A new hydrothermal hot isostatic pressing (HHIP) approach, involving hydrothermal water conditions and no usage of inert gas, was hypothesized and tested on 3D-printed Al-10%Si-0.3%Mg (%Wt) parts. The aluminum-based metal was practically inert at the applied HHIPing conditions of 300-350 MPa and 250-350 °C, which enabled the employment of a long (6-24 h) HHIP treatment with hardly any loss of material (the overall loss due to corrosion was mostly <0.
View Article and Find Full Text PDFThe operation of municipal wastewater treatment plants (WWTPs) invariably results in significant emission of greenhouse gases (i.e., CH, NO, and CO) into the atmosphere.
View Article and Find Full Text PDFA new concept is presented for eliminating off-flavor from cold-water RAS-grown fish, while feeding, and as a part of the normal grow-out period. The technology is based on disconnecting the nitrification biofilter, and instead passing the water through an electrolysis system, which both oxidizes the ammonia and disinfects the water, while also removing the off-flavor compounds from the water, which thereby results in the purging of the fish. The purging period was expected to last up to 2 weeks and the fish are fed throughout it.
View Article and Find Full Text PDFA new general method is presented for separating pure RbCl from solutions rich in Na and K. The method relies on Rb adsorption via ion exchange performed by self-synthesized PES coated Zn-Hexa-Cyanoferrate material. The procedure starts by passing the wastewater through an ion exchange column, which is thereafter regenerated with 1 M NHCl.
View Article and Find Full Text PDFThe continuous removal of TOC and the degradation efficiency of carbamazepine and 17β-estradiol were investigated using actual secondary municipal-effluent RO-retentate solutions. A specific set of operating parameters were applied within the supercritical water oxidizing conditions: temperature range 420-480 °C, 25.1 MPa, hydraulic retention time (HRT) of 1-2 min, excess oxidant molar-ratio of 3-10 and presence of a homogenous catalyst (IPA) at 50-100 mg/L.
View Article and Find Full Text PDFA new water treatment technology is presented for extending the longevity and increasing the maximal bio-load of container-bound, lucrative live seafood transportations. The technology is designed for removing ammonia and minimizing the bacterial concentration that develop in the water during the transport. This paper focuses on the characteristics of self-synthesized polyether-sulfone (PES) coated Zn-HCF composite beads, which have a high adsorbing capacity for NH in seawater and constitute the heart of the developed technology.
View Article and Find Full Text PDFContinuous subcritical and supercritical water oxidation experiments were conducted on dilute carbamazepine- and estradiol-containing synthetic solutions used to simulate the removal of model emerging pollutants from secondary municipal effluents. The operating conditions comprised 340-500 °C, retention time of 24-453 s and a stoichiometric oxidant ratio (O.C.
View Article and Find Full Text PDFWastes from concentrated animal feeding operations (CAFOs) are challenging to treat because they are high in organic matter and nutrients. Conventional swine waste treatment options in the U.S.
View Article and Find Full Text PDFThe transport of hydronium and hydroxide ions through reverse osmosis membranes constitutes a unique case of ionic species characterized by uncommonly high permeabilities. Combined with electromigration, this leads to complex behavior of permeate pH, e.g.
View Article and Find Full Text PDFA new operational approach is presented, which has the potential to substantially cut down on the energy and cost demand associated with seawater reverse osmosis (SWRO) desalination, without changing the currently-installed infrastructure. The approach comprises acidification/decarbonation of the feed seawater followed by high-pH single RO pass using high-flux membranes. Since the limitation imposed by CaCO3(s) precipitation is overcome, the recovery ratio can be significantly increased.
View Article and Find Full Text PDFSeawater nanofiltration (SWNF) generates a softened permeate stream and a retentate stream in which the multivalent ions accumulate, offering opportunities for practical utilization of both streams. This study presents an approach to simulation of SWNF including all major seawater ions (Na(+), Cl(-), Ca(2+), Mg(2+), and SO4(2-)) based on the Nernst-Planck equation, and uses it for permeate and retentate streams composition prediction. The number of degrees of freedom in the system was reduced by assuming a very high ionic permeability for Na(+), which only weakly affected the other parameters in the system.
View Article and Find Full Text PDFDeliberate struvite (MgNH4PO4) precipitation from wastewater streams has been the topic of extensive research in the last two decades and is expected to gather worldwide momentum in the near future as a P-reuse technique. A wide range of operational alternatives has been reported for struvite precipitation, including the application of various Mg(II) sources, two pH elevation techniques and several Mg:P ratios and pH values. The choice of each operational parameter within the struvite precipitation process affects process efficiency, the overall cost and also the choice of other operational parameters.
View Article and Find Full Text PDFPlacement of water quality sensors in a water distribution system is a common approach for minimizing contamination intrusion risks. This study incorporates detailed chemistry of organophosphate contaminations into the problem of sensor placement and links quantitative measures of the affected population as a result of such intrusions. The suggested methodology utilizes the stoichiometry and kinetics of the reactions between organophosphate contaminants and free chlorine for predicting the number of affected consumers.
View Article and Find Full Text PDFMeasuring and modeling pH in concentrated aqueous solutions in an accurate and consistent manner is of paramount importance to many R&D and industrial applications, including RO desalination. Nevertheless, unified definitions and standard procedures have yet to be developed for solutions with ionic strength higher than ∼0.7 M, while implementation of conventional pH determination approaches may lead to significant errors.
View Article and Find Full Text PDFAs a complementary step towards solving the general event detection problem of water distribution systems, injection of the organophosphate pesticides, chlorpyrifos (CP) and parathion (PA), were simulated at various locations within example networks and hydraulic parameters were calculated over 24-h duration. The uniqueness of this study is that the chemical reactions and byproducts of the contaminants' oxidation were also simulated, as well as other indicative water quality parameters such as alkalinity, acidity, pH and the total concentration of free chlorine species. The information on the change in water quality parameters induced by the contaminant injection may facilitate on-line detection of an actual event involving this specific substance and pave the way to development of a generic methodology for detecting events involving introduction of pesticides into water distribution systems.
View Article and Find Full Text PDFWastewaters generated during hydraulic fracturing of the Marcellus Shale typically contain high concentrations of salts, naturally occurring radioactive material (NORM), and metals, such as barium, that pose environmental and public health risks upon inadequate treatment and disposal. In addition, fresh water scarcity in dry regions or during periods of drought could limit shale gas development. This paper explores the possibility of using alternative water sources and their impact on NORM levels through blending acid mine drainage (AMD) effluent with recycled hydraulic fracturing flowback fluids (HFFFs).
View Article and Find Full Text PDFA new, simple and accurate method is introduced for determining H(2)CO(3)(*) alkalinity in fresh waters dominated by the carbonate weak-acid system. The method relies on a single H(3)PO(4) dosage and two pH readings (acidic pH value target: pH~4.0).
View Article and Find Full Text PDFThe ferrite process is an established method for treating wastewaters containing dissolved toxic metals, using precipitation at temperatures above 65 °C. Various ambient-temperature operation methodologies have also been proposed, but the effects of temperature reduction on product stability, and on the extent of isomorphous substitution (in terms of x in Me(x)Fe(3-x)O(4), Me representing a non-iron metal), have not been adequately quantified. At ambient temperature precipitation, maximal x of Zn(2+), Co(2+), Ni(2+) and Cd(2+) was found in the current study to be approximately 0.
View Article and Find Full Text PDFJ Colloid Interface Sci
June 2011
The ability of many noniron metals to be incorporated into the structure of ferrites is being utilized in numerous industrial and environmental applications. The incorporation of some of these metals during Fe(II) oxidation-induced precipitation at moderate temperatures (80-100°C) appears to be limited, for reasons not fully understood, and to extents not always agreed (e.g.
View Article and Find Full Text PDFJ Hazard Mater
November 2010
Incomplete oxidation of Fe(II) species released from the anode to Fe(III) may impede iron electrocoagulation processes conducted under low dissolved oxygen and/or pH<7 conditions, accompanied by the typically high buffering capacity of wastewater. This paper introduces a new approach to overcome this drawback by applying a second electrochemical cell (Ti/RuO(2) anode and Ti cathode) to be operated in parallel to the electrocoagulation cell. The second unit oxidizes Cl(-) ions invariably present in the water to HOCl, which is capable of oxidizing Fe(II) species at a high rate, irrespective of pH or O(2(aq)) concentration.
View Article and Find Full Text PDFOver 90% of the water supplied in the coastal region in Israel in 2013 (600 Mm(3) y(-1)) will be from desalination plants. The wastewater generated from this water (>400 Mm(3) y(-1)) is planned, after proper treatment, to be reused for agricultural irrigation, making this low-salinity water the main agricultural-sector future water source. In this respect both the Mg(2 + ) concentration and the Sodium Adsorption Ratio value of the water are of concern.
View Article and Find Full Text PDFA modified pH 1.0 liquid redox sulfur recovery (LRSR) process, based on reactive absorption of H(2)S((g)) in an acidic (pH 1.0) iron solution ([Fe(III)] = 9-8 g L(-1), [Fe(II)] = 1-2 g L(-1)) and electrochemical regeneration of the Fe(III)/Fe(II) catalyst couple, is introduced.
View Article and Find Full Text PDFDesalinated water is expected to become the major source of drinking water in many places in the near future, and thus the major source of wastewater to arrive at wastewater treatment plants. The paper examines the effect of the alkalinity value with which the water is released from the desalination plant on the alkalinity value that would develop within the wastewater treatment process under various nitrification-denitrification operational scenarios. The main hypothesis was that the difference in the alkalinity value between tap water and domestic wastewater is almost exclusively a result of the hydrolysis of urea (NH(2)CONH(2), excreted in the human urine) to ammonia (NH(3)), regardless of the question what fraction of NH(3(aq)) is transformed to NH(4)(+).
View Article and Find Full Text PDFRemoval of sulfide species from municipal sewage conveyance systems by dosage of iron salts is a relatively common practice. However, the reactions that occur between dissolved iron and sulfide species in municipal sewage media have not yet been fully quantified, and practical application relies heavily on empirical experience, which is often site specific. The aim of this work was to combine theoretical considerations and empirical observations to enable a more reliable prediction of the sulfide removal efficiency for a given dosing strategy.
View Article and Find Full Text PDFA novel post-treatment approach for desalinated water, aimed at supplying a balanced concentration of alkalinity, Ca(2+), Mg(2+) and SO(4)(2-), is introduced. The process is based on replacing excess Ca(2+) ions generated in the common H(2)SO(4)-based calcite dissolution post-treatment process with Mg(2+) ions originating from seawater. In the first step, Mg(2+) ions are separated from seawater by means of a specific ion exchange resin that has high affinity toward divalent cations (Mg(2+) and Ca(2+)) and an extremely low affinity toward monovalent cations (namely Na(+) and K(+)).
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