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This study explored the impact of eco-friendly polydopamine (PDA) coated ZnFe2O4 nanocomposites (PDA@ZnFe2O4 NCs) as nanofillers to fabricate a new class of polyethersulfone (PES) hybrid ultrafiltration (UF) membranes for wastewater treatment applications. The hybrid UF membrane was prepared by incorporating PDA@ZnFe2O4 NCs into PES via the non-solvent induced phase separation (NIPS) process. The PDA@ZnFe2O4 NC was characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Additionally, the morphology and performance of the prepared hybrid membranes were characterized by SEM, contact angle, surface charge, and thermogravimetric analysis (TGA). The incorporation of PDA@ZnFe2O4 NC into the PES membrane affects the porosity, mean pore radius, hydrophilicity, and thermal stability of the developed hybrid membranes. The pure water flux of the PES hybrid membrane with 4 wt% PDA@ZnFe2O4 reached ∼687 L/m2 h, which is about 188% higher than that of the pristine PES membrane. The performance of the PES/ PDA@ZnFe2O4ultrafiltration hybrid membrane was also investigated using humic acid (HA) foulant and oil/water emulsion individually. Compared to the pristine PES and PES/ZnFe2O4 membranes, the developed hybrid membranes showed enhanced permeability and HA foulant removal. HA's removal efficiency has improved from ∼65% in the pristine PES membrane to ∼94% in the 4 wt% PDA@ZnFe2O4 hybrid membrane. The abundant functional groups on the PDA@ZnFe2O4 NC surface also enhanced the separation of the oil/water emulsion (96%). In both the HA and oil/water emulsion separation tests, the flux recovery ratio (FRR) and reversible fouling ratio (Rr) were also significantly improved, suggesting that the PES/PDA@ZnFe2O4 membrane was a very promising candidate for HA removal and treatment of oily wastewater.

Introduction Self-forming dynamic membrane (SFDM) technology has been gaining significant interest due to its potential advantages, notably lower capital and operational cost and easier fouling con...

Understanding the microbial ecology of a system allows linking members of the community and their metabolic functions to the performance of the wastewater bioreactor. This study provided a comprehensive conceptual framework for microbial communities in wastewater treatment electro-bioreactors (EBRs). The model was based on data acquired from monitoring the effect of altering different bioreactor operational parameters, such as current density and hydraulic retention time, on the microbial communities of an EBR and its nutrient removal efficiency. The model was also based on the 16S rRNA gene high-throughput sequencing data analysis and bioreactor efficiency data. The collective data clearly demonstrated that applying various electric currents affected the microbial community composition and stability and the reactor efficiency in terms of chemical oxygen demand, N and P removals. Moreover, a schematic that recommends operating conditions that are tailored to the type of wastewater that needs to be treated based on the functional microbial communities enriched at specific operating conditions was suggested. In this study, a conceptual model as a simplified representation of the behavior of microbial communities in EBRs was developed. The proposed conceptual model can be used to predict how biological treatment of wastewater in EBRs can be improved by varying several operating conditions.

The concept of nanomaterials membranes (NMs) promises to be a sustainable route to improve the membrane characteristics and enhance the performance of membrane bioreactors (MBRs) treating wastewater. This paper provided a critical review of recent studies on the use of membranes incorporating nanomaterials in membrane bioreactor (NMs-MBR) applications for wastewater treatment. Novel types of nanomaterials membranes were identified and discussed based on their structural morphologies. For each type, their design and fabrication, advances and potentialities were presented. The performance of NMs-MBR system has been summarized in terms of removal efficiencies of common pollutants and membrane fouling. The review also highlighted the sustainability and cost viability aspects of NMs-MBR technology that can enhance their widespread use in wastewater treatment applications.

This research aimed at synthesizing polyethersulfone/α-zirconium phosphate (PES/ α-ZrP) flat-sheet nanocomposite ultrafiltration (UF) membranes. The impact of α-ZrP nanoparticle (NP) addition on the morphology, functionalities, hydrophilicity, and surface charge of the membrane, among others, were investigated. Different concentrations of α-ZrP NPs (0.25, 0.50, 0.75, and 1.00 wt.%) were tested. Membranes surface morphology was investigated by Fourier-transform infrared (FT-IR), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM). Microscopic analyses affirmed that the α-ZrP NPs were successfully incorporated into the PES membranes. Also, the composite membranes were hydrophilic reporting increased mechanical strength, porosity, and thermal stability than the pristine PES membrane. An overall removal efficiency of 70.2 ± 1.0, 99.7 ± 0.2, 81.7 ± 1.1, 74.4 ± 1.5, and 91.5 ± 2.0% for Cd2+, Cu2+, Ni2+, Pb2+, and Zn2+ was reported, respectively when 0.25 wt.% of α-ZrP NPs was added. The enhanced capabilities of the composite membranes in the heavy metal removal was ascribed to the increased electrostatic attraction forces with the metal ions in the solution and the surface of the PES/α-ZrP composite membrane. Lastly, the developed membranes demonstrated less fouling with self-cleaning properties which can be very beneficial in the field of industrial wastewater treatment.

BACKGROUND: Reverse osmosis (RO) is becoming the predominant technology for the future of desalinated of seawater Nonetheless, operational challenges such as membrane biofouling in RO desalination plants result in membrane deterioration and high energy costs In this regard, pre-treatment technologies, such as microfiltration (MF) membranes, are proven to reduce the impact of membrane biofouling in RO systems Hence, surface modifications of commercial cellulose MF membranes with graphene oxide nanosheets (GONSs) at different concentrations were carried out in this research study The new membranes were characterized by scanning electron microscopy (SEM) and Raman spectroscopy amongst other methods of analysis A continuous cross-flow MF system was used to investigate the performance of the new cellulose/GONS membranes with regards to total bacteria count (TBC) removal, water flux, and biofouling resistance RESULTS: TBC removal efficiency of 93 6 ± 2 4% and 27 4 ± 12 5% was achieved using the new cellulose/GONS membranes and control pristine cellulose membranes, respectively This higher removal efficiency was achieved at a water flux of 334 7 ± 10 4 L/(m2 h) Furthermore, a dramatic 55% increase in the transmembrane pressure (TMP) of the pristine cellulose membrane was observed after 24 h operation compared to only a 6% increase in the newly fabricated cellulose/GONS membranes, reflecting their strong anti-fouling properties CONCLUSION: Surface modification of MF membranes with anti-fouling nanomaterials such as GONS has the potential to be implemented in the pretreatment of seawater to improve the RO performance and lower the energy consumption © 2020 Society of Chemical Industry

Acid mine drainage (AMD) presents severe ecological pollution challenges because of its extreme acidity and sulphate and toxic metal contents. The bacterial separation of metals by sulphate reducing bacteria (SRB) and diffusion dialysis (DD) are considered as the most efficient techniques for the treatment/valorisation of AMD owing to their low energy consumption and waste effluents. However, the performance of SRB or DD standalone technologies still face several challenges. The integration strategy of these techniques can lead to an improved treatment/valorisation process, with the AMD components recovered and converted into value-added marketable products. These products can financially reduce the total costs of the AMD treatment. In the current review, both approaches, representing the biotic and abiotic methods, are compared in terms of their mechanisms, challenges and efficiencies. In addition, critical evaluations of the feasibility of both methods along with the potential of their integrated processes are discussed and future strategies proposed Refereed/Peer-reviewed

In this study, commercial cellulose membranes were surface coated with alpha‑zirconium phosphate nanoparticles (α-ZrP-n) to study their impact on the overall removal efficiency of heavy metals from synthetic metal mixture wastewater solution. A total of four homogeneous solutions (0.25, 0.50, 0.75, and 1.00 wt%) of α-ZrP-n were prepared by sonicating the nanoparticles in deionized water. These solutions were used to surface coat the commercial cellulose membranes. The Scanning Electron Microscopy (SEM) along with Energy Dispersive Spectroscopy (EDS) were used to confirm the attachment of α-ZrP-n on the cellulose membrane surface. Furthermore, the structural characteristics of the α-ZrP-n modified cellulose membranes were also studied. The water contact angle results showed that all coated membranes remained super-hydrophilic. The porosity of the membranes decreased to 48% with the addition of 1.00 wt% α-ZrP-n compared to 65% for the pristine membrane. The mechanical strength has improved from 3.4 MPa for the pristine membrane to about 4 MPa for the 1.00 wt% α-ZrP-n membrane. Similarly, the thermal stability was found to be slightly enhanced as evidenced by the increase in decomposition temperature to 280 and 285 °C in the 0.75 and 1.00 wt% α-ZrP-n membranes, respectively. Furthermore, a removal efficiency of 97.0 ± 0.6, 98.0 ± 0.5, 99.5 ± 0.2, and 91.5 ± 2.0% for Cu (II), Zn (II), Ni (II), and Pb (II), respectively, was observed with the 0.50 wt% α-ZrP-n membrane. This removal was achieved at a flux of 41.85 ± 0.87 × 103 LMH. Increasing the α-ZrP-n concentration further did not show any improvement in the overall removal efficiency. However, it led to 46% flux reduction in the 1.00 wt% α-ZrP-n membrane. The mechanism of removal of the heavy metal ions was postulated to be a combination of ion exchange and electrostatic attraction of the strong negatively charged α-ZrP-n membranes and the free metal ions in the wastewater solution.

The assessment of bacterial communities in wastewater electro-bioreactors has garnered attention to improve efficiency of wastewater treatment plant (WWTP) processes. This study evaluated the effects of applying different current densities on the function and microbial community structure of an electro-bioreactor by measuring nutrient removal efficiency and analyzing 16S rRNA gene high-throughput sequencing. The electro-bioreactors at current density of 3, 5 and 7 A/m2 resulted in an enrichment of operational taxonomic units belonging to distinct functional bacterial families such as (Nitrospiraceae: 8.5, 12.5 and 12.6% relative abundance, respectively) and (Rhodocyclaceae: 8.1, 8.8 and 9.7% relative abundance, respectively), leading to efficient N-removal (>98%) and P-removal (>98%) higher than the control bioreactor (9.6 and 5.0%, respectively). Applying different electric currents proved to affect microbial community composition in electro-bioreactors. The results reported here could prove to be valuable for process control, optimization and improving WWTPs design and operation.

A two-stage treatment for efficient removal of organic matter, heavy metal ions, and other contaminants from raw wastewater is presented in this manuscript. The two stages include electrically-enhanced membrane bioreactor (eMBR) and filtration using titanium dioxide (TiO2) aerogel membrane. The aerogel membrane was highly porous (with 90% porosity), superhydrophilic, highly permeable (with water permeability of 850 LMH/bar), and contained networks of interconnected nanowires with nano-sized pores. The combined system removed 100% bacteria, 97.8% COD, 96.9% Zn2+, 99.3% Cr6+, and 84.1% Cd2+ from raw municipal wastewater sampled from Masdar City Wastewater Treatment Plant, Abu Dhabi, United Arab Emirates. Residual contaminants were removed from eMBR effluent by the aerogel membrane through surface charge interactions, nano-sized pores, and photodegradation. The aerogel membrane was characterized before and after filtration through Scanning Electron Microscopy, X-ray Diffraction, Fourier-Transforms Infrared Spectroscopy, Raman Spectroscopy, and Energy Dispersive X-ray spectroscopy. After filtration and chemical cleaning of the aerogel membrane, ˜90% flux recovery was shown. The cost of water production was US$1.03/m3, which was less than the cost of water production using seawater desalination and industrial wastewater treatment. The final effluent is suitable for advanced applications such as agricultural irrigation and industrial process heating/cooling, based on the pollutants measured.

This review paper aims to identify the main sources of carbon dioxide (CO2) emissions from wastewater treatment plants (WWTPs) and highlights the technologies developed for CO2 capture in this milieu. CO2 is emitted in all the operational units of conventional WWTPs and even after the disposal of treated effluents and sludges. CO2 emissions from wastewater can be captured or mitigated by several technologies such as the production of biochar from sludge, the application of constructed wetlands (CWs), the treatment of wastewater in microbial electrochemical processes (microbial electrosynthesis, MES; microbial electrolytic carbon capture, MECC; in microbial carbon capture, MCC), and via microalgal cultivation. Sludge-to-biochar and CW systems showed a high cost-effectiveness in the capture of CO2, while MES, MECC, MCC technologies, and microalgal cultivation offered efficient capture of CO2 with associate production of value-added by-products. At the state-of-the-art, these technologies, utilized for carbon capture and utilization from wastewater, require more research for further configuration, development and cost-effectiveness. Moreover, the integration of these technologies has a potential internal rate of return (IRR) that could equate the operation or provide additional revenue to wastewater management. In the context of circular economy, these carbon capture technologies will pave the way for new sustainable concepts of WWTPs, as an essential element for the mitigation of climate change fostering the transition to a decarbonised economy.

Pyrolysis of agricultural biomass is a promising technique for producing renewable energy and effectively managing solid waste. In this study, groundnut shell (GNS) was processed at 500 °C in an inert gas atmosphere with a gas flow rate and a heating rate of 10 mL/min and 10 °C/min, respectively, in a custom-designed fluidized bed pyrolytic-reactor. Under optimal operating conditions, the GNS-derived pyrolytic-oil yield was 62.8 wt.%, with the corresponding biochar (19.5 wt.%) and biogas yields (17.7 wt.%). The GC-MS analysis of the GNS-based bio-oil confirmed the presence of (trifluoromethyl)pyridin-2-amine (18.814%), 2-Fluoroformyl-3,3,4,4-tetrafluoro-1,2-oxazetidine (16.23%), 5,7-dimethyl-1H-Indazole (11.613%), N-methyl-N-nitropropan-2-amine (6.5%) and butyl piperidino sulfone (5.668%) as major components, which are used as building blocks in the biofuel, pharmaceutical, and food industries. Furthermore, a 2 × 5 × 1 artificial neural network (ANN) architecture was developed to predict the decomposition behavior of GNS at heating rates of 5, 10, and 20 °C/min, while the thermodynamic and kinetic parameters were estimated using a non-isothermal model-free method. The Popescu method predicted activation energy (Ea) of GNS biomass ranging from 111 kJ/mol to 260 kJ/mol, with changes in enthalpy (ΔH), Gibbs-free energy (ΔG), and entropy (ΔS) ranging from 106 to 254 kJ/mol, 162–241 kJ/mol, and −0.0937 to 0.0598 kJ/mol/K, respectively. The extraction of high-quality precursors from GNS pyrolysis was demonstrated in this study, as well as the usefulness of the ANN technique for thermogravimetric analysis of biomass.

The effect of addition of algae to activated sludge as active biomass in membrane bioreactors (MBRs) and electro-MBRs (e-MBRs) for wastewater remediation was examined in this study. The performances of Algae-Activated Sludge Membrane Bioreactor (AAS-MBR) and electro Algae-Activated Sludge Membrane Bioreactor (e-AAS-MBR) were compared to those observed in conventional MBR and e-MBR, which were previously reported and utilized activated sludge as biomass. The effect of application of electric field was also examined by the comparison of performances of e-AAS-MBR and AAS-MBR. Similar chemical oxygen demand (COD) reduction efficiencies of AAS-MBR, e-AAS-MBR, MBR, and e-MBR (98.35 ± 0.35%, 99.12 ± 0.08%, 97.70 ± 1.10%, and 98.10 ± 1.70%, respectively) were observed. The effect of the algae-activated sludge system was significantly higher in the nutrient removals. Ammoniacal nitrogen (NH3−N) removal efficiencies of AAS-MBR and e-AAS-MBR were higher by 43.89% and 26.61% than in the conventional MBR and e-MBR, respectively. Phosphate phosphorous (PO43−-P) removals were also higher in AAS-MBR and e-AAS-MBR by 6.43% and 2.66% than those in conventional MBR and e-MBR. Membrane fouling rates in AAS-MBR and e-AAS-MBR were lower by 57.30% and 61.95% than in MBR and e-MBR, respectively. Lower concentrations of fouling substances were also observed in the reactors containing algae-activated sludge biomass. Results revealed that addition of algae improved nutrient removal and membrane fouling mitigation. The study also highlighted that the application of electric field in the e-AAS-MBR enhanced organic contaminants and nutrients removal, and fouling rate reduction.

The first case of Coronavirus Disease 2019 (COVID-19), which is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), in Europe was officially confirmed in February 2020. On 11 March 2020, after thousands of deaths from this disease had been reported worldwide, the WHO changed their classification of COVID-19 from a public health emergency of international concern to a pandemic. The SARS-CoV-2 virus has been shown to be much more resistant to environmental degradation than other coated viruses. Several studies have shown that environmental conditions can influence its viability and infectivity. This review summarizes current knowledge on the transmission pathways of the novel coronavirus, and directs attention towards potentially underestimated factors that affect its propagation, notably indoor spread and outdoor risk sources. The contributions of significant indoor factors such as ventilation systems to the spread of this virus need to be carefully ascertained. Outdoor risk sources such as aerosolized particles emitted during wastewater treatment and particulate matter (PM), both of which may act as virus carriers, should be examined as well. This study shows the influence of certain underestimated factors on the environmental behavior and survival of the SARS-CoV-2 virus. These aspects of coronavirus propagation need to be accounted for when devising actions to limit not only the current pandemic but also future outbreaks. Graphic abstract

The removal of heavy metal ions from industrial wastewater is essential as they pose serious threats to human health and the environment. In this study, novel poly(vinylidene fluoride) (PVDF)-alpha-zirconium phosphate (PVDF-α-ZrP) mixed matrix membranes (MMM) were prepared via the phase inversion method. Membranes with different α-ZrP nanoparticles (NPs) loadings (0.25, 0.50, 0.75, or 1.00 wt%) were fabricated. The impacts of α-ZrP NP loading on the membrane’s morphology, functionality, surface charge, and hydrophilicity were evaluated. Fourier-transform infrared and the energy-dispersive X-ray spectroscopy were performed to verify the presence of α-ZrP NPs in the fabricated membranes. The PVDF membranes became more hydrophilic after incorporating the α-ZrP NPs. The thermal and mechanical stability and porosity of the PVDF-α-ZrP MMM were higher than those of the pristine PVDF membrane. The increased hydrophilicity, pore size and porosity and reduced surface roughness of the PVDF-α-ZrP membrane led to significant flux increase and reduced fouling propensity. The PVDF-α-ZrP membrane containing 1.00 wt% α-ZrP was capable of removing 42.8% (Cd2+), 93.1% (Cu2+), 44.4% (Ni2+), 91.2% (Pb2+), and 44.2% (Zn2+) from an aqueous solution at neutral pH during filtration.

Waterborne enteric viruses that are commonly found in wastewater can cause several sporadic cases of diseases and outbreaks as a result of water or food contamination. Their detection, quantification, and effective removal from wastewater is of great importance. In this context, this review paper describes the different types of waterborne enteric viruses that are frequently found in wastewater and evaluated the various techniques developed for their concentration and detection. Furthermore, the review comprehensively discusses the different traditional, membrane filtration, and advanced/hybrid technologies used in the removal of these viruses. Over the past few decades, several efforts have been made to employ the membrane-based and other hybrid technologies to eliminate waterborne enteric viruses effectively. In this regard, technologies, such as microfiltration (MF), ultrafiltration (UF), membrane bioreactor (MBR) among others, have been widely applied. The major concerns related to these technologies are in the factors that would have an impact on membrane performance in terms of viruses' removal efficiency and sustainable operation. The advantages, limitations, and other related factors of the application of these technologies will be discussed in this review. Lastly, Light will be shed on the future perspectives and research opportunities for the widespread implementation of these technologies in the treatment of viruses-rich wastewater., The authors appreciate the support provided by the Center for Membranes and Advanced Water Technology (CMAT) at Khalifa University of Science and Technology (Abu Dhabi, UAE) (Award No. RC2-2018-009).

Produced water, a by-product generated from the oil and gas extraction processes, represents a major challenge in the oil and gas industry as it is generally characterized with a very high salinity and oil content. Currently used ceramic membranes for oil-water separation suffer from the low water flux in spite of their several distinctive advantages. To overcome this limitation and to increase the water flux and oil rejection, commercial ceramic TiO2 membranes were dip coated with silica (SiO2) nanoparticles at different concentrations of 0.25, 0.50, 0.75, and 1.0 wt %. Coated membranes were characterized using scanning electron microscopy (SEM), energy-dispersive x-ray sSpectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR) and Raman Spectroscopy and contact angle. Results showed that SiO2 nanoparticles were successfully deposited on the surface of the ceramic membranes confirming the dip coating approach. Furthermore, water flux of 817, 2724, 3636, 627, and 1292 L m−2 h−1 (LMH) was reported at control, 0.25, 0.50, 0.75 and 1.0 wt%; respectively. Also, contact angle reported 75°, 50°, 40°, 24°, 0° at control, 0.25, 0.50, 0.75 and 1.0 wt%; respectively. Finally, total organic carbon (TOC) in the treated water samples reported 100, 28, 11, 9, 10, 13 mg L−1 at control, 0.25, 0.50, 0.75 and 1.0 wt%, respectively. This study can be a preliminary to further studies that accommodate industry-like conditions to help decrease the gap between ideal laboratory setups and harsh real life conditions to fully optimize and exploit the advantages of ceramic membranes in oil-water separation.

Many emerging contaminants (ECs) are not currently removed by conventional water treatment methods and consequently, often reach the aquatic environment. In the absence of proper management strategies, ECs can accumulate in water bodies, which poses potential environmental and health risks. This paper critically reviews, for the first time, the reported occurrence and treatment of ECs in the Middle Eastern and North Africa (MENA) region. The paper also provides recommendations to properly manage EC risks. In the MENA region, pharmaceuticals and personal care products (PPCPs) have been detected in surface water, seawater, groundwater, and wastewater treatment plants. A focus on surface water in the published literature suggests that studies are skewed towards worldwide trends, whereas studies on ECs in seawater are of great importance in the study region. The types of PPCPs detected in the MENA region vary, but anti-inflammatories and antibiotics dominate. In comparison, microplastics have mainly been studied in surface waters and seawater with much less focus on drinking water. The majority of microplastics in the region are secondary types resulting from the degradation of larger plastic debris; polyethylene (PE) and polypropylene (PP) fibers are the most frequently detected polymers, which are indicative of local anthropogenic sources. Research progress on ECs varies between countries, having received more attention in Iran and Tunisia. Most MENA countries have now begun monitoring water bodies for ECs; however, studies are still lacking in some countries including Sudan, Djibouti, Syria, Ethiopia, and Bahrain. Based on this review, critical knowledge gaps and research needs are identified. Countries in the MENA region require further research on a broader range of EC types. Overall, water pollution due to the use and release of ECs can be tackled by improving public awareness, public campaigns, government intervention, and advanced monitoring and treatment methods.

The low-level presence of emerging contaminants (ECs) in the environment has raised a great concern due to their persistence, chronic toxicological, and endocrine disrupting effects on terrestrial and aquatic organisms. Wastewater treatment plants (WWTPs) have become hotspots for the spread of these contaminants to the environment as conventional processes are not efficient in removing them. Thus, the integration of advanced treatment methods within the chain of WWTPs is very essential. In this study, the innovative hybrid process USAMe® which integrates ultrasound irradiation (US), adsorption (A) and membrane filtration (Me) was investigated for the removal of ECs from secondary effluents. Diclofenac, carbamazepine, and amoxicillin were selected due to their large consumption and frequent presence in the aquatic environment. All three ECs were spiked into real secondary wastewater effluent at two concentrations of 10 ppm and 100 ppb. Membrane ultrafiltration and its combination with US (USMe) or adsorption (AMe) were also studied as control tests. The hybrid combination of all the three methods in the USAMe® processes elevated the EC removals to above 99% as compared to only around 90% in the AMe process. All effluents of the hybrid USAMe® processes gave “No Effect” to D. magna, with immobilization of ≤20%. Therefore, results showed that the USAMe® process was efficient in not only removing ECs, but also in generating safe and less toxic treated effluents; thereby displaying its potential as an advanced method for wastewater treatment.

In this work, electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofiber membranes were loaded with tungsten oxide (WO3) nanoparticles, surface coated with polydopamine (PDA) hierarchical structures, and tested in oil/water separation, photothermal water evaporation, and degradation of ampicillin. The electrospun nanofiber membranes (ENMs) consisted of three layers and the WO3 nanoparticles were incorporated into the top layer to increase their surface exposure. These layers were then heat-pressed for dimensional stability and surface coated with PDA hierarchical structures. Characterization was conducted using microscopic, goniometric, gravimetric, and spectroscopic methods. All ENMs displayed randomly oriented, smooth microporous structure and EDS mapping revealed a uniform distribution of WO3 nanoparticles on the nanofiber matrix. WO3-blended ENMs showed improved mechanical strength, higher UV/Vis absorption, and similar thickness as pristine ENM. PDA deposition has reduced the water contact angle of pristine PVDF-HFP membrane from 130.3 to 0°, whereas, the underwater oil contact angle has increased from 55.8 to 159.7°. The PDA-coated ENMs exhibited enhanced oil/water separation with 384.3 L m−2h−1 (LMH) of flux and 97.6% oil rejection when filtered under gravity. Photothermal interfacial evaporation and ampicillin degradation tests also demonstrated the multifunctionality and exciting features of the fabricated membranes for a wide range of applications.

Nanocomposite membranes consisting of functionalized β-cyclodextrin (fβ-CD) and polyethersulfone (PES) were fabricated, characterized, and used for low-pressure wastewater post-treatment. The impact of nucleophilic functionalization of β-CD on the performance of these membranes was evaluated via three substitution routes: Crosslinking with nucleophilic dicarboxyl groups (M1) in maleic acid; co-polymerization with excess amino group (M2) in hyperbranched polyethyleneimine (HPEI); and nucleophilic modification with amino and hydroxyl groups (M3) in chitosan. All fβ-CD-incorporated membranes were hydrophilic as a result of the highly populated –OH groups at the exterior of β-CD. Although there are higher-energy intermolecular C–O bonds in M1 membrane, less degree of nucleophilic crosslinking restricted kinetic hindrance and led to an increase in the mean pore size of M1 membrane to 52 nm. A dense structure, the lowest mean pore size of 22 nm, and the highest porosity of 45% was imparted to M2 membrane by the flexible C–N linkages provided by HPEI. Nucleophilic attack by the abundant N–H groups in HPEI also improved the tensile strength of M2 membrane reaching 20 MPa. Consequently, the water permeability of M2 membrane was significantly enhanced via β-CD's solution-diffusion property. M1, M2, and M3 membrane water permeability were 61, 239, and 167 LMH bar−1, respectively. M3 membrane showed the highest removal efficiencies for heavy metal ions (92% of Cr6+, 90% of Zn2+, 82% of Fe2+, and 87% of Cd2+) since it is the most hydrophilic membrane with abundant –OH groups in chitosan. However, M2 membrane displayed the highest removal efficiencies for residual organics, i.e. 67% chemical oxygen demand (COD) and 84% bacteria due to the hydrophobic interior of its dense fβ-CD.

Recently, thermosiphon has been considered as an economically competitive approach for the withdrawal of thermal energy from molten salt. This feature of thermosiphon is particularly attractive for concentrated solar power (CSP) technology because molten salt can be used both as the direct receiver and thermal energy storage material, and pumping requirements can be minimized. However, the thermosiphon loop must be properly designed; otherwise the heated molten salt can flow in the reverse direction or solidify before heat exchange is fully carried out. In this paper, the dependence of important molten salt flow characteristics such as temperature, velocity and friction factor on the thermosiphon loop dimensions is theoretically investigated. The model is carried out for the withdrawal of 1 MW of thermal energy from the molten salt. The economic assessment of the conversion of this energy to electricity for reverse osmosis desalination is also carried out. It is observed that by using the minimum possible value of leg length and maximum possible values of diameter and pressure head, the lowest decline of temperature and highest velocity of flow can be achieved along the loop. Fresh water production is more valuable than electricity and steam production by 460% and 480%, respectively.

The fabrication of polyvinylidene fluoride (PVDF) membranes was studied using chitosan as a hydrophilic additive for flux enhancement and stability. Chitosan (CS) was blended with PVDF at 0.5, 1.0, 1.5, 2.0 and 2.5% (w/w) concentration, to prepare mixed matrix membrane using the phase inversion method. CS presence within the polymer matrix was confirmed using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The fabricated membranes were also analyzed for their structural and surface characteristics, including pore size distribution, porosity, contact angle, wettability and surface roughness. The water contact angle of the membranes has decreased upon the addition of CS. However, the wettability of the membranes was affected more profoundly due to an increase in their pore size. Microfiltration tests showed that the addition of CS was helpful in the reduction of fouling by bovine serum albumin (BSA). However, membranes with CS content higher than 1.0% endured surface micro-ruptures during the filtration tests due to swelling resulting from high water uptake. This simple method of fabrication of PVDF/CS membranes is a potential solution for the low flux and fouling of common PVDF microfiltration membranes. Furthermore, understanding the impact of CS on the fabricated membranes can facilitate the fine tuning of the membrane properties to achieve higher efficiencies.

Hollow fiber membranes consisting of polyethersulfone (PES) reformed with high proportions of OH, aryl-N and alkyl-F groups in nonsolvent additives were compared for the removal of residual Cr (VI), COD, and bacteria from treated wastewater effluent by studying the underlying functional and molecular interactions during dope preparation and phase separation. These interactions were also studied and compared in the context of dope and membrane characteristics such as dope viscosity, membrane morphology, water contact angle, functionalities in the fabricated membranes, pure water permeability and rejection of residual solute. The membranes were characterized via Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FT-IR) spectroscopy and Raman spectroscopy. For nonsolvent additives with OH group, molecular weights and dope viscosity exhibited more impact on phase separation whereas for those with aryl-N and alkyl-F groups, phase separation was influenced by thermodynamic instability. Functional interactions also influenced the lumen shapes and membrane thickness. The lumens changed from spherical to elliptical-type shapes when aryl-amide and fluoroalkyl groups were added. Additives containing –OH group provided the highest contaminant rejection and the least flux whereas those containing aryl amide and fluoroalkyl groups enhanced the water permeability across the PES-based membranes but reduced the contaminant rejection. The PES membrane modified with OH group was able to reduce residual contaminant concentrations from 14 ppb Cr(VI), 36.9 ppm COD, and 18,300 ppm total bacterial counts (TBC) to 8.3 ppb Cr(VI), 20.3 ppm COD, and 8601 ppm TBC with an intrinsic water permeability of 22.94 LMH/bar.

Water is one of many viral transmission routes, and the presence of Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) in wastewater has brought attention to its treatment. SARS CoV-2 primarily transmits in the air but the persistence of the virus in the water possibly can serve as a secondary source even though current studies do not show this. In this paper, an evaluation of the current literature with regards to the treatment of SARS-CoV-2 in wastewater treatment plant (WWTP) effluents and biosolids is presented. Treatment efficiencies of WWTPs are compared for viral load reduction on the basis of publicly available data. The results of this evaluation indicate that existing WWTPs are effectively removing 1–6 log10 viable SARS-CoV-2. However, sludge and biosolids provide an umbrella of protection from treatment and inactivation to the virus. Hence, sludge treatment factors like high temperature, pH changes, and predatory microorganisms can effectively inactivate SARS-CoV-2., Graphical abstract Unlabelled Image

Considerable attention has been recently given to possible transmission of SARS-CoV-2 via water media. This review addresses this issue and examines the fate of coronaviruses (CoVs) in water systems, with particular attention to the recently available information on the novel SARS-CoV-2. The methods for the determination of viable virus particles and quantification of CoVs and, in particular, of SARS-CoV-2 in water and wastewater are discussed with particular regard to the methods of concentration and to the emerging methods of detection. The analysis of the environmental stability of CoVs, with particular regard of SARS-CoV-2, and the efficacy of the disinfection methods are extensively reviewed as well. This information provides a broad view of the state-of-the-art for researchers involved in the investigation of CoVs in aquatic systems, and poses the basis for further analyses and discussions on the risk associated to the presence of SARS-CoV-2 in water media. The examined data indicates that detection of the virus in wastewater and natural water bodies provides a potentially powerful tool for quantitative microbiological risk assessment (QMRA) and for wastewater-based epidemiology (WBE) for the evaluation of the level of circulation of the virus in a population. Assays of the viable virions in water media provide information on the integrity, capability of replication (in suitable host species) and on the potential infectivity. Challenges and critical issues relevant to the detection of coronaviruses in different water matrixes with both direct and surrogate methods as well as in the implementation of epidemiological tools are presented and critically discussed., Graphical Abstract ga1

Capacitive deionization (CDI) is an evolving technology for eradicating salt and toxic heavy metal ions from brackish wastewater. However, traditional CDI electrodes have lower salt adsorption capacity and inadequate adsorption of selective metal ions for long-term operations. Herein, Ag nanospheres incorporated pomegranate peel-derived activated carbon (Ag/P-AC) was prepared and implied to the CDI process for removing NaCl, toxic mono-, di-, and trivalent metal ions. Morphological analysis revealed that the 80-100 nm-sized Ag nanospheres were uniformly decorated on the surfaces of P-AC nanosheets. The Ag/P-AC has a higher specific surface area (640 m2 g−1), superior specific capacitance (180 F g−1 at 50 mV s−1) and a lower charge transfer resistance (0.5 Ω cm2). CDI device was fabricated by Ag/P-AC as an anode, which adsorbed anions and P-AC as cathode for adsorption of positively charged ions at 1.2 V in an initial salt concentration of 1000 mg L−1. An asymmetric Ag/P-AC//P-AC exhibited a maximum NaCl adsorption capacity of 36 mg g−1 than symmetric P-AC//P-AC electrodes (22.7 mg g−1). Furthermore, Pb(II), Cd(II), F−, and As(III) ions were successfully removed from simulated wastewater by using Ag/P-AC//P-AC based CDI system. These asymmetric CDI-electrodes have an excellent prospect for the removal of salt and toxic contaminants in industrial wastewater.

Harmful algal blooms (HABs) caused by microalgae are becoming increasingly common and pose serious threats to human health, aquaculture, and marine environments and, therefore, their removal is becoming essential. Colloidal gas aphrons (CGAs), a recent technology adapted in flotation, showed promise in removing several contaminants from aqueous solutions. This study aimed to investigate the potency of CGAs in removing several microalgae strains (Spirulina platensis, Nannochloropsis oculata, and Chlorella vulgaris) from aqueous solutions. Surfactants, including cationic hexadecyl trimethyl ammonium bromide (HTAB), anionic sodium dodecylbenzene sulfonate (SDBS), sodium dodecyl sulfate (SDS), and their mixes, were used to prepare stable CGAs. The effect of different environmental parameters like algae concentration, pH, and salinity, on removing Spirulina platensis was thoroughly investigated. Operating conditions, including surfactant type, flotation time, flowrate, and solution temperature, were optimized. At pH 5 and 50 °C, Spirulina platensis, Chlorella vulgaris, and mixed microalgae were fully removed using CGAs produced from cationic HTAB surfactant. About 95% removal of Nannochloropsis oculata was achieved using mixed surfactant CGAs. The results obtained from this work demonstrated the promising potential of CGAs produced from both single and mixed surfactants in harvesting various microalgae from aqueous media.

A novel estimation of membrane specie permeability coefficient ( K s i ) in a polycomposite electro-membrane bioreactor (eMBR) was carried out in this study. The susceptibility of the eMBR to membrane fouling was assessed via the estimation of the temporal variations of K s i and specific cake resistance (α). These membrane fouling parameters and unit cost of treated water produced from the eMBR are being reported for the first time. The increasing order of K s i for individual measured contaminants was PO43−-P K s i obtained for COD, NH4+-N, PO43−-P, Ni, Fe and Cr were 20, 33, 1.0, 58, 70, and 102 mg/d.m2, respectively. The peak value of α obtained was 33.7 × 109 m/kg. This means that heavy metals were more permeable through the membrane than COD and nutrients and the specific cake filtration was much lower than the typical range. These results were also confirmed by a reduction in the rate of membrane fouling, as established by the peaks and troughs of the transmembrane pressure. With an operational life time of 15 years, the unit cost of treated water obtained was $0.86/m3. This assessment presents the studied method as more cost-competitive than many wastewater treatment approaches.

Reject brine is the product from desalination processes containing high salinity, high temperature, and at many times, dissolved chemicals. With the growing demand of water, increasing amounts of brine are being produced from the desalination plants leading to significant adverse impacts on the environment. It is necessary therefore to effectively manage desalination reject brine in order to ensure more efficient disposal and reuse. This review gives a general idea on the recent and currently devised brine management processes, which have been employed to reduce the environmental issues related to concentrate dumping. Those management approaches consist of minimization techniques that can be divided into membrane-based, thermal-based and emerging technologies. Moreover, this critical review gives an overview of the various applications of brine and some sustainability aspects of the reject brine disposal and reuse. The most obvious sustainable improvements in reject brine management are based on minimization techniques or reuse that can be achieved through the recovery of valuable materials such as salts, metals, and chemicals. Many new research works in this field have been introduced and scientists have continued to devise reject brine reuse strategies and minimization technologies leading to very low quantities of residual brine.

Electrokinetic cells with three different electrode arrangements were supplied with raw seawater collected from the Gulf. The electrode arrangements included anode-cathode (A-C), anode-cathode-cathode-anode (A-C-C-A), and cylindrical (three cathodes surrounded by an anode) configurations. The electrokinetic cells were tested at different current densities ranging from 0.05 to 0.2 mA/cm2 for 6 h. The results showed that inorganic ions and bacteria removal increased with increasing current density. For example, at a current density of 0.2 mA/cm2, 78, 76, and 91% of the Mg2 + ions were removed by the A-C, A-C-C-A, and cylindrical configurations, respectively, whereas these cells removed 64, 63, and 51% of the Mg2 + ions, respectively, at a current density of 0.1 mA/cm2. In addition, the A-C, A-C-C-A, and cylindrical cells removed 21, 40, and 44% of the Ca2 + ions, respectively, and 47, 79, and 79% of the SO42 − ions, respectively, at a current density of 0.2 mA/cm2. The removal efficiencies obtained with the A-C, A-C-C-A, and cylindrical cells were 15, 18, and 13%, respectively, for Ca2 + and 47, 26, and 22%, respectively, for SO42 − at a current density of 0.1 mA/cm2. Furthermore, nearly all of the bacteria were removed under the tested operating conditions (total bacteria count (TBC) was zero).

The treatment of oily wastewater continues to pose a challenge in industries worldwide. Membranes have been investigated recently for their use in oily wastewater treatment due to their efficiency and relatively facile operational process. Graphene oxide (GO) and silica (SiO2) nanoparticles have been found to improve membrane properties. In this study, a polyethersulfone (PES) based GO-SiO2 mixed matrix membrane (MMM) was fabricated, using the phase inversion technique, for the treatment of oil refinery wastewater. The PES/GO-SiO2 membrane exhibited the highest water flux (2,561 LMH) and a 38% increase in oil removal efficiency by comparison to a PES membrane. Compared to PES/GO and PES/SiO2 membranes, the PES/GO-SiO2 MMM also displayed the best overall properties in terms of tensile strength, water permeability, and hydrophilicity.

Pharmaceutical active compounds (PhACs) have been detected at significant concentrations in various natural and artificial aquatic environments. In this study, electro membrane bioreactor (eMBR) technology was used to treat simulated municipal wastewater containing widely-used pharmaceuticals namely amoxicillin (AMX), diclofenac (DCF) and carbamazepine (CBZ). The effects of varying current density on the removal of PhACs (AMX, DCF and CBZ) and conventional pollutants (chemical oxygen demand (COD), dissolved organic carbon (DOC), humic substances, ammonia nitrogen (NH4-N), nitrate nitrogen (NO3-N) and orthophosphate (PO4-P) species) were examined. High COD and DOC removal efficiencies (~100%) were obtained in all the experimental runs regardless of applied current density. In contrast, enhanced removal efficiencies for AMX, DCF and CBZ were achieved at high current densities. Membrane fouling rate in eMBR with respect to conventional MBR was reduced by 24, 44 and 45% at current densities of 0.3, 0.5 and 1.15 mA/cm2, respectively. The mechanism for pharmaceutical removal in this study proceeded by: (1) charge neutralization between negatively-charged pharmaceutical compounds and positive electro-generated aluminium coagulants to form larger particles and (2) size exclusion by membrane filtration.

Recently, supercritical fluid CO2 extraction (SFE) has emerged as a promising and pervasive technology over conventional extraction techniques for various applications, especially for bioactive compounds extraction and environmental pollutants removal. In this context, temperature and pressure regulate the solvent density and thereby effects the yield, selectivity, and biological/therapeutic properties of the extracted components. However, the nature of plant matrices primarily determines the extraction mechanism based on either density or vapor pressure. The present review aims to cover the recent research and developments of SFE technique in the extraction of bioactive plant phytochemicals with high antioxidant, antibacterial, antimalarial, and anti-inflammatory activities, influencing parameters, process conditions, the investigations for improving the yield and selectivity. In another portion of this review focuses on the ecotoxicology and toxic metal recovery applications. Nonpolar properties of Sc-CO2 create strong solvent strength via distinct intermolecular interaction forces with micro-pollutants and toxic metal complexes. This results in efficient removal of these contaminants and makes SFE technology as a superior alternative for conventional solvent-based treatment methods. Moreover, a compelling assessment on the therapeutic, functional, and solvent properties of SFE is rarely focused, and hence this review would add significant value to the SFE based research studies. Furthermore, we mention the limitations and potential of future perspectives related to SFE applications.

Testing SARS-CoV-2 viral loads in wastewater has recently emerged as a method of tracking the prevalence of the virus and an early-warning tool for predicting outbreaks in the future. This study reports SARS-CoV-2 viral load in wastewater influents and treated effluents of 11 wastewater treatment plants (WWTPs), as well as untreated wastewater from 38 various locations, in the United Arab Emirates (UAE) in May and June 2020. Composite samples collected over twenty-four hours were thermally deactivated for safety, followed by viral concentration using ultrafiltration, RNA extraction using commercially available kits, and viral quantification using RT-qPCR. Furthermore, estimates of the prevalence of SARS-CoV-2 infection in different regions were simulated using Monte Carlo. Results showed that the viral load in wastewater influents from these WWTPs ranged from 7.50E+02 to over 3.40E+04 viral gene copies/L with some plants having no detectable viral RNA by RT-qPCR. The virus was also detected in 85% of untreated wastewater samples taken from different locations across the country, with viral loads in positive samples ranging between 2.86E+02 and over 2.90E+04 gene copies/L. It was also observed that the precautionary measures implemented by the UAE government correlated with a drop in the measured viral load in wastewater samples, which were in line with the reduction of COVID-19 cases reported in the population. Importantly, none of the 11 WWTPs’ effluents tested positive during the entire sampling period, indicating that the treatment technologies used in the UAE are efficient in degrading SARS-CoV-2, and confirming the safety of treated re-used water in the country. SARS-CoV-2 wastewater testing has the potential to aid in monitoring or predicting an outbreak location and can shed light on the extent viral spread at the community level., Graphical abstract Unlabelled Image, Highlights • First study to detect and quantify SARS-CoV-2 in wastewater in the UAE.

The contamination of aquatic ecosystems by fluoride and heavy metal ions constitute an environmental hazard and has been proven to be harmful to human health. This study explores the feasibility of using asymmetric capacitive deionization (CDI) electrodes to remove such toxic ions from wastewater. An asymmetric CDI cell was fabricated using 2D Ni/MAX as an anode and 3D porous reduced graphene oxide (pRGO) as a cathode for the electrosorption of F−, Pb2+, and As(III) ions. A simple microwave process was used for the synthesis of Ni/MAX composite using fish sperm DNA (f-DNA) as a cross-linker between MAX nanosheets (NSs) and the metallic Ni nanoparticles (NPs). Further, pRGO anode was prepared through effective reduction of RGO using lemon juice as green reducing agent with the assist of f-DNA as a structure-directing agent for the formation of 3D network. With this tailored nanoarchitecture, pRGO and Ni/MAX electrodes exhibited a high specific capacitance of 760 and 385 F g−1, respectively. The fabricated Ni/MAX and pRGO based CDI system demonstrated a high electrosorption capacity of 68, 76, and 51 mg g−1 for the monovalent F−, divalent Pb2+, and trivalent As(III) ions at 1.4 V in neutral pH. Furthermore, Ni/MAX//pRGO system was successfully applied for the removal of total F(T), Pb(T), and As(T) ions from real industrial wastewater and contaminated groundwater. The present findings indicate that the fabricated Ni/MAX//pRGO electrode has excellent electrochemical properties that can be exploited for the removal of anionic and cationic metal ions from aqueous solutions in a CDI based system.

In this work, a new configuration of an electrically-enhanced membrane bioreactor has been introduced to treat medium strength wastewater at Masdar City, Abu Dhabi, United Arab Emirates (UAE). The integrated setup enhanced the reduction of wastewater contaminant concentrations. The investigated components in this study were chemical oxygen demand (COD), orthophosphates (PO 4 3− -P) and ammonium (NH 4 + -N). The percentages of COD, PO 4 3− -P, and NH 4 + -N removal obtained were 98, 99, and 98%, respectively. Variation in environmental compositions such as mixed liquor dissolved oxygen (DO), volatile suspended solids (MLVSS), pH, and electrical conductivity influenced the effluent concentration of wastewater components. Artificial neural networks (ANNs) based ensemble model was used to model the experimental findings of COD, PO 4 3− -P and NH 4 + -N removal given the initial mixed liquor compositions. Comparison between the model results and experimental data set gave high correlation coefficients for COD ( r = 0.9942), PO 4 3− -P ( r = 0.9998) and NH 4 + -N ( r = 0.9955).

Polyvinylidene fluoride (PVDF) membranes are widely used in membrane industry, especially for membrane bioreactors (MBRs). Many PVDF membranes contain residual polyvinyl pyrrolidone (PVP) that acts as a pore-forming additive. The presence of residual PVP in some commercial PVDF membranes is often not specified and, therefore, its impact is mostly overlooked in the literature. In this study, we investigated the effect of PVP leaching on membrane structure and its implication on membrane fouling in a lab-scale MBR. PVP leaching can occur in two ways: (1) over the course of filtration from PVDF/PVP blend membranes or (2) prior filtration operation by treating the aforementioned membrane. We prepared PVDF, PVDF/PVP blend, and PVDF/PVP blend post-treated with sodium hypochlorite (NaClO), then assessed their performance. Leaching of PVP prior to the filtration operation significantly enlarged membrane pore size and thus reduced the membrane resistance. However, this advantage was dismissed during operation in MBR because PVP leaching also induced surface hydrophobicity that promoted membrane fouling, suggesting the detrimental effect of post-treatment. For PVDF/PVP blend sample, two counter-acting phenomena occurred: (1) slow leaching of PVP which gradually enlarged the membrane pores and rendered the membrane surface more hydrophobic and (2) adsorption of foulants that formed a secondary layer atop of membrane surface, restricted the pore mouth, and rendered the surface hydrophilic. The findings are significant since the change of membrane morphology over the course of filtration, as demonstrated in this study, is often overlooked when assessing membrane performance.

Greener prospective of soap production using natural products is a promising alternative for synthetic chemicals used in the soaps. Recently, valorization of antioxidant rich biomass wastes for soap formulation has received increased research attention. The present study reported the use of date syrup biomass waste (DSW) for the manufacture of soaps with enhanced bactericidal and antioxidant activity. DSW extract synthesis from Khalas date fruit type was optimized for operational parameters such as solvent type, temperature, and feed-to-solvent ratio. Maximum antioxidant activity of 605 ppm gallic acid equivalent was obtained for DSW extract obtained at 30 °C and feed-to-solvent ratio of 120 g/L using water as a solvent. Antioxidants assessment of pomace olive soaps modified with DSW extract showed an optimal extract concentration of 3 wt% for soap formulation. Inclusion of this optimal concentration of DSW extract decreased the pH and moisture content, with an increase in foam height, surface hardness, and total fatty matter of the resultant soaps derived from pomace olive, coconut, and palm oils. Physicochemical characteristics of the DSW extract included soaps were comparable to that of commercial turmeric soap. Furthermore, antibacterial assays demonstrated the enhanced bactericidal properties for DSW extract soaps against gram-positive Streptococcus pyogenes and gram-negative Pseudomonas aeruginosa bacteria. Overall, the results support the usage of DSW extract as an economic and effective natural antioxidant and antibacterial agent for soap preparation.

In this study, commercial hydrophobic polyethylene (PE) membranes were impregnated with 1-butyl-3-methylimidazolium dicyanamide ([BMIM][DCA]) hydrophilic ionic liquid (IL) and tested for the rejection of metals ions. Three homogenous mixtures containing ethanol and IL with ethanol: IL volume ratio of 15:5 (M-IL1), 12:8 (M-IL2), and 10:10 (M-IL3) were prepared. The impregnation of the IL was ascertained using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Structural and surface characteristics of the membranes, including porosity, water contact angle, tensile strength, and surface charge, were studied. Results showed that the IL impregnation has led to remarkable changes in the surface properties of the PE membrane. For instance, the water contact angle and surface porosity of the membranes have decreased from 130.1 ± 1.5° to 94.5 ± 6.7°, and from 85% to 10% in the PE and M-IL3 membranes; respectively. The heavy metal ions Cd2+, Ni2+, and Zn2+ rejection percentage has increased from 35.73 ± 4.41, 39.40 ± 1.23, and 52.89 ± 3.08% in the pristine PE membrane to 52.87 ± 1.82, 51.47 ± 0.61, and 68.05 ± 1.27%; respectively in the M-IL3 membrane. This removal was reported at pure water flux of 22.12 ± 1.22 L m−2 h−1. The enhanced removal was attributed to the ability of the IL DCA- anion to form stable complexes with the heavy metal cations through ion exchange, the formation of hydroxides species, and electrostatic attraction forces. The new membranes have great potential for their application in the remediation of industrial wastewater containing heavy metal ions.

In this study, phase-inverted polyethersulfone (PES)-maghemite (γ-Fe2O3) composite membranes were fabricated and tested for oil-water separation. The performance of five different composite membranes with various loadings of γ-Fe2O3 (0.25, 0.50, 0.75, and 1.00 wt.%) in terms of water flux, flux recovery, and oil rejection was investigated. The surface morphology, crystallinity, and functionalities of the membranes were characterized via scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Fourier-transform infrared (FT-IR). Furthermore, the porosity, pore size, water contact angle, and underwater oil contact angle of the composite membranes were examined. Results showed that the pristine PES membrane reported a pure water flux of 1242 ± 12 L/m2h (LMH) compared to 1323 ± 27 LMH for the 0.25 wt.% PES/γ-Fe2O3 membrane. Additionally, 56 and 23 % flux recovery ratio (FRR) were reported for the PES/γ-Fe2O3 and the pristine PES membrane, respectively. Also, the removal efficiency has increased from 39.2 % in the PES membrane to 81.7 % in the 1.00 wt.% PES/γ-Fe2O3 composite membrane. Two phenomena played a role in the removal trends, namely size exclusion and electrostatic repulsion forces. The developed membranes exhibited significant application potential for the removal of oil from wastewater.

This study aimed at understanding how bacterial communities fluctuate and correlate with wastewater treatment plant (WWTP) efficiency over a ten-month period. Illumina sequencing of 16 s rRNA gene variable regions was performed on genomic DNA extracted from aeration tank samples collected twice a week and analyzed using the Bioinformatics Tool Quantitative Insights into Microbial Ecology 2 (QIIME2). This was done in order to track and relate changes in the bacterial community in the aeration tank to the performance of the plant. The results revealed that the most dominant bacterial phyla present in the aeration tank were Proteobacteria (15 %–40 % of total sequences in all samples), and Bacteroidetes (14 %–41 %) followed by Planctomycetes (2 %–23 %), Patescibacteria (2 %–13 %), Chloroflexi (3 %–12 %), and Nitrospirae (1 %–9 %). Beta analysis revealed clear shifts in the bacterial communities with an overall cyclic pattern that correlated well with the month of the year the aeration tank samples were collected through which samples clustered in groups with samples taken in the same month clustering closer together. Planctomycetes and Bacteroidetes were enriched during the colder, while Chloroflexi and Nitrospirae were enriched during the warmer months. Lastly, it was also found that the efficiency of biological oxygen demand (BOD) and ammonia-N removals were significantly correlated (P

Thin film deposition (TFD) allows for precise tuning of the chemical and physical properties of a membrane to improve performance, including the selectivity, flux, chemical resistance, and antifouling and antimicrobial properties. TFD techniques have a unique advantage over other traditional surface modification methods (e.g., grafting) vis-a-vis their applicability to low-surface energy polymers, which usually resist modification through other techniques. TFD is also an economical approach to surface modification as inexpensive base materials can be functionalized with small amounts of more expensive active chemistries. Here, we review a range of TFD techniques and their applicability for the modification of polymeric membranes to improve durability and performance across water treatment applications. The discussed techniques include sputtering, thermal evaporation, chemical vapor deposition, atomic layer deposition, electrochemical deposition, electron beam deposition, Langmuir-Blodgett deposition, and colloidal deposition. We review how recent developments in TFD techniques have made these methods a competitive alternative to other methods of membrane modification and discuss how modified membranes lead to improved performance for water applications, including microfiltration, nanofiltration, reverse osmosis, and membrane distillation. Relative advantages of each coating process are discussed. We also discuss how process parameters for the various TFD techniques (deposition speed, versatility, conformality, thickness, bonding strength, temperature, etc.) influence the final chemical and physical properties of modified membranes. We conclude with an outlook for how further developments in TFD techniques will continue to introduce new possibilities for unique membrane properties and applications.

Electrochemical technologies have proven to be plausible technology for the treatment of oily wastewater. This study aimed to evaluate the performance of electrocoagulation (EC) process with and without aeration for the treatment of oily wastewater. Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) techniques were used to analyze the sludge and the electrodes. The maximum removal of the chemical oxygen demand (COD) was higher with the aerated cells (93.3 %) than with the non-aerated cells (84 %) at 120 A m−2 current density but at the expense of higher specific energy consumption. Electrophoresis and electrodeposition of oil were observed on both electrodes, with higher intensity on the anodes. The sludge of the aerated cell was of a gel-like structure compared to the foamy and grainy sludge obtained from the non-aerated cell. Anodes in the EC aerated cells were consumed more “homogeneously”, having more depositions of oil on their surfaces. Aeration helped to improve the performance of the process, highlighting the great potential of electrocoagulation processes for the treatment of oily wastewater.

Polymers are sometimes preferred for membrane filtration because they are more flexible, easier to handle, and less expensive than inorganic membranes fabricated from oxides, metals, and ceramics. The polymers are used as the membrane active layer and porous support in reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF), microfiltration (MF) processes. However, the application of polymers for filtration suffers critical drawbacks, such as the chemical attack of polymers, membrane fouling, and hydrophobicity of most polymers. In this chapter, the polymers used for membrane filtration in recent studies and their fabrication procedures are presented and discussed. The polymers used in recent applications include cellulose acetate (CA), polyamide (PA), polyvinylidene fluoride (PVDF), polysulfone (PSF), polyethersulfone (PES), polyvinyl chloride (PVC), polyimide (PI), polyacrylonitrile (PAN), polyethylene glycol (PEG), polyvinyl alcohol (PVA), poly(methacrylic acid) (PMAA), poly(arylene ether ketone) (PAEK), poly(ether imide) (PEI), and polyaniline nanoparticles (PANI). A new polymeric material named polyethersulfone amide (PESA) has also been presented recently. Most of the recent studies have focused on improving the specific energy consumption, salt rejection, water flux, chemical resistance and antifouling properties of polymeric membranes and nanocomposites through blending and surface modification techniques. These techniques involve the use of zwitterionic coatings, sulfonated poly(arylene ether sulfone) (SPAES), perfluorophenyl azide (PFPA), carbon nanotubes (CNTs) and graphene oxide (GO) as nanofillers, polyether ether ketone (PEEK), and nanoparticles such as titanium dioxide (TiO2), and mesoporous silica. The use of polymers for filtration is still gaining tremendous attention, and further improvements of polymeric characteristics for enhanced membrane performance are expected in the coming years.

Several studies have been carried out to understand bulking phenomena and the importance of environmental factors on sludge settling characteristics. The main objective of this study was to carry out functional characterization of microbial community structure of wastewater electro-bioreactor sludge as it undergoes serial passaging in the presence or absence of a current density over 15 days. Illumina MiSeq sequencing and QIIME were used to assess sludge microbial community shifts over time. (α) and (β) diversity analysis were conducted to assess the microbial diversity in electro-bioreactors. A phylogeny-based weighted UniFrac distance analysis was used to compare between bacterial communities while BIO-ENV trend and Spearman’s rank correlation analysis were performed to investigate how reactor operational parameters correlated with bacterial community diversity. Results showed that the removal efficiency of soluble chemical oxygen demand (sCOD) ranged from 91–97%, while phosphorous (PO43−-P) removal was approximately 99%. Phylogenetic analysis revealed stark differences in the development of sludge microbial communities in the control and treatment reactor. There was no mention of any studies aimed at characterizing functional microbial communities under electric field and the results communicated here are the first, to our knowledge, that address this gap in the literature.

Photocatalysis and photocatalytic ozonation under visible light have been applied for the purification of a complex aqueous matrix such as the grey water of Masdar City (UAE), by using N-doped brookite-rutile catalysts. Preliminary runs on 4-nitrophenol (4-NP) solutions allowed to test the reaction system in the presence of a model pollutant and to afford the relevant kinetic parameters of the process. Subsequently, the remediation of grey water effluent has been evaluated in terms of the reduction of total organic carbon (TOC) and bacterial counts. The concentration of the most abundant inorganic ionic species in the effluent has been also monitored during reaction. Photocatalytic ozonation under visible light allowed to reduce the TOC content of the grey water by ca. 60% in the optimized experimental conditions and to reduce the total bacterial count by ca. 97%. The extent of TOC mineralization reached ca. 80% when the photocatalytic ozonation occurred downstream to a preliminary electro-membrane bioreactor (eMBR). Coupling the two processes enhanced the global efficiency. In fact, the eMBR treatment lowered the turbidity and the organic load of the effluent entering the photocatalytic ozonation treatment, which in turn enhanced the extent of purification and disinfection.

This paper uses fuzzy logic-based models to predict and evaluate the performance of multimedia filters utilized in wastewater treatment. A fuzzy logic-based model is constructed and trained to predict the operating time (i.e., treated volume of water) of a multimedia filter. A preset acceptable turbidity value of 5 nephelometric turbidity units (NTU) is used as the breakthrough point. The model is based on a set of experimental data with variable flow rates and influent turbidity. The results from the fuzzy-based model indicate that the simulated treated volume at different inputs of turbidity and flow rate fits the experimental results with a coefficient of multiple determination (R2) of 91.6%. To examine the efficiency of the developed model predicting treated volume, the results obtained from the model are compared with the results obtained from a multiple linear regression model. The accuracy of prediction of both models are examined using the mean absolute error (MSE), root-mean-square error (RMSE), and R2. The MSE, RMSE, and R2 for the fuzzy-based model are 5,318, 72.92, and 98%, respectively, whereas for the regression model they are 3,302, 57.46, and 99%, respectively. Although the regression model appears to be more accurate, the fuzzy-based model is deemed to be more advantageous because it can incorporate the uncertainties in inputs as a result of human judgments and can indicate the errors in the outputs. 1 2017 American Society of Civil Engineers. The authors wish to acknowledge Qatar University for the financial support. Scopus