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Alternative water disinfectants to chlorination need to be identified because its effectiveness is limited by water pH and potentially carcinogen by−products resulted from chlorination and organic compound reaction. The first study aimed to evaluate the effect of different drinking water chemical disinfection treatments on water quality, its potential hazard effects on animal health, water and feed consumption, and apparent total tract digestibility in dairy beef bulls fed high-concentrate diets. For 224 days, 24 Holstein bulls (176 ± 16.3 kg BW, and 149 ± 5.8 days of age) were individually assigned to one of four treatments with different drinking water chemical disinfectants: without disinfection (CTR); acidification and chlorination (ACCHL; 0.65 mL/L H3PO4 and 0.14 mL/L NaClO 15%); hydrogen peroxide (PER; 0.15 mL/L); and chlorine dioxide (DIO; 2.50 mL/L). Data were analysed with a mixed-effects model. Treatments affected the chemical characteristics of the water: in ACCHL, pH was 6.60 and free residual chlorine was 0.75 mg/L; in PER, H2O2 was 10.6 mg/L; and in DIO, ClO2 was 0.52 mg/L. Water physicochemical quality parameters in all treatments were below maximal thresholds established for safe water consumption by the Water Safety Royal Decree (RD 140/2003). In addition, the total coliform count of treated waters was reduced (P = 0.01) compared with CTR; moreover, ACCHL and DIO treatments were more effective in reducing total coliform count than PER. Dry matter intake tended (P = 0.07) to increase in DIO compared with CTR. Treatments did not affect blood parameters nor apparent total tract digestibility. The second study aimed to evaluate the potential benefit on animal performance of two drinking water disinfectants under commercial conditions in dairy beef crossbred Holstein bulls fed high-concentrate diets. Ninety-six animals (307 ± 4.4 kg BW, and 224 ± 1.8 days of age) were allocated to six pens for 140 days and assigned to one of two treatments: ACCHL, most common water disinfectant, and DIO. Data were analysed with a mixed-effects model. Water total coliform count and water consumption were similar between treatments. Concentrate intake was greater (P = 0.02) in ACCHL for the last 14 study days. Growth performance and carcass quality were similar between treatments. In summary, acidification and chlorination, H2O2, and ClO2 as drinking water disinfectants in dairy beef bulls had good disinfecting activity without detrimental effects on health and nutrient digestibility, and performance.

Clean and safe water is a fundamental requirement for human survival and well-being. The destruction of civilian infrastructure during wars or natural disasters can severely limit access to clean water for the local population, military, rescue workers and volunteers. The objective of the study was the evaluation of the efficiency of fresh water disinfection by electrolytic ozonation. The ozone concentration was measured photometrically by the intensity of the colour change in the reaction with N, N-diethyl-p-phenylenediamine sulfate. The water quality was assessed microbiologically by determining the total microbial count of the samples and by analysing the colour of the bottom of the flasks in which the water samples were stored. The efficiency of ozonation of artesian water in the field was evaluated. Electrolytic ozonation of 500 mL of spring water for two and five minutes produced an aqueous ozone solution with a concentration of 0.74 and 1.72 mg/L, respectively. Electrolytic ozone decomposed slowly and was detected in the samples three days after the water treatment. Ozonation of spring water for 5 and 10 minutes effectively inactivated all natural microorganisms (2.11 log CFU/mL), the water remained sterile and without any colour changes for a month. Water samples ozonated for 2 minutes did not demonstrate any visible changes after a month of storage, however the natural microflora partially recovered. Planktonic microorganisms in the amount of 2.33 log CFU/mL, as well as biofilms on the walls of the flasks, were detected in a month in the control water samples. The colour of the bottom of the control flasks changed to dirty yellow. In the field, ozonation of water for 10 minutes prevented its spoilage even when the recommended treatment volume was increased by 10 times. The obtained results indicate that electrolytic ozonation is an effective method of freshwater disinfection, and portable ozonators can play an important role in emergency water purification in areas of armed conflicts or natural disasters

Singlet oxygen (1O2) plays a significant role in environmental and biomedical disinfection fields. Electrocatalytic processes hold great potential for 1O2 generation, but remain challenging. Herein, a facile Ni doping converted spin‐state transition approach is reported for boosting 1O2 production. Magnetic analysis and theoretical calculations reveal that Ni occupied at the octahedral site of Co3O4 can effectively induce a low‐to‐high spin‐state transition. The high‐spin Ni−Co3O4 generate appropriate binding strength and enhance electron transfer between the Co centers with oxygen intermediates, thereby improving the catalytic activity of Ni−Co3O4 for effective generating 1O2. In neutral conditions, 1×106 CFU mL−1 Gram‐negative ESBL‐producing Escherichia coli (E. coli) could be inactivated by Ni−Co3O4 system within 5 min. Further antibacterial mechanisms indicate that 1O2 can lead to cell membrane damage and DNA degradation so as to irreversible cell death. Additionally, the developed Ni−Co3O4 system can effectively inactivate bacteria from wastewater and bioaerosols. This work provides an effective strategy for designing high‐spin electrocatalysis to boost 1O2 generation for disinfection process. [ABSTRACT FROM AUTHOR]

Water scarcity and contamination are urgent issues to be addressed. In this context, different materials, techniques, and devices are being developed to mitigate contemporary and forthcoming water constraints. Photocatalysis-based approaches are suitable strategies to address water contamination by degrading contaminants and eliminating microbes. Photoreactors are usually designed to perform photocatalysis in a scalable and standardised way. Few or none have been developed to combine these characteristics with portability, flexibility, and cost effectiveness. This study reports on designing and producing a portable (490 g), low-cost, and multifunctional photoreactor that includes adjustable radiation intensity and two types of wavelengths (UV-A and visible), including combined agitation in a compact mechanism produced through 3D printing technology. The mechanical, electrical, and optical subsystems were designed and assembled into a robust device. It is shown that it is possible to apply radiations that can reach 65 mW/cm2 and 110 mW/cm2 using the installed visible and UV LEDs and apply mechanical agitation up to 200 rpm, all under a ventilated system. Regarding functionality, the photoreactor proof of concept indicated the ability to degrade ~80% and 30% ciprofloxacin under UV and visible irradiation of TiO2 and Ag/TiO2 nanoparticles. The device also showed the ability to eliminate E. coli bacteria, recurring to radiation set-ups and nanoparticles. Therefore, the originally designed and constructed photoreactor concept was characterised and functionally validated as an exciting and flexible device for lab-scaled or outdoor experiments, assuring standardised and comparable results. [ABSTRACT FROM AUTHOR]

Designing efficient antimicrobials for the rapid disinfection of water is increasingly critical owing to the rising threat of pathogenic microorganisms. In this study, direct Z-scheme Bi 2 WO 6 /TiO 2 heterojunctions were constructed using a simple in situ hydrothermal method. The optimal Bi 2 WO 6 /TiO 2 Z-scheme heterojunction inhibited 98.80 % of Escherichia coli (5 × 108 CFU mL−1) at 0.35 mg mL−1 and 99.33 % of Staphylococcus aureus (5 × 108 CFU mL−1) at 0.5 mg mL−1 after 10 min of light-emitting diode (LED) light irradiation. Furthermore, in antibiotic degradation experiments, Bi 2 WO 6 /TiO 2 had a 92.91 % removal rate for ciprofloxacin with a pseudo-second-order degradation rate constant (k) of 0.056 min−1 after 240 min of irradiation. The antibacterial mechanism of Bi 2 WO 6 /TiO 2 was systematically investigated and confirmed to occur by LED light-driven surface activation and efficient charge transfer. The surface and interfacial structures of the Bi 2 WO 6 /TiO 2 samples were studied by high-resolution transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The antibacterial mechanism was studied by controlled experiments and electron spin resonance analyses, which revealed that the primary antibacterial mechanism of Bi 2 WO 6 /TiO 2 is oxidative sterilisation via generated reactive oxygen species. Time-resolved fluorescence spectroscopy was used to analyse the charge-transfer pathway in Bi 2 WO 6 /TiO 2 , which demonstrated that the spatial separation of the redox-active sites extended the lifetimes of the photogenerated carriers, enhancing the oxidative destruction of bacteria. This comprehensive understanding paves the way for the design of new Z-type heterojunction photocatalytic materials for antimicrobial applications. [ABSTRACT FROM AUTHOR]

In food safety implementation, bacterial inactivation is an imperative aspect of hygiene and sanitation. Studies on lithium magnesium silicate (LMS) hydrosol incorporated with slightly acidic electrolyzed water (SAEW) for decontamination of pathogenic bacteria are limited. This present study aimed to investigate the bactericidal efficacy of LMS hydrosol incorporated with SAEW against Escherichia coli. Optimum combination conditions of SAEW, hydrosol concentration, and available chlorine concentration (ACC) were optimized by response surface methodology under the central composite design against the growth of E. coli. The optimum combination conditions of exposure time, hydrosol concentration, and ACC were 9.5 minutes, 1.7%, and 20.5 ppm, respectively. The results showed that the increase in ACC led to inactivation in the survival of E. coli compared with the control (p<0.05). It can be concluded that the best combination percentage between SAEW and hydrosol ranged from 1.5-1.7%, in which E. coli was reduced by 4.50 log10 CFU/mL at an ACC of 9.94 ppm. When increasing the ACC to 14.84 ppm, E. coli was reduced by 4.51 log10 CFU/mL compared with the initial number of bacteria (8.20 log10 CFU/mL) in the control group. The number of bacteria was undetected after increasing ACC to 19.93, 25.15, and 29.88 ppm at 10 min. This study suggests that LMS hydrosol incorporated with SAEW could potentially be used as an effective sanitizer. [ABSTRACT FROM AUTHOR]

In this paper, IEC 61511 was used to evaluate the hazards and risks associated with the continuous operation of the hydrolysis reactor system in the copper-chlorine thermochemical hydrogen production cycle, with a specific focus on the application of automated active safety systems and safety integrated systems. The analysis presented herein was performed using a speculative but representative hydrolysis piping and instrumentation diagram (P&ID) for the hydrolysis reaction, which was based on currently published systems as well as experience with experimental hydrolysis reactors. This analysis was then used to inform the design of a set of automated safety systems that provide the redundant operation of critical devices and can bring the hydrolysis to a safe shutdown state if needed. [ABSTRACT FROM AUTHOR]

Leafy vegetables contain nutritious levels of vitamin C. Good postharvest management and food safety are the focus of reducing food loss. This study aims to evaluate the effectiveness of superoxide water in stabilizing the Vitamin C level and simultaneously prolonging the storage period for bok choy (Brassica rapa var. chinensis). The bok choy samples were immersed in superoxidised water [100 ppm Active chlorine concentration, neutral pH] and sodium bicarbonate solution for three different soaking periods: 5, 10, and 15 minutes and stored at 4°C. Weight loss, vitamin C, and chlorophyll content were evaluated during the 12 days of storage. The shelf life of bok choy treated with superoxidised water was extended from 3 days at room temperature to 8 days at 4°C. The results indicated that superoxidised water with a 5-minute treatment time could maintain a better quality of bok choy, which provides a cost-effective and sustainable alternative for chemical washing agents in the food industry compared to market-available sodium bicarbonate. [ABSTRACT FROM AUTHOR]

The use of integrated plasma-activated water (PAW) with micro/nanobubbles (MNBs), ultraviolet (UV) photolysis, and ultrasonication (US) for the synergistic efficiency of Escherichia coli inactivation in chicken meat was investigated. A 2k factorial design was employed to optimize the combined treatment parameters for pathogen disinfection in Design of Experiments (DOE) techniques. Its effectiveness was evaluated based on electrical conductivity (EC), oxidation–reduction potential (ORP), hydrogen peroxide (H2O2) concentration, and E. coli inactivation. The most significant impact on E. coli reduction was observed for MNBs, UV treatment time, and their interaction (MNBs and UV). Optimal E. coli inactivation (6 log10 CFU/mL reduction) was achieved by combining PAW with MNB and UV for 10 and 20 min, respectively. Integrating PAW with appropriate supplementary technologies enhanced E. coli inactivation by 97% compared to PAW alone. This novel approach provides a promising alternative for pathogen control in chicken meat, potentially improving food safety and shelf life in the poultry industry. [ABSTRACT FROM AUTHOR]

Electro-catalytic technology is a promising approach for wastewater treatment, owing to its easy operation, minimal generation of secondary pollution, small foot-print and rapid start-up. In this work, the chlorine evolution potential of the Pd-Sn modified ruthenium(Ru)-iridium(Ir) electrode was investigated for the electro-catalytic treatment of high chlorine ammonia-nitrogen wastewater. The effect of reaction conditions on the removal of ammonia-nitrogen, kinetics and apparent activation energy of ammonia-nitrogen removal were studied. The possible denitrification process of high chlorine ammonia-nitrogen wastewater was discussed. The results indicated that the chlorine evolution potential of the Pd-Sn modified Ru-Ir electrode was 1.0956 V(vs. SCE). The electro-catalytic treatment of high chlorine ammonia-nitrogen conformed to zero-order kinetic law, and the apparent activation energy of removal process was 14.089 kJ/mol. With a current was 0.5 A, the removal efficiency of ammonia-nitrogen could achieve 100% at a reaction time of 40 min. Indirect oxidation played an essential role in the electro-catalytic ammonia-nitrogen removal using the Pd-Sn modified Ru-Ir electrode. This paper demonstrated that the electro-catalytic technology was a promising approach for efficiently treating the high chlorine ammonia-nitrogen wastewater. [ABSTRACT FROM AUTHOR]

Sodium hypochlorite (NaClO) is used on a large scale for water disinfection, fabric bleaching, and odor removal. It is preferred due to the environmental risk of liquid chlorine associated with storage and transport. The objective of the research was the electrochemical generation of sodium hypochlorite from an aqueous solution of sodium chloride. Different operating conditions affecting the sodium hypochlorite generation process were studied, including electrical potential (6 and 10 V), sodium chloride concentration (80 and 120 g/L), and electrolysis time (30 and 60 minutes. To analyze the effect of the factors with respect to the response variable such as sodium hypochlorite concentration and energy consumption per kilogram of hypochlorite produced, a two-level factorial design was used for each factor. The best operating conditions produced when the applied electric potential was 10 V, sodium chloride concentration 120 g/L, and treatment time of 60 minutes reaching a concentration of 2276 g/L NaClO and a free chlorine percentage of 0.23 %. As well, the energy consumption per kilogram of hypochlorite is in the range of 3.31 and 11.78 kWh/kg. [ABSTRACT FROM AUTHOR]

α‐Methylene‐γ‐butyrolactone is an important skeleton in many natural products and pharmaceuticals. The factors influencing the palladium‐catalyzed asymmetric synthesis of α‐chloromethylene‐γ‐butyrolactones were investigated, including ligands, additives, the chlorine source, temperature, and solvents. We found that the reaction had broad substrate scope for the synthesis of the corresponding chiral products when the ligand, chlorine source and additives were optimized. The results will improve the catalytic synthesis of chiral α‐chloromethylene‐γ‐butyrolactones. [ABSTRACT FROM AUTHOR]

We report a ligand‐to‐metal charge‐transfer (LMCT) process that used ferric (III) chloride as efficient chlorination reagent to mediate the vicinal dichlorination of alkenes. Under 420 nm LED light, the easily available and safe ferric (III) chloride could facilitate various alkenes to transform as 1,2‐dichloride compounds with good to excellent yields (19 examples). The strategy showed a more economic protocol than CuCl2, and provided a significant reference for the light‐Induced dichlorination in industrial catalysis. [ABSTRACT FROM AUTHOR]

Powdered infant formula (PIF) is prone to Cronobacter sakazakii (C. sakazakii) contamination, which can result in infections that endanger the lives of newborns and infants. Slightly acidic electrolytic water (SAEW) has shown antibacterial effects on a variety of foodborne pathogens and has a wide applicability in the food industry. Here, the antibacterial activity of SAEW against C. sakazakii and its use as a disinfectant on contact surfaces with high infection transmission risk were investigated. The inactivation of SAEW on C. sakazakii was positively correlated to the SAEW concentration and treatment time. The antibacterial effect of SAEW was achieved by decreasing the intracellular adenosine triphosphate (ATP), K+, protein, and DNA contents of C. sakazakii, reducing the intracellular pH (pHin) and destroying the cell morphology, which led to inactivation of C. sakazakii ultimately. To test the applicability of this study, the results showed that approximately 10³ CFU/cm² of C. sakazakii were successfully inactivated on stainless steel and rubber surfaces after a 30 mg/L SAEW treatment for 20 s. These results indicate the antibacterial mechanism and potential application of SAEW against C. sakazakii, as well as a new strategy for the prevention and control of C. sakazakii on stainless steel and rubber surfaces. [ABSTRACT FROM AUTHOR]

[Display omitted] • The evolution and speciation of chlorine during ASR pyrolysis are studied. • Org-chlorine can be converted to InO-chlorine and remain in char. • Up to 12% and over 64% of chlorine are migrated to HCl and char, respectively. • Rising temperature promotes the conversion from Org-chlorine to inorganic in char. • Calcium-based compounds in ASR play a predominant role in the capture of chlorine. Disposal of automobile shredder residue (ASR) via pyrolysis enables the recovery of valuable products; however, the production of hazardous pollutants and low-value products is inevitable due to its high chlorine content. In this work, chlorine evolution behavior and the conversion mechanism during ASR pyrolysis between 480 and 600 °C were systematically studied. The experimental results for organic chlorine (Org-Cl) showed that released chlorinated gases were complex, and HCl only accounted for 35% of the gas phase products, while short-chain hydrocarbons with carbon atoms between two and four accounted for 52%. Chlorine was predominantly retained in the char, and Org-Cl was the primary contributor to the residual chlorine, accounting for over 50% of the char. The content of inorganic chlorine (InO-Cl) was low in the raw sample but significantly increased in the char. Through the distinction between organic and inorganic chlorine content in char, it was confirmed that Org-Cl could be converted to InO-Cl due to complex secondary reactions with metallic compounds. The conversion was favored by increasing the Org-Cl content and the temperature. Our findings clarified the evolution mechanism of chlorine and the transformation from Org-Cl to InO-Cl, thus providing guidance for chlorine regulation and the efficient recycling of metal resources. [ABSTRACT FROM AUTHOR]

Chlorination is a commonly used disinfection method in sewage treatment process. However, resistant bacteria may survive chlorination and enter the receiving aquatic environment upon effluent discharge. There has been limited research on the effects of chlorination on bacterial survival in seawater. To address this knowledge gap, microcosm experiments were conducted to simulate the discharge of chlorinated effluents into coastal seawater. The results revealed that bacterial communities in seawater‐based effluents survived better in seawater than those in freshwater‐based effluents. High chlorine dosages could significantly reduce the viable bacterial populations and their chance of regrowth in seawater. Additionally, faecal indicator bacteria (FIB) that entered the viable but non‐culturable (VBNC) state under chlorination tended to persist in the VBNC state without resuscitation during seawater incubation. Because of the prevalence of VBNC indicator bacteria, qPCR quantification of FIB was more effective than conventional culture‐based methods in tracing viable pathogenic chlorine‐resistant bacteria, although the correlation strength varied depending on the type of effluent. This study sheds light on how chlorine dosages and the intrinsic properties of effluents affect bacterial survival in seawater and highlights the potential and limitations of using FIB in monitoring the health risks associated with the discharge of chlorinated effluents. [ABSTRACT FROM AUTHOR]

Predictive models of disinfection byproducts (DBPs) formation in treated drinking water have been widely used to guide operational decisions. However, very few studies have addressed the issue of managing DBPs through watershed protection programs and proactive management of water supply systems through predictive modeling of DBP formation potential in source waters. Here, we propose a two‐component, simple statistical approach to predict the formation potentials of the sum of five haloacetic acids (HAA5fp) and total trihalomethanes (TTHMfp) in source water streams using environmental variables and ultraviolet absorbance at 254 nm wavelength (UV254) as a surrogate for DBP precursors. In the first component of the model, using three feature selection regression models and cross‐validation of subsets of the selected predictors, we identified three commonly monitored variables—streamflow, soil temperature, and total phosphorus for predicting UV254. In the second component, HAA5fp and TTHMfp are predicted from UV254. The approach is successfully demonstrated for two source water streams of the New York City water supply system (R2 was 0.8, and 0.7–0.8 for the two model components). Long‐term predictions of HAA5fp and TTHMfp showed distinct seasonal patterns that are linked to differences in land uses of the two watersheds. Moreover, sensitivity analysis showed that transport processes were important in one watershed whereas production processes were more important in the other. [ABSTRACT FROM AUTHOR]

As chloride (Cl−) is a commonly found anion in natural water, it has a significant impact on electrocatalytic oxidation processes; yet, the mechanism of radical transformation on different types of anodes remains unexplored. Therefore, this study aims to investigate the influence of chlorine-containing environments on the electrocatalytic degradation performance of levofloxacin using BDD, Ti4O7, and Ru-Ti electrodes. The comparative analysis of the electrode performance demonstrated that the presence of Cl− improved the removal and mineralization efficiency of levofloxacin on all the electrodes. The enhancement was the most pronounced on the Ti4O7 electrode and the least significant on the Ru-Ti electrode. The evaluation experiments and EPR characterization revealed that the increased generation of hydroxyl radicals and active chlorine played a major role in the degradation process, particularly on the Ti4O7 anode. The electrochemical performance tests indicated that the concentration of Cl− affected the oxygen evolution potentials of the electrode and consequently influenced the formation of hydroxyl radicals. This study elucidates the mechanism of Cl− participation in the electrocatalytic degradation of chlorine-containing organic wastewater. Therefore, the highly chlorine-resistant electrocatalytic anode materials hold great potential for the promotion of the practical application of the electrocatalytic treatment of antibiotic wastewater. [ABSTRACT FROM AUTHOR]

Tracing disinfectant (e.g., chlorine) and contaminants evolution in water networks requires the solution of one-dimensional (1D) advection-reaction (AR) partial differential equations (PDEs). With the absence of analytical solutions in many scenarios, numerical solutions require high-resolution time and space discretizations, resulting in large model dimensions. This adds complexity to the water quality control problem. In addition, considering multispecies water quality dynamics rather than the single-species dynamics produces a more accurate description of the reaction dynamics under abnormal hazardous conditions (e.g., contamination events). Yet, these dynamics introduce a nonlinear reaction formulation to the model. To that end, solving nonlinear 1D AR PDEs in real time is critical to achieving monitoring and control goals for various scaled networks with a high computational burden. In this work, we propose a novel comprehensive framework to overcome the large-dimensionality issue by introducing different approaches for applying model order reduction (MOR) algorithms to the nonlinear system followed by applying a real-time water quality regulation algorithm that is based on an advanced model to maintain desirable disinfectant levels in water networks under multispecies dynamics. The performance of this framework is validated using rigorous numerical case studies under a wide range of scenarios demonstrating the challenges associated with regulating water quality under such conditions. [ABSTRACT FROM AUTHOR]

Hospital wastewater is an important source of pollutants resulting from medical activities. It has a high vulnerability towards the outbreak of several diseases. The aim of the study was to investigate the disinfection efficiency of different dosages and contact times of chlorine and peracetic acid (PAA) to reduce the contaminated microbes. The consequences after treatments such as regrowth capacity, disinfection by-products, and water quality were also observed. The result showed that in all fourth-time samplings of effluent, its physical, chemical, and biological characteristics exceeded the standard requirement and needed further treatment before discharge. The disinfection experiments were run in parallel among 3 chlorine dosages (1.388, 1.588, and 1.988 mg/l) and 3 PAA dosages (5, 10, 15 mg/l) at contact times of 15 and 30 min. PAA performed faster than chlorine from the beginning, after that, they all provided similar microbial reduction around 2.38-4.47 log 10 MPN/100 ml. Chlorine provided higher efficiency in reducing total coliform while PAA was greater for E. coli. The efficiencies increased as contact time was increased. PAA exhibited higher physical and chemical treating capacities than those of chlorine. The study suggested that chlorine at 1.528 mg/l and/or PAA at 5 mg/l, at a contact time of 15 min, are suitable microbial treatments for this effluent. These suggested conditions could improve all water quality parameters to meet the standard requirement and inhibit regrowth of microbes during the three-day incubation period. The stakeholders should also continue to monitor effluent characteristic variation and treatment conditions regarding the application of these infectants. [ABSTRACT FROM AUTHOR]

[Display omitted] Water environmental pollution especially caused by bacteria, viruses and other microorganisms always would accelerate the spread of infectious diseases and has been one of the issues highly concerned by the World Health Organization for a long time. The development of novel antibacterial materials with high activity for water cleanness was of great importance for public health and ecological sustainable development. In this work, we developed two really free-standing conjugated microprous polymers (CMPs) film with large size and processibility by a simple and convenient solid surface-assisted polymerization between bromo- and aryl-acetylene monomers. With the solid interfacial orientation from silica nanofibers, the resulting CMPs film exhibited nanotube-liked morphology with BET surface area of 379.5 m2 g−1 and 480.1 m2 g−1. The introduction of antibacterial isocyanurate and acetanilide group into polymer skeleton brings the resulting CMPs film intrinsically antimicrobial capability and durability. The growth of E. coli can be completely inhibited by the resulting CMPs film even after several cycles. Our work was suggested to provide a new route for rational design of CMPs film or membrane with antibacterial activity for water treatment and sterilization. [ABSTRACT FROM AUTHOR]

Chlorine decay over time and distance travelled poses challenges in maintaining consistent chlorine levels from treatment plants to demand nodes in water distribution networks (WDNs). Many studies have focused on optimizing chlorine booster systems and addressing dosage and location. This study proposes a chlorine injection optimization model for maintaining spatial and temporal chlorine residuals within an acceptable range. First, the approach involves identifying potential pathways from the source to demand nodes using a breadth-first search (BFS) algorithm. Subsequently, the required chlorine injection to maintain a 0.2 mg/L residual chlorine level at demand nodes is estimated based on water age. Finally, a single-objective genetic algorithm optimizes the chlorine injection schedule at the source. The results demonstrated that chlorine estimation based on water age exhibited promising results with an average error below 10%. In addition, the four-interval injection scheme performed well in adapting to changing demand patterns, making the method robust to varying demand patterns. Moreover, the model could accommodate fluctuating water temperature conditions according to operating seasons. This study provides valuable insights into effectively managing chlorine levels and operations of WDNs, and paves the way for using water age for chlorine estimation. [ABSTRACT FROM AUTHOR]

A biofilm is a biologically active matrix attached to the surface of cells and their extracellular products. As they are a mixture of many microorganisms, the microbiological activity of biofilms varies according to their position in the aggregate. With particular emphasis on drinking water distribution systems, this review focuses on the process of biofilm formation, associated bacteria, chlorine resistance of bacteria, and the predominant surface materials. We have compiled studies on the bacteria in drinking water distribution systems and their interactions with biofilm formation on different materials, and we also analysed the chlorine-resistant bacteria and their problems in the water networks. The materials used in the drinking water network are significantly affected by the disinfection method used to produce the biofilm that adheres to them. Some studies propose that the material is inconsequential, with the disinfection process being the most significant factor. Studies suggest that materials based on plastics (such as PVC and HDPE) tend to be more effective in controlling biofilm formation or removal than those based on metals (such as stainless steel), which have been found to be less effective in some instances. Chlorine-resistant strains are becoming more and more common in drinking water networks, resulting in the occurrence of diseases such as typhus and cholera. [ABSTRACT FROM AUTHOR]

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Cyanotoxins, produced from cyanobacteria-dominated harmful algal blooms (cHABs), pose a threat to ecosystems, as well as drinking water systems. Disinfection via chlorine is the last step in a conventional drinking water treatment plant (DWTP) to remove any extracellular toxins present in the water. This research investigated the impact of pH on the oxidation of different saxitoxin (STX) and anatoxin-a (ANTX-a) concentrations in the post-filtration water collected from two DWTPs. STX degradation was the most efficient at higher pH levels. For instance, pH 6 resulted in 13–43% degradation and pH 9 resulted in 56–74% degradation of STX. The presence of microcystin-LR (MC-LR) did not significantly inhibit the removal of STX, with STX removal (at pH 6–8) higher than when MC-LR was not present. A dose of 1.8 mg/L chlorine and 235-min contact achieved 38% removal of ANTX-a while the dose of 3.2 mg/L chlorine and the contact time of 118 min removed 75% of ANTX-a at pH 6. [ABSTRACT FROM AUTHOR]

High-temperature chlorination of C76 fullerene with SbCl5 proceeds via five Stone–Wales rearrangements, resulting in non-classical (NC) C76(NC1a)Cl24 with two heptagons and 14 pentagons partically fused in pairs and triples. C76(NC2b)Cl28 with isomeric carbon cage was obtained by chlorination-promoted cage shrinkage of C80via two C2 losses. The pathways of skeletal cage trasformations, the chlorination patterns, and formation energies are discussed in detail. [ABSTRACT FROM AUTHOR]

High-temperature chlorination of C76 fullerene with SbCl5 proceeds via five Stone–Wales rearrangements, resulting in non-classical (NC) C76(NC1a)Cl24 with two heptagons and 14 pentagons partically fused in pairs and triples. C76(NC2b)Cl28 with isomeric carbon cage was obtained by chlorination-promoted cage shrinkage of C80via two C2 losses. The pathways of skeletal cage trasformations, the chlorination patterns, and formation energies are discussed in detail. [ABSTRACT FROM AUTHOR]

The unrestricted utilization of antibiotics poses a critical challenge to global public health and safety. Levofloxacin (LEV) and sulfaphenazole (SPN), widely employed broad-spectrum antimicrobials, are frequently detected at the terminal stage of water treatment, raising concerns regarding their potential conversion into detrimental disinfection byproducts (DBPs). However, current knowledge is deficient in identifying the potential DBPs and elucidating the precise transformation pathways and influencing factors during the chloramine disinfection process of these two antibiotics. This study conducts a comprehensive analysis of reaction pathways, encompassing piperazine ring opening/oxidation, Cl-substitution, OH-substitution, desulfurization, and S−N bond cleavage, during chloramine disinfection. Twelve new DBPs were identified in this study, exhibiting stability and persistence even after 24 h of disinfection. Additionally, an examination of DBP generation under varying disinfectant concentrations and pH values revealed peak levels at a molar ratio of 25 for LEV and SPN to chloramine, with LEV contributing 11.5% and SPN 23.8% to the relative abundance of DBPs. Remarkably, this research underscores a substantial increase in DBP formation within the molar ratio range of 1:1 to 1:10 compared to 1:10 to 1:25. Furthermore, a pronounced elevation in DBP generation was observed in the pH range of 7 to 8. These findings present critical insights into the impact of the disinfection process on these antibiotics, emphasizing the innovation and significance of this research in assessing associated health risks. [ABSTRACT FROM AUTHOR]

In harsh environments, bacteria often enter a viable but nonculturable (VBNC) state, which cannot be detected using heterotrophic plate counting (HPC). Importantly, VBNC bacteria can potentially resuscitate under favorable conditions, posing a risk to drinking water safety. This study introduces an innovative approach, combining improved quantitative polymerase chain reaction (qPCR) with propidium monoazide (PMA) dye and HPC to accurately quantify VBNC Pseudomonas aeruginosa (P. aeruginosa). The method was applied to assess the ability of various disinfection techniques to induce P. aeruginosa into the VBNC state. Different disinfection methods, including ultraviolet radiation (UV), sodium hypochlorite (NaClO), and peracetic acid (PAA), significantly reduced bacterial culturability (>99.9%), with the majority entering the VBNC state. Notably, under favorable conditions, UV-induced VBNC cells were resuscitated faster than those induced by NaClO. VBNC P. aeruginosa exhibited relatively high intracellular adenosine triphosphate (ATP) levels, indicating ongoing metabolic activity. Scanning electron microscopy (SEM) reveals that some bacteria maintained cellular integrity for UV and PAA treatment, while evident membrane disruption was observed after NaClO disinfection. This study represents a significant advancement in quantitatively detecting VBNC state P. aeruginosa, contributing to an accurate assessment of microbial inactivation during drinking water disinfection. [ABSTRACT FROM AUTHOR]

In this study, Escherichia coli (E. coli) was used as an indicator bacterium treated with five different concentrations of chlorine (0.1; 0.5; 1.0; 2.0, and 5.0 mg/L) and without chlorine (0.0 mg/L) to evaluate the changes in the DOM characteristics. The dissolved organic carbon (DOC) concentration initially increased along with the chlorine concentrations and decreased after 24 h (0.0 and 0.1 mg/L) and 168 h (0.5; 1.0; 2.0 and 5.0 mg/L). Ultra-violet absorbance at 260 nm (UV260) showed that the absorbance decreased for control without chlorine (0.0 mg/L) and 0.1 mg/L chlorine, while increased for other concentrations of chlorine within 120 h. The DOC and UV260 results indicated that the high concentrations of chlorine initiated high contents of DOM which contained more humic-like molecules than the DOM released from E. coli without chlorine. Fluorescence excitation–emission matrix (EEM) analysis suggested that the DOM released from E. coli without chlorine enriched with protein-like substances, whereas the fulvic-like and humic-like substances more intensified in the DOM for the high concentrations of chlorine (>1.0 mg/L). The molecular weight distribution of DOM showed that the intensity of high molecular weight substances and polydispersity increased along with chlorine concentration and contact time, whereas the low molecular weight substances were relatively higher in the DOM for control without chlorine. The obtained results of this study would be useful for a better understanding of the variation of DOM during treatment and could be used as an important reference for optimizing the operation condition of the water treatment plants. [ABSTRACT FROM AUTHOR]

Water treatment for most public pools involves disinfection with active chlorine leading to the formation of disinfection by-products (DBPs). Among them, nitrogen-containing compounds (N-DBPs) having increased toxicity and adverse effects on human health are of the greatest concern. Being the major component of various body washers for swimmers, cocamidopropyl betaine (CAPB) represents a potential and still underestimated anthropogenic precursor of N-DBPs in pool water. The purpose of this study was to investigate CAPB transformation pathways and mechanisms under the aqueous chlorination conditions. High-performance liquid and two-dimensional gas chromatography hyphenated with high-resolution mass spectrometry were used for the search and tentative identification of the primary and final CAPB transformation products. A wide range of DBPs containing up to five chlorine atoms including these in combination with hydroxyl and additional carbonyl groups has been revealed in model chlorination experiments for the first time. The proposed mechanism of their formation involves nucleophilic substitution of the secondary amide hydrogen atom at the first stage with subsequent free radical and electrophilic addition reactions resulting in non-selective introduction of halogen atoms and hydroxyl groups in the alkyl chain. The deep transformation products include short-chain chlorinated hydrocarbons and their oxidation products as well as dimethylcarbamoyl chloride possessing high toxicity and carcinogenic properties. Targeted analysis of real swimming pool water samples confirmed the results of model experiments enabling semi-quantitative determination of CAPB (0.8 µg L–1) and 18 primary DBPs, including 10 chlorine-containing compounds with the total concentration of 0.1 µg L–1. Among them, monochloro (50%) and hydroxydichloro (25%) derivatives predominate. The toxicity and health of the main DBPs has been estimated using QSAR/QSTR approach. Thus, the possibility of formation of new classes of potentially toxic chlorine-containing DBPs associated with the widespread use of detergents and cosmetics was shown. [ABSTRACT FROM AUTHOR]

In this experimental research the adsorption and photocatalytic properties of silica nanoparticles were used to disinfection water against the gram-negative Escherichia coli bacteria. Silica nanoparticles were synthesized by modified Stober method and characterized. TEM image shows that the ¨ prepared nanoparticles were spherical with 20−30 nanometers diameter and 4.25 eV bandgap energy. The disc diffusion test was employed to evaluate the antimicrobial properties of produced nanoparticles against the Escherichia coli bacteria. The optimal pH of water disinfection was determined for decontamination. And finally silica nanoparticles activity was assayed to disinfect the suspended Escherichia coli bacteria in water by adsorption and photocatalytic mechanisms. Results were compared with photolysis process. According to disc diffusion test, the antimicrobial effects of silica nanoparticles strongly depend of their concentration. Results confirm that silica nanoparticles are capable for cheap and fast decontamination of bacterial infected water. [ABSTRACT FROM AUTHOR]

• IPM could be effectively degraded by the Mn(VII)/S(IV) process. • SO 4 ·– was the major active oxidant contributing to the degradation of IPM. • I– and IO 3 – were generated during IPM degradation by the Mn(VII)/S(IV) process. • IPM degradation by Mn(VII)/S(IV) caused the I-DBPs generation during chlorination. • More attention should be paid to the toxicity of the generated DBPs in this study. Permanganate/sulfite (Mn(VII)/S(IV)) process is a promising pre-oxidation technology for sequestering the emerging organic contaminants in drinking water treatment plant. Iopamidol (IPM), a representative of iodinated X-ray contrast media, has been widely detected in water sources and has the risk of forming iodinated disinfection byproducts (I-DBPs) in water treatment system. In this study, we investigated the evolution of iodine species during the IPM degradation by the Mn(VII)/S(IV) process and its effect on the subsequent formation of I-DBPs during chlorination at pH 7.0 and 8.0. IPM could be effectively degraded in the Mn(VII)/S(IV) process at environmentally relevant pH (pH 7.0 and 8.0). The results of quenching and competitive oxidation kinetic experiments revealed that SO 4 ·– was the major reactive oxidizing species contributing to the degradation of IPM whereas the contributions of HO· and reactive manganese species were negligible in the Mn(VII)/S(IV) process. I– and IO 3 – were generated while no HOI was detected during the degradation of IPM in the Mn(VII)/S(IV) process. The effects of IPM oxidation by Mn(VII)/S(IV) on the subsequent formation of chlorinated disinfection by-products (Cl-DBPs) during chlorination were related to the category of Cl-DBPs. The pre-oxidation of IPM by Mn(VII)/S(IV) resulted in the generation of I-DBPs during the disinfection process although no I-DBPs were detected if no pre-oxidation was applied. The finding of this study suggested that attention should be paid to the toxicity of DBPs when water containing iodinated organic contaminants is treated by Mn(VII)/S(IV) process or other pre-oxidation technologies. [Display omitted] [ABSTRACT FROM AUTHOR]

Infectious diseases caused by waterborne viruses have attracted researchers' great attention. To ensure a safe water environment, it is important to advance water treatment and disinfection technology. Photocatalytic technology offers an efficient and practical approach for achieving this goal. This paper reviews the latest studies on visible-light composite catalysts for bacteriophage inactivation, with a main focus on three distinct categories: modified UV materials, direct visible-light materials and carbon-based materials. This review gives an insight into the progress in photocatalytic material development and offers a promising solution for bacteriophage inactivation. [ABSTRACT FROM AUTHOR]

Efforts continue to be made to eliminate pathogenic bacteria in drinking water by using safer disinfection materials. The use of local plants as disinfection materials is highly desirable. The durian plant (Durio zibethinus) can be a very promising alternative as a natural disinfection agent to destroy pathogenic bacteria in drinking water. This narrative review comes from three online journal databases that provide free journal articles in PDF format, collected over the last ten years. The main keywords in conducting a literature review through online journals are "Durian, Durio Zibethinus, antibacterial, disinfectant, drinking water". Of the 5,693 journals identified in the three databases, 21 studies remained that met the requirements for inclusion in this review. This included study illustrates that fruit rind, seed, and leaf extracts from the durian plant have antimicrobial properties. Durian plants have antibacterial active compounds such as phenolics, alkaloids, steroids, saponins, tannins, flavonoids and triterpenoids. The antimicrobial potential tested using the diffusion and dilution method indicated that the presence of antimicrobial ingredients in the durian plant extraction was in the strong category. Some pathogenic bacteria in water that can be inhibited or killed are Escherichia coli, Pseudomonas aerugenosa, Bacillus subtilis, Bacillus cereus, Enterococcus faecalis, Staphilococcus aureus, Shigella boydii and Salmonella Typhi. This shows that there is an opportunity for the durian plant to provide a solution and great hope as a safe and economical alternative disinfection material as a replacement for current disinfection materials. [ABSTRACT FROM AUTHOR]

One of the bigger problems in drinking water is disinfection by-products (DBPs) that come from chlorinated disinfection. This study’s goal was to evaluate the drinking water in Al-Yarmouk Teaching Hospital, Ibn Sina Hospital and Ibn-AlNafis Hospital. Samples were collected between October 2018 and September 2019. Physical and chemical characteristics of the water were studied, including (temperature, hydrogen ion (pH), total dissolved solids (TDS), electrical conductivity (EC), turbidity, free residual chlorine, total organic carbon (TOC), total trihalomethanes (THMs), total halo acetic acid (THAAs)). Data analysis showed the highest value of study temperature, pH, TDS, EC, turbidity, free residual chlorine and TOC which was 37oC, 8.4,790 mg/l, 1251 µS/cm-1, 15 NTU, 1.7 mg/l, and 6.7 mg/l respectively. Total trihalomethanes (THMs) results of drinking water samples from different sites showed that the highest value was 129.6 µg/l in Ibn Sina Hospital during summer while the lowest value was 41.3 µg/l in Ibn Sina Hospital in winter. The results of total halo acetic acid (THAAs) of drinking water sampled from different sites showed that the highest value of 72.9 µg/l was recorded in the sample collected from Ibn Sina Hospital during summer and the lowest THAAs water content of 40.2 µg/l was obtained in the sample collected from Ibn-Al-Nafis during winter. The results of this research were acceptable and within the range of Iraqi standards. [ABSTRACT FROM AUTHOR]

Electrochemical water treatment for recirculating aquaculture systems (RAS) is a promising approach for replacing the biological water treatment methods and establishing a new RAS generation with improved cost‐effectiveness, lower environmental footprint, and no start‐up periods. On top of ammonia oxidation directly into N2(g), electrochemical oxidation results in effective disinfection, and in the removal of organic matter, including specific organic constituents such as off‐flavour agents. The paper provides an overview of incentives for the implementation of electrochemical methods in RAS. It covers the electrochemical principles relevant to aquaculture applications, the effects of physical and chemical parameters, as well as design considerations. In addition, the research performed to date for integrating electrochemical methods in RAS operation is reviewed and the variety of designs and operational configurations described. The electrochemical water treatment is perceived beneficial over biological water treatment especially in cold saline‐seawater aquaculture (e.g., Atlantic salmon), where large nitrification reactors are required and the large water consumption for purging processes can be curtailed. It is also beneficial for the culturing of nitrate‐sensitive species (e.g., L. vannamei). The paper points out the gaps to be overcome for allowing commercial breakthroughs based on electrochemical water treatment, including the need for expanding the practice and improving engineering practices by operating pilot systems for growing fish at both small and large scales; adjusting of electrochemical cell designs for reducing both capital and operational costs; developing full‐proof malfunction‐free dechlorination strategies, and evaluating and optimizing the disinfection abilities for inactivating typical pathogens in aquaculture. [ABSTRACT FROM AUTHOR]

Purpose. Determination by means of computer simulation of the most efficient modes of operation of the installation for water disinfection using discharges in gas bubbles, in which (modes) the amplitude of voltage pulses at the processing unit and on the layer of treated water is not less than the voltage amplitude immediately after the switching discharger. Methodology. To achieve this goal, we used computer simulation using Micro-Cap 10. We used two different electrical circuits that simulate the operation of the experimental setup in two different modes: in a mode with a restoring electrical strength of the discharge gap in the gas bubble between two adjacent voltage pulses on the discharge node and in the mode without restoring this dielectric strength. In computer simulation, we varied the following factors: the maximum simulation step, inductances, capacitances, active resistances, wave resistance of a long line, and the delay time for the operation of a spark gap simulating a discharge gap in a gas bubble. Results. Computer modeling has shown that in order to increase the voltage amplitude at the treatment unit and on the layer of treated water, it is necessary to reduce the load capacitance – the capacitance of the water layer in the treatment unit to 10 pF or less, to increase the active resistance of the water layer to 500 Ω or more. An important factor for increasing the voltage and electric field strength in the discharge unit and, consequently, for increasing the efficiency of treated water disinfection is the discharge delay time in gas bubbles. The most rational delay time for the operation of the arrester, which is the gap in the gas bubble inside the water, under the conditions considered by us is 4-5 ns. It is with this delay time that the amplitude of voltage pulses at the node of disinfecting water treatment and on the layer of treated water is maximum, all other things being equal. Furthermore, with such a delay time this amplitude of voltage pulses significantly exceeds the voltage amplitude directly after the main high-voltage discharger, switching energy from the high-voltage capacitive storage to the processing unit through a long line filled with water. Originality. Using computer simulation, we have shown the possibility of increasing the voltage at the discharge unit of the experimental setup by 35 % without increasing the voltage of the power source. This provides a higher efficiency of microbiological disinfection of water by nanosecond discharges in gas bubbles and lower specific energy consumption. Practical value. The obtained results of computer simulation confirm the prospect of industrial application of installations using nanosecond discharges for disinfection and purification of wastewater, swimming pools and post-treatment of tap water. References 15, figures 10. [ABSTRACT FROM AUTHOR]

Monitoring bacterial contamination in water is essential for human health, as certain waterborne bacteria can pose serious illnesses. This pilot-scale study aimed to identify biofilmforming Aeromonas spp. within stainless steel water dispensers (SWD) in an educational institute, while also elucidating the underlying contributing factors. Aeromonas spp. were isolated from nineteen SWDs. Distinct biochemical characteristic aeromonads were selected for biofilm-formation testing by glass tube experiment. Water samples were collected and assessed for pH, turbidity, color, and free chlorine residue. The study revealed that sixteen of nineteen SWDs had 48 aeromonads (84.21%). The most identified species were A. bestiarum, A. hydrophila, and A. veronii. Interestingly, this study documented the occurrence of globally distributed pathogens such as A. hydrophila, A. veronii, and A. caviae. All twenty-nine tested isolates were able to form biofilms, and A. hydrophila exhibited the most potent biofilmproducing properties. There was no association between the biofilm formation and the measured physicochemical parameters. The occurrence of biofilm-forming Aeromonas spp. within SWDs underscores the urgency for heightened awareness among public health professionals about the effects of biofilm-forming microorganisms and offers guidance on mitigating their presence. In addition, it is imperative to conduct regular monitoring in educational institutions and other public buildings. [ABSTRACT FROM AUTHOR]

One novel method for disinfecting water is the use of silver nanoparticles. The aim of this work was to prepare a granular antibacterial composite based on chitosan boehmite, enhanced with silver nanoparticles (Ag-CHB), and evaluate its antibacterial activity. The composite was prepared by the sol-gel method and characterized by FTIR, AFM, FESEM, EDS, and UV-VIS techniques. The topographical study using the AFM revealed a clear change in the surface shape of the composite after it was reinforced with silver nanoparticles. Additionally, FESEM images displayed that the particles of chitosan-boehmite supported with silver nanoparticles are polygonal granules with an average size of 61.93 nm. The EDX analysis showed that the percentage of silver atoms in the composite is about 1.24 wt%. The results of FTIR indicated that chitosan's functional groups have specific interactions with silver and aluminum. According to XRD analysis, boehmite nanocrystals are orthorhombic, with a mean crystal size of 30 nm was confirmed. Optical characterization of the colloidal silver nanoparticles by UV-VIS technique revealed the presence of a clear surface plasmon band, with a peak wavelength of 389 nm. The stability in the water of the prepared composite was verified by the swelling test, and the swelling index was about 11.82%. The ability of the composite to kill bacteria was also verified before and after being reinforced with silver nanoparticles by the agar well diffusion method. The composite reinforced with silver nanoparticles showed antibacterial activity against E. coli, with a 10 mm inhibition zone diameter. Overall, these results indicated that the Ag-CHB composite has the potential for water disinfection and incorporation into household filtration systems. Highlights: Chitosan-boehmite, enhanced with silver nanoparticles, is synthesized by the sol-gel method. The successful formation of the composite was corroborated through several techniques. The composite exhibits full stability in water and demonstrates antibacterial properties. Chitosan-boehmite enhanced with silver nanoparticles granules, can be used in multimedia household filters. [ABSTRACT FROM AUTHOR]

Water treatment technology is advancing to extend the supply of pure drinking water to low-income societies. The application of biomass-based silver nanoparticles for the purification of water is among the outstanding innovations in this respect. Silver has less reactivity and excellent stability, which makes it preferable for biological applications such as drinking water. In this research review, the synthesis of silver nanoparticles (AgNPs) using different techniques of chemical synthesis, physical synthesis, photochemical synthesis, and biological synthesis was discussed. The synthesis of AgNPs supported by biomass-driven silica gel and its application for the treatment of water were found to be promising technologies. The use of biobased silica aerogel supported AgNPs for water disinfection has recently been the subject of promising research findings as an effective method for killing microorganisms from drinking water. The characteristics of bio-silica aerogel are unequalled, in large part because of its increased porosity, greater surface area, extraordinarily inadequate thermal conductivity density, and potent antibacterial action against both Escherichia coli (E. coli) and Staphylococcus aureas (S. aureus) at low concentrations. These features exhibited that the synthesis of bio-based silica aerogel-coated AgNPs for water disinfection is a promising research interest for the disinfection of drinking water. AgNPs also have anti-fouling properties that prevent the clogging of membrane filters, which enhances their potential for improving water quality and safety.

Nanotechnology has been rapidly developing in the past decade, and metal nanomaterials have shown promising improvement in microbial control. Metal nanoparticles have been applied in medical settings for adequate disease spread control and to overcome the challenges of multidrug-resistant microorganisms. Recently, the demand for safe water supply has increased, requiring higher sanitation of the water treatment technology as well as being environmentally sustainable. However, the employed water disinfection technologies cannot meet the elevated demand due to limitations including chemical byproducts, immobility, energy consumption, etc. Metal nanomaterials are considered to be an alternative disinfection technology considering their high efficiency, mobility, and stability. A significant amount of research has been carried out on enhancing the antimicrobial efficiency of metal nanomaterials and determining the underlying antimicrobial mechanisms. This paper provides an overview of emerging metal nanomaterials development, including the synthesis method, material characteristics, disinfection performance, environmental factors, potential mechanism, limitations, and future opportunities in the water disinfection process. HIGHLIGHTS Antimicrobial mechanisms are governed by microbe–metal nanoparticles interactions.; Synthesis methods and material characteristics impact microbial control performance.; Demonstrations via experimental study and simulation support its applicability.; Nanoscale metal materials have multi-tasking ability versus conventional treatments.; Limitations of possible toxicity, cost, and manufacturing call for further research.;

BackgroundConventional techniques for water disinfection are fraught with issues like personnel exposure to damaging radiation and formation of harmful and carcinogenic disinfection byproducts. There are difficulties related to transportation and handling, and expensive capital and working costs also are involved like costs associated with on-site generation of disinfectants. There is a dire need for newer disinfection technologies that are environment and health friendly.Scope and benefitsThis article reviews the use of natural disinfectants derived from plants to enhance the quality of water. Researchers have utilized herbal extracts, phytochemicals, and phytochemical-metal complexes for the disinfection of water. Various factors for these chemicals like efficacy, toxicity, cost, and water solubility have been discussed and some useful phytochemical disinfectants are also identified. These disinfection methods particularly when using only pure phytochemicals are generally thought to be free from the deleterious effects associated with chlorination and other conventional technologies. Inherently, chlorinated and other harmful disinfection byproducts are not formed.Key findings and conclusionsIn various studies eugenol, thymol and extracts of Ocimum sanctum and Azadirachta indica have been utilized with fairly effective disinfection capabilities. The significant antimicrobial effects of allicin, berteroin, sanguinarine, and thymol are reflected from their very low minimum inhibitory concentration values. Even so, presently the efficiency of phytochemicals is not comparable to conventional disinfectants. The use of phytochemical metal complexes is, however, a plausible option that might be investigated further. The metal complexes because of their greater water solubility than pure phytochemicals result in improved disinfection efficiency. Notable among those are flavonoid-metal complexes that should be considered further for use in water disinfection. It is also concluded that phytochemicals may be added to water that has also been disinfected with some other commonly-used technology. A way to do this may be to design a fixed bed tower of phyto-disinfectant through which water should pass.