Water Systems Research Articles

Synergistic adsorption and photocatalytic degradation of tetracycline using a Z-scheme kaolin/g-C3N4/MoO3 nanocomposite: A sustainable approach for water treatment

This research focuses on the synthesis and application of a novel kaolin-supported g-C3N4/MoO3 nanocomposite for the degradation of tetracycline, an important antibiotic contaminant in water systems. The nanocomposite was prepared through a facile and environmentally friendly approach, leveraging the adsorption and photocatalytic properties of kaolin, g-C3N4 and MoO3 nanoparticles, respectively. Comprehensive characterization of the nanocomposite was conducted using techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and optical spectra. The surface parameters were studied using N2 adsorption-desorption isotherm. The elemental composition was studied using X-ray photoelectron spectroscopy. The efficiency of the developed nanocomposite in tetracycline degradation was evaluated and the results revealed an efficient tetracycline degradation exhibiting the synergistic effects of adsorption and photocatalytic degradation in the removal process. The tetracycline degradation was achieved in 60 min. Kinetic studies and thermodynamic analyses provided insights into the degradation mechanism, suggesting potential applications for the nanocomposite in wastewater treatment. Additionally, the recyclability and stability of the nanocomposite were investigated, demonstrating its potential for sustainable and long-term application in water treatment.

Infrastructure Conditions and Service Quality in Rural Drinking Water Systems: A Cluster Analysis of Community-Based Organizations in Chile

Infrastructure Conditions and Service Quality in Rural Drinking Water Systems: A Cluster Analysis of Community-Based Organizations in Chile

Exact Solutions of the Shallow Water System with an Inclined Bottom

Exact Solutions of the Shallow Water System with an Inclined Bottom

Biodegradation of Pharmaceutical Pollutants Using Fungal Enzyme

Abstract: The potential of filamentous fungi and their enzymes are investigated for bioremediating pharmaceutical pollutants from wastewater thereby addressing the growing concern of emerging pollutants in water resources. Among the various microorganisms, the current abstract discusses the role of fungi in degrading antibiotics and persistent pharmaceutical compounds. These fungi allow the biodegradation via the formation of highly oxidative hydroxyl radicals. It summarizes the role of both intra (cytochrome P450) and extracellular (laccase) enzyme systems for the bioremediation of emerging clinical pollutants. It emphasizes the importance of both biosorption and biodegradation for effective pollutant removal by breaking down pharmaceuticals (e.g. antibiotics) and other hazardous compounds (e.g. endocrine-disrupting compounds, polycyclic aromatic hydrocarbons). Although the enzymes CYP450 are not directly engaged, their metabolic pathways execute mechanisms such as oxidation, the formation of reactive intermediates, and chemical modification, all of which result in the degradation of clinical pollutants. Amongst all enzyme systems in the case of laccase which oxidise a wide spectrum of substrates, converts them to free radicals. Additionally, the role of recombinant enzyme production and transgenic strains for pollutant degradation has also been elaborated. These considerations emphasise the need for ongoing research and biotechnological advancements to address the growing concern of pharmaceuticals and personal care product pollutants in water systems.

Resource classification of coal bed methane and its contribution in energy transition and decarbonization path of oil and gas industry (A synopsis of CBM Life Cycle Analysis)

World economies are becoming increasingly more dependent on energy and countries have a voracious appetite for energy therefore, the need for an abundant clean energy is becoming a necessity. Energy companies are challenging environmental costs of coal bed methane as with advancement of new technology the impact from production of coal bed methane can reduce and to a certain extent avoided or offset. Production of coal bed methane results in changes to the land, to surface water and to ground water systems. Carbon quantification is required to understand, monitor and manage these changes. Previous life cycle analysis for this resource class has lack of process design details because of which there is a knowledge gap in understanding of emission profile of coal bed methane’s production. The objective of this study is to add value and reduce the scientific gap with respect to the production techniques of coal bed methane and its environmental impact. Removal of water continuously from coal seams depletes ground water and may eventually lower surface water flows (streams and rivers). It can also change the flow of groundwater drawing fresh water into the coal seams. To better understand this phenomenon the work establishes the Coal Bed Methane production foundation by in depth understanding of · Coal Bed Methane reservoir types; · Coal Bed Methane depositional environment, generation, and geological distributions; · Coal Bed Methane resource energy supply methods by understanding its construction, production and processing. The study then uses Life Cycle Assessment approach and understands previous emission numbers of Coal Bed Methane’s resource development. The work does systematic analysis and summarizes the previously published Life Cycle Analysis to understand further the potential environmental impacts of resource development of Coal Bed Methane. This will help energy companies to understand the field development, production, and operations of coal bed methane’s resource in terms of carbon numbers thereby optimizing the operations through carbon management thus reducing the potential impacts.

Remediation of arsenic and fluoride from groundwater: a critical review on bioadsorption, mechanism, future application, and challenges for water purification.

In the past few decades, the excessive and inadequate use of technological advances has led to groundwater contamination, mainly caused by organic and inorganic pollutants, which are highly harmful to human health, agriculture, water bodies, and aquaculture. Among all toxic pollutants, As and F- play a significant role in groundwater contamination due to their excellent reactivity with other elements. To mitigate the prevalence of arsenic and fluoride within the water system, the use of biochar gives an attractive strategy for removing them mainly because of the substantial surface area, pore size, pH, aromatic structure, and functional groups inherent in biochar, which are primarily dependent upon its raw material and pyrolysis temperature. Researcher develops different methods like physiochemical and electrochemical for treating arsenic and fluoride contamination. Among all removal methods, bioadsorption using agricultural waste residues shows effective/feasible removal of As and F- due to its low cost, ecofriendly nature, readily available, and efficient reuse compared with several other harmful synthetic materials that demand costly design specifications. This study discusses current developments in bioadsorption methods for As and F- that use agricultural-based biomaterials and describes the prevailing state of arsenic and fluoride removal strategies that use biomaterials precisely.

Modeling of a PV/Thermal Hybrid Panel for Residential Hot Water System

Abstract Despite the extensive body of research on PV/thermal systems, a gap remains in evaluating their performance in residential settings. This study aims to bridge this gap by focusing on the energy modeling of a PV/Thermal (PVT) hybrid panel that incorporates heat pipe technology. The evaluation is conducted through MATLAB code to assess the system's capability to fulfill the electricity and heating demands of residential buildings. The model's reliability is affirmed by comparing it with experimental data from a PVT panel tested in Sydney, exploring the transient variations in both water heat gain rates and power generation. The model's precision is evident from the percentage of error in the estimated temperatures of the PV panel based on the test results under various weather conditions, which ranged from −8% to 6%. This method was also utilized to determine the overall energy efficiency of the PVT under different climatic conditions. The results reveal that the overall energy efficiency of the proposed PVT panel, on a typical day, is approximately 45%, significantly outperforming traditional PV panels by more than double. Furthermore, the payback period for a typical residential PVT system, providing both hot water and electricity, is found substantially shorter than that of installing separate PV and solar hot water systems, highlighting the economic and environmental benefits of the proposed hybrid system.

Factors Associated with Public Water Supply Unreliability

Public water supply unreliability is a problem that causes human hardships and remains common in the United States. In this paper, we attempt to examine the factors associated with public water supply unreliability. We measure public water service unreliability by the issuance of boil water notices (BWNs). By using a Negative Binomial regression model and data from West Virginia community water systems in 2020, we find that water systems that purchase their water from other water systems, have more educated and experienced operators, and serve high-income areas and a higher percentage of Native residents are expected to issue more BWNs. On the other hand, water systems that are small and serve a higher percentage of rural, educated, employed residents are expected to issue fewer BWNs. The findings emphasize the need to move beyond simplistic assumptions about water system reliability and consider the combined influence of technical, socio-economic, and demographic factors.

PHREEQ C Modelling Tool Application to Determine the Effect of Anions on Speciation of Selected Metals in Water Systems within Kajiado North Constituency in Kenya

Heavy metals and anions in water pose a significant risk to living organisms, including humans, and must therefore be carefully monitored. There are numerous approaches and methods of analysis to choose from. Using the PHREEQ C chemical modeling technique, this study looked at the effect of certain anions on the speciation of selected metals in the water environment of Kajiado North. Twenty-five sampling points were used in the study, which covered five Kajiado North election wards. Samples were taken twice during the dry and rainy seasons, in November 2019 and March 2020. Using standard methods, physicochemical characteristics were analyzed, concentrations of selected heavy metals using the (ICP- OES) 7000 series, and selected anions using a multi parameter photometer, their concentration values compared to the specified maximum contaminant level and speciation analysis done using the Computer-based technique PHREEQ C. The range observed for pH, temperature, electrical conductivity, sulphate, chloride, fluoride, nitrate and carbonates was 7.43- 9.30, 23.0 -28.0oC, 335-1265μS/cm, 4.54-361.41mgL-1, 5.19-184.6 mgL-1, 0.01-2.90 mgL-1, 0.1-8.6 mgL-1, and 3.18-55.19 mgL-1 respectively. The range observed for heavy metals was 0.06-1.08 mgL-1 , 0.00 -0.05082 mgL-1, 0.01-0.02597 mgL-1, 0.01-0.01610 mgL-1, 0.00 -0.0327 mgL-1, 0.00-42.7842 mgL-1, and below detection limit, for Fe, Mn, Cu, Zn, Pb, Mg, and Cd respectively. The findings revealed that Cd, Zn, Cu, Cl-, NO2-, and eElectrical cconductivity concentrations were below the WHO levels. At certain sampling points, however, SO42-, F-, Pb, Fe, and Mn were above WHO limits. In some water systems, traces of SO42-, F-, Cu, Fe, Cd, and Mn were found to pose significant health risks, according to PHREEQ C speciation analysis. Anion concentrations, pH, temperature, and metal concentrations are all important variables in modeling. Metals formed anion complexes and the total abundance of metal species was classified at the highest levels as Fe(OH)3, PbCO3, Zn(CO3)2, Cu(CO3)2, Mn+2, MgF-, and Mg+2. At a water system temperature of 25oC without anions, it was found to have the highest chemical species. CuCO3, CuNO3, and CuOH+ complexes are also formed at low pH. Based on the data for different metal species at different pH values, the bioavailability of metal species definitely depends on pH.

An Atmospheric Water-Harvester with Ultrahigh Uptake-Release Efficiency at Low Humidity.

Atmospheric water harvesting is a practical strategy that is achieved by removing materials from air moisture to relieve global water scarcity. Here we design a water-harvester (i.e., MOF-303/thiolated polymer composite (MTC)) by using a metal-organic framework (MOF-303) and thiolated chitosan (TC) skeleton. Intermolecular hydrogen bonding between TC and MOF-303 facilitates porous structures with enlarged air-polymer interfaces for long cycling life and high capacity at low relative humidity. Benefiting from synergetic effects on porosity and anchorage for accelerating the uptake-release of moisture, MTC exhibits a rapid water uptake capacity of 0.135 g/g in 60 min under 12.5 RH% and ultrafast water desorption kinetics of 0.003 g/g/min at 8.5 RH%, which is superior to the as-reported MOF-303 based adsorbents. At low heat (∼40 °C), the water desorption and collection rate, respectively, are 0.0195 and 0.0168 g/g/min within 210 min, showing ultrahigh harvesting efficiency. These results highlight the enormous potential as promising materials for solving the world's water scarcity crisis. This study offers an insight into the design of AWH materials, which can be extended into applications in some realms, e.g., freshwater development for industry in arid areas, water engineering-related devices and systems, etc.

Changes in the limiting nutrients and dominant phytoplankton communities of three major European rivers: Response to catchment lithologies and human activities

Catchment lithologies and human activities can cause variations in riverine carbon (C), nitrogen (N), and phosphorus (P) loads, and the ratio of these nutrients may affect the primary productivity of rivers and their phytoplankton communities. We conducted a comparative study of biogeochemical variations in three major European rivers—the Rhine, Danube, and Seine—which reveals the impacts of different carbonate outcrops and human impacts (agricultural activities and sewage input) on the changes in the limiting nutrients and phytoplankton community compositions of flowing water systems. N limitation was observed in the Rhine and Danube owing to their low average NO3– loads (4.04–6.45 mg/L). Although the extensive outcrops of carbonate rocks in the Seine catchment result in high average HCO3– concentrations of ∼ 4.68 mmol/L, the elevated inorganic C input did not match the high average NO3– loads (∼19.38 mg/L), driven by intensive agricultural activity and urban sewage input, demonstrating a potential C limitation on productivity. Our results show that the productivity of the Seine River, determined by the chlorophyll-a concentration, was significantly related to the dissolved inorganic carbon (DIC) concentration (coefficient of determination: R2 = 0.68, P < 0.05). Our results demonstrate that changes in DIC content can significantly alter the dominant phytoplankton species in the water column. The high inputs of DIC and aqueous CO2(aq) to the Seine lead to Bacillariophyta proportions that are 3.96–8.81 % and 19.87–22.56 % higher than those of the Rhine and Danube in the wet and dry seasons, respectively. This can be explained by the difference in the efficiency of carbon concentrating mechanisms (CCMs) among phytoplankton species. Therefore, to mitigate river eutrophication and improve the quality of the aquatic environment, we suggest that future water–carbon management in the flowing water systems with abundant nutrients should consider C-limitation alleviation and its potential effect for reducing the abundance of harmful algae.

Role of Calcium Chloride on the Eluting Process of Residual Ammonium from Weathered Crust Elution-Deposited Rare Earth Ore Tailings

A large amount of ammonium salt leaching agent will remain in the leaching site of weathered crust elution-deposited rare earth ore (WREOs). The release of residual ammonium (RA) will seriously affect the water system ecology of the mining area, and it is urgent to control it. In this paper, column eluting was used to simulate the eluting process of RA in rare earth (RE) ore tailings, and the effects of calcium chloride concentration, eluting temperature, liquid-solid ratio, eluent pH and eluent flow rate on the eluting process of RA in rare earth ore tailings were discussed. It was found that calcium chloride could effectively elute the RA from ore tailings. Eluting agent pH almost had no effect on the eluting process of RA in the pH range of 4–6, and a greater impact on it at pH 8. The flow rate could effectively enhance the elution efficiency. The optimum conditions were calcium ion concentration of 0.1 mol/L, liquid-solid ratio of 2:1, pH 4–6, flow rate of 0.6 mL/min and elution at room temperature. At this time, the elution efficiency of RA was 91.85%. The eluting process of RA in ore tailings was controlled by the inner particle diffusing according to the kinetic analysis. The reaction order was 0.368, and the activation energy of the reaction is 12.450 kJ/mol. This will provide a theoretical basis and technical support for the efficient eluting process of residual ammonium in the leaching site of WREOs.

Impact of institutional overlapping on water governance of Himalayan City, Nainital, India

ABSTRACT This article investigates the current institutional arrangement concerning water governance in Nainital, India, located in the Western Himalayas. It assesses the availability of water resources, the functioning of the supply system, and sheds light on the role of institutions in managing water resources, supply, and distribution. Through qualitative methods (such as focus group discussions and key informant interviews with officials from water management institutions, citizens, etc.) supplemented by a literature review, the study reveals a complex network of institutions and stakeholders involved in water management. This complexity results in overlapping jurisdictions, leading to accountability gaps and various issues. The study identifies that in Nainital, existing institutions operate independently, impacting water governance in terms of water supply, resources, and environmental aspects. Considering the fragile biophysical environment of Nainital, the study also recommends integration of nature-centric approaches into institutional frameworks, which can be helpful in improving the resilience of water systems and promoting sustainable water governance

Operators Keep Pace With Industry Changes

Water treatment advances bring improved water quality but also difficult choices for water system operators. Over the past 50 years, plant operators have kept pace with these changes to ensure public health.

Making a vicious cycle virtuous: A research and policy agenda for advancing the water security of unregulated users in the Southwestern U.S.

AbstractIn the United States, most residents receive water from centralized utilities regulated under the federal Safe Drinking Water Act. Yet, a sizable portion of U.S. residents satisfy their household water needs through decentralized means, including domestic wells, very small water systems, and hauled water. These federally unregulated water users are among the most vulnerable to the impacts of climate change, particularly in aridifying regions like the Southwest. They are, however, inconsistently monitored and regulated at the Tribal, federal, state, and local levels. Compared to regulated users, very few programs exist to assist this population in securing and maintaining safe, affordable drinking water access. This neglect creates a vicious cycle whereby their water security needs remain both poorly understood and inadequately addressed. We review available data sources, regulations, assistance programs, and published studies relevant to unregulated water users across the Southwestern U.S. to illustrate this injurious feedback loop. We then propose four key areas for intervention to transform this vicious cycle into a virtuous one. Drawing on new insights from the emerging literature on modular, adaptive, and decentralized (MAD) water infrastructure, we highlight opportunities for investment and innovation to support decentralized service alongside existing investments in centralized infrastructure, and the critical need to attend to justice in the design and implementation of such policies.This article is categorized under: Science of Water &gt; Water and Environmental Change Human Water &gt; Water Governance Human Water &gt; Rights to Water

Assessing Drinking Water Systems to Improve Performance and Capacity

Key TakeawaysFragmented data across state agencies and subagencies reduce the ability to assess a community water system's overall condition.Identifying relationships among different dimensions of performance can help assess how well systems respond to challenges.Balancing affordability with capacity for reliable drinking water delivery over time is an ongoing challenge for many utilities.Focusing only on safe drinking water compliance in research and oversight may overlook systems with other critical vulnerabilities.

Oregon's Unprecedented Labor Day 2020 Fires: Impacts and Response

Key TakeawaysThe prevalence of hotter, more destructive wildfires will continue to threaten water systems’ ability to maintain source water quality and effective treatment.Over the Labor Day weekend in 2020, wildfires burned more than one million acres in Oregon; case studies illustrate three communities’ recovery and restoration strategies.Preparing for and responding to wildfires is done most effectively as a collaborative effort of utilities and local organizations and agencies.Utilities can protect their drinking water systems from a distribution standpoint and at a landscape level (i.e., protecting the source water).

Lessons From 30 Years of Water Crises and Water Policy

Key TakeawaysMost water crises are caused by events that are beyond the control of water system managers.New or updated regulations will not necessarily address all water crises.Extreme weather events are increasingly problematic, so water systems need to invest in preparedness; the question is how much to invest.

Hydrate Formation and Methane Mass Transfer Characteristics in Static Systems of Pure Water and Saline Water with Varied Initial Dissolved Methane Concentrations

Hydrate Formation and Methane Mass Transfer Characteristics in Static Systems of Pure Water and Saline Water with Varied Initial Dissolved Methane Concentrations

Influence of synthesis conditions and raw materials on the properties of N‐chlorosulfonamides immobilized on granular styrene–divinylbenzene polymer carriers

AbstractPolymer materials with immobilized functional groups–donors of active chlorine are widely used to create products with a microbiocidal effect and increased resistance to microbial contamination. In this work, various methods for the synthesis of granular styrene–divinylbenzene polymers with N‐chlorosulfonamide groups were investigated. It has been shown that the synthesis of polymers with chlorine‐active SO2NNaCl groups from a non‐functionalized styrene–divinylbenzene polymer matrix through the stage of its sulfochlorination with chlorosulfonic acid in dichloromethane for 6–7 h is optimal. These products contain approximately 11% of active chlorine and maintain a stable particle size distribution. When cation exchangers such as Purolite C100 are used as the initial polymer carrier, the content of chlorine‐active groups in the target product is approximately 9%, and an increase in the content of the dust fraction is observed. The obtained samples, regardless of the synthesis method, are capable of releasing active chlorine into solutions containing amino compounds. The microbial impurities in water also cause the emission of active chlorine in an amount that does not depend on the loading of the polymer, but is determined by the concentration of microbes, due to which a pronounced antimicrobial effect is observed. In this case, the resulting products do not cause further decomposition of the functional groups of the polymer, which indicates the high service life of the latter. The availability of raw materials, relative ease of synthesis, stability, possibility of regeneration and microbiocidal properties of the studied polymers make them promising for use as components of water and air purification systems and other products for medical and industrial purposes. © 2024 Society of Chemical Industry.