Global water shortage and potable water safety; Today's concern and tomorrow's crisis

Recent developments of (bio)-sensors for detection of main microbiological and non-biological pollutants in plastic bottled water samples: A critical review

The importance of water in all biological processes is undeniable. Ensuring access to clean and safe drinking water is crucial for maintaining sustainable water resources. To elaborate, the consumption of water of inadequate quality can have a repercussion on human health. Furthermore, according to the instability of tap water quality, the consumption rate of bottled water is increasing every day at the global level. Although most people believe bottled water is safe, it can also be contaminated by microbiological or chemical pollution, which can increase the risk of disease. Over the last decades, several conventional analytical tools applied to analyze the contamination of bottled water. On the other hand, some limitations restrict their application in this field. Therefore, biosensors, as emerging analytical method, attract tremendous attention for detection both microbial and chemical contamination of bottled water. Biosensors enjoy several facilities including selectivity, affordability, and sensitivity. In this review, the developed biosensors for analyzing contamination of bottled water were highlighted, as along with working strategies, pros and cons of studies. Challenges and prospects were also examined.

A regulatory framework for bottled water quality monitoring: A case of Emfuleni local municipality

Background

The quality of drinking water has recently become of utmost concern to consumers worldwide, especially in areas where Water Service Authorities (WSAs) failed to provide safe water. To combat this challenge, government entities regulate water to ensure that safe water is provided. The Emfuleni Local Municipality (ELM) has experienced cases of water contamination by human excretion, whereby communities were affected. As a result, there was a sharp increase in bottled water (BW) use, which however gave rise to unregulated and counterfeit versions of popular brands. This situation poses threats to public health.

Aim

This study sought to determine the regulation of drinking water and to assess whether environmental health practitioners (EHPs) monitor the quality of water sources (BW and tap water) in ELM as outlined by the National Environmental Health Norms and Standards (NEHNS).

Settings

The study was conducted in the Emfuleni Local Municipality in South Africa.

Methods

A quantitative cross-sectional study design was employed in this research. Fifteen online questionnaires using a Google Forms survey were distributed amongst all EHPs servicing ELM. Secondary data that included the Integrated Development Plan (IDP) and Service Delivery Budget Implentation Plan (SDBIP) for the 2017-2020 financial years were also evaluated, specifically for water quality monitoring (tap and bottled water). The dataset was analysed using the Statistical Package for the Social Sciences (SPSS) version 29.

Results

Due to complexity in the legislation and NEHNS in relation to Municipal Health Services (MHS), bottled water was not sampled at all. A number of EHPs were also not conversant with the regulations governing BW. Moreover, NEHNS consider bottled water as food, which does not fall under the MHS.

Conclusion

There should be clarity in the legislation to ensure that bottled water monitoring is intensified to protect public health within the WSAs.

Contribution

The findings of this study could assist policy-makers to make informed decisions on water quality monitoring, as well as clarify legislative issues on bottled water.

Release potential, neglected leakage and reduction countermeasures of COD and Ammonia in MSWLs

In order to eliminate the impact of the industrial revolution on the environment and improve the water ecological environment, pollutant discharge reduction is imperative. With the acceleration of global discharge reduction process, the huge pollutant release potential and potential environmental effects of municipal solid waste landfills gradually appear, but its release amount and intensity have not been quantitatively revealed. We propose a coupling method of parameter stochastic simulation and physical process model simulation to estimate the hidden leakage of large-scale regional municipal solid waste landfills, and provide a methodology for estimating the hidden leakage of landfills in other countries and even in the whole world by taking China, which has the largest amount of waste generation among developing countries, as an example. Prior to the implementation of stringent construction quality control and assurance management requirements, the average annual leachate generation potential over the entire life cycle of 2600 landfills in China was estimated to be 4.66 × 108 m3, in which the concentrations of COD and NH3-N are 5.38 × 102-6.48 × 104 mg/L and 6.10-3.50 × 103 mg/L, respectively, and the total amounts are 5.21 × 103-7.81 × 108 t and 8.09 × 102-6.65 × 107 t, respectively. About 14 % of these pollutants may leak into the environmental media through the landfill liner with the average number of holes of 21.5/ha. For different regions, the overall release, discharge and leakage of COD and NH3-N in East China account for 35.70 %, 36.68 % and 29.60 % respectively, making it the region with the highest potential for discharge and risk of leakage. Meanwhile, the implementation of mandatory regulations related to leachate generation and control has led to a significant reduction in the leakage of pollutants. For instance, comprehensively detecting and repair of holes in the impermeable liner has reduced the number of holes to 2/ha, resulting in a reduction of >90 % in the leakage of pollutants.

Towards sustainable management of polyacrylamide in soil-water environment: Occurrence, degradation, and risk

Polyacrylamide (PAM) possesses unique characteristics, including high water solubility, elevated viscosity and effective flocculation capabilities. These properties make it valuable in various sectors like agriculture, wastewater treatment, enhanced oil recovery, and mineral processing industries, contributing to a continually expanding market. Despite its widespread use globally, understanding its environmental fate at the soil-water interface remains limited. This article aims to provide an overview of the occurrence, degradation pathways, toxicity, and risks associated with PAM in the bioenvironment. The findings indicate that various degradation pathways of PAM may occur in the bioenvironment through mechanical, thermal, chemical, photocatalytic degradation, and/or biodegradation. Through a series of degradation processes, PAM initially transforms into oligomers and acrylamide (AM). Subsequently, AM may undergo biodegradation, converting into acrylic acid (AA) and other compounds such as ammonia. Notably, among these degradation intermediates, AM demonstrates high biodegradability, and the bioaccumulations of both AM and AA are not considered significant. Ensuring the sustainable use of PAM necessitates a comprehensive understanding among policymakers, scholars, and industry professionals regarding PAM, encompassing its properties, applications, degradation pathways, toxic effect on humans and the environment, and relevant regulations. Additionally, this study offers insights into future priority research directions, such as establishing of a reliable source-to-destination supply chain system, determining the maximum allowable amount for PAM in farmlands, and conducting long-term trials for the PAM-containing demolition residues.

Assessing the Influence of Hand-Dug Well Features and Management on Water Quality

Underground water quality can be affected by natural or human-made influences. This study investigates how the management and characteristics of hand-dug wells impact water quality in 3 suburbs of Kumasi, Ghana, using a combination of qualitative and quantitative research methods. Descriptive analysis, including frequency and percentages, depicted the demographic profiles of respondents. Box plot diagrams illustrated the distribution of physicochemical parameters (Total Dissolved Solid [TDS], Electrical Conductivity [EC], Turbidity, Dissolved Oxygen [DO], and Temperature). Factor analysis evaluated dominant factors among these parameters. Cluster analysis (hierarchical clustering) utilized sampling points as variables to establish spatial variations in water physicochemical parameters. Cramer's V correlation test explored relationships between demographic variables and individual perceptions of water management. One-way ANOVA verified significant mean differences among the physicochemical parameters. Logistic regression models assessed the influence of selected well features (e.g., cover and apron) on TDS, pH, Temperature, Turbidity, and DO. The findings revealed that proximity to human settlements affects water quality, and increasing turbidity is associated with unmaintained covers, significantly impacting water quality (P < .05). Over 80% of wells were located within 10 to 30 m of pollution sources, with 65.63% situated in lower ground and 87.5% being unmaintained. Other significant contamination sources included plastic bucket/rope usage (87.50%), defective linings (75%), and apron fissures (59.37%). Presence of E. coli, Total coliform, and Faecal coliform rendered the wells unpotable. Factor analysis attributed 90.85% of time-based and spatial differences to organic particle decomposition factors. However, Cramer's V correlation analysis found establishing association between demographic factor associations with individual perceptions of hand-dug well management difficult. It is encouraged to promote hand-dug well construction and maintenance standards to ensure that wells are properly built and protected from contamination sources.

Biofortification of Plant- and Animal-Based Foods in Limiting the Problem of Microelement Deficiencies-A Narrative Review

With a burgeoning global population, meeting the demand for increased food production presents challenges, particularly concerning mineral deficiencies in diets. Micronutrient shortages like iron, iodine, zinc, selenium, and magnesium carry severe health implications, especially in developing nations. Biofortification of plants and plant products emerges as a promising remedy to enhance micronutrient levels in food. Utilizing agronomic biofortification, conventional plant breeding, and genetic engineering yields raw materials with heightened micronutrient contents and improved bioavailability. A similar strategy extends to animal-derived foods by fortifying eggs, meat, and dairy products with micronutrients. Employing "dual" biofortification, utilizing previously enriched plant materials as a micronutrient source for livestock, proves an innovative solution. Amid biofortification research, conducting in vitro and in vivo experiments is essential to assess the bioactivity of micronutrients from enriched materials, emphasizing digestibility, bioavailability, and safety. Mineral deficiencies in human diets present a significant health challenge. Biofortification of plants and animal products emerges as a promising approach to alleviate micronutrient deficiencies, necessitating further research into the utilization of biofortified raw materials in the human diet, with a focus on bioavailability, digestibility, and safety.

Enhancing the anti-biofouling property of solar evaporator through the synergistic antibacterial effect of lignin and nano silver

Solar desalination is an effective solution to address the global water scarcity issue. However, biofouling poses a significant challenge for solar evaporators due to the presence of bacteria in seawater. In this study, an anti-biofouling evaporator was constructed using the synergistic antibacterial effect of lignin and silver nanoparticles (AgNPs). The AgNPs were easily synthesized using lignin as reductant under mild reaction conditions. Subsequently, the Lignin-AgNPs solution was integrated into polyacrylamide hydrogel (PAAm) without any purification steps, resulting in the formation of Lignin/AgNPs-PAAm (LAg-PAAm). Under the combined action of AgNPs and the hydroquinone groups present in oxidized lignin, LAg-PAAm achieved over 99 % disinfection efficiency within 1 h, effectively preventing biofilm formation in pore channels of solar evaporators. The anti-biofouling solar evaporator demonstrated an evaporation rate of 1.85 kg m-2 h-1 under 1 sun irradiation, and maintained stable performance for >30 days due to its high efficient bactericidal effect. Furthermore, it also exhibited exceptional salt-rejection capability attributed to its superior hydrophilicity.

Efficient dye adsorption of mesoporous activated carbon from bamboo parenchyma cells by phosphoric acid activation

In order to solve the environmental damage caused by the discharge of dyes as industrial wastewater, the development of efficient and sustainable adsorbents is the key, while most of the previous studies on bamboo parenchyma cells have focused on their microstructural, functional and mechanical properties, and few of the properties in adsorption have been investigated. To evaluate the role of the unique microstructure of bamboo parenchyma cells on adsorption after carbonization and activation, PC-based activated carbon (PPAC) was fabricated by the phosphoric acid activation method and tested for adsorption using methylene blue (MB). The effect of mesoporous structure on MB adsorption was investigated in detail using PPAC-30C impregnated with phosphoric acid at a concentration of 30%. The results showed that the adsorption performance was influenced by single-factor experiments (e.g., pH, activated carbon dosing). The adsorption isotherms and kinetics could conform to the Langmuir model (R2 = 0.983-0.994) and pseudo-second-order kinetic model (R2 = 0.822-0.991) respectively, and the maximum MB adsorption capacity of adsorbent was 576 mg g-1. The adsorption mechanism of MB on PPAC-30C includes physical adsorption, electrostatic attraction, hydrogen bonding, and the π-π conjugation effect, which was dominated by physical adsorption. The results of this study show that PPAC has good application prospects for cationic dye removal.

Characterizing the water resource-environment-ecology system harmony in Chinese cities using integrated datasets: A Beautiful China perspective assessment

Integrated management and synergistic improvement of the water system is a topic of widespread concern. This study innovatively integrates three functions of quality assessment, synergy evaluation, and driving influence determination to establish a systematic framework assessing water system harmony. A case study of 336 Chinese cities is further performed by combining multi-scale and multi-source datasets. The results show China's water system quality has improved from 2015 to 2022. Development in the water resource, environment, and ecology subsystems have been differentiated, with 0.05 %, 4.33 %, and -1.64 % changes, respectively. The degradation of water ecology and the weak synergy with the other two subsystems have limited China's water system harmony. Water environment improvement played a contributive role in improving the water system quality. The contribution structure of water resources, environment, and ecology has shifted towards equilibrium in recent years. We found and highlighted the north-south differentiation of water system harmony in Chinese cities. The Beijing-Tianjin-Hebei and its surroundings, the Yangtze River Delta, and the middle reaches of the Yangtze River are identified as priority regions for water system harmony improvement. The primary contribution of this study is to propose an assessing concept of water resource-environment-ecology system harmony, establish well-structured assessment methods, and integrate the multiple data sources. The novel methods and findings, including the indicator system, application of data mining and decomposing methods, and the city-level water system harmony map, deconstruct and quantify the complex and diverse water system, supporting clearer and more efficient water management policymaking.

Coupling coordination and driving mechanisms of water resources carrying capacity under the dynamic interaction of the water-social-economic-ecological environment system

The water resources carrying capacity (WRCC) is a complex and comprehensive system that is jointly influenced by water resources, society, the economy and the ecological environment. Previous WRCC studies have primarily focused on estimating the overall level of regional WRCC. Few studies have explored the interactions among the various elements in the WRCC system and their influence on the WRCC evolution. Therefore, the purpose of this paper is, on the one hand, to explore the dynamic interactive relationships within the WRCC system from the perspectives of water resources, society, the economy and the ecological environment using a coupling coordination degree model and a panel vector autoregressive (PVAR) model, and on the other hand, to determine the evolutionary driving mechanism of the WRCC using the geographically and temporally weighted regression (GTWR) model to improve the regional WRCC. Taking 21 cities in Guangdong Province as an example, the results show that (1) the coupling coordination degree among the four WRCC subsystems in Guangdong Province shows an overall upward trend from 2009 to 2020, and the coordination between water resources utilization and other subsystems needs to be further strengthened. (2) The economic subsystem is the core of the WRCC system with reinforcing effects on both water resources and social subsystems but significant inhibitory effects on the ecological environment subsystem. Notably, the development of the ecological environment plays a crucial role in promoting social and economic development. (3) From 2009 to 2020, the development of the WRCC in Guangdong Province is initially driven by social and economic development, followed by economic development and ecological environmental protection, and then mainly by ecological environmental protection, which gradually becomes the primary driving force. This study provides a new entry point for studying the regional WRCC and formulating targeted measures for enhancing the regional WRCC.

Preparation of N-MG-modified PVDF-CTFE substrate composite nanofiltration membrane and its selective separation of salt and dye

Poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE) is considered an ideal membrane material for the treatment of complex environmental water due to its exceptional thermal stability and chemical resistance. Thus, to expand its application in the field of nanofiltration (NF) membranes, in this study, N-methylglucamine (N-MG) was used to hydrophilically modify PVDF-CTFE, overcoming the inherent hydrophobicity of PVDF-CTFE as a porous substrate membrane, which leads to difficulties in controlling the interfacial polymerization (IP) reaction and instability of the separation layer structure. The -OH present in N-MG could replace the C-Cl bond in the CTFE chain segment, thus enabling the hydrophilic graft modification of PVDF-CTFE. The influence of the addition of N-MG on the surface and pore structure, wettability, permeability, ultrafiltration separation, and mechanical properties of the PVDF-CTFE substrate membrane was studied. According to the comparison of the comprehensive capabilities of the prepared porous membranes, the M4 membrane with the addition of 1.5 wt% N-MG exhibited the best hydrophilicity and permeability, indicating that it is a desirable modified membrane for use as an NF substrate membrane. The experiments showed that the rejection of Na2SO4 by the NF membrane was 96.5% and greater than 94.0% for various dyes. In the test using dye/salt mixed solution, this membrane exhibited a good separation selectivity (CR/NaCl = 177.8) and long-term operational stability.

Monitoring water harvesting in metal-organic frameworks, one water molecule at a time

Metal-organic frameworks (MOFs) have gained prominence as potential materials for atmospheric water harvesting, a vital solution for arid regions and areas experiencing severe water shortages. However, the molecular factors influencing the performance of MOFs in capturing water from the air remain elusive. Among all MOFs, Ni2X2BTDD (X = F, Cl, Br) stands out as a promising water harvester due to its ability to adsorb substantial amounts of water at low relative humidity (RH). Here, we use advanced molecular dynamics simulations carried out with the state-of-the-art MB-pol data-driven many-body potential to monitor water adsorption in the three Ni2X2BTDD variants as a function of RH. Our simulations reveal that the type of halide atom in the three Ni2X2BTDD frameworks significantly influences the corresponding molecular mechanisms of water adsorption: while water molecules form strong hydrogen bonds with the fluoride atoms in Ni2F2BTDD, they tend to form hydrogen bonds with the nitrogen atoms of the triazolate linkers in Ni2Cl2BTDD and Ni2Br2BTDD. Importantly, the large size of the bromide atoms reduces the void volume in the Ni2Br2BTDD pores, which enable water molecules to initiate an extended hydrogen-bond network at lower RH. These findings not only underscore the prospect for precisely tuning structural and chemical modifications of the frameworks to optimize their interaction with water, but also highlight the predictive power of simulations with the MB-pol data-driven many-body potential. By providing a realistic description of water under different thermodynamic conditions and environments, these simulations yield unique, molecular-level insights that can guide the design and optimization of energy-efficient water harvesting materials.

Progressive Insights into Metal-Organic Frameworks and Metal-Organic Framework-Membrane Composite Systems for Wastewater Management

The sustainable management of wastewater through recycling and utilization stands as a pressing concern in the trajectory of societal advancement. Prioritizing the elimination of diverse organic contaminants is paramount in wastewater treatment, garnering significant attention from researchers worldwide. Emerging metal-organic framework materials (MOFs), bridging organic and inorganic attributes, have surfaced as novel adsorbents, showcasing pivotal potential in wastewater remediation. Nevertheless, challenges like limited water stability, elevated dissolution rates, and inadequate hydrophobicity persist in the context of wastewater treatment. To enhance the performance of MOFs, they can be modified through chemical or physical methods, and combined with membrane materials as additives to create membrane composite materials. These membrane composites, derived from MOFs, exhibit remarkable characteristics including enhanced porosity, adjustable pore dimensions, superior permeability, optimal conductivity, and robust water stability. Their ability to effectively sequester organic compounds has spurred significant research in this field. This paper introduces methods for enhancing the performance of MOFs and explores their potential applications in water treatment. It delves into the detailed design, synthesis strategies, and fabrication of composite membranes using MOFs. Furthermore, it focuses on the application prospects, challenges, and opportunities associated with MOF composite membranes in water treatment.

Multi-trait efficiency and interactivity of bacterial consortia used to enhance plant performance under water stress conditions

Water stress is a major limiting factor for agricultural production under current and projected climate change scenarios. As a sustainable strategy, plant growth-promoting bacterial consortia have been used to reduce plant water stress. However, few studies have examined the effects of stress on multi-trait efficiency and interactivity of bacterial species. In this study, we used several in-vitro experiments, plant assays and greenhouse trials to investigate the effects of stress and bacterial consortia on 1-aminocyclopropane-1-carboxylic acid deaminase (ACCD) activities, indole-3-acetic acid (IAA) production and plant growth-promoting traits (Phosphate-solubilization, starch hydrolysis, siderophores and ammonium production). We further assessed biofilm formation and the chemotactic behaviour in response to ACC. A total of fifteen ACCD rhizobacteria with multiple growth-promoting traits from the dominant plant species from the hyperseasonal Aripo Savannas were screened in this study. Five of the isolates were further analyzed based on their ACCD activities and were tested in single and dual consortium to assess their abilities in promoting growth under simulated drought stress (-0.35 MPa) and chemically induced ACC conditions (0.03 mM). Our findings showed that bacteria which produce high concentrations of IAA affected the isolates' ability to promote growth under stress, irrespective of microbial combination with ACCD activity above the minimal threshold of 20 nmol α-ketobutyrate mg-1 h-1. Biofilm production with co-culture interaction varied greatly across treatments, however, the general trend showed an increase in biofilm under stress induce conditions. The best performing co-culture, UWIGT-83 and UWIGT-120 (Burkholderia sp.) showed enhanced growth in germination assays and in greenhouse trials with Capsicum chinense (Moruga red hot peppers) under drought stress, when compared to non-inoculated treatments. The findings highlight the importance of testing interactivity of bacterial species with multiple growth promoting traits under stress conditions; and proposed the use of ACC growth media as a novel biofilm screening method for selecting potential stress plant growth-promoting bacteria. Better screening strategies for appropriate plant growth-promoting bacteria may narrow the inconsistency observed between laboratory and field trials.

Removal of sulfonylurea herbicides with g-C3N4-based photocatalysts: A review

The accumulation of agricultural chemicals in the environment has become a global concern, of which sulfonylurea herbicides (SUHs) constitute a significant category. Solar-driven photocatalysis is favored for removing organic pollutants due to its high efficiency and environmental friendliness. Graphite carbon nitride (g-C3N4)-based materials with superior catalytic activities and physicochemical stabilities are promising photocatalysts. This review describes the g-C3N4-based materials and their uses in the photocatalytic degradation of SUHs or other organic pollutants with similar structures. First, the fundamentals of g-C3N4-based materials and photocatalytic SUHs degradation are discussed to provide an in-depth understanding of the mechanism for the photocatalytic activity. The ability of different g-C3N4-based materials to photocatalytically degrade SUH-like structures is then discussed and summarized based on different modification strategies (morphology modulation, elemental doping, defect engineering, and heterojunction formations). Meanwhile, the effects of different environmental factors on the photocatalytic performance of g-C3N4-based materials are described. Finally, the major challenges and opportunities of g-C3N4-based materials for the photocatalytic degradation of SUHs are proposed. It is hoped that this review will show the feasibility of photocatalytic degradation of SUHs with g-C3N4-based materials.

High-performance self-desalination powered by triboelectric-electromagnetic hybrid nanogenerator

Freshwater is an essential resource in today's world, and how to produce freshwater with low or even zero power consumption is a major challenge. Here, a desalination system powered by a triboelectric-electromagnetic hybrid nanogenerator (TEHG) is presented, which can utilize the water's own energy to remove the salt ions from itself, demonstrating a new concept of "self-desalination". At a relatively low rotation speed of 150 rpm, the system can dilute NaCl brine from 4000 ppm to 145 ppm with a high salt removal rate of 147.1 μg cm-2 min-1 and a freshwater productivity of up to 31.1 L m-2 h-1. The actual seawater can also be treated with a total ion removal efficiency of 99.6 % and a freshwater productivity of 2.7 L m-2 h-1, which is superior to other renewable-energy-powered desalination systems. More importantly, fully self-powered desalination process can be realized by manual cranking and hydrokinetic energy impact, both of which are capable of treating 1000 ppm salt feed to the drinking water level. The TEHG-powered desalination system not only provides excellent desalination performance but also addresses the challenges of power consumption and limited capacity, which offers a completely new paradigm of "self-desalination".

Construction of Bi2WO6/g-C3N4 Z-Scheme Heterojunction and Its Enhanced Photocatalytic Degradation of Tetracycline with Persulfate under Solar Light

Z-scheme heterojunction Bi2WO6/g-C3N4 was obtained by a novel hydrothermal process; its photocatalysis-persulfate (PDS) activation for tetracycline (TC) removal was explored under solar light (SL). The structure and photoelectrochemistry behavior of fabricated samples were well characterized by FT-IR, XRD, XPS, SEM-EDS, UV-vis DRS, Mott-Schottky, PL, photocurrent response, EIS and BET. The critical experimental factors in TC decomposition were investigated, including the Bi2WO6 doping ratio, catalyst dosage, TC concentration, PDS dose, pH, co-existing ion and humic acid (HA). The optimum test conditions were as follows: 0.4 g/L Bi2WO6/g-C3N4 (BC-3), 20 mg/L TC, 20 mg/L PDS and pH = 6.49, and the maximum removal efficiency of TC was 98.0% in 60 min. The decomposition rate in BC-3/SL/PDS system (0.0446 min-1) was 3.05 times higher than that of the g-C3N4/SL/PDS system (0.0146 min-1), which might be caused by the high-efficiency electron transfer inside the Z-scheme Bi2WO6/g-C3N4 heterojunction. Furthermore, the photogenerated hole (h+), superoxide (O2•-), sulfate radical (SO4•-) and singlet oxygen (1O2) were confirmed as the key oxidation factors in the BC-3/SL/PDS system for TC degradation by a free radical quenching experiment. Particularly, BC-3 possessed a wide application potential in actual antibiotic wastewater treatment for its superior catalytic performance that emerged in the experiment of co-existing components.

Assembling 99% MOFs into Bioinspired Rigid-Flexible Coupled Membrane with Significant Permeability: The Impacts of Defects

Assembling metal-organic frameworks (MOFs) into high-performance macroscopic membranes is crucial but still challenging. MOF-containing hybrid membranes can effectively integrate the advantages of flexible guest materials and MOFs. Nevertheless, the inherent limitations in fully harnessing the distinct characteristics of MOFs persist due to the substantial guest material content necessitated in membrane fabrication. Herein, inspired by the rigid and flexible structures in biological systems, rigid MIP-202(Zr) and defective MIP-202(Zr) (D-MIP-202(Zr)) modified flexible graphene oxide (GO) sheets are synthesized in situ and then assembled into a rigid-flexible coupled MOF-based membrane. The defects in D-MIP-202(Zr) are introduced by using acetic acid as the modulation agent. The obtained GO@MIP-202(Zr) membrane possesses a hierarchical porous structure with a 99 wt% MOF proportion, which is higher than the GO@D-MIP-202(Zr) (75 wt%) membrane with a compact bulge-structured surface. The water permeability of the GO@MIP-202(Zr) membrane attains remarkedly 5762.92 L h-1 m-2 bar-1 , which is 960 and 2.6 times higher than that of the GO membrane and GO@D-MIP-202(Zr) membrane. Additionally, benefiting from the superhydrophilicity and underwater superoleophobicity, the resultant membrane not only demonstrates high rejection for oil-water emulsions but also exhibits exceptional recyclability and anti-fouling ability. These findings provide valuable insights into the assembly of MOFs into high-performance membranes.

Bird's Nest-Shaped Sb2 WO6 /D-Fru Composite for Multi-Stage Evaporator and Tandem Solar Light-Heat-Electricity Generators

Herein, an integrated solar-thermal-power protocol is presented at a micro-nanoscopic level to maximize the energy utilization efficiency involving utilization period and utilization patterns, and the nexus of freshwater production and nanogeneration is realized. This sophisticated vaporization device is constructed with the merits of thermally confined evaporation space in favor of recycling latent heat of condensation and optimizing light absorption based on the local sunlight angle of incidence. Inspired by a bird's nest, Sb2 WO6 /D-Fructose composites are prepared as photothermal absorbers to achieve a superior water evaporation rate of 2.78 kg m-2  h-1 in the Multi-stage evaporator. In addition, a synergistic tandem photo thermal-electric device with a combination of solar-driven water evaporation and further waterflow-driven hydrovoltaic generation, which can output a stable voltage of up to 360.8 mV with effective utilization of steam energy and a limited water source, is exploited. Such integrated configurations pave a pathway for clean water production and renewable power generation simultaneously toward energy issues.

Novel eco-friendly polylactic acid nanocomposite integrated membrane system for sustainable wastewater treatment: Performance evaluation and antifouling analysis

Water contamination caused by heavy metals, nutrients, and organic pollutants of varying particle sizes originating from domestic and industrial processes poses a significant global challenge. There is a growing concern, particularly regarding the presence of heavy metals in freshwater sources, as they can be toxic even at low concentrations, posing risks to human health and the environment. Currently, membrane technologies are recognized as effective and practical for treating domestic and industrial wastewater. However, these technologies are hindered by fouling issues. Furthermore, the utilization of conventional membranes leads to the accumulation of non-recyclable synthetic polymers, commonly used in their production, resulting in adverse environmental consequences. In light of our previously published studies on environmentally friendly, biodegradable polylactic acid (PLA) nanocomposite mixed matrix membranes (MMMs), we selected two top-performing PLA-based ultrafiltration nanocomposite membranes: one negatively charged (PLA-M-) and one positively charged (PLA-M+). We integrated these membranes into systems with varying arrangements to control fouling and eliminate heavy metals, organic pollutants, and nutrients from raw municipal wastewater collected by the local wastewater treatment plant in Abu Dhabi (UAE). The performance of two integrated systems (i.e., PLA-M+/PLA-M- and PLA-M-/PLA-M+) was compared in terms of permeate flux, contaminant removal efficiencies, and fouling mitigation. The PLA-M+/PLA-M- system achieved removal efficiencies of 79.6 %, 92.6 %, 88.7 %, 85.2 %, 98.9 %, 94 %, 83.3 %, and 98.3 % for chemical oxygen demand (COD), nitrate (NO3--N), phosphate (PO43--P), ammonium (NH4+-N), iron (Fe), zinc (Zn), nickel (Ni), and copper (Cu), respectively. On the other hand, the PLA-M-/PLA-M+ system recorded removal efficiencies of 85.8 %, 95.9 %, 100 %, 81.9 %, 99.3 %, 91.9 %, 72.9 %, and 98.9 % for COD, NO3--N, PO43--P, NH4+-N, Fe, Zn, Ni, and Cu, respectively. Notably, the PLA-M-/PLA-M+ system demonstrated superior antifouling resistance, making it the preferred integrated system. These findings demonstrate the potential of eco-friendly PLA nanocomposite UF-MMMs as a promising alternative to petroleum-based polymeric membranes for efficient and sustainable wastewater treatment.

Progress in layered double hydroxides (LDHs): Synthesis and application in adsorption, catalysis and photoreduction

Layered double hydroxides (LDHs), also known as anionic clays, have attracted significant attention in energy and environmental applications due to their exceptional physicochemical properties. These materials possess a unique structure with surface hydroxyl groups, tunable properties, and high stability, making them highly desirable. In this review, the synthesis and functionalization of LDHs have been explored including co-precipitation and hydrothermal methods. Furthermore, extensive research on LDH application in toxic pollutant removal has shown that modifying or functionalizing LDHs using materials such as activated carbon, polymers, and inorganics is crucial for achieving efficient pollutant adsorption, improved cyclic performance, as well as effective catalytic oxidation of organics and photoreduction. This study offers a comprehensive overview of the progress made in the field of LDHs and LDH-based composites for water and wastewater treatment. It critically discusses and explains both direct and indirect synthesis and modification techniques, highlighting their advantages and disadvantages. Additionally, this review critically discusses and explains the potential of LDH-based composites as absorbents. Importantly, it focuses on the capability of LDH and LDH-based composites in heterogeneous catalysis, including the Fenton reaction, Fenton-like reactions, photocatalysis, and photoreduction, for the removal of organic dyes, organic micropollutants, and heavy metals. The mechanisms involved in pollutant removal, such as adsorption, electrostatic interaction, complexation, and degradation, are thoroughly explained. Finally, this study outlines future research directions in the field.

A simulation and risk assessment framework for water-energy-environment nexus: A case study in the city cluster along the middle reach of the Yangtze River, China

In the Anthropocene, there is a strong interlinkage among water, energy, and the environment. The water-energy-environment nexus (WEEN) has been vigorously advocated as an emerging development paradigm and a global research agenda. Based on the nexus concept, a framework for the WEEN complex system simulation and risk assessment is developed. The three metropolitan areas of the city cluster along the middle reaches of the Yangtze River (CCMRYR) are taken as the objects. Regional policies are combined with generic shared socio-economic pathways (SSPs) to form a localized SSPs suitable for the research region. The dynamic simulation of the WEEN complex system and the risk analysis are carried out with the combination of system dynamics models and copula functions. Results show that: There are obvious differences in water utilization, energy consumption, air pollutant emissions, and water pollutant emissions among the three metropolitan areas. The issue of high carbon intensity in the Wuhan Metropolitan Coordinating Region needs to be emphasized and solved from the perspective of optimizing the industrial structure. Adhering to current development patterns, there will be successive peaks in water utilization, energy consumption, and carbon emissions in Wuhan, Dongting Lake, and Poyang Lake Metropolitan Coordinating Region by 2030, leading to high synergy risks at the systemic level, with maximum values of 0.84, 0.85, 0.62, respectively. A development path based on conservation priorities indicates that future policymaking needs to prioritize a resource-saving and pollution-control development pattern directed by technological upgrading against the backdrop of scarce natural resource endowments. The localized SSPs are a beneficial extension that enriches the narrative of regional-scale SSPs. The evolutionary trajectories and risk assessments of WEEN complex systems under different localized SSPs provide a sweeping insight into the consequences of policy decisions, thus enabling policymakers to appraise policy rationality and implement appropriate corrective measures.

Sustainability in Membrane Technology: Membrane Recycling and Fabrication Using Recycled Waste

Membrane technology has shown a promising role in combating water scarcity, a globally faced challenge. However, the disposal of end-of-life membrane modules is problematic as the current practices include incineration and landfills as their final fate. In addition, the increase in population and lifestyle advancement have significantly enhanced waste generation, thus overwhelming landfills and exacerbating environmental repercussions and resource scarcity. These practices are neither economically nor environmentally sustainable. Recycling membranes and utilizing recycled material for their manufacturing is seen as a potential approach to address the aforementioned challenges. Depending on physiochemical conditions, the end-of-life membrane could be reutilized for similar, upgraded, and downgraded operations, thus extending the membrane lifespan while mitigating the environmental impact that occurred due to their disposal and new membrane preparation for similar purposes. Likewise, using recycled waste such as polystyrene, polyethylene terephthalate, polyvinyl chloride, tire rubber, keratin, and cellulose and their derivates for fabricating the membranes can significantly enhance environmental sustainability. This study advocates for and supports the integration of sustainability concepts into membrane technology by presenting the research carried out in this area and rigorously assessing the achieved progress. The membranes' recycling and their fabrication utilizing recycled waste materials are of special interest in this work. Furthermore, this study offers guidance for future research endeavors aimed at promoting environmental sustainability.

Research Progress on Hygroscopic Agents for Atmospheric Water Harvesting Systems

Adsorptive atmospheric water harvesting systems (AWHs) represent an innovative approach to collecting freshwater resources from the atmosphere, with a hygroscopic agent at their core. This method has garnered significant attention due to its broad applicability, strong recycling capacity, and sustainability. It is being positioned as a key technology to address global freshwater scarcity. The core agent's hygroscopic properties play a crucial role in determining the performance of the AWHs. This article provides a comprehensive review of the latest advancements in hygroscopic agents, including their adsorption mechanisms and classifications. This study of hygroscopic agents analyzes the performance and characteristics of relevant porous material composite polymer composites and plant composites. It also evaluates the design and preparation of these materials. Aiming at the problems of low moisture adsorption and desorption difficulty of the hygroscopic agent, the factors affecting the water vapor adsorption performance and the method of enhancing the hygroscopic performance of the material are summarized and put forward. For the effect of hygroscopic agents on the volume of water catchment devices, the difference in density before and after hygroscopicity is proposed as part of the evaluation criteria. Moisture absorption per unit volume is added as a performance evaluation criterion to assess the effect of hygroscopic agents on the volume of water collection equipment. The article identifies areas that require further research and development for moisture absorbers, exploring their potential applications in other fields and anticipating the future development direction and opportunities of moisture-absorbing materials. The goal is to promote the early realization of adsorptive atmospheric water harvesting technology for large-scale industrial applications.

Simultaneous removal of calcium, cadmium and tetracycline from reverse osmosis wastewater by sycamore deciduous biochar, shell powder and polyurethane sponge combined with biofilm reactor

The treatment of reverse osmosis concentrate generated from urban industrial sewage for resource recovery has been hot. In this research, a biofilm reactor was constructed by combining sycamore deciduous biochar, shell powder, and polyurethane sponge loaded with Zobellella denitrificans sp. LX16. For ammonia nitrogen (NH4+-N), calcium (Ca2+), chemical oxygen demand (COD), cadmium (Cd2+), and tetracycline (TC), the removal efficiencies were 98.69 %, 83.95 %, 97.26 %, 98.34 %, and 69.12 % at a hydraulic retention time (HRT) of 4 h, pH of 7.0, and influent salinity, Ca2+, and TC concentrations of 1.0, 180.0, and 3.0 mg/L, respectively. The biofilm reactor packing has a three-dimensional structure to ensure good loading of microorganisms while promoting electron transfer and metabolic activity of microorganisms and increasing the pollutant tolerance and removal efficiency. The reactor provides a practical reference for the sedimentation of reverse osmosis concentrate to remove Cd2+ and TC by microbial induced calcium precipitation (MICP).

JUJUNCAO-Stem-Based Interfacial Solar-Driven Evaporator with Natural Two-Phase Composite Structures of Functional Partition and Inherent Ultralow Vaporization Enthalpy of Water for Stable and Efficient Steam Production

The interfacial solar-driven evaporation has been deemed as an environmentally friendly approach for freshwater generation. Nevertheless, there is still a challenge to obtain solar evaporators with efficient vapor production from low-cost and renewable biomass through a simple preparation process. Herein, the JUJUNCAO stem was selected as the substrate material, and a kind of interfacial solar-driven evaporator with natural two-phase composite structures and inherent ultralow water vaporization enthalpy was constructed by a dip-coating process. The natural two-phase composite structures were utilized as independent functional partition: the low-tortuosity and hydrophilic vascular bundles served as hierarchical channels for rapid water transportation and continuous steam escape, and the honeycomb-like parenchyma cells were considered natural heat insulators for effective thermal management. Furthermore, the JUJUNCAO stem exhibited inherent ultralow water vaporization enthalpy which was only 1.15 kJ g-1. Benefiting from the natural two-phase composite structures of functional partition and inherent ultralow water vaporization enthalpy, the C-Js evaporator could achieve an evaporation rate of 2.77 kg m-2 h-1 with an efficiency of 85.6% under 1 sun illumination. Meanwhile, the C-Js exhibited a stable and ideal evaporation performance and metal ion rejection behavior in the actual brine desalination process. Owing to the cost-effective and simple pretreatment process, the C-Js evaporator has the potential for freshwater generation in undeveloped areas.

Water quality and phenotypic antimicrobial resistance in isolated of E. coli from water for human consumption in Bagua, under One Health approach

The One Health approach acknowledges the interconnection between human health, animal health, and environmental health, recognizing that these domains are closely intertwined, as many diseases affecting humans are also common in animals. Water acts as a vehicle for the transmission of such diseases, highlighting the significance of monitoring the quality of water intended for human consumption. In 2022, a research study was conducted to evaluate the water quality for human consumption in Bagua, Amazonas Region. The physicochemical analysis indicated that most parameters were within normal range, except for residual chlorine, which was predominantly absent. Microbiological analysis revealed the presence of total coliforms and E. coli. Phenotypic characterization of E. coli isolates exhibited resistance to the several antibiotics, including nalidixic acid, gentamicin, amoxicillin plus clavulanic acid, norfloxacin, and ciprofloxacin. These findings indicate a compromised production of water for human consumption, as per the water quality regulations in Peru. The presence of fecal contamination poses a significant microbiological risk to consumers. These results underscore the breakdown of the human-environment-animal interface within the One Health approach, thereby endangering public health.

Highly Efficient Arginine Intercalated Graphene Oxide Composite Membranes for Water Desalination

Graphene oxide-based composite membranes have received enormous attention for highly efficient water desalination. Herein, we prepare arginine/graphene oxide (Arg/GO) composite membranes by surface functionalizing GO nanosheets with arginine amino acid. Arginine has a unique combination of hydroxyl and amino functional groups that cross-link GO nanosheets through hydrogen bonding and electrostatic interactions. The as-prepared Arg@GO composite membranes with different thicknesses are used to separate the salt and dye molecules. The 900-nm-thick Arg@GO composite membrane shows high rejection of 98% for NaCl and 99.8% for MgCl2, Ni(NO3)2, and Pb(NO3)2 with good water permeance. Such a membrane also shows a high separation efficiency (100%) for methylene blue, rhodamine B, and Evans blue dyes. At the same time, the ultrathin Arg@GO composite membrane (220 ± 10 nm) exhibits high water permeance of up to 2100 ± 10 L m-2 h-1 bar-1. Furthermore, the 900-nm-thick Arg@GO composite membrane is stable in an aqueous environment for 40 days with significantly less swelling. Therefore, these membranes can be utilized in future desalination and separation applications.

Pressure-driven membrane filtration technology for terminal control of organic DBPs: A review

Disinfection by-products (DBPs), a series of undesired secondary contaminants formed during the disinfection processes, deteriorate water quality, threaten human health and endanger ecological safety. Membrane-filtration technologies are commonly used in the advanced water treatment and have shown a promising performance for removing trace contaminants. In order to gain a clearer understanding of the behavior of DBPs in membrane-filtration processes, this work dedicated to: (1) comprehensively reviewed the retention efficiency of microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) for DBPs. (2) summarized the mechanisms involved size exclusion, electrostatic repulsion and adsorption in the membrane retention of DBPs. (3) In conjunction with principal component analysis, discussed the influence of various factors (such as the characteristics of membrane and DBPs, feed solution composition and operating conditions) on the removal efficiency. In general, the characteristics of the membranes (salt rejection, molecular weight cut-off, zeta potential, etc.) and DBPs (molecular size, electrical property, hydrophobicity, polarity, etc.) fundamentally determine the membrane-filtration performance on retaining DBPs, and the actual operating environmental factors (such as solute concentration, coexisting ions/NOMs, pH and transmembrane pressure) exert a positive/negative impact on performance to some extent. Current researches indicate that NF and RO can be effective in removing DBPs, and looking forward, we recommend that multiple factors should be taken into account that optimize the existed membrane-filtration technologies, rationalize the selection of membrane products, and develop novel membrane materials targeting the removal of DBPs.

Removal of intI1, ARGs, and SARS-CoV-2 and changes in bacterial communities in four sewage treatment facilities

Currently, discharge regulations for wastewater treatment plants (WWTPs) are based on conventional parameters, but more is needed to ensure safe water reuse. In particular, emerging pollutants, as antimicrobials and antibiotic resistance genes (ARGs), are not considered. This research focuses on the fate of emerging biological contaminants during wastewater treatment in Mexico City. intI1 and the ARGs cphA-02, OXA-10 and sul1 were analyzed by qPCR; pathogenic bacteria species were characterized by high throughput sequencing of complete 16S rRNA gene, and fragments of SARS-CoV-2 were quantified by RT-qPCR. Conventional parameters (chemical oxygen demand and coliform bacteria) were also determined. Two sampling campaigns (rainy and dry seasons) were carried out in four municipal WWTPs in Mexico City, representing five biological treatment processes: conventional activated sludge, extended aeration activated sludge, membrane bioreactor, direct anaerobic digestion, and constructed wetland, followed by ultraviolet light or chlorine disinfection. In most cases, gene fragments of SARS-CoV-2 were eliminated below the detection limit of RT-qPCR. The abundance of intI1 positively correlated with the sul1, OXA-10, and cphA-02 abundances; intI1 and the ARGs here studied were partially removed in the WWTPs, and in most cases, the number of copies per second discarded in the sludge were higher those in the effluent. The treatment processes decreased the abundance of dominant bacterial groups in the raw wastewater, while enriching bacterial groups in the effluent and the biological sludge, with possible pollutant removal capabilities. Bacterial communities in the raw wastewater showed the predominance of the genus Arcobacter (from 62.4 to 86.0 %) containing potentially pathogenic species. Additionally, DNA of some species persisted after the treatment processes: A. johnsonii, A. junii, A. caviae, A. hydrophila, A. veronii, A. butzleri, A. cryaerophilus, Chryseobacterium indologenes, Hafnia paralvei, M. osloensis, Pseudomonas putida and Vibrio cholerae, which deserves special attention in future regulation for safe water reuse.

Source, transport, and toxicity of emerging contaminants in aquatic environments: A review on recent studies

Emerging contaminants (ECs) are gaining global attention owing to their widespread presence and adverse effects on human health. ECs comprise numerous composite types and pose a potential threat to the growth and functional traits of species and ecosystems. Although the occurrence and fate of ECs has been extensively studied, little is known about their long-term biological effects. This review attempts to gain insights into the unhindered connections and overlaps in aquatic ecosystems. Microplastics (MPs), one of the most representative ECs, are carriers of other pollutants because of their strong adsorption capacity. They form a complex of pollutants that can be transmitted to aquatic organisms and humans through the extended food chain, increasing the concentration of pollutants by tens of thousands of times. Adsorption, interaction and transport effects of emerging contaminants in the aquatic environment are also discussed. Furthermore, the current state of knowledge on the ecotoxicity of single- and two-pollutant models is presented. Herein, we discuss how aquatic organisms within complex food networks may be particularly vulnerable to harm from ECs in the presence of perturbations. This review provides an advanced understanding of the interactions and potential toxic effects of ECs on aquatic organisms.

Smart Buildings: Water Leakage Detection Using TinyML

The escalating global water usage and the increasing strain on major cities due to water shortages highlights the critical need for efficient water management practices. In water-stressed regions worldwide, significant water wastage is primarily attributed to leakages, inefficient use, and aging infrastructure. Undetected water leakages in buildings' pipelines contribute to the water waste problem. To address this issue, an effective water leak detection method is required. In this paper, we explore the application of edge computing in smart buildings to enhance water management. By integrating sensors and embedded Machine Learning models, known as TinyML, smart water management systems can collect real-time data, analyze it, and make accurate decisions for efficient water utilization. The transition to TinyML enables faster and more cost-effective local decision-making, reducing the dependence on centralized entities. In this work, we propose a solution that can be adapted for effective leakage detection in real-world scenarios with minimum human intervention using TinyML. We follow an approach that is similar to a typical machine learning lifecycle in production, spanning stages including data collection, training, hyperparameter tuning, offline evaluation and model optimization for on-device resource efficiency before deployment. In this work, we considered an existing water leakage acoustic dataset for polyvinyl chloride pipelines. To prepare the acoustic data for analysis, we performed preprocessing to transform it into scalograms. We devised a water leak detection method by applying transfer learning to five distinct Convolutional Neural Network (CNN) variants, which are namely EfficientNet, ResNet, AlexNet, MobileNet V1, and MobileNet V2. The CNN models were found to be able to detect leakages where a maximum testing accuracy, recall, precision, and F1 score of 97.45%, 98.57%, 96.70%, and 97.63%, respectively, were observed using the EfficientNet model. To enable seamless deployment on the Arduino Nano 33 BLE edge device, the EfficientNet model is compressed using quantization resulting in a low inference time of 1932 ms, a peak RAM usage of 255.3 kilobytes, and a flash usage requirement of merely 48.7 kilobytes.

Effects of water chemistry and flow on lead release from plastic pipes versus copper pipes, implications for plumbing decontamination

Despite being corrosion-resistant, plastic potable water pipes might accumulate heavy metals on their surface if they convey metal-contaminated tap water. This study examined the influence of water pH and flow conditions on lead (Pb) release from new and biofilm-laden potable water pipes to provide insights regarding decontamination. For this purpose, biofilms were grown onto new crosslinked polyethylene (PEX-A), high-density polyethylene (HDPE), and copper pipes for three months. Lead was then deposited onto the new and biofilm-laden pipes through 5 d exposure experiments under flow conditions. After that, lead release experiments were conducted by exposing the lead-accumulated pipes to lead-free synthetic tap water for 5 d, under both stagnant and water flow conditions. The metal accumulation study showed no significant difference in lead uptake by new pipes and their biofilm-laden counterparts under flow conditions. This could be attributed to the detachment of biofilms that have accumulated lead as water flows through the pipes. Water flow conditions significantly influenced the lead release from new and biofilm-laden water pipes. A lower water pH of 5.0 increased the release of lead from plastic pipes into the contact water, compared to pH 6.0 and 7.8. The greatest percentage of lead was released from biofilm-laden HDPE pipes (5.3%, 120 h) compared to biofilm-laden copper pipes (3.9%, 6 h) and PEX-A (3.7%, 120 h) and after exposure to lead-free synthetic tap water at pH 5.0, under stagnant conditions. On the other hand, under water flow conditions, the greatest lead release was found for new PEX-A pipes (4.4%, 120 h), new HDPE pipes (2.7%, 120 h), and biofilm-laden copper pipes (3.7%, 2 h).

Lead (Pb) deposition onto new and biofilm-laden potable water pipes

Heavy metals' interactions with plumbing materials are complicated due to the differential formation of biofilms within pipes that can modulate, transform, and/or sequester heavy metals. This research aims to elucidate the mechanistic role of biofilm presence on Lead (Pb) accumulation onto crosslinked polyethylene (PEX-A), high-density polyethylene (HDPE), and copper potable water pipes. For this purpose, biofilms were grown on new pipes for three months. Five-day Pb exposure experiments were conducted to examine the kinetics of Pb accumulation onto the new and biofilm-laden pipes. Additionally, the influence of Pb initial concentration on the rate of its accumulation onto the pipes was examined. The results revealed greater biofilm biomass on the PEX-A pipes compared to the copper and HDPE pipes. More negative zeta potential was found for the biofilm-laden plastic pipes compared to the new plastic pipes. After five days of Pb exposure under stagnant conditions, the biofilm-laden PEX-A (980 μg m-2) and HDPE (1170 μg m-2) pipes accumulated more than three times the Pb surface loading compared to the new PEX-A (265 μg m-2) and HDPE pipes (329 μg m-2), respectively. However, under flow conditions, Pb accumulation on biofilm-laden plastic pipes was lower than on the new pipes. Moreover, with increasing the initial Pb concentration, greater rates of Pb surface accumulation were found for the biofilm-laden pipes compared to the new pipes under stagnant conditions. First-order kinetics model best described the Pb accumulation onto both new and biofilm-laden water pipes under both stagnant and flow conditions.

The first evidence of microplastic occurrence in mine water: The largest black coal mining area in the Czech Republic

Climate change is creating new challenges for water supply worldwide, making the search for new sources of water vital. As mine water could serve as a potential source, this study investigated the presence of microplastics in water from terminated deep mines in the largest coal basin in the Czech Republic, as well as in water from nearby shallow wells. The particles found were analyzed for size, polymer composition, color and morphology using the ImageJ tool, infrared spectroscopy with Fourier transform (FTIR) and an optical stereomicroscope with a digital camera. Microplastics were detected in all tested sites. Their range accounted for 2.5-17.5 items/L for mine water samples and 2.5-20 items/L for well samples, with fibers being the dominant type. The average width of particles from mine water and wells amounted to 58 µm; 71 µm, length to 655 µm; 501 µm and area to 22,067 µm2; 28,613 µm2, respectively. Blue color was prevalent, among materials, in both cases, plastic coated paper was found dominant to Polyethylene terephthalate (PET), Polyester (PES), Tetrafluoroethylene-perfluoro (Propyl Vinyl Ether) - Copolymer (TFE-PPVE), and polypropylene (PP). The research provides the first evidence of microplastics' presence in underground waters from deep mines and shallow wells in the same area. The data suggest that it is almost impossible to find underground water sources free of microplastic contamination. In this context, atmospheric contamination from mine ventilation and infiltration through terminated mines were identified as potential sources, while infiltration through soil and rock formations is unlikely given the geological composition. The results of this study can serve as a relevant basis for further research on microplastics in mine waters. Additionally, the conclusions can advance the development in remediation technologies of microplastics from deep underground waters and their implementation in practice, particularly in light of upcoming legislation.

Theoretical and Experimental Analysis of Osmotically Assisted Reverse Osmosis for Minimum Liquid Discharge

Osmotically assisted reverse osmosis (OARO) is an innovative process that shows promising potential in the treatment of brine produced by conventional reverse osmosis (RO) systems. This study presents a theoretical and experimental analysis of the OARO process, focusing on its application to achieve minimum liquid discharge (MLD). This theoretical analysis includes the development of a mathematical model to describe the transport phenomena occurring during OARO. By considering mass balance equations coupled with transport equations, the theoretical model allows for the simulation of a full-scale system consisting of a single-stage RO and a four-stage OARO. Experimental investigations are also conducted to validate the theoretical model and to evaluate the performance of the OARO process. A laboratory-scale OARO system is designed and operated using a synthetic RO brine. Various operating conditions, including applied pressure, feed concentration, and draw concentration, are varied to investigate their effects on process performance. The experimental results demonstrate the feasibility of OARO as an MLD solution and also validate the predictions of the theoretical model, confirming its reliability for process optimization and design. The results of the theoretical analysis show that OARO has the potential to significantly improve water recovery compared to conventional RO. Based on the simulation, the optimal operating conditions are explored, leading to a significant reduction (up to 89%) in the volume of brine discharge.

Synthesis and investigation on synergetic effect of activated carbon loaded silver nanoparticles with enhanced photocatalytic and antibacterial activities

In this study, we synthesized silver nanoparticle-loaded cashew nut shell activated carbon (Ag/CNSAC). The synthesized samples were characterized by XRD, XPS, SEM with EDS, FT-IR, and BET analysis. The XRD, XPS, and EDS data provided convincing proof that Ag loaded on CNSAC is formed. The energy dispersive spectrum analysis and X-ray diffraction pattern both supported the face-centered cubic and amorphous structures of Ag/CNSAC. The SEM micrographs showed the inner surface development of Ag NPs and many tiny pores in CNSAC. The photodegradation of methylene blue (MB) dye by the Ag/CNSAC photocatalyst was investigated. This effective degradation of MB dye by Ag/CNSAC is attributed to the cooperative action of Ag as a photocatalyst and CNSAC as a catalytic support and adsorbent. In tests with gram-positive and negative bacteria including Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), the as-synthesized Ag/CNSAC showed outstanding antibacterial efficiency. Additionally, this study demonstrates a workable procedure for creating an affordable and efficient Ag/CNSAC for the photocatalytic eradication of organic contaminants.

The application and future of biofloc technology (BFT) in aquaculture industry: A review

This review describes the applicability of biofloc technology (BFT) to future aquaculture technologies. BFT is considered an innovative alternative for solving the problems of traditional aquaculture (for example, environmental pollution, high maintenance costs, and low productivity). Extensive research is being conducted to apply BFT to breed and raise many aquatic animal species. In BFT, maintaining an appropriate C:N ratio by adding a carbon source promotes the growth of microorganisms in water and maintains the aquaculture water quality through microbial processes such as nitrification. For the efficient use and sustainability of BFT, various factors such as total suspended solids, water turbidity, temperature, dissolved oxygen, pH, and salinity, stocking density, and light should be considered. The application of the transformative fourth industrial revolution technologies, Information and Communications Technology (ICT) and Internet of Things (IoT), to aquaculture can reduce the risk factors and manual interventions in aquaculture through automation and intelligence. The combination of ICT/IoT with BFT can enable real-time monitoring of the necessary elements of BFT farming using various sensors, which is expected to increase productivity by ensuring the growth and health of the organisms being reared.

Quantifying irrigation water demand and supply gap using remote sensing and GIS in Multan, Pakistan

Human interventions and rapid changes in land use adversely affect the adequate distribution of water resources. A research study was conducted to quantify the gap between demand and supply for irrigation water in Multan, Pakistan, which may lead to sustainable water management. Two remotely sensed images (Landsat 8 OLI and Landsat 5 TM) were downloaded for the years 2010 and 2020, and supervised classification method was performed for the selected land use land cover (LULC) classes and basic framework. During the evaluation, the kappa coefficient was found in the ranges of 0.83-0.85, and overall accuracy was found to be more than 80% which indicated a substantial agreement between the classified maps and the ground truth data for both years and seasons. The LULC maps showed that urbanization has increased by 49% during the last decade (2010-2020). Reduction in planting areas for wheat (9%), cotton (24%), and orchards (46%) was observed. An increase in planting areas for rice (92%) and sugarcane (63%) was observed. The changing LULC pattern may be related to variation in water demand and supply for irrigation. The irrigation water demand has decreased by 370.2 Mm3 from 2010 to 2020, due to the reduction in agricultural land and an increase in urbanization. Available irrigation water supply (canals/rainfall) was estimated as 2432 Mm3 for the year 2020 which was 26% less than that of total irrigation water demand (3281 Mm3). The findings also provide the database for sustainable water management and equitable distribution of water in the region.

OsmiR159 Modulate BPH Resistance Through Regulating G-Protein γ Subunit GS3 Gene in Rice

Brown planthopper (BPH) is the most destructive insect pest to rice that causes tremendous yield loss each year in rice planting Asia and South-East Asia areas. Compared with traditional chemical-based treatment, utilization of plant endogenous resistance is a more effective and environmental-friendly way for BPH control. Accordingly, quite a few quantitative trait loci (QTLs) for BPH resistance were cloned using forward genetics. However, BPH is apt to change quickly into new biotypes to overcome plant resistance, therefore, new resistance resources and genes are continuously needed. miRNAs are important regulators in both plant development and physiological regulation including immunity, and might be used as effective supplements for BPH resistance QTLs. miR159 is an ancient and conserved miRNA. In this study, we found that each OsMIR159 gene in rice responded to BPH feeding very obviously, and genetic function assay proved them to negatively regulate BPH resistance, with STTM159 showing resistance to BPH, and over expression of OsmiR159d susceptible to BPH. One target genes of OsmiR159, OsGAMYBL2, positively regulated BPH resistance. Further biochemical studies revealed that OsGAMYBL2 could directly bind to the promoter of G-protein γ subunit encoding GS3 gene and repress its expression. And genetically, GS3 responded to BPH feeding promptly and negatively regulated BPH resistance, GS3 over expression plants were susceptible to BPH, while GS3 knock-out plants were resistant to BPH. Thus, we identified new function of OsmiR159-OsGAMYBL2 in mediating BPH response, and revealed a new OsmiR159-G protein pathway that mediates BPH resistance in rice.

Nitrogen reduction combined with ETc irrigation maintained summer maize yield and increased water and nitrogen use efficiency

Introduction

High rainfall and excessive urea application are counterproductive to summer maize growth requirements and lower grain yield and water/nitrogen (N) use efficiency. The objective of this study was to determine whether ETc irrigation based on summer maize demand and reduced nitrogen rate in the Huang Huai Hai Plain increased water and nitrogen use efficiency without sacrificing yield.

Methods

To achieve this, we conducted an experiment with four irrigation levels [ambient rainfall (I0) and 50% (I1), 75% (I2), and 100% (I3) of actual crop evapotranspiration (ET_c)] and four nitrogen rates [no nitrogen fertilizer (N0), recommended nitrogen rate of urea (NU), recommended nitrogen rate of blending controlled-release urea with conventional urea fertilizer (BCRF) (NC), and reduced nitrogen rate of BCRF (NR)] in 2016-2018.

Results

The results show that reduced irrigation and nitrogen rate reduced Fv/Fm, ¹³C-photosynthate, and nitrogen accumulation both in the kernel and plant. I3NC and I3NU accumulated higher ¹³C-photosynthate, nitrogen, and dry matter. However, ¹³C-photosynthate and nitrogen distribution to the kernel was decreased from I2 to I3 and was higher in BCRF than in urea. I2NC and I2NR promoted their distribution to the kernel, resulting in a higher harvest index. Compared with I3NU, I2NR increased root length density by 32.8% on average, maintaining considerable leaf Fv/Fm and obtaining similar kernel number and kernel weight. The higher root length density of I2NR of 40-60 cm promoted ¹³C-photosynthate and nitrogen distribution to the kernel and increased the harvest index. As a result, the water use efficiency (WUE) and nitrogen agronomic use efficiency (NAUE) in I2NR increased by 20.5%-31.9% and 11.0%-38.0% than that in I3NU, respectively.

Discussion

Therefore, 75%ET_c deficit irrigation and BCRF fertilizer with 80% nitrogen rate improved root length density, maintained leaf Fv/Fm in the milking stage, promoted 13C-photosynthate, and distributed nitrogen to the kernel, ultimately providing a higher WUE and NAUE without significantly reducing grain yield.

Membranes in Water Reclamation: Treatment, Reuse and Concentrate Management

In this article, an extensive examination is provided on the possible uses of membranes and hybrid processes in wastewater treatment. While membrane technologies face certain constraints, such as membrane fouling and scaling, the incomplete elimination of emerging contaminants, elevated expenses, energy usage, and brine disposal, there are approaches that can address these challenges. Methods such as pretreating the feed water, utilizing hybrid membrane systems and hybrid dual-membrane systems, and employing other innovative membrane-based treatment techniques can enhance the efficacy of membrane processes and advance sustainability.

Mechanical Mechanism of Ion and Water Molecular Transport through Angstrom-Scale Graphene Derivatives Channels: From Atomic Model to Solid-Liquid Interaction

Ion and water transport at the Angstrom/Nano scale has always been one of the focuses of experimental and theoretical research. In particular, the surface properties of the angstrom channel and the solid-liquid interface interaction will play a decisive role in ion and water transport when the channel size is small to molecular or angstrom level. In this paper, the chemical structure and theoretical model of graphene oxide (GO) are reviewed. Moreover, the mechanical mechanism of water molecules and ions transport through the angstrom channel of GO are discussed, including the mechanism of intermolecular force at a solid/liquid/ion interface, the charge asymmetry effect and the dehydration effect. Angstrom channels, which are precisely constructed by two-dimensional (2D) materials such as GO, provide a new platform and idea for angstrom-scale transport. It provides an important reference for the understanding and cognition of fluid transport mechanism at angstrom-scale and its application in filtration, screening, seawater desalination, gas separation and so on.

Nanotechnology as an efficient and effective alternative for wastewater treatment: an overview

The increase in the surface and groundwater contamination due to global population growth, industrialization, proliferation of pathogens, emerging pollutants, heavy metals, and scarcity of drinking water represents a critical problem. Because of this problem, particular emphasis will be placed on wastewater recycling. Conventional wastewater treatment methods may be limited due to high investment costs or, in some cases, poor treatment efficiency. To address these issues, it is necessary to continuously evaluate novel technologies that complement and improve these traditional wastewater treatment processes. In this regard, technologies based on nanomaterials are also being studied. These technologies improve wastewater management and constitute one of the main focuses of nanotechnology. The following review describes wastewater's primary biological, organic, and inorganic contaminants. Subsequently, it focuses on the potential of different nanomaterials (metal oxides, carbon-based nanomaterials, cellulose-based nanomaterials), membrane, and nanobioremediation processes for wastewater treatment. The above is evident from the review of various publications. However, nanomaterials' cost, toxicity, and biodegradability need to be addressed before their commercial distribution and scale-up. The development of nanomaterials and nanoproducts must be sustainable and safe throughout the nanoproduct life cycle to meet the requirements of the circular economy.

Treatment of high-salinity brine containing dissolved organic matters by vacuum membrane distillation: A fouling mitigation approach via microbubble aeration

In this study, a laboratory-scale vacuum membrane distillation (VMD) system coupled with microbubble aeration (MBA) was developed for the treatment of high-salinity brine containing organic matters. Herein, at the beginning, feedwater only containing model organics such as humic acid (HA), bovine serum albumin (BSA) and sodium alginate (SA) was utilized to investigate the organic-fouling behavior, results indicated that the permeate flux was not affected by a thin and loose contaminated layer deposited on the membrane surface. Furthermore, dissolved organics in the feed brine inhibited the occurrence of membrane wetting due to the existence of a compact and protective crystals/organic-fouling layer, which can prevent the intrusion of scaling ions into membrane substrates. Besides, organics in the feedwater have a high tendency to adsorb on the membrane surface based on molecular dynamics simulations, thus, forming an organic-fouling layer prior to inorganic scaling. Finally, the effect of MBA on fouling alleviation was evaluated in VMD system, nearly 50% of salt precipitation from fouled membrane was effectively removed with the introduction of MBA, which can be ascribed to a combination of mechanisms, including surface shear forces and electrostatic attractions induced by microbubbles, meanwhile, about 2.2% of the total energy was only consumed, when using MBA. Together, these results demonstrated that MBA was a promising approach to alleviate membrane fouling in VMD.

Water crisis in Iran: A system dynamics approach on water, energy, food, land and climate (WEFLC) nexus

Water scarcity is a highly complex, multifaceted and dynamic issue, which has become a severe global challenge. Water scarcity is a hyperconnected phenomenon and thus should be studied through nexus approach, however current water-energy-food (WEF) nexus underrepresents the impacts of land use change and climate change on water scarcity. Therefore, this study was investigated to expand the WEF nexus coverage of further systems, improving the accuracy of nexus models for decision-making and narrowing science-policy gap. Current study developed a water-energy-food-land-climate (WEFLC) nexus model to analyze the water scarcity. Modeling the complex behavior of water scarcity enables the analysis of the efficiency of some adaptation policies in addressing water scarcity and will provide suggestions for improving adaptation practices. The results showed that there is a substantial water supply-demand gap in study region, with an excess consumption of 62,361 million m³. Under baseline scenario, the gap between water supply and demand will enlarge, leading to water crisis in Iran as our study region. Climate change was found to be the prime cause of exacerbating water scarcity in Iran, raising evapotranspiration from 70 % to 85 % in 50 years, and considerably increasing the water demand in various sectors. In terms of policy/adaptation measure analysis, the results showed that neither supply-side nor demand-side scenarios could solely address water crisis, and mixed supply-demand side interventions can be the most effective policy to alleviate water crisis. Overall, the study suggests that water resource management practices and policies in Iran should be reevaluated to include a system thinking management approach. The results can be used as a decision support tool that can recommend suitable mitigation and adaptation strategies for water scarcity in the country.

Network Biology Analyses and Dynamic Modeling of Gene Regulatory Networks under Drought Stress Reveal Major Transcriptional Regulators in Arabidopsis

Drought is one of the most serious abiotic stressors in the environment, restricting agricultural production by reducing plant growth, development, and productivity. To investigate such a complex and multifaceted stressor and its effects on plants, a systems biology-based approach is necessitated, entailing the generation of co-expression networks, identification of high-priority transcription factors (TFs), dynamic mathematical modeling, and computational simulations. Here, we studied a high-resolution drought transcriptome of Arabidopsis. We identified distinct temporal transcriptional signatures and demonstrated the involvement of specific biological pathways. Generation of a large-scale co-expression network followed by network centrality analyses identified 117 TFs that possess critical properties of hubs, bottlenecks, and high clustering coefficient nodes. Dynamic transcriptional regulatory modeling of integrated TF targets and transcriptome datasets uncovered major transcriptional events during the course of drought stress. Mathematical transcriptional simulations allowed us to ascertain the activation status of major TFs, as well as the transcriptional intensity and amplitude of their target genes. Finally, we validated our predictions by providing experimental evidence of gene expression under drought stress for a set of four TFs and their major target genes using qRT-PCR. Taken together, we provided a systems-level perspective on the dynamic transcriptional regulation during drought stress in Arabidopsis and uncovered numerous novel TFs that could potentially be used in future genetic crop engineering programs.

Water footprint and virtual water flows from the Global South: Foundations for sustainable agriculture in periods of drought

Freshwater availability has decreased alarmingly worldwide, with agriculture playing a vital role in this trend. The assessment of the agricultural water footprint (WF_agricultural) and virtual water flows (VWF) is fundamental not only in local water resources management and protection, but also in our understanding of the synergies between local water consumption and global markets. Thus, the WF_agricultural - broken down into its components (blue, green, and gray) - of the leading 21 crops (grouped in fruit, legumes, cereals, and vegetables), grown in four basins with the most significant agricultural activity in central Chile was determined, estimated in two consecutive years 2017-2018. In addition, due to their great importance in exports, VWFs were assessed, establishing connections according to their origins and destinations. The results show that the green and gray water footprints increased significantly in the south-central basins, while blue water consumption increased in the basins of the central zone, reflecting an evident WF_agricultural transition in accord with latitude and climate conditions. Furthermore, VWF showed an annual increase of 44 %, in about 116 destinations, with Asia, Europe, and North America being the preferred destinations, with annual variations of VWF_{blue- gray} associated with increases in exports of apples, cherries, grapes, blueberries, and walnuts, market preferences and growing areas. The present study is an initial step toward sustainable agriculture in a commodity exporting country, one that is relevant in the exploitation of virtual water yet faces severe water deficit problems, distribution, and local water policies. Therefore, contributing to encouraging the efficiency and value of water in the process of a new institutional framework.

No-free-lunch-theorem: a page taken from the computational intelligence for water resources planning and management

The long pursuit to alleviate the global water crisis has been riddled with revolutionary decision-making paradigms, forward-thinking theoretical concepts, and even ground-breaking technologies. This journey, however, is centered around the expectation of discovering what could be seen as the ultimate solution to all water-related problems. These nuances, revolutionary ideas, and cutting-edge technologies raise an ostensibly simple but fundamentally crucial question: Is there or can there ever be a singular universal ideal solution to address the water resources crisis that can potentially ensure the ideas of the sustainable development paradigm? This paper tends to take inspiration from the well-established no-free-lunch theorem (NFLT) to refute the possibility of such a solution in the context of water resources management. Such an interpretation also emphasizes that any remedy intended to address water resources issues must be tailored to the particular circumstances of each case. However, it should be noted that these findings are not intended to undermine the importance of current approaches but rather to emphasize how these concepts or technologies should be used as an inspiration to curate an ad hoc version of the said solution that can reflect local requirements or constraints.

Nanoparticle-Enhanced PVDF Flat-Sheet Membranes for Seawater Desalination in Direct Contact Membrane Distillation

In this study, hydrophobic functionalized carbon nanotubes (fCNTs) and silica nanoparticles (fSiO₂NPs) were incorporated into polyvinylidene fluoride (PVDF) flat-sheet membranes to improve their performance in membrane distillation (MD). The performance of the as-synthesized membranes was evaluated against commercial reference polytetrafluoroethylene (PTFE) flat-sheet membranes. The water contact angle (WCA) and liquid entry pressure (LEP) of the PVDF membrane were compromised after incorporation of hydrophilic pore forming polyvinylpyrrolidone (PVP). These parameters were key in ensuring high salt rejections in MD processes. Upon incorporation of fCNTS and fSiO₂NPs, WCA and LEP improved to 103.61° and 590 kPa, respectively. Moreover, the NP additives enhanced membrane surface roughness. Thus, an increase in membrane roughness improved WCA and resistance to membrane wetting. High salt rejection (>99%) and stable fluxes (39.77 kg m^-2 h^-1) were recorded throughout a 3 h process evaluation where 3.5 wt% NaCl solution was used as feed. These findings were recorded at feed temperature of 60 ℃. Evidently, this study substantiated the necessity of high feed temperatures towards high rates of water recovery.