The development of 5G system provides a unique opportunity to implement a unified wireless transmission platform that can simultaneous deliver unicast, multicast and broadcast services using the same ...spectrum and the same infrastructure. This can be achieved by developing a more capable point-to-multipoint transmission (PTM) system component, also called 5G Multimedia Broadcast Multicast Services (5G-MBMS). A properly designed 5G-MBMS could achieve the convergence of terrestrial mobile broadband and TV broadcasting systems.By inherently allowing dynamic spectrum allocation among different types of services, this converged system could offer significant higher spectrum utilization. In this paper, the power-based non-orthogonal multiplexing (P-NOM) technology is proposed in addition to the existing orthogonal time-division-multiplexing (TDM) scheme. Significant capacity gains could be achieved by using P-NOM in a 5G-MBMS system for delivering different types of broadcast services, and for delivering mixed unicast and broadcast services. The capacity benefits of a 5G-MBMS with P-NOM is demonstrated by both theoretical analysis and computer simulations. A key finding is that using a two-layer P-NOM can essentially deliver a broadcast service on top of a unicast network, each achieving nearly full capacity. Next, a complexity analysis will reveal that implementing P-NOM in a 5G-MBMS system does not require significant additional complexity at consumer devices. Finally, it will be shown that, different from the non-orthogonal-multiple-access (NOMA) technologies, using P-NOM in 5G-MBMS system requires little or no change to the existing radio resource allocation mechanisms in LTE and 5G, when one power layer is used for broadcast services delivery.
•Non-fixed bed ion exchange for NOM removal is reviewed for the North Sea region.•Ion exchange treatment removed 40 to 60% of NOM, mainly humic fractions.•Ion exchange lowered the coagulant dosage ...and the UV/advanced oxidation energy use.•Ion exchange had low influence on fouling limitation of microfiltration membranes.•Ion exchange lowered the formation of disinfection by-products.
Natural organic matter (NOM) fractions cause problems in drinking water treatment and supply. In the North Sea region, anionic ion exchange (IEX) in non-fixed bed configurations has been considered for NOM removal in drinking water treatment plants. This paper discusses several experiences of the impact of anion IEX on NOM removal and on NOM-related problems in water treatment locations of the North Sea region, considering the specific situation of the sites. The investigated parameters include the effect of anionic IEX on the removal of total NOM and specific NOM fractions, the amount of chemicals used for coagulation, the development of trans membrane pressure in microfiltration, the formation of assimilable organic carbon and the energy consumption during advanced oxidation, the removal of organics by activated carbon, and the formation of disinfection by-products. The pilot experiences at three treatment locations in Belgium, United Kingdom and the Netherlands show that anionic IEX (1) removed typically 40 to 60 percent of total NOM; (2) targeted mostly humic NOM fractions, and was not effective to remove biopolymers (3) contributed to lower coagulant doses and energy consumption in UV/advanced oxidation; (4) had limited influence on limiting the fouling of microfiltration membranes; (5) lowered the formation of disinfection by-products; and (6) it can improve biological stability.
Arsenic mobility in soils, sediments and groundwater systems is strongly controlled by adsorption occurring at iron oxide/water interfaces, and the extent of this adsorption may be influenced by the ...presence of natural organic matter (NOM). This study aims to investigate the adsorption of As(III) and As(V) onto coprecipitates made with ferrihydrite (Fh) and humic acid (HA) with two organic carbon (OC) loadings of 5 and 15 wt% OC. We show that the coprecipitation of HA with Fh can significantly reduce the retention of both As(III) and As(V) over a wide pH range (4–11), and with increased OC loading, there is reduced arsenic adsorption. On pure Fh, As(III) is adsorbed to a greater extent than As(V) at pH > 6.5 (the crossover pH), whereas the crossover pH shifts to more acidic pH in the presence of HA, implying that the binding of As(III) is more favorable than As(V) in the presence of NOM. Both As(III) and As(V) are complexed with the ferric hydroxyl functional groups, and no ternary Fh-HA-As complexes are detected. We observe that ∼40% of the adsorbed As(III) is oxidized to As(V) on pure Fh, compared to only ∼29% of As(III) oxidation on the Fh-HA coprecipitate, indicating that NOM hinders As(III) oxidation on iron (hydr)oxide. The results of this study suggest that NOM interacts with arsenic in ways that promote arsenic mobility and especially promote the mobility of arsenate relative to arsenite, which is of great significance for evaluating the migration and bioavailability of arsenic in both natural and contaminated environments.
•Pre-coprecipitated NOM decreases arsenic adsorption onto ferrihydrite.•As(III) adsorption is more favorable than As(V) in the presence of NOM.•NOM inhibits the oxidation of As(III) on ferrihydrite.
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► Removal of atrazine was studied by UV/H2O2/Fe2+, UV/S2O82-/Fe2+ and UV/HSO5-/Fe2+. ► UV/HSO5-/Fe2+ was found to be the most efficient at pH 3.0 in degrading atrazine. ► ...UV/S2O82-/Fe2+ showed to be the most efficient at pH 5.8. ► Natural organic matter negatively impacted the efficiency of these processes. ► The stability of S2O82- possibly led to a higher removal of TOC by UV/S2O82-/Fe2+.
The degradation of atrazine, a widely used endocrine disrupting, carcinogenic and persistent herbicide, was investigated by photo-Fenton and photo-Fenton-like advanced oxidation technologies (AOTs): UV/H2O2/Fe2+, UV/S2O82-/Fe2+ and UV/HSO5-/Fe2+. The study was carried out at two pH value conditions, i.e., pH 3.0 and pH 5.8. At pH 3.0, UV/HSO5-/Fe2+ was found to be the most efficient technology whereas UV/S2O82-/Fe2+ was observed to be the most effective at pH 5.8. The degradation of atrazine followed pseudo-first-order reaction with the highest observed rate constant of 2.00×10−2cm2/mJ in UV/HSO5-/Fe2+ system at the initial concentrations of 4.64μM atrazine, 46.4μM HSO5- (PMS) and 35.81μM Fe2+. The UV fluence required for the complete removal of 4.64μM atrazine at initially 92.80μM of oxidant and 8.95μM of Fe2+ concentrations at pH 3.0 was found to be 480, 720 and 960mJ/cm2 in UV/HSO5-/Fe2+, UV/S2O82-/Fe2+ and UV/H2O2/Fe2+ systems, respectively. Humic and fulvic acids were found to negatively impact the degradation of atrazine. The removal of TOC was not significant unless a high UV fluence was applied. At an initial concentration of 18.56μM atrazine, 1856.00μM oxidant and 17.91μM Fe2+, a 62.94%, 47.10% and 44.09% decrease in TOC was achieved at a UV fluence of 6000mJ/cm2 in UV/PS/Fe2+, UV/PMS/Fe2+ and UV/H2O2/Fe2+ systems, respectively. Nevertheless, it is suggested in this study that photo-Fenton and photo-Fenton-like technologies are capable of removing atrazine from water efficiently.
Les noms bibliques font référence aux nombreux noms propres qui ont souvent une signification symbolique ou historique importante dont certains d’entre eux sont associés à des figures religieuses ...majeures, comme « Abraham », « Moïse », « David » et « Jésus ». Dans cet article, nous essayons de traiter les noms bibliques ayant toujours existé dans l’usage onomastique en Algérie et sont souvent sujets à des modifications phonétiques, résultant de la diversité linguistique inhérente à la langue arabe de manière générale et au parler algérien en particulier. Ainsi, ces noms, porteurs d’une histoire millénaire et d’une richesse symbolique indéniable, traversent les frontières géographiques et linguistiques, reflétant la complexité et la transcendance des récits bibliques dans le tissu culturel arabo-musulman.Dans le cadre de cette démarche, nous avons opté pour l'utilisation de la méthode du recensement sur toute l'étendue de l'année 2020. Par la suite, nous avons entrepris la catégorisation et la classification de quarante-deux (42) noms propres (prénoms et noms de familles) transcrits dans les registres d'état civil de la ville de Mostaganem au cours de cette période. Ce corpus a été soumis à une analyse linguistique en mettant l’accent sur leur signification et évolution historique.Il convient de dire qu’à travers cet article les anthroponymes d'origine biblique, largement répandus en Algérie, connaissent une expansion manifestement significative. Cependant, au sein de cette profusion, seuls ceux documentés dans le présent texte ont réussi à dépasser l'oubli, faisant ainsi face à l'épreuve du temps et préservant leur essence authentique. Cette constatation met en lumière l'importance de la préservation de ces noms, qui témoignent non seulement de l'héritage culturel et religieux du pays, mais également de sa diversité linguistique et de son identité plurielle à travers l’émergence et la conquête de l’arène onomastique contemporaine par de nouveaux noms propres.
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•Catalytic ceramic membrane was prepared through filtration of catalyst suspension.•SO4– was confirmed as predominant in the PMS/catalytic membrane system.•Increased NOM removal and ...decreased flux decline were observed with catalytic membrane.•Enhanced PMS cleaning efficiency was obtained with fouled catalytic membrane.
Catalytic membranes have gained increasing interest in water treatment due to their improved performance on contaminants removal, fouling mitigation, and cleaning efficiency. The reactive species generated in the catalytic membrane system play a critical role in the process. However, the performance of SO4–-based catalytic membrane has been considerably less studied. The current research investigated the performance of a novel SO4–-based ceramic ultrafiltration membrane on organics removal, fouling mitigation, and cleaning efficiency. The catalytic membrane was prepared through the filtration of a MnO2-Co3O4 nanoparticle solution, followed by sintering and sonication. Characterization results demonstrated the successful deposition of nanoparticles onto the membrane surface. Besides, the influence of 0.06 mg/cm2 of coating on membrane permeability was negligible. The production of SO4– (i.e., with the presence of peroxymonosulfate (PMS)) as predominant radical species was confirmed using para-chlorobenzoic acid (pCBA) and nitrobenzene (NB) as probe compounds. Due to the reaction with SO4–, a higher NOM removal rate was observed with the coated membrane as compared to the pristine membrane. However, the permeate flux of the coated membrane was only slightly increased in the presence of PMS (i.e., 8% increase in normalized flux), possibly due to the formation of small molecules leading to internal pore fouling. Contrariwise, the PMS cleaning efficiency with the coated membrane was remarkably higher than the pristine membrane and stable within three cycles of membrane filtration. The results of this study would significantly assist in the optimization of SO4–-based catalytic membrane processes for future successful industrial implementation.
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•Photothermally-activated PMS pre-treatment was applied for MD fouling alleviation.•NOM in the surface water can be effectively removed after PMS pre-treatment.•Stable permeance (PMS ...(2 mM)) vs 50 % reduction (control) of flux were obtained.••OH and SO4•− radicals generated by PMS contributed to the NOM removal.•The MD membrane properties could be kept conserved by the PMS pre-treatment step.
Membrane distillation (MD) has demonstrated its efficacy for seawater desalination, which prompted researchers to investigate its performance for the treatment of surface water containing natural organic matter (NOM). However, membrane fouling remains a significant technological constraint in the acceptability and implementation of MD modules. Herein, for the first time, a photothermally-activated PMS pre-treatment process is coupled to a direct contact (DC)-MD module for effective membrane fouling control. Photothermally-activated PMS (2 mM) pre-treatment achieved 69 % of UV254 removal and 30.9 % of dissolved organic carbon removal and allowed stable operation of the DCMD without any reduction in water permeance vs 50 % reduction obtained without the pretreatment step. The analysis of NOM fractions after pre-treatment using Parallel Factor Analysis and molecular weight distribution indicated changes in NOM composition, which facilitated membrane fouling control. The photothermally-activated PMS pre-treatment seems to alleviate membrane fouling by limiting the foulant-membrane interaction, which was observed to result in the formation of the fouling layer containing aromatic proteins, microbial byproducts-like substances, and inorganic (e.g., calcium) foulants. Finally, characterization of the used MD membranes revealed that the MD membrane properties could be kept unchanged by the photothermally-activated PMS pre-treatment step, thereby making the integrated DCMD system sustainable and attractive for widespread applications.
The removal of natural organic matter (NOM) from lake water was studied in two pilot-scale adsorbers containing granular activated carbon (GAC) with different physical properties. To study the ...adsorption behavior of individual NOM fractions as a function of time and adsorber depth, NOM was fractionated by size exclusion chromatography (SEC) into biopolymers, humics, building blocks, and low molecular weight (LMW) organics, and NOM fractions were quantified by both ultraviolet and organic carbon detectors. High molecular weight biopolymers were not retained in the two adsorbers. In contrast, humic substances, building blocks and LMW organics were initially well and irreversibly removed, and their effluent concentrations increased gradually in the outlet of the adsorbers until a pseudo-steady state concentration was reached. Poor removal of biopolymers was likely a result of their comparatively large size that prevented access to the internal pore structure of the GACs. In both GAC adsorbers, adsorbability of the remaining NOM fractions, compared on the basis of partition coefficients, increased with decreasing molecular size, suggesting that increasingly larger portions of the internal GAC surface area could be accessed as the size of NOM decreased. Overall DOC uptake at pseudo-steady state differed between the two tested GACs (18.9 and 28.6 g-C/kg GAC), and the percent difference in DOC uptake closely matched the percent difference in the volume of pores with widths in the 1–50 nm range that was measured for the two fresh GACs. Despite the differences in NOM uptake capacity, individual NOM fractions were removed in similar proportions by the two GACs.
► Biopolymers do not adsorb on GAC while the adsorbability of the remaining NOM fractions increased with decreasing molecular size (i.e., humics < building blocks < LMW organics). ► All NOM fractions adsorbed similarly on the two GACs even though the GACs exhibited different pore size distributions. ► No displacement of individual NOM fractions occurred. The adsorption of individual NOM fractions can therefore be considered as irreversible.
In this study, the membrane autopsy was performed on a full-scale seawater reverse osmosis (SWRO) desalination plant located on the Red Sea. Several techniques were employed to characterize the ...nature and the fate of the foulants in the process, including LCOCD, ICP-MS, SEM-EDS, TSS, and ATP. The efficiency of the pretreatment in removing the fouling potential was assessed by analyzing the seawater after the intake feed pump, after the spruce media filter (SMF) and after the cartridge filter (CF). The autopsy of the membrane modules and CF operated for long-term revealed the presence of a heterogeneous fouling layer. The organic fraction composition of the fouling layer depended on the module position in the vessel. The inorganic deposits embedded in the layer were mainly composed of aluminum, iron, and magnesium silicate. The inorganic sediments entered the plants from the shoreline seawater intake and accumulated on the CF filter and the membrane. The analysis of the pretreatment performance showed an increase of TSS and ATP after CF, highlighting the inappropriate CF filter replacement time.
•Membrane autopsy in a full-scale SWRO plant located on the Red Sea was assessed.•Pretreatment efficiency was evaluated in terms of fouling potential reduction.•Sediments from shoreline seawater intake were found in the modules.•Inappropriate replacement of cartridge filters increased the fouling potential.•Organic fouling composition depended on the module position in the vessel.
Membrane fouling is posing a critical obstacle limiting the widespread application of ultrafiltration (UF). Among the numerous membrane foulants, natural organic matter (NOM) is one of the most ...problematic since it exists ubiquitously in natural waters and can cause severe membrane fouling. This study investigated the removal of NOM in surface water and the mitigation of membrane fouling using heat-activated peroxydisulfate (PDS) as a pretreatment for UF process. The results demonstrated that the NOM was efficiently removed, with ultraviolet absorbance (UV254) and dissolved organic carbon (DOC) decreasing by approximately 71% and 52%, respectively, at a PDS dose of 0.8 mM within 60 min (80 °C). The chromatograms of high performance size exclusion chromatography (HPSEC) indicated that some high molecular weight humic substances with a peak at approximately 10 kDa were oxidized to low molecular weight organic matters distributed in the range of < 100 Da during the pretreatment process. Moreover, three-dimensional fluorescence parallel factor analysis (PARAFAC) indicated that humic-like substances were much more easily degraded by heat-activated PDS pretreatment than protein-like substances. These results indicated that some unsaturated NOM fractions were first degraded and then mineralized to carbon dioxide during pretreatment. Meanwhile, the destroyed structure of humic substances might hinder its binding with high valence cations to reduce the possibility of high valence cations deposited on the membrane surface, thereby reducing membrane fouling. Therefore, membrane fouling could be significantly mitigated due to the shifts of NOM concentration and structure by heat-activated PDS pretreatment in the surface water treatment.
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•The heat-activated peroxydisulfate was adopted as a pretreatment prior to ultrafiltration.•Suitable temperatures for mitigating membrane fouling by pre-oxidation were above 50 °C.•Structural destruction and mineralization of natural organic matter occurred simultaneously in oxidation process.•The destroyed structure of humic substances might hinder its binding with high valence cations.
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