Water Treatment Research Articles

Aluminum hydroxide-coated pumice and biochar enhance biosand filter defluoridation and water treatment.

Chronic exposure to high fluoride levels in drinking water can cause serious health effects, including skeletal and dental fluorosis. Although conventional biosand filters (BSFs) can provide safe drinking water at the household scale, it has a low fluoride adsorption capacity. In this study, fluoride removal in BSF was enhanced by using aluminum hydroxide coated materials, such as pumice and biochar in place of sand. Bench-scale BSFs were set up with (a) uncoated sand as a control, (b) coated pumice, and (c) coated biochar. BSFs were charged with fluoride spiked surface water (≥ 5mg/L) for more than a year. While fluoride breakthrough was observed in the sand column on day 49, fluoride concentrations remained below the World Health Organization limit (< 1.5mg/L) for 313 and 418days for coated biochar and coated pumice, respectively. Columns with coated media also effectively removed turbidity, fecal indicator bacteria, and organic matter and maintained acceptable filtration rates (> 0.25m/h) without requiring frequent cleaning. Although pumice had a higher fluoride adsorption capacity (1.1mg/g) than biochar (0.94mg/g),filtered water pH in the pumice column was unacceptable (4.18 ± 0.25). However, apost-treatmentprocess, using an oyster shell-filled column, restored pH to within drinking water standards without compromising water quality.

Ceramic-carbon Janus membrane for robust solar-thermal desalination

The desalination performance of conventional distillation membranes is limited by insufficient stability and energy efficiency, impeding their application in sustainable water production. Herein, we report a ceramic-carbon Janus membrane with solar-thermal functionality for enhanced desalination performance, energy efficiency, and stability for hypersaline water treatment. The feed and permeate sides of this Janus membrane are designed with different properties such as wettability, conductivity, and solar-thermal conversion to enhance performance. We demonstrate that this membrane exhibits higher solar-thermal efficiency (66.8–68.8%) and water flux (3.3–5.1 L m–2 h–1) than most existing polymeric solar-thermal distillation membranes. Simulation results ascribe enhanced performance to an increased membrane surface temperature, which mitigates temperature polarization and attenuation, thus enhancing the desalination driving force. The nano-carbon membrane surface accelerates water evaporation by inducing a transition from free water to intermediate water with decreased hydrogen bonding and a lower evaporation energy barrier. Water vapor molecules transport through the membrane pores by a combined mechanism of Knudsen diffusion and viscous flow. Even for seawater and hypersaline water, the membrane exhibits stable water flux and salt rejection due to its scaling-resistant surface and stable interfacial temperature. This work provides a strategy for rationally designing next-generation Janus membranes for sustainable water purification.

Impact of different water treatments of peanuts during the roasting process on the flavour profile and chemical qualities of the peanut oil

Impact of different water treatments of peanuts during the roasting process on the flavour profile and chemical qualities of the peanut oil

High-Efficiency and Stable Cathode Disinfection in Real Water Systems via Convenient In Situ Prepared Copper-Cuprous Oxide Nanowires.

As global pollution intensifies, water contamination─a critical issue for both human and ecological survival─has become increasingly severe. Consequently, there is an urgent need for a rapid and stable water disinfection method to ensure clean water. In this study, high-surface-area Cu composite films were first deposited on a conductive substrate through an in situ electrodeposition process. The derived copper nanowire (M-Cu/Cu2O NWs) electrodes were then synthesized by controlled in situ growth and electrochemical reduction-decomposition of the Cu composite films. The working electrode was then placed on the cathode for water disinfection. The results demonstrated excellent and stable antimicrobial performance against Escherichia coli, Staphylococcus aureus, and Citrobacter freundii. The in situ reduction method for preparing derived copper electrodes can help prevent reoxidation during synthesis, promote the formation of an excellent crystal structure, and reduce grain boundaries and defects, thereby enhancing the mechanical strength and chemical stability of the Cu/Cu2O nanowires. Furthermore, the cathodic environment of the working electrode significantly reduces metal corrosion caused by oxidation, further enhancing its durability. The sterilization mechanism is the membrane's electroporation caused by nanowires' tip effect. It has been demonstrated that the M-Cu/Cu2O NWs cathode electrode can continuously maintain a bacterial inactivation rate above 90% for 30 days at an 8 V working potential. Due to the simple electrode fabrication method, stable disinfection efficiency, and significant reduction in copper ion release, which minimizes secondary environmental contamination, this system holds great potential for safe and stable water treatment applications.

The Effectiveness of Polysilicone Coated Chitosan-Nanosilver as a Disinfectant in Drinking Water Treatment Processes

The Effectiveness of Polysilicone Coated Chitosan-Nanosilver as a Disinfectant in Drinking Water Treatment Processes

Presence of 17β-Estradiol, Bisphenol A and Caffeine in the Treatment Stages of A Water Treatment Plant (WTP)

Objective: The objective of this study is to show an evaluation of the presence of 17β-Estradiol, BPA, and Caffeine, in different stages of treatment in a conventional WTP, located in the South of Brazil. Theoretical Framework: The presence of micropollutants (drugs, hormones, etc.) in water sources is identified. These contaminants, although in low concentrations, can cause negative impacts on the environment and the health of the population. In Brazil, there is an aggravation due to deficiencies in basic sanitation. The national conventional water treatment plants are not efficient in removing these micropollutants, as they are not designed and operated for this purpose. Method: The methodology involved the collection of water samples from different processes of a Conventional Water Treatment Plant Case Study. The presence of 17β-estradiol, Bisphenol A (BPA), and Caffeine was evaluated. To determine the concentrations of these micropollutants, the Solid Phase Extraction (SPE) and Liquid Chromatography technique was used. Results and Discussion: Concentrations for RW ranged from 2.084 ng.L-1 up to 3.174 ng.L-1 for 17β-Estradiol, 0.029 ng.L-1 up to 0.064 ng.L-1 for Caffeine, and 1.951 ng.L-1 up to 7.753 ng.L-1 for BPA. For TW, the concentrations of 17β-estradiol, Caffeine, and BPA were respectively, &lt;DL up to 2.821 ng.L-1, &lt;DL up to 0.078 ng.L-1, and 1.154 ng.L-1 up to 2.229 ng.L-1. Research Implications: The research showed that there is presence of 17β-estradiol, Caffeine, and BPA in all stages of water treatment of the case study plant. This result confirmed the hypothesis that conventional water treatment plants used in Brazil may not be removing micropollutants. Originality/Value: The presence and detection of micropollutants in environmental matrices is still not regulated in the vast majority of countries. As this is a relatively recent topic, many researchers are seeking to understand the concentrations and effects of these contaminants on the environment and health. Therefore, any research that contributes to this database is considered relevant. In the case of this work, the presence of 17β-Estradiol, BPA, Caffeine; Micropollutants in all stages of a conventional national Water Treatment Plant, including in the drinking water that is distributed to the population, stands out. In other words, there is a risk of serious impacts on the quality of the water that reaches the taps of homes.

Innovative ZnO-W18O49 nanocomposites and ZnWO4 nanostructures for water treatment

Nanomaterials including zinc oxide (ZnO) and non-stoichiometric (W18O49) tungsten oxide can be applied to solve the challenge related to optical properties of nanomaterials like global problems related to water treatment. Therefore, successful syntheses of zinc oxide-tungsten oxide nanocomposites and ZnWO4 nanostructures are reported by hydrothermal method and using different masses of green synthesized ZnO nanoparticles (NPs). The nanostructures are pure and only zinc, tungsten, and oxygen elements are observed in the synthesized samples. Alterations of green synthesized ZnO NPs mass used in the nanocomposite synthesis process influence the nanocomposites’ structural, morphological, and optical properties. Different morphologies including nanorods, nanofibers, cabbage-like structures, short nanorods, and nanoflakes are formed using different masses of the used ZnO NPs. The photocatalytic activities of the nanocomposites are evaluated by removing methylene blue (MB- 10 ppm) under UV irradiation in the neutral (pH = 7) and acidic (pH = 5) solutions. Interestingly, 10 mg of ZW0.05 nanocomposite demonstrates the excellent deterioration of MB with efficiencies of 99% and 91% within 170 min in the neutral and acidic solutions, respectively. Furthermore, the quantity of catalyst was reduced to 5 mg, demonstrating the capacity to degrade 87% (94%) of MB at pH = 7 (pH = 5). Therefore, one of the synthesized nanocomposites can be an excellent candidate for water treatment even in acidic condition.

Nanomaterial-enhanced membranes for advanced water and wastewater treatment: a comprehensive review

Nanomaterial-enhanced membranes for advanced water and wastewater treatment: a comprehensive review

A hybrid multi-objective optimization approach for wastewater treatment plant construction: balancing time, cost, environmental impact, energy efficiency, and land use using NSGA-III and MODE

A hybrid multi-objective optimization approach for wastewater treatment plant construction: balancing time, cost, environmental impact, energy efficiency, and land use using NSGA-III and MODE

Long-term metagenomic insights into the roles of antiviral defense systems in stabilizing activated sludge bacterial communities.

Bacteria have evolved various antiviral defense systems to protect themselves, but how defense systems respond to the variation of bacteriophages in complex bacterial communities and whether defense systems function effectively in maintaining the stability of bacterial community structure and function remain unknown. Here, we conducted a long-term metagenomic investigation on the composition of bacterial and phage communities of monthly collected activated sludge samples from two full-scale wastewater treatment plants over six years and found that defense systems were widespread in activated sludge, with 91.1% of metagenome-assembled genomes having more than one complete defense system. The stability of the bacterial community was maintained under the fluctuations of the phage community, and defense system abundance and phage abundance were strongly positively correlated; there was a 0-3-month time lag in the responses of defense systems to phage fluctuations. The rapid turnover of CRISPR spacer repertoires further highlighted the dynamic nature of bacterial defense mechanisms. A pan-immunity phenomenon was also observed, with nearly identical metagenome-assembled genomes showing significant differences in defense system composition, which contributed to community stability at the species level. This study provides novel insights into the complexity of phage-bacteria interactions in complex bacterial communities, and reveals the key roles of defense systems in stabilizing bacterial community structure and function.

Confinement-Modulated Singlet-Oxygen Nanoreactors for Water Decontamination.

Water decontamination with singlet oxygen (1O2) has shown advantages over the traditional radical-based treatment processes, which are frequently inhibited by the background inorganic/organic substances and produce toxic byproducts. However, earlier reported treatment systems mostly suffer from side reactions against efficient and cost-effective production of 1O2, together with insufficient utilization of 1O2 limited by the extremely short diffusion length. To overcome the drawbacks, we here designed high-performance nanoreactors by modulating the MnO2 phase to nanotube structures (with ∼5 nm diameter, termed "NT5"). With nanoconfinement, our developed NT5 directed efficient and almost 100% utilization of peroxymonosulfate (PMS) to produce 1O2 and achieved maximal kinetics on organic pollutant elimination. The mechanism study revealed that the geometric strain of NT5 together with spatial confinement modulated the adsorption properties of PMS molecules and led to their transformation to 1O2. To demonstrate the applicability of NT5, we developed a reactive filter with a particulate catalyst (NT5 grown on an alumina substrate) that can effectively and stably work in a broad range of contaminated scenarios (surface water, groundwater, municipal secondary effluent, and industrial wastewaters), due to the confined treatment together with the fouling-resistance nature. Our study may boost the deployment of nanomaterials with confined catalysis and their applications in practical water treatment scenarios.

Uncertainty analysis of field trials of low-cost Bi-TiO2-P25 solar photocatalyst for sustainable water treatment

Uncertainty analysis of field trials of low-cost Bi-TiO2-P25 solar photocatalyst for sustainable water treatment

Preparation of TiO2/α-Fe2O3@SiO2 Nanorod Heterostructures and Their Applications for Efficient Photodegradation of Methylene Blue

A facile solvo-hydrothermal method was used to synthesize sub-100 nm diameter TiO2/α-Fe2O3@SiO2 nanorods (TiO2/HNRs@SiO2). Thermal annealing of TiO2/HNRs@SiO2 activated the photosensitizing crystalline TiO2 domains containing mixed anatase and rutile phases. The photocatalytic degradation of methylene blue (MB), conducted using thermally annealed TiO2/HNRs@SiO2 photocatalysts, was successfully demonstrated with ~95% MB removal efficiency under mild conditions of pH = ~7 and room temperature using ~150 min of solar irradiation. The enhanced removal efficiency was attributed to the rapid adsorption of MB onto the TiO2/HNRs@SiO2 surface via favorable electrostatic interactions and the synergistic integration of α-Fe2O3 and TiO2 into nanorod heterostructures with bandgaps of 1.99–2.03 eV, allowing them to absorb visible light for efficient photocatalytic decomposition. This study provides insights into designing photocatalysts with improved selectivity for sustainable water treatment and environmental remediation.

Nutrient Recovery from Zeolite and Biochar Columns: The Case Study of Marineo (Italy) Wastewater Treatment Plant

Nutrient Recovery from Zeolite and Biochar Columns: The Case Study of Marineo (Italy) Wastewater Treatment Plant

Multifunctional Z‐scheme NaGdF4:Yb,Tm@ZnO/Ag3PO4 nanoheterojunction photocatalysts for water purification and antibacterial wound healing

AbstractPhotocatalysts with dual functionalities of decomposing organic pollutants in water and combating bacterial infections are increasingly important. Herein, NaGdF4:Yb,Tm@ZnO/Ag3PO4 (UZA) nanoheterojunction photocatalysts were synthesized via hydrothermal, sol–gel, and in situ deposition methods. The UZA photocatalyst demonstrated exceptional efficiency in generating reactive oxygen species (ROS), crucial for organic pollutant degradation. The incorporation of Ag facilitated efficient charge transfer in the all‐solid‐state Z‐scheme nanoheterojunction system. Furthermore, UZA exhibited potent antibacterial properties against both Gram‐positive Staphylococcus aureus (S. aureus) and Gram‐negative Escherichia coli (E. coli). The minimum bactericidal concentrations (MBC) of UZA were 50 µg/mL for S. aureus and 25 µg/mL for E. coli under natural irradiation, and 100 µg/mL for S. aureus and 25 µg/mL for E. coli under 980 nm irradiation, respectively. In vivo studies using a mouse model of acute bacterial‐infected wounds demonstrated that UZA incorporated into chitosan hydrogel dressings accelerated wound healing through photodynamic therapy within 9 days. The treated wounds exhibited rapid reduction to 9.95% of the initial area, diminished inflammatory responses, and enhanced re‐epithelialization attributed to sustained antibacterial effects and pathogen inhibition. Moreover, UZA composites showed excellent biocompatibility with a minimal hemolysis rate of 0.5% on erythrocytes. These findings underscore the promising application of UZA in water treatment for organic pollutants and in the treatment of skin wound infections caused by pathogenic bacteria.

Evaluation of neem gum-poly(acrylic acid) based adsorbent for cationic dye removal using adsorption isotherm, kinetics and thermodynamics: Linear regression models.

Evaluation of neem gum-poly(acrylic acid) based adsorbent for cationic dye removal using adsorption isotherm, kinetics and thermodynamics: Linear regression models.

Investigation of the Potentials of Local Strains of Pseudomonas for Aquaculture Water Treatment

The need for human and animal food production cannot be over-emphasized. Aquaculture and related activities have become an important sustainable business in Nigeria. Water pollution rates have increased in modern times owing to the various chemical usage. The receiving water bodies therefore constitute a potential source of danger to both humans and animals. Several metabolites of the bacteria can cause detoxification of polluted water. There is a need to develop indigenous bacteria consortia for application in the treatment of wastewater bodies in order to reduce importation and earn local earnings. Some indigenous Pseudomonas strains were isolated from waste soil sites using standard microbiological techniques including pour-plating serially diluted 1g of the soil sample in 9 ml of sterile peptone water. The basic features of the developed discrete colonies were studied, sub-cultured and then the purified isolates; PM05, PM78, PM13 and PM56 were challenged by growing them respectively with wastewater. Specifically, the NH4+-N content decreased from 230 mg/L to a range of between 0.5 to 12 mg/L. While NO3-N decreased from 25 mg/l to between 5.3 to 14.6mg/L. NO2-N decreased from 12mg/L to between 1.3 to 5.7 mg/L. and available/total N decreased from 235 to 103 mg/L respectively. The results indicated that the strains generally have the potential to remove nitrogen through the metabolic pathway of nitrogen assimilation which may make them fit for further development for bio-remediation purposes. Also, the results generated will add to the previous knowledge that such important strains can be obtained from the local soils and sediments in Nigeria.

Defining alarm thresholds for the load of pathogenic viruses in wastewater for decision making: An application to three French cities.

Defining alarm thresholds for the load of pathogenic viruses in wastewater for decision making: An application to three French cities.

Treatment of Diesel Oil-Contaminated Water Using Hydrochar Derived from the Hydrothermal Carbonization of Aloe Vera Leaves

The cultivation of aloe vera and the exploitation of the valuable gel is an emerging agro-industry in various parts of the world, including the Mediterranean region and south-east Asia. Following the separation of the gel from the aloe vera leaf, the latter is considered waste and a sustainable valorization pathway has not been established so far. Due to its high moisture content, it is well-suited for hydrothermal carbonization (HTC). In this study, HTC of aloe vera leaves was carried out at temperatures of 180—220 °C and residence times of 2- 8 h. After an initial screening of the hydrochars for diesel oil (DO) adsorption, the optimum sample was prepared at 180 °C and 2 h treatment time (AV-180–2). This sample was characterized using elemental and surface analysis methods and was used without modification in the adsorption DO from aqueous solutions. The maximum achievable adsorption capacity of hydrochar AV-180–2 was 12 g g−1 at 25 °C, with an initial DO content of 10 g L−1, rotating speed of 100 rpm, hydrochar quantity of 1.0 g L−1 and pH ~ 7.0, adsorption equilibrium was achieved after 15 min of contact time. The adsorption process followed the pseudo-second-order kinetic model with a correlation coefficient R2 = 0.995. The experimental data fitted best to the Freundlich isotherm (R2 = 0.998) and the thermodynamic study indicated a spontaneous and endothermic adsorption process. Overall, hydrothermal carbonization offers a new and sustainable exploitation pathway for aloe vera waste and the hydrochars showed a promising behaviour towards DO-contaminated aqueous phases.

Life cycle assessment of UVC-based advanced oxidation processes as quaternary treatments: Clostridium spp. inactivation and comparison with CECs removal.

In this work, Life Cycle Assessment has been applied for the evaluation of UVC-based photochemical treatments to deal with wastewater treatment plant effluents. In particular, UVC photolysis, UVC/H2O2 combination and UVC/H2O2/Fe(II) (namely photo-Fenton) were tested at pH ca. 7.5. Clostridium spp. was chosen as target species to test disinfection. Both, UVC/H2O2 and photo-Fenton were able to decrease Clostridium spp. below detection limit in 5min. Best results were reached with H2O2 concentration of 21mM. Coupling coagulation-flocculation with the photochemical process was tested for effluents with high organic load and turbidity. Global warming potential selected UVC photolysis as the best treatment for disinfection from the environmental point of view, despite its lower efficiency. However, when CECs removal was considered using acetaminophen as target contaminant, photo-Fenton was the most efficient and the most sustainable option. Finally, LCA was applied to the experimental work performed in the laboratory, showing that the effect of reactions was negligible vs. sample collection and transportation, as well as analytical procedures which accounted for more than 99% of the impact.