reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF), and microfiltration (MF), which play key roles in desalination and wastewater purification. For example, MF is generally used for the retention of dispersed dyes or pigments and as pretreatment for RO, while UF is often applied to groundwater purification or as pretreatment for NF and RO. Membrane performance depends on composition, structure, morphology, and operating parameters, and can be enhanced by incorporating nanomaterials or other specific additives. Membrane materials can be organic or inorganic. Ceramic membranes, in particular, offer advantages under high temperature, high pressure, and aggressive environments, and the use of natural mineral resources has enabled cost-effective production. Conventional polymer membranes, however, face limitations such as fouling, low chemical resistance, and limited mechanical strength, which affect long-term performance and economic viability. Hybrid membranes have been developed to overcome these challenges and improve pollutant removal efficiency. This paper reviews the main raw materials used to synthesize porous MF and UF membranes, highlighting cost-effective options such as zeolites, chitosan, and waste-derived resources, as well as methods for producing high-performance porous membranes. Despite these advances, addressing challenges related to large-scale fabrication, long-term stability, and industrial implementation remains crucial for the widespread adoption of MF and UF membranes in sustainable water treatment.

With the widespread use of antibiotics in medicine and aquaculture, their environmental residues have become a global issue, disrupting aquatic ecosystems, fostering antibiotic-resistant bacteria and genes, and impairing biological wastewater treatment efficiency. Norfloxacin (NOR), a broad-spectrum antibiotic, enters wastewater treatment systems via incomplete metabolism, exerting chronic adverse effects on functional microbes, pollutant removal efficiency and microbial community stability of traditional biological treatment systems. Aerobic granular sludge (AGS), regarded as an innovative direction in wastewater biological treatment technology owing to its high degradation capacity and resistance to shock loads, has an unclear response mechanism under NOR stress. In this study, 7 mg L⁻¹ NOR was added to sequencing batch reactor (SBR) systems, C–C (graphite-graphite dual-electrode modified SBR) and C–Fe (iron-graphite electrode modified SBR) systems, where the single-point NOR degradation rates reached 92.3%, 87.6% and 95.8% respectively. The dynamic effects of NOR on the morphological structure, biomass, structural-settling stability, extracellular polymeric substances (EPS), and microbial communities of AGS were investigated individually over the long term. After 40 days of NOR exposure, the average AGS particle size rose to 4.03 mm in the SBR system, while stably remaining at 3.19 mm (C–C) and 2.84 mm (C–Fe). The PN/PS ratio of EPS in the C–Fe system was stably maintained at 2–3, and the system exhibited the highest EPS secretion. This research reveals the differential impacts of NOR on AGS stability in different systems, providing a theoretical basis for constructing wastewater treatment systems with high resistance to antibiotics and preventing antibiotic-related environmental risks.