Water Treatment Devices Research Articles

Effect of Magnetic Treatment on Water Permeability Through a Semi-Permeable Membrane

Magnetic water treatment devices (MWT), while attractive because of their safety, simplicity, environmental friendliness and effectiveness in agriculture have been difficult to assess scientifically because a single, generally accepted, repeatable and measurable indicator of their decree of impact on the physical properties of water, has not been discovered. Experimental results have shown that MWT offers many agricultural benefits and that magnetically-treated water can more easily penetrate various media such as membranes, which are generally considered excellent proxies for plant cell walls. This study evaluated how MWT changes permeability through a semi-permeable membrane, how that change is impacted by flow velocity and proposed membrane permeability as a reliable indicator of MWT effectiveness. Results obtained from this study indicated that MWT changed permeability through a semi-permeable membrane and these changes depended on water flow velocity. Results further indicated that the permeability differential in the MWT treatment group decreased by almost 9% at low-flow velocities (laminar regime; Re 4000). At low-flow velocities, the electro-conductivity of MWT and the control group were statistically different at p ≤ 0.01. However, at higher-flow velocities, the difference between MWT and the control group was smaller and a statistically sufficient level was reached only at p ≤ 0.05 and p ≤ 0.10. The differences observed between the low, and high-flow velocity treatment groups was somewhat expected as high flow rates reduce the retention time of water in the treatment area and thus reduces the efficiency of magnetic treatment. These results also provide a clear indication that water has been impacted by MWT and demonstrate the degree that water has been impacted by MWT under various flow rates.

Ultrahigh Desalinization Performance of Asymmetric Flow-Electrode Capacitive Deionization Device with an Improved Operation Voltage of 1.8 V

Flow-electrode capacitive deionization (FCDI) is an emerging desalinization technology for high-concentration saline water treatment. However, in practical cases the operation voltage of FCDI is usually limited by the decomposition potential of water (1.23 V), which does harm the desalinization performance of FCDI. To address this issue, here for the first time we propose a novel asymmetric FCDI (AFCDI) device by using an activated carbon (AC)/MnO2 suspension as the positive electrode and AC suspension as the negative electrode. In AFCDI, the operation voltage can be improved to be 1.8 V, and a high salt removal efficiency of 78% is achieved in 0.1 M NaCl solution within 2 h, much higher than that for conventional FCDI (59%). To the best of knowledge, this value is also much higher than those for other FCDI devices reported previously. The present work may provide a promising high-performance desalinization device for high-concentration saline water treatment.

Point-of-use Unit Based on Gravity Ultrafiltration Removes Waterborne Gastrointestinal Pathogens from Untreated Water Sources in Rural Communities

In developing countries, rural communities often face the lack of potable water infrastructure and must rely on untreated sources for drinking, which are often contaminated with waterborne pathogens. The use of home water treatment devices is seen as one means of reducing the risk of exposure to waterborne pathogens. The aim of this study was to evaluate the microbiological and physicochemical performance of a simple in-home point-of-use device based on gravity ultrafiltration through an ultrafilter membrane. Twenty-five randomly selected households from 2 rural communities in Culiacán, Mexico, were enrolled. Water samples were collected before and after treatment and during storage for a period of 8 weeks. Heterotrophic bacteria, total coliforms, fecal coliforms, Escherichia coli, and Giardia spp were quantified, as well as various physicochemical parameters. All of the untreated water samples contained high levels of indicator bacteria, but none were detected in the treated water fulfilling the requirements set by the Mexican Norm (NOM-127-SSA1-1994) and the World Health Organization guidelines for drinking water. However, indicator bacteria (fecal coliforms and E coli) were detected in every sample from water stored 24 hours after treatment. This study demonstrated that point-of-use filters using gravity-fed ultrafilters are a low-cost, effective water treatment technology for water of poor microbial quality. However, further identification of the sources and mechanisms by which water is contaminated when stored after treatment will help with designing and implementing better strategies for keeping water safe for domestic use.

Microbiological effectiveness of mineral pot filters as household water treatment in the coastal areas of Bangladesh

Mineral pot filters (MPFs) are commercially produced household water purifiers, used by millions of people in Bangladesh and other Asian countries. The effectiveness of the filters in reducing microbial indicators and other potential pathogens under realistic household usage conditions has not been previously investigated. A total of 75 filters were distributed among rural households in two coastal areas of Bangladesh and their performances were monitored in four cycles in an interval of about 1.5 months. The results showed a median log10 reduction of E.coli from 1.8 to 2.7 in four monitoring cycles. For pond water, E.coli reduction >2 log10 was observed. The filters also removed Vibrio cholerae non-O1/non-O139. The number of filtered water samples satisfying the WHO no risk level increased significantly. The turbidity of the filtered water was found to be less than 1 NTU (Nephelometric Turbidity Unit). The results suggest that MPFs are effective in reducing indicator bacteria substantially from the available water supply options. However, the performance of the filters was found inconsistent and was not sufficient to consistently meet the WHO guidelines for drinking water. More evidence based data obtained under laboratory and household usage conditions are necessary to further verify the filter performance and also to recommend the filter as household water treatment device for the population with unreliable water supply.

Inter-Laboratory Evaluation and Successful Implementation of MS2 Coliphage as a Surrogate to Establish Proficiency Using a BSL-3 Procedure

The U.S. Environmental Protection Agency’s (EPA) Water Laboratory Alliance relies on the Centers for Disease Control and Prevention’s ultrafiltration-based Water Processing Procedure (WPP) for concentration of biosafety level 3 (BSL-3) agents from 10 L to 100 L of drinking water. The WPP requires comprehensive training and practice to maintain proficiency, resulting in a critical need for quality control (QC) criteria. The aim of this study was to develop criteria using male-specific (MS2) coliphage (BSL-2 agent) to minimize safety hazards associated with BSL-3 agents and to use the criteria to evaluate analytical proficiency during a demonstration exercise. EPA Method 1602 with EasyPhage was used during the study to develop QC criteria for 100-mL, and 40–100 L samples. The demonstration exercise indicated that the MS2 criteria would allow laboratories to demonstrate proficiency using the WPP with 40–100 L samples. In addition, the QC criteria developed for 100-mL samples has broad applicability at laboratories that are using MS2 for other types of analyses, such as assessment of water treatment devices. The development of MS2 QC criteria allows laboratories to develop and confirm ongoing proficiency using the WPP.

Bioinspired Multifunctional Paper-Based rGO Composites for Solar-Driven Clean Water Generation.

Reusing polluted water through various decontamination techniques has appeared as one of the most practical approaches to address the global shortage of clean water. Rather than relying on single decontamination mechanism, herein we report the preparation and utilization of paper-based composites for multifunctional solar-driven clean water generation that is inspired by the multiple water purification approaches in biological systems. The reduced graphene oxide (rGO) sheets within such composites can efficiently remove organic contaminants through physical adsorption mechanism. Under solar irradiation, the floating rGO composites can instantly generate localized heating, which not only can directly generate clean water through distillation mechanism but also significantly enhance adsorption removal performance with the assistance of upward vapor flow. Such porous-structured paper-based composites allow for facile incorporation of photocatalysts to regenerate clean water out of contaminated water with combined adsorption, photodegradation, and interfacial heat-assisted distillation mechanisms. Within a homemade all-in-one water treatment device, the practical applicability of the composites for multifunctional clean water generation has been demonstrated.

IMPROVING THE QUALITY OF DESALINATED WATER WITH COMBINED WATER TREATMENT PLANT BOILER

It is shown the current ways of water treatment which are recommended by Classifyer of ground water purification and their disadavnatages with considerable operational cost. The common disadvantage of these installations is high energy consumption for production of one unit of distillate. The article presents an energy efficient solution of existing problem of water dessalination with low power consumption in combined water treatment device. The received results of experimental research of reverse distillate quality indicators after water treatment installation are to prove it’s operationability and effectiveness for small power engineering and systems of heat supply. The complex shows an energy consumption decrease, allows to engineers exclude the use of chemical reagents, the volumes of waste waters, to reduce considerably consumption of rinse water for own needs and cost of dessalination and purification of water, as well as cost on its warming. The article analyzes the current situation in technogenic zone of Aral Sea region.

Green synthesis of magnetic iron nanoparticles coated by olive oil and verifying its efficiency in extraction of nickel from environmental samples via UV–vis spectrophotometry

In this research, we report the synthesis and functionalization of magnetic iron nanoparticles using green chemistry (olive oil) for application of dispersive solid–liquid phase microextraction (DSLME) as a novel method for preconcentration and determination of nickel ions in soil, potato, red tea, white tea, mushroom, lettuce, cabbage, apple, urban water, purified drinking water through household water treatment device. Nickel is a dangerous toxic metal that can cause serious damage to the environment and then its removal is necessary. Recently, iron oxide nano materials have gained much attention due to their properties, such as extremely small, non-toxic, excellent magnetic properties, high surface area, great biocompatibility and high level of reactivity with metal which makes them worthwhile in the removal of these metals. For optimizing the important parameters affecting the extraction procedure, analyte concentration, pH, type of disperser solvent, absorption time, ionic strength effect, type of desorption solvent and desorption time investigated. SEM and FT-IR spectrum used for characterization of the synthesized magnetic nanoparticles. The measurements were done under the optimized conditions. Matrices effect and accuracy were examined by the determination of the relative recovery (RR%) of the real samples. Linear range, detection limit and relative standard deviation (RSD) are 1–5000ng/ml, 0.821ng/ml and 0.196%, respectively.

Strong Coupling between Nanofluidic Transport and Interfacial Chemistry: How Defect Reactivity Controls Liquid-Solid Friction through Hydrogen Bonding.

Defects are inevitably present in nanofluidic systems, yet the role they play in nanofluidic transport remains poorly understood. Here, we report ab initio molecular dynamics (AIMD) simulations of the friction of liquid water on defective graphene and boron nitride sheets. We show that water dissociates at certain defects and that these "reactive" defects lead to much larger friction than the "nonreactive" defects at which water molecules remain intact. Furthermore, we find that friction is extremely sensitive to the chemical structure of reactive defects and to the number of hydrogen bonds they can partake in with the liquid. Finally, we discuss how the insight obtained from AIMD can be used to quantify the influence of defects on friction in nanofluidic devices for water treatment and sustainable energy harvesting. Overall, we provide new insight into the role of interfacial chemistry on nanofluidic transport in real, defective systems.

Effect of electromagnetic treatment of saline water on soil and crops

Two experiments were carried out to study the effect of the electromagnetic treatment of saline water on seed germination of corn and the response of soil and potato crop irrigated with such water. The experiments were performed under controlled conditions with different water quality and soil texture. The electromagnetic water treatment was applied using Aqua-4D physical water treatment device. Results showed a significant increase in germination rate of corn seedlings watered with electromagnetic-treated saline water (EC=4dSm−1), particularly when water was exposed to electromagnetic fields for 15min. The experiments carried on potato crop with two soil textures, showed a significant increase in tuber yield when irrigated with electromagnetic treated water. It was also observed a significant decrease of soil salinity (ECe), Na+ and Cl− contents of soils irrigated with electromagnetic treated saline water compared to the soils irrigated with non-treated saline water. In contrast, compared to both treatments (control treatment and saline water treatment), the electromagnetic saline water treatment produced non-significant effect on tuber yield, Mg2+ and HCO3-. However, the electromagnetic treatment of saline water increased significantly K+, N and P adsorption in all tissues of potato and decreased significantly the adverse effects of saline water. Based on our results, electromagnetic treatment of saline water can reduce the negative effect of salinity on corn germination and potato crop and increase yield in about 10% in test conditions.

Automatic devices for electrochemical water treatment with cooling of electrolyte

The most common disinfectants for water treatment are based on chlorine and its compounds. Practically, water treatments with chlorine compounds have no alternative, since they provide, in comparison to other effective processes such as ozonization or ultraviolet irradiation, high residual disinfection capacity. Unfortunately, all of chlorine-based compounds for disinfection tend to degrade during storage, thus reducing the concentration of active chlorine. Apart from degradation, additional problems are transportation, storage and handling of such hazardous compounds. Nowadays, a lot of attention is paid to the development of electrochemical devices for in situ production of chlorine dioxide or sodium hypochlorite as efficient disinfectants for water treatment. The most important part of such a device is the electrochemical reactor. Electrochemical reactor uses external source of direct current in order to produce disinfectants in electrochemical reactions occurring at the electrodes. Construction of an electrochemical device for water treatment is based on evaluation of optimal conditions for electrochemical reactions during continues production of disinfectants. The aim of this study was to develop a low-cost electrochemical device for the production of disinfectant, active chlorine, at the place of its usage, based on newly developed technical solutions and newest commercial components. The projected electrochemical device was constructed and mounted, and its operation was investigated. Investigations involved both functionality of individual components and device in general. The major goal of these investigations was to achieve maximal efficiency in extreme condition of elevated room temperature and humidity with a novel device construction involving coaxial heat exchanger at the solution inlet. Room operation of the proposed device was investigated when relative humidity was set to 90% and the ambient temperature of 38?C. The obtained results in such extreme operation conditions reveled that it was possible to obtain required concentration of 0.85% of active chlorine with maximal temperature of outlet electrolyte of 35.3?C, which is within the limits of optimal temperatures.

Bio-Sand Filter (BSF): A Simple Water Treatment Device for Safe Drinking Water Supply and to Promote Health in Hazard Prone Hard-to-Reach Coastal Areas of Bangladesh

This study investigated a locally assembled ‘Bio-Sand Filter (BSF)’ water treatment device for low cost household level drinking water supply in hazard-prone hard-to-reach coastal areas of Bangladesh to promote health. The device was made using locally available materials (plastic bucket, sand and gravel). Overall study results revealed a greater portion of turbidity reduction (>99%) in the filtrate. The filter was found to reduce 1.5-log of total coliform and 1.6-log of fecal coliform, though it is not capable of consistently meeting the WHO guideline to be less than 1CFU per 100 ml for both fecal and total coliform. The chlorination results showed that 2.4 mg/L chlorine doses were effective in post treatment of the filtrate and meet the recommended WHO guidelines to have free chlorine at least 0.5 mg/L to 1.0 mg/L in the stored water after 24hr to protect water from recontamination. The results led to the conclusion that one device could provide enough drinking water (24 to 50 L) to satisfy the needs of a large representative household. The filters reduce the risks of contamination between the water source and at the point of consumption through improving water quality that can be translated into improved health outcomes.

The effect of electromagnetic fields, from two commercially available water treatment devices, on bacterial culturability.

Commercially available pulsed-electromagnetic field (PEMF) devices are currently being marketed and employed to ostensibly manage biofouling. The reliable application and industry acceptance of such technologies require thorough scientific validation - and this is currently lacking. We have initiated proof-of-principle research in an effort to investigate whether such commercially available PEMF devices can influence the viability (culturability) of planktonic bacteria in an aqueous environment. Thus two different commercial PEMF devices were investigated via a static (i.e. non-flowing) treatment system. 'Healthy' Escherichia coli cells, as well as cultures that were physiologically compromised by silver nano-particles, were exposed to the PEMFs from both devices under controlled conditions. Although relatively minor, the observed effects were nevertheless statistically significant and consistent with the hypothesis that PEMF exposure under controlled conditions may result in a decrease in cellular viability and culturability. It has also been observed that under certain conditions bacterial growth is actually stimulated.

CaCO3 scaling of oilfield produced water in “electrochemical pre-oxidation–coagulation sedimentation–filtration” process: reason, mechanism, and countermeasure

Chemical stability of oilfield injection water is a critical factor to avoid corrosion and scaling of water treatment devices and pipelines. Especially, Guangli oilfield (a branch of Shengli Oilfield) has achieved remarkable success in anti-corrosion by applying an electrochemical pre-oxidation process into strong corrosive wastewater treatment, while scaling was aggravated therefore. XRD, SEM, EDS, and chemical analysis demonstrated the major component of the scale deposit was calcite. Succeedingly, chemical analysis of produced water along the process showed that pH, concentration of calcium ions, bicarbonate ions, and suspended solids changed remarkably before and after the mixing reactor. Further studies revealed that the addition of water treatment chemicals (Na2CO3) in the mixing reactors induced the precipitates of CaCO3, which could serve as crystal seeds and resulted in the continuous precipitation of calcium ions. Moreover, calcite saturation ratio increased from 0.97 to 3.94 could contribute to the rise of pH and bicarbonate ions. Consequently, both of them created favorable conditions for crystal growth and incurred more severe scaling problem. The final scale inhibition experiments suggested that the amount of calcium carbonate scale could be mitigated through the dose of scale inhibitors.

Photothermal-Responsive Single-Walled Carbon Nanotube-Based Ultrathin Membranes for On/Off Switchable Separation of Oil-in-Water Nanoemulsions.

Oil-contaminated wastewater threatens our environment and health, especially that stabilized by surfactants. Conventional separation protocols become invalid for those surfactant-stabilized nanoemulsions due to their nanometer-sized droplets and extremely high stability. In this paper, photothermal-responsive ultrathin Au nanorods/poly(N-isopropylacrylamide-co-acrylamide) cohybrid single-walled carbon nanotube (SWCNT) nanoporous membranes are constructed. Such membranes are capable of separating oil-in-water nanoemulsions with a maximum flux up to 35 890 m(2)·h(-1)·bar(-1) because they feature hydrophilicity, underwater oleophobicity, and nanometer pore sizes. It is remarkable that the permeation flux can be simply modulated by light illumination during the process of separation, due to the incorporation of thermal-responsive copolymers and Au nanorods. Meanwhile, it shows ultrahigh separation efficiency (>99.99%) and desired antifouling and recyclability properties. We anticipate that our ultrathin photothermal-responsive SWCNT-based membranes provide potential for the generation of point-of-use water treatment devices.

ChemInform Abstract: Polydopamine and Eumelanin: From Structure‐Property Relationships to a Unified Tailoring Strategy

AbstractReview: 84 refs.

Polydopamine and eumelanin: from structure-property relationships to a unified tailoring strategy.

CONSPECTUS: Polydopamine (PDA), a black insoluble biopolymer produced by autoxidation of the catecholamine neurotransmitter dopamine (DA), and synthetic eumelanin polymers modeled to the black functional pigments of human skin, hair, and eyes have burst into the scene of materials science as versatile bioinspired functional systems for a very broad range of applications. PDA is characterized by extraordinary adhesion properties providing efficient and universal surface coating for diverse settings that include drug delivery, microfluidic systems, and water-treatment devices. Synthetic eumelanins from dopa or 5,6-dihydroxyindoles are the focus of increasing interest as UV-absorbing agents, antioxidants, free radical scavengers, and water-dependent hybrid electronic-ionic semiconductors. Because of their peculiar physicochemical properties, eumelanins and PDA hold considerable promise in nanomedicine and bioelectronics, as they are biocompatible, biodegradable, and exhibit suitable mechanical properties for integration with biological tissues. Despite considerable similarities, very few attempts have so far been made to provide an integrated unifying perspective of these two fields of technology-oriented chemical research, and progress toward application has been based more on empirical approaches than on a solid conceptual framework of structure-property relationships. The present Account is an attempt to fill this gap. Following a vis-à-vis of PDA and eumelanin chemistries, it provides an overall view of the various levels of chemical disorder in both systems and draws simple correlations with physicochemical properties based on experimental and computational approaches. The potential of large-scale simulations to capture the macroproperties of eumelanin-like materials and their hierarchical structures, to predict the physicochemical properties of new melanin-inspired materials, to understand the structure-property-function relationships of these materials from the bottom up, and to design and optimize materials to achieve desired properties is illustrated. The impact of synthetic conditions on melanin structure and physicochemical properties is systematically discussed for the first time. Rational tailoring strategies directed to critical control points of the synthetic pathways, such as dopaquinone, DAquinone, and dopachrome, are then proposed, with a view to translating basic chemical knowledge into practical guidelines for material manipulation and tailoring. This key concept is exemplified by the recent demonstration that varying DA concentration, or using Tris instead of phosphate as the buffer, results in PDA materials with quite different structural properties. Realizing that PDA and synthetic eumelanins belong to the same family of functional materials may foster unprecedented synergisms between research fields that have so far been apart in the pursuit of tailorable and marketable materials for energy, biomedical, and environmental applications.

Comparing the effectiveness of five low-cost home water treatment devices for Cryptosporidium, Giardia and somatic coliphages removal from water sources

This study compared the effectiveness and sustainability of five selected cost-effective home water treatment systems in removing Cryptosporidium and Giardia spp. from water sources. These systems included: silver impregnated porous pot (SIPP), biosand filter combined with zeolite (BSF-Z), biosand filter without zeolite (BSF-S), bucket filter (BF) and ceramic candle filter (CCF). The USEPA Methods 1623 were used for the isolation and the detection of the protozoan parasites. The flow rates of the devices ranged between 0.05 and 160.5 L/h. The average turbidity of the environmental intake water samples ranged between 1.47 and 42.93 NTU before filtration and between 0.05 and 14.49 NTU after filtration. The performance of the SIPP in removing the parasites (98–100% of both oocysts and cysts from synthetic water; 96–99.6% oocysts and 96.6–99.8% cysts from the environmental water sources) and in removing viral indicator (97.7–100%) was found to be significantly higher (p < 0.05) compared to other filters. In spite of its low flow rate, the SIPP filter consistently produced drinking water that complied with the limits set by the South African National Standards 241 in terms of turbidity and somatic coliphages.

Drinking water source and human Toxoplasma gondii infection in the United States: a cross-sectional analysis of NHANES data

BackgroundToxoplasma gondii imparts a considerable burden to public health. Human toxoplasmosis can be life-threatening in immunocompromised individuals, has been associated with psychiatric disorders, and can cause severe congenital pathologies, spontaneous abortion, or stillbirth. Environmental modes of transmission contributing to the incidence of human toxoplasmosis are poorly understood. We sought to examine National Health and Nutrition Examination Survey (NHANES) data for risk factors associated with T. gondii seroprevalence.MethodsT. gondii serology results reported for Continuous NHANES survey years 1999–2004 and 2009–10 were examined. To explore associations with toxoplasmosis seropositivity, covariates of interest were selected a priori, including source and home treatment of tap water. Associations between potential risk factors and evidence of IgG antibodies against T. gondii were assessed using multivariable logistic regression.ResultsAmong 23,030 participants with available T. gondii serology across 8 years of continuous NHANES survey data (1999–2004; 2009–2010), persons born outside the United States were significantly more likely to be seropositive, and seropositivity was inversely associated with years spent in the United States. Among US-born participants, participants with homes on well water (both those who used at-home water treatment devices and those who did not), as well as participants with public/private company-provided tap water who did not use at-home water treatment devices, were significantly more likely to be seropositive compared to participants who used home treatment devices on tap water provided by a private or public water company. A comparative subpopulation analysis revealed age-adjusted seroprevalence among US-born persons 12-49 yrs old significantly declined to 6.6% (95% CI, 5.2-8.0) (P <0.0001) in 2009–10, compared to previously published reports for NHANES data from 1988–1994 (14.1%) and 1999–2004 (9.0%).ConclusionsData suggests that T. gondii infections continue to decline in the United States, but the overall infection rate remains substantial at nearly 7%. Despite the limitations in the Continuous NHANES cross-sectional survey, the association between well water use and T. gondii infection warrants further research.

Ecotoxicological effects of carbon nanotubes and cellulose nanofibers in Chlorella vulgaris.

BackgroundMWCNT and CNF are interesting NPs that possess great potential for applications in various fields such as water treatment, reinforcement materials and medical devices. However, the rapid dissemination of NPs can impact the environment and in the human health. Thus, the aim of this study was to evaluate the MWCNT and cotton CNF toxicological effects on freshwater green microalgae Chlorella vulgaris.ResultsExposure to MWCNT and cotton CNF led to reductions on algal growth and cell viability. NP exposure induced reactive oxygen species (ROS) production and a decreased of intracellular ATP levels. Addition of NPs further induced ultrastructural cell damage. MWCNTs penetrate the cell membrane and individual MWCNTs are seen in the cytoplasm while no evidence of cotton CNFs was found inside the cells. Cellular uptake of MWCNT was observed in algae cells cultured in BB medium, but cells cultured in Seine river water did not internalize MWCNTs.ConclusionsUnder the conditions tested, such results confirmed that exposure to MWCNTs and to cotton CNFs affects cell viability and algal growth.