Search Results (540)

Access to safe drinking water remains a global public health concern due to its role in the transmission of infectious diseases. Despite the 20th-century achievement of chlorine-based disinfection, drinking water systems face threats from aging infrastructure, climate-induced stressors, and emerging pathogens that evade traditional treatment. This bibliometric review maps three decades of research on microbial contamination in drinking water systems to explain its historical developments, current knowledge, and important updates. Only original and review articles retrieved on 13 April 2026 were screened for inclusion, requiring a focus on detecting, monitoring, or mitigating microbial contamination in drinking water systems. Analysis of 93 records identified a linear growth pattern, shifting from acute enteric pathogen monitoring to the management of opportunistic pathogens (OPs), antimicrobial resistance (AMR), and disinfection by-products (DBPs). Additionally, traditional fecal indicator bacteria (FIB), such as Escherichia coli, may not fully predict the presence of resilient pathogens protected within biofilms or free-living amoebae (FLA), which serve as environmental reservoirs for infection. To address these limitations, this review presents a conceptualization of waterborne pathogens by proposing formal case definitions and diagnostic criteria for critical contamination events (CCE) and chronic low-level exposure (CLLE). Lastly, knowledge gaps and open research questions relevant to future studies on microbial contamination in drinking water systems were identified and discussed. Full article

The valorization of drinking water treatment sludge (DWTS) and eggshell waste represents a promising route for reducing landfill disposal and developing alternative stabilized materials for geotechnical applications. This study aimed to evaluate the mechanical and microstructural behavior of DWTS stabilized with commercial lime (CL) and eggshell-derived hydrated lime (EHL), including alkali-activated EHL systems. EHL was produced from locally collected eggshell waste through washing, drying, grinding, calcination at 1000 °C for 4 h, hydration, drying, and sieving. The mixtures were prepared with lime contents of 5%, 8%, 11%, and 14%, while NaOH solutions of 0.5, 1.0, and 1.5 M were used for the activated systems. A total of 120 cylindrical specimens were compacted under controlled dry unit weight and moisture content and cured for 7 and 28 days. The stabilized DWTS was evaluated through unconfined compressive strength (q_u), SEM–EDS analysis, and multifactorial ANOVA. The highest q_u for CL-treated specimens was 4561.72 kPa at 14% lime and 28 days, while EHL reached its best response at 11% lime and 7 days, with a q_u of 3195.13 kPa. In general, EHL showed a competitive performance at intermediate and high lime contents, although increasing NaOH molarity tended to reduce strength. Full article

Microfiltration membranes are widely used in drinking water treatment due to their high efficiency. However, long-term operation of polymeric membranes may lead to deterioration of hydraulic properties as a result of fouling and material aging. This study aims to determine the impact of long-term aging on hydraulic permeability and separation properties, and to determine the lifespan of microfiltration polyvinylidene fluoride (PVDF) membranes. The practical and industrial novelty of this study lies in providing an authentic, 11-year operational baseline for a full-scale microfiltration system treating highly variable surface water. The study evaluates membranes installed in a full-scale plant in Jarosław (Poland), treating surface water from the San River. The system includes 120 PVDF capillary modules (0.1 μm). After 11 years, the membranes maintained very high separation efficiency, ensuring almost complete removal of turbidity and microorganisms. However, membrane resistance increased nearly threefold, while permeability decreased by about 86%. Maintaining capacity required a gradual increase in transmembrane pressure. The permeability loss exceeded the commonly accepted replacement threshold of 70%, suggesting that membrane replacement after more than a decade of operation is technically and economically justified. Full article

Urban water insecurity is an increasingly critical challenge in rapidly urbanizing regions of the Global South, driven by population growth, environmental degradation, infrastructure limitations, and institutional constraints. Kathmandu Valley, Nepal, exemplifies these interconnected pressures. This study presents a systematic review of 45 peer-reviewed and selected grey literature sources published between 2000 and 2025, conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were included if they examined drinking water contamination, public health risks, household coping practices, wastewater-related exposure, or governance dynamics in Kathmandu Valley, Nepal. Findings were synthesized using a narrative thematic approach. The review identifies widespread contamination across municipal supply systems, groundwater, tanker water, traditional water sources, and household-stored water. Microbial contamination, particularly total coliforms, fecal coliforms, and Escherichia coli, emerged as the most consistently reported and immediate public health concern. Chemical and physicochemical contaminants, including ammonia, iron, arsenic, nitrate, and turbidity, were also widely reported, especially in shallow and deep groundwater systems. Seasonal dynamics further influenced exposure risks, with increased microbial contamination during monsoon periods and greater dependence on alternative and less regulated water sources during dry seasons. The findings further indicate that unsafe water exposure is associated with a substantial burden of waterborne diseases and emerging risks such as antimicrobial resistance. Although household water treatment practices reduced contamination in some cases, risks often persisted due to recontamination during storage and handling. These burdens disproportionately affected marginalized and peri-urban populations with limited access to safe and reliable water infrastructure. The review also highlights persistent governance challenges, including institutional fragmentation, weak regulatory enforcement, inadequate infrastructure investment, and growing dependence on informal water supply systems. Together, these conditions contribute to a hybrid urban water system in which formal and informal sources coexist without consistent quality control. Overall, the evidence demonstrates that water insecurity in Kathmandu Valley is a systemic condition shaped by the interaction of environmental contamination, unequal exposure, household coping limitations, and fragmented governance. By integrating environmental, public health, and governance evidence, this review advances understanding of urban water insecurity in rapidly urbanizing contexts and highlights the need for integrated, equity-oriented, and governance-informed interventions. These findings have broader relevance for cities across the Global South experiencing similar environmental and infrastructural pressures. Full article

Access to clean and safe drinking water for all remains a global challenge, mainly for rural populations and areas affected by natural disasters or humanitarian crises. The traditional water quality treatment technologies can work well in laboratory or controlled settings, but they are usually applied under conditions unavailable in these types of conditions. Traditional water quality treatment methods are limited by established infrastructure, expensive operating costs, energy requirements, and the ability to perform in-field water treatment. To improve the barriers of traditional water quality treatment technologies, recently developed scientific discoveries of nanozymes, a new class of nanomaterials with enzyme-like catalytic activity, have shown the ability to decentralise water purification. Nanozymes provide a mechanism for water treatment that does not require the infrastructure or the cost of traditional water quality treatment methods. Also, nanozymes possess extremely high catalytic activity, chemical stability, are inexpensive, and are suitable for a variety of contaminants. This review gives a systematic overview of the development of suitable nanozyme-based portable water purification systems. It shows their catalytic mechanisms, the class of nanozymes used, and the design characteristics related to their working use, also highlighting the developments that consider the specific needs of rural contexts, provide rapid responses to disaster areas, and offer drinking water with reliable, simple, and sustainable apparatus. Full article

Ensuring safe and palatable drinking water is critical for long-duration space travel and part of NASA’s 2022 strategic goals. This study investigated whether the formation of iodoform occurred when iodine reacts with trace levels of dissolved organic carbon (DOC) leaching from spacecraft water system components. A simplified model of the International Space Station’s Environmental Control and Life Support System was constructed, focusing on disinfection. The system included water storage in low-density polyethylene (LDPE) bags followed by activated carbon block filtration. Three scenarios were tested: iodine treatment in the storage tank, iodine treatment in-line after storage, and a control with no iodine. Preliminary results showed I₂ concentrations of 0.1–5.42 mg/L prior to filtration, which decreased below detection after filtration. DOC concentrations ranged from below detection to 1.1 mg/L. Concentrations of iodoform, determined by gas chromatography–mass spectrometry, were assessed to observe potential risks to spacecraft drinking water quality. Iodine-based disinfection did result in significant iodoform formation or increased leaching of DOC. This study supports that long-term water storage can be achieved using iodine disinfection and LDPE storage. These results also inform the use of iodine disinfection in emergency situations by drinking water managers when water supply is interrupted in disaster situations. Full article

Water is an indispensable resource for the survival of all living organisms on Earth. However, many coastal villages continue to face challenges in accessing potable water, particularly during extended droughts. This comprehensive study evaluates the implementation and performance of a solar desalination system that employs photovoltaic (PV) panels and a parabolic solar concentrator to meet clean water demand in a drought-prone area of Indonesia. The system harnesses both solar-generated electricity and thermal energy to power an advanced desalination apparatus, effectively converting seawater into safe drinking water. Over a rigorous 4-month testing period, the device maintained an average steam outlet temperature of 105.9 °C, enabling a direct single-stage evaporation and condensation desalination process. Under optimal sunlight conditions, the system produced 1500 mL of purified water every 30 min, resulting in a total daily output of approximately 12 L (1500 mL × 8 cycles over 4 h). Laboratory analysis revealed a decrease in pH from 8.0 in raw seawater to 6.8 in treated water after post-treatment pH adjustment, meeting established safety standards for human consumption. Electrical conductivity measurements fell from 40–50 mS/cm to 480–500 µS/cm, confirming substantial salt removal. These results demonstrate the system’s capacity to generate potable water using sustainable energy sources and support circular economy principles by repurposing renewable resources for water desalination in water-scarce environments. Full article

Antibiotic resistance genes (ARGs) are increasingly recognized as a concern in drinking water, yet the factors influencing their persistence from raw to finished water in drinking water treatment plants remain poorly understood. This study investigated the occurrence, removal, and potential factors associated with the persistence of ARGs (sul1, sul2, and tetG) in a full-scale rapid sand filtration drinking water treatment system with intermediate and post-chlorination. ARGs were detected in raw water at a median total concentration of 10⁶ copies/L and remained detectable in finished water at 10⁴ copies/L. Relative ARG abundance increased after treatment despite substantial absolute reductions (2.1–3.6 log). Intermediate chlorination achieved the greatest ARG log reduction value (0.53–2.4 log), likely due to higher chlorine dose and lower pH favoring HOCl formation. By contrast, post-chlorination at higher pH provided limited additional removal, possibly due to predominance of less reactive OCl⁻ and survival of chlorine-tolerant bacteria. Multivariate analyses showed a shift from particle-bound ARGs in raw water to dissolved organic matter (DOM) and fine-particle-associated fractions along the treatment train. These findings suggest that reducing fine particles and DOM, together with optimized disinfection, may help lower ARG-associated risk in finished water. Full article

Safe drinking water production from compositionally variable surface sources requires treatment systems that combine effective contaminant removal with stable membrane operation. This study experimentally evaluated a hybrid treatment train consisting of slow sand or zeolite pretreatment followed by NF for surface water representative of South-East Kazakhstan. The results showed that pretreatment reduced turbidity, iron, and organic load before the membrane stage, thereby improving flux stability and decreasing fouling propensity. Among the tested pretreatment options, zeolite provided the most favorable feed conditions and extended stable membrane operation. These findings demonstrate that the practical performance of NF depends not only on membrane properties but also on effective upstream conditioning of the feed stream. Under the tested recovery conditions, the selected operating regime produced permeate of acceptable final quality, confirming that hybrid pretreatment–NF systems are a robust option for drinking-water treatment from challenging surface sources. Full article

The standard for effective communication between Internet of Things (IoT) devices has been demonstrated by the increasing demand for IoT technologies in Industry 5.0, along with the growing use of actuators, sensors, and automated processes in these settings. De-vice-to-device interactions controlled by communication protocols that specify data sharing are essential to effective operation. By establishing a single standard that permits plug-and-play integration and improves flexibility across various IoT devices, the IEEE 1451 standard represents an approach. This standard ensures interoperability and enables smooth communication with devices from various companies, regardless of their features. By addressing major obstacles to system integration, the IEEE 1451 standard enables IoT technologies to reach their full potential. By integrating information technology (IT) through automation and industrial control systems (ICSs), the Industrial IoT (IIoT) is transforming many industries, especially essential sectors such as energy, chemicals, oil and gas, and water plants. Although drinking water is an essential resource for life and an aspect of technological progress, little is known about the potential for cyberattacks, including the disastrous consequences they could have for water treatment plants. This re-view identifies and documents several adversarial cyberattacks targeting the water distribution and purification sector. Understanding the range of risk factors in this sector is our primary objective. This study presents a technical assessment from an IIoT perspective that addresses attack scenarios, real-world instances of cyberattacks in the water industry, a range of security challenges, and security measures. The contribution is an informative, up-to-date resource that benefits both prospective scholars and industrial practitioners. By integrating key findings to build a secure and reliable digital future, this work will advance a comprehensive understanding of the cybersecurity environment in water plants in Industry 5.0 and smart cities. Full article

Taste is a critical yet under-monitored parameter influencing consumer trust in drinking water. Despite its importance, conventional systems rarely quantify taste objectively for operational management. This study introduces a novel sensor-based Taste Index (TI), developed using a potentiometric electronic tongue (E-tongue) with seven ion-selective electrodes, to enable continuous, quantitative evaluation of taste stability across treatment and distribution systems. Multivariate analyses, including principal component analysis and partial least squares discriminant analysis, characterized treatment-dependent variations and spatial heterogeneity. The TI was defined as the normalized Euclidean distance from the final treated water reference (TI = 0.00). Results showed raw water at TI = 1.00, while a temporary increase to TI = 0.38 post-ozonation indicated the formation of taste-active byproducts. Notably, distribution samples with TI > 0.4 precisely corresponded to areas with documented aesthetic complaints. This research presents the first application of a sensor-derived TI for proactive taste monitoring. By enabling early anomaly detection and process tracking, the TI supports data-driven, consumer-centered water management. Its scalability and real-time applicability position it as a practical tool for smart water infrastructure and enhanced operational control. Full article

This study presents a short-term, IoT-enabled sensor-based assessment of treated municipal water and decentralized groundwater in Bragança, northeastern Portugal. Two drinking-water supply contexts were compared: treated surface-water-derived municipal water from the public supply system and groundwater from a decentralized supply system serving part of a higher education campus. Five sampling points were monitored during three campaigns between January and March 2026. At each point, pH, electrical conductivity, temperature, oxidation–reduction potential, and total dissolved solids were recorded at 10 s intervals over approximately 10 min monitoring windows using a multiparameter probe integrated into an IoT-enabled data acquisition workflow. Microbiological analyses were performed on groundwater samples as complementary information. Treated municipal water showed lower mineralization, narrower parameter ranges, and higher oxidation–reduction potential, reflecting source-water characteristics, treatment, and operational control. Groundwater showed higher mineralization, lower oxidation–reduction potential, and greater variability among sampling points and campaigns, consistent with stronger local hydrogeochemical and operational influences. The repeated short-interval readings provided more detailed physicochemical profiles than isolated spot measurements, although the short monitoring windows do not represent continuous long-term high-frequency monitoring. Overall, the results support standardized IoT-enabled sensor-based monitoring as a complementary tool for short-term water-quality assessment and indicate the need for longer seasonal datasets and laboratory confirmation. Full article

Large portions of rural population in South Africa lack access to basic water and sanitation. This advocates for urgent interventions in support of water supply. This study assessed the performance of solar-powered groundwater pumping systems established at nine pilot sites in rural areas of Greater Giyani Municipality (Limpopo, South Africa). Performance assessment indicators, namely weather, groundwater abstraction, power supply, water supply, water quality, number of beneficiaries and farm productivity, were monitored (2023–2024). Increased groundwater abstraction reduced groundwater levels by 0.4–11 m, depending on the monitored borehole. This was replenished by above-average rainfall in 2023 (≈650 mm). Power supply and pump discharge rates were stable with generally low fluctuations at recommended pumping rates (0.5–2.0 L s⁻¹). Groundwater quality was generally fit to marginal for irrigation and drinking. High levels of NO₃⁻ and total organic carbon, especially in the proximity of villages, mandated the installation of mini water treatment plants for drinking water. The implementation of solar-powered groundwater pumping schemes was generally successful, with more than 5000 villagers benefiting directly from the interventions, whilst smallholder farms turned into commercial and financially viable enterprises. Long-term monitoring of bio-physical and socio-economic drivers is essential to ensure long-term sustainability of the solar-powered groundwater pumping systems. Full article

Damage to urban water supply infrastructure can rapidly compromise access to safe water and force households to rely on alternative sources of uncertain quality. This study presents a case-based assessment of water quality and emergency household-level treatment options in Mykolaiv, Ukraine, following conflict-induced disruption of the centralized water supply system. Water samples collected from selected groundwater and distribution-network points were analyzed for physicochemical, organoleptic, and microbiological indicators, including total dissolved solids, hardness, sulfates, chlorides, iron, permanganate oxidizability, total microbial count, and E. coli. The results showed elevated mineralization, increased sulfate and chloride concentrations, high hardness, organic load indicators, and episodic microbiological contamination in several samples. A low-cost four-stage household treatment procedure combining chemical oxidation, thermal treatment, sorption, and short-term preservation was evaluated as a preliminary emergency approach. The procedure improved odor, taste, hardness, iron content, permanganate oxidizability, and microbiological safety; however, it did not fully reduce total dissolved solids, sulfates, or chlorides to drinking-water standards. Therefore, the treated water should be considered non-potable and suitable mainly for limited domestic and hygienic uses unless additional desalination or blending is applied. The study highlights both the potential and the limitations of simple household-level interventions under emergency water supply disruption and emphasizes the need for decentralized treatment support, monitoring, and long-term infrastructure recovery. Full article

Santiago, Dominican Republic, faces a growing deficit in the supply of drinking water. Rainwater harvesting systems have the potential to provide a reliable and sustainable source of drinking water. This research examines water quality from the pilot testing of a rainwater harvesting system designed to directly capture rainwater in planter boxes, pre-filter it and store it. The pilot testing consisted of a field experiment comparing rainwater harvested with four filter media compositions with varying levels of sand (34, 62, 66 and 76%). From May 2024 to May 2025, bi-weekly water samples were tested for physicochemical and microbiological parameters including pH, electrical conductivity, total dissolved solids, turbidity, biochemical oxygen demand, heterotrophic bacteria, total and fecal coliforms, E. coli, and Enterobacteriaceae. Statistical models were fitted for each water quality parameter, using linear mixed-effects models or generalized linear mixed-effects models with a logit link, to evaluate the association between filter unit design and water quality outcomes. Results showed that physicochemical quality met Dominican drinking water standards but infrequently met bacteriological standards. However, filters with higher sand composition produced higher quality water for both physicochemical and microbiological parameters. Additional treatment such as chlorination would reduce bacteria and protect the water during storage. Full article