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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...

Natural dyes exhibit a low dye uptake when cellulosic fiber dyeing is carried out using a conventional water bath dyeing process. In this research, cotton fabric was exhaust dyed in a microemulsion dyebath containing cacao husk extracts dye and decamethylcyclopentasiloxane (D5) to achieve higher dye exhaustion percentage on cotton fiber, which is an environmentally beneficial dyeing process. The adsorption behavior of cacao husk extract dye in a D5 microemulsion system was investigated under conditions of varied dye mass (1–8% o.w.f), dyeing time (5–500 min), and dyeing temperatures (333–373 K). Kinetic modelling of cacao husk extracts dye/D5 adsorption on cotton fiber was studied by fitting experimental data to pseudo first-order and pseudo second-order kinetics, and the intraparticle diffusion model. Early results indicated that the kinetic model of adsorption of cacao husk extracts dye on cotton fiber followed the pseudo second-order model. Langmuir, Freundlich, and Dubinin–Radushkevich adsorption isotherm models were employed to analyze the adsorption isotherms, and the results showed that the adsorption process fit well with the Langmuir model compared to the Freundlich isotherm. The mean adsorption energy from the Dubinin–Radushkevich isotherm model implied that adsorption of the cacao husk extracts onto cotton was accompanied with a physical process. The values of standard enthalpy (ΔH° > 0), standard entropy (ΔS° > 0), and Gibbs free energy (ΔG° < 0) strongly reflected that the adsorption of the cacao husk extracts onto cotton was thermodynamically favourable and feasible. Thus, waterless dyeing of cotton fabric using a natural dye/D5 system explores a sustainable dyeing technology with higher dye exhaustion percentage.

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.

The concept of a novel living encapsulated self-forming dynamic bio-membranes (ESFDM) for an innovative wastewater treatment in membrane bioreactor (MBR) is presented in the current study. The active filtering membrane is encapsulated, and thus stabilized, between two support meshes with pore in micrometer size. The combination of activated sludge, the ESFDM and the cake layer formed external to the filtering module contributed to the treatment of municipal wastewater. COD concentration reductions (average value of 95.55 ± 1.44%) by ESFDM bioreactor (ESFDMBR) were comparable to those obtained with a previously reported membrane bioreactor (MBR), where a conventional membrane was studied under the same operating conditions. The ESFDMBR, compared to the conventional MBR, obtained higher reductions of NH3-N, NO3–N and PO43–P concentrations. Increased removals of nitrogen-containing nutrients were ascribed to anoxic conditions reached in the ESFDM layer protected from the aeration by the external cake layer. Rate of increase of transmembrane pressure (TMP) per day in the ESFDMBR (0.03 kPa/day) was lower than the value obtained in the previously reported conventional MBR (8.08 kPa/day). Lower concentrations of fouling precursors in combination with the effective filtration capacity of the porous living ESFDM resulted in the reduction of the fouling rate. Analysis of microbiological community revealed that the microbial community structures in the mixed liquor and ESFDM were different. The ESFDM layer promoted growth of bacteria as indicated by the higher total cell count and higher microbial diversity compared to those observed in the mixed liquor.

Alkaline chlorination, an efficient but high chemical cost process, is commonly employed for cyanide (CN−) removal from CN-rich wastewater streams. CN− removal and recovery through the precipitation of Prussian Blue (Fe4III[FeII(CN)6]3, PB) or Turnbull’s Blue (Fe3II[FeIII(CN)6]2, TB) were realized using iron salts, leading to a cost-effective and sustainable process producing a valuable recovery product. However, the precipitation of PB and TB is highly affected by pH and dissolved oxygen (DO). CN− removal and recovery from CN-containing water by crystallization of PB and/or TB were investigated using dissolved iron that was electrochemically generated from a sacrificial iron anode under various pH values, initial CN− levels (10 to100 mg/L) and DO levels (aeration, mechanical mixing, and N2 purging). It was shown that the complexation of CN− with Fe ions prevented the vaporization of HCN under acidic pH. At pH of 7 and initial CN− concentration of 10 mg/L, CN− removal efficiency increases linearly with increasing Fe:CN− molar ratios, reaching 80% at the Fe:CN− molar ratio of 5. A clear blue precipitate was observed between the pH range of 5–7. CN− removal increases with increasing initial CN− concentration, resulting in residual CN− concentrations of 8, 7.5 and 12 mg/L in the effluent with the Fe:CN− molar ratio of 0.8 for initial concentrations of 10, 50 and 100 mg CN−/L, respectively. A polishing treatment with H2O2 oxidation was employed to lower the residual CN− concentration to meet the discharge limit of &lt, 1 mg CN−/L.

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 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 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.

The rising of greenhouse-gas emissions (GHG), during the last 200 years, is associated to the well known global warming phenomena. One of the main sources of CO2-equivalent GHGs emissions are the environmental protection plants accounting for 1.57% of the global emissions and thus sustainable and effective technologies for their mitigation are strongly needed. The current paper presents and discusses the assessment of an innovative membrane photo-bioreactor (MPBR) whose aim was the promotion of CO2 capture from conveyed flows, such as those from wastewater treatment plants (WWTPs), landfill and composting plants, for production and energy valorisation of algal biomass. Chlorella vulgaris microalgae strain was selected as photosynthetic platform for the abovementioned purposes. The influence of various operating parameters has been explored, including the photosynthetic photon flux densities (PPFD) (60 and 120 μmol m−2 s−1), liquid/gas ratio (L/G = 5, 10 or 15) and CO2 concentration (5, 10 and 15%) in order to investigated their effects on carbon capture effectiveness and biomass production. The results demonstrated that the increasing of PPFD significantly enhanced the biomass production in terms of biomass productivity (P) and total dry weight (DW). The highest biomass concentration of 1.01 g L−1 was achieved at PPFD of 120 μmol m−2 s−1 with a L/G of 15. Under the aforementioned conditions, carbon dioxide removal efficiency (RE) reached values up to 80%. In addition, the novel MPBR equipped with an innovative self-forming dynamic membrane (SFDM) showed a simultaneous biomass harvesting rate of 41 g m−2 h−1.

Organic ligands have great potential to modulate the structure of iron oxides mineral in the natural environment and affect those minerals' adsorption performances for arsenic species. This study was designed to examine the adsorption potential of goethite quantum dots impregnated graphene oxide hybrids (α-FeOOH QDs@GO) obtained through the consecutive modulation of β-FeOOH with organic ligands acetate (Ac) and graphene oxide (GO) comparing with that of akaganeite impregnated GO (β-FeOOH@GO) and akaganeite (β-FeOOH). The organic modulation greatly changes the structural properties of those three iron oxides hybrids with various crystalline, morphology, particle size, and surface area, thus leading to the obviously different arsenate (As(V)) and arsenite (As(III)) adsorption performances. The maximum As(III) adsorption capacity on α-FeOOH QDs@GO is 147.38 mg g−1, which is 2.52 and 4.60 times larger than that of β-FeOOH@GO and β-FeOOH, respectively. The maximum As(V) adsorption capacity on β-FeOOH@GO is 69.03 mg g−1, which is 1.62 and 4.15 times larger than that of α-FeOOH QDs@GO and β-FeOOH, respectively. The arsenic adsorption mechanism on α-FeOOH QDs@GO reveals that hydroxyl and Ac ligand exchange were the main pathways for arsenic adsorption.

Environment-friendly chitosan-modified-poly(vinyl alcohol) or (PVA)/sodium alginate (SA) electrospun nanofiber membrane (ENM) adsorbent was prepared for the removal of As(III) from an aqueous solution. The chitosan(CS)-functionalized-PVA/SA ENM (CS-f-PVA/SA) was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and X-Ray diffraction (XRD). The CS-f-PVA/SA ENM showed the maximum As (III) adsorption capacity at neutral pH (540.40 mg g−1). The adsorption experiments were conducted by varying the initial pH of the arsenic solutions and also in the presence of different coexisting anions, such Cl- and F-, SO42−, and PO43−. Moreover, the kinetic studies were performed to depict the rate of As(III) sorption onto CS-f-PVA/SA ENM. The As(III) adsorption reached equilibrium within 90 min, which well fitted to the pseudo-second-order kinetic model. The initial pH of arsenic solutions greatly affected the adsorption efficiency but the presence of competing anions in arsenic solutions showed a moderate effect on the arsenic adsorption. The FTIR and XRD analyses suggest that–NH2, –OH, and C–O functional groups of CS-f-PVA/SA ENM are responsible for As(III) uptake. The prepared CS-f-PVA/SA ENM can be easily regenerated using 0.003 M NaOH, and the As(III) removal rate was still above 90–50% after ten successive adsorption-desorption cycles. Thus, such a nanofiber-based adsorbent is quite promising for the removal of As(III) from potable water and can be beneficial in combating the current challenges of arsenic pollution.

The conventional dyeing process requires a substantial amount of auxiliaries and water, which leaches hazardous colored effluents to the environment. Herein, a newly developed sustainable spray dyeing system has been proposed for cotton fabric in the presence of reactive dyes, which has the potential to minimize the textile dyeing industries environmental impact in terms of water consumption and save significant energy. The results suggest that fresh dye solution can be mixed with an alkali solution before spray dyeing to avoid the reactive dye hydrolysis phenomenon. After that, drying at 60–100 °C, wet fixation treating for 1–6 min, and combined treatments (wet fixation + drying) were sequentially investigated and then dye fixation percentages were around 63–65%, 52–70%, and above 80%, respectively. Following this, fixation conditions were optimized using L16 orthogonal designs, including wet fixation time, temperature, dye concentration, and pH with four levels where the “larger-the-better” function was selected to maximize the dye fixation rate. Additionally, the color uniformity and wash and rubbing fastnesses were at an acceptable level when both treatments were applied. Finally, the dyes were hydrolyzed after wet fixation, and the hydrolysis percentages were enhanced after the drying process.

Tannery wastewater contains large amounts of pollutants that, if directly discharged into ecosystems, can generate an environmental hazard. The present investigation has focused the attention to the remediation of wastewater originated from tanned leather in Tunisia. The analysis revealed wastewater with a high level of chemical oxygen demand (COD) of 7376 mgO2/L. The performance in reduction of COD, via electrocoagulation (EC) or UV photolysis or, finally, operating electrocoagulation and photolysis in sequence was examined. The effect of voltage and reaction time on COD reduction, as well as the phytotoxicity were determined. Treated effluents were analysed by UV spectroscopy, extracting the organic components with solvents differing in polarity. A sequential EC and UV treatment of the tannery wastewater has been proven effective in the reduction of COD. These treatments combined afforded 94.1 % of COD reduction, whereas the single EC and UV treatments afforded respectively 85.7 and 55.9 %. The final COD value of 428.7 mg/L was found largely below the limit of 1000 mg/L for admission of wastewater in public sewerage network. Germination tests of Hordeum Vulgare seeds indicated reduced toxicity for the remediated water. Energy consumptions of 33.33 kW h/m3 and 314.28 kW h/m3 were determined for the EC process and for the same followed by UV treatment. Both those technologies are yet available and ready for scale-up.

Volatile Organic Compounds (VOCs) are toxic for the environment and human health and their tendency to readily volatilize in the atmosphere can lead to problems connected to odours annoyance. Conventional VOCs gaseous emissions treatments entail the application of chemical-physical processes, only promoting the transfer of the contaminants from gas to liquid and/or solid phases. Advanced Oxidation Process (AOPs) and biological processes, conversely, support the oxidation of the organic pollutants, promoting their conversion into harmless and odourless compounds. The integration of booth processes is suggested to increase treatability of VOC. The research presents the application of an innovative treatment system composed by an AOPs pretreatment coupled with a bio-scrubbing unit for the abatement of VOCs, with the aim to increase the removal efficiency. The evaluation of the performance of the proposed system is discussed with reference to the analysis carried out using toluene as model substance. Different operating conditions have been analyzed and investigated to optimize the removal efficiency. The results show that the ozonation applied as pretreatment to the biological process may promote an increase of the pollutant biodegradability along with synergic effects due to the absorption of the ozone derived compounds into the culture growth, resulting in a significant enhancement of removal performances respect to the conventional biotechnologies. A toluene removal efficiency up to 95% were obtained under the investigated conditions.

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.

Persulfate (PS)-activated, iron-based heterogeneous catalysts have attracted significant attention as a potential advanced and sustainable water purification system. Herein, a novel Fe3O4 impregnated graphene oxide (Fe3O4@GO)-activated persulfate system (Fe3O4@GO+K2S2O8) was synthesized by following a sustainable protocol and was tested on real wastewater containing dye pollutants. In the presence of the PS-activated system, the degradation efficiency of Rhodamine B (RhB) was significantly increased to a level of &asymp, 95% compared with that of Fe3O4 (&asymp, 25%). The influences of different operational parameters, including solution pH, persulfate dosage, and RhB concentration, were systemically evaluated. This system maintained its catalytic activity and durability with a negligible amount of iron leached during successive recirculation experiments. The degradation intermediates were further identified through reactive oxygen species (ROS) studies, where surface-bound SO4&minus, was found to be dominant radical for RhB degradation. Moreover, the degradation mechanism of RhB in the Fe3O4@GO+K2S2O8 system was discussed. Finally, the results indicate that the persulfate-activated Fe3O4@GO catalyst provided an effective pathway for the degradation of dye pollutants in real 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.

This study presents the synthesis of a novel graphene oxide-manganese oxide (GO-MnO2) nanohybrid and its incorporation into sulfonated polyethersulfone (SPES) ultrafiltration (UF) membranes for wastewater treatment applications. The nanohybrid was first prepared by grafting ethylenediamine (ED) onto the edge of GO followed by direct mixing with the MnO2 nanosheets. The composite membranes were prepared via the phase inversion method and optimized by varying the concentration of the GO-MnO2 nanohybrid (0–6 wt%). The membranes were characterized using scanning electron microscopy, surface zeta potential, water flux, porosity, among others. The results showed that the pure water flux increased from 59.5 ± 2.5 L·m−2·h−1 in the pristine SPES membrane to 129.7 ± 4.1 L·m−2·h−1 in the SPGM4 (4 wt% GO-MnO2). Furthermore, the heavy metal ions rejection improved from 70.1, 49.1, and 55.8% for Cu2+, Zn2+, and Ni2+ ions, respectively, in the pristine SPES membrane to 81.1, 64.0, and 67.4% in the SPGM4 membrane. Also, the composite membranes revealed improvement in the anti-fouling properties over the pristine SPES membrane. For example, the SPGM4 membrane recovered 90.5 ± 2.9% of its initial flux compared to only 72.6 ± 3.1% in the pristine membrane after 4 cycles of heavy metal filtration and simple acid cleaning steps. Overall, the addition of GO-MnO2 nanohybrid enhanced the properties of the pristine SPES, creating new potential for such composite membranes in the wastewater treatment industry.

Although it can effectively degrade refractory organic pollutants, advanced oxidation processes (AOPs) can be seriously interfered with the co-existing substance in salinity water. Herein, three-dimensional hierarchical cobalt-doped LaFeO3 perovskites (LaCo0.5Fe0.5O3) micron spheres composed of nano-rods were hydrothermally synthesized and applied to activate peroxymonosulfate (PMS) for degrading bisphenol A (BPA). Nearly 100% BPA was removed by LaCo0.5Fe0.5O3/PMS system in presence of more than 50 mM Cl- within only 2 min compared that of 30 min without Cl-, which was attributed to reactive chlorine species (RCS) including Cl• and HOCl with higher oxidation capacity. •OH and SO4•- produced by LaCo0.5Fe0.5O3 activating PMS played crucial roles as the source of RCS in LaCo0.5Fe0.5O3/Cl-/PMS system. The synergistic effect between ROS and RCS promoted by the enhanced oxygen vacancies and the efficient redox recycling of FeIII/FeII and CoIII/CoII. Other anions like SO42- and NO3- hardly affected the BPA degradation. BPA degradation efficiency was also improved either in a wide pH range or in the presence of natural organic matters in salty water. This work also demonstrated the potential application of FeCo bimetallic LaCo0.5Fe0.5O3 activating PMS system for degradation of BPA or other organic micropollutants in seawater system.

The aerial parts of the Argy Worm Wood (AWW) plant have been used in different Chinese foods as a colorant and a taste enhancer for a long time. Despite its application as a food colorant, it has rarely been considered for the coloration of textiles. Keeping in mind the variation in color strength due to the change in phytochemical contents by seasonal change and other variables, the extraction of AWW aerial parts was optimized using the Taguchi method. Optimization was performed on the basis of total phytochemical contents (phenols, flavonoids, and tannins) in the extracted solutions. For this purpose, two different solvent systems, namely sodium hydroxide/water (NaOH/water) and ethanol/water (EtOH/water), were applied through a simple aqueous extraction method at varying levels of solvent concentration, and extraction temperature and duration. Maximum phytochemicals yield of 21.96% was obtained using NaOH/water system with 9 g/L NaOH/water at 85 °C for 20 min and 25.5% with 75% aqueous ethanol at 85 °C for 40 min. Optimized extracts were characterized by UV-Vis and FTIR spectrophotometry, which showed the presence of multiple phytochemicals in the extracts. The dyeing temperature and time were also optimized. Dyed cotton fabrics showed medium to high colorfastness to washing and excellent antibacterial and UV radiation absorption properties. The effect of pre-mordanting with salts of iron and copper was also studied on the color fastness properties. Cotton fabrics dyed with two different solvent system extracts displayed various shades of brown with NaOH/water, and green with aqueous ethanol with and without pre-mordanting. The present study provides the textile industry with a promising source of functional bio-colorant and a value-adding approach for the AWW plant industry.

Presence of organic micropollutants (OMP) in wastewater has become an emerging concern due to OMP's bioaccumulation capacity in the aquatic environment and their harmful effects. As a result, numerous processes have been explored as alternatives to conventional activated sludge (CAS) to address OMP removal. Among these, membrane bioreactor (MBR) has become a promising option due to its capacity to retain high microorganism concentration and produce high effluent quality with low sludge production. MBR has been proven effective in OMP removal. Nonetheless, recalcitrance of other OMPs and membrane fouling limited MBR efficiency. Integration of MBR with other processes such as advanced oxidation, ozonation, adsorption, reverse osmosis, and electrochemical processes increased MBR efficiency while quorum sensing (QS) inhibition through quorum quenching (QQ) was proven effective in membrane fouling mitigation.

It is well known that wastewaters from the food industry are a potential source of valuable compounds, such that these wastewaters may be considered by-products awaiting the development of appropriate treatment methodologies. Whey is one of the most important polluting effluents from the milk industry because of its very high biological oxygen demand (BOD). Nevertheless, whey is rich in by-products such as whey proteins and lactose, both of which are widely used industrially. Integrated processes could permit the selective recovery of these by-products in conjunction with the generation of clean, reusable water, thus reducing the environmental impact of this wastewater. Ultrafiltration is a crucial step in the separation and recovery of whey protein and lactose, but this technology suffers from fouling problems that can reduce its performance. New technologies assisted by smart modeling and control systems could improve this ultrafiltration step. In this work, a novel system that allows the recovery of the whey protein in milk industry effluent and the disposal of wastewater was developed and tested. This system utilizes an ultrafiltration process, as this permits the purification of the effluent at room temperature, ensuring the preservation of the recovered proteins. A specially designed autoadaptive fuzzy logic controller evaluates the level of filter membrane fouling and controls a mechanical device that induces filter regeneration. Experimental testing showed that this approach permits process intensification.

Lignin forms a recalcitrant structure in lignocellulosic biomass and hence huge amount of enzymes are required for disintegrating it into their subsequent components, like glucose and other by-products. Thus, the pretreatment is an ineluctable step in the bioethanol scheme for the delignification of biomass and also the recovery of lignin, an emerging value added polymer in many industrial applications. A green facile method was developed wherein humic acid (HA) acts as a catalyst and surfactant in the alkali pretreatment of sugarcane bagasse for the step reduction in lignin recovery scheme with phenomenal properties and enhanced enzymatic-hydrolysis. HA assisted experiments were performed with and without calcium chloride (CaCl2). Effective disintegration of lignocellulose by the cleavage of β-O-4 moieties resulted in forming lignin and hydrolyzable biomaterial via two pathways. Possible covalent linkages between the HA and lignin resulted in the release of esters as a byproduct. Thus, the delignified biomass, the isolated lignin and a variety of esters, could be valorised in various industrial applications. The biomass was characterized by XRD and SEM analysis. The isolated lignin was characterized using FTIR, NMR, GPC, SEM, and TGA – DTA studies. The yield of recovered pure lignin for the two process was 90–100%, as measured through gravimetric analysis. The produced esters were confirmed using FTIR studies. Batch enzymatic hydrolysis was performed for the HA assisted de-lignified bagasse (without CaCl2), which demonstrated a 19% increase in glucose yield compared to the alkali treated bagasse. The produced hydrolysates were subjected to fermentation for the production of ethanol.

Ultrasonication with water recirculation slightly enhanced the removal of toluene compared to water recirculation alone due to conjunction of pyrolysis and hydroxyl radical oxidation with absorption. On the other hand, the addition of ozone with ultrasonication decreased the removal efficiency due to scavenging of hydroxyl radicals. The reaction rate for ozone and OH radicals produced during the US process was faster compared to the rate for ozone and toluene.

Arsenite (As(III)) is less efficient removal than arsenate (As(V)) by adsorption process. Integration of pre-oxidation to convert As(III) to As(V) with simultaneous in-situ adsorption of formed As(V) would be highly desirable. In this work, a novel three-dimensional (3D) bifunctional α -FeOOH@GCA nanocomposite prepared through goethite anchored graphene oxide nanosheet (GO)-carbon nanotubes (CNTs) as supporting materials for arsenic removal. The adsorption process of arsenic species (As(III)/As(V))onto α -FeOOH@GCA nanocomposite surface is independent of pHs, however, the arsenic adsorption edges migrate along with the competition between arsenic species due to the same adsorption sites to form inner-sphere complexes. α -FeOOH@GCA shows remarkably enhanced iron mass normalized adsorption capacity of 236.50 mg-As(III)/g-Fe or 450.72 mg-As(V)/g-Fe which were about 6 or 10 fold that of pristine α -FeOOH, respectively. GO-CNTs play a very important role in enhancing arsenic adsorption capacity by α -FeOOH through forming unique interfacial structures and measured by X-ray photoelectron analysis (XPS) study: (1) greatly miniaturize the size of pristine α -FeOOH and uniformly dispersed onto GO-CNTs surface; (2) increase the adsorption surface area of pristine α -FeOOH nanoparticles. α -FeOOH@GCA nanocomposite also exhibits superior high selectivity/affinity for As(V) to As(III) and facilitates the pre-oxidation of As(III) and simultaneous As(V) adsorption. In-situ photo Fenton-like oxidation increased the adsorption efficiency of As(III) to 80% comparing with direct adsorption ratio of As(III) ( ∼ 36%). The complete regeneration of arsenic adsorbed α -FeOOH@GCA proves the durability of this efficient bifunctional composite for synergistically realizing oxidation–adsorption for arsenic removal in water system, especially for more mobile As(III) removal.

Membrane bioreactor (MBR) technology is becoming increasingly popular as wastewater treatment due to the unique advantages it offers. However, membrane fouling is being given a great deal of attention so as to improve the performance of this type of technology. Recent studies have proven that the application of electrochemical processes to MBR represents a promising technological approach for membrane fouling control. In this work, two intermittent voltage gradients of 1 and 3 V/cm were applied between two cylindrical perforated electrodes, immersed around a membrane module, at laboratory scale with the aim of investigating the treatment performance and membrane fouling formation. For comparison purposes, the reactor also operated as a conventional MBR. Mechanisms of nutrient removal were studied and membrane fouling formation evaluated in terms of transmembrane pressure variation over time and sludge relative hydrophobicity. Furthermore, the impact of electrochemical processes on transparent exopolymeric particles (TEP), proposed as a new membrane fouling precursor, was investigated in addition to conventional fouling precursors such as bound extracellular polymeric substances (bEPS) and soluble microbial products (SMP). All the results indicate that the integration of electrochemical processes into a MBR has the advantage of improving the treatment performance especially in terms of nutrient removal, with an enhancement of orthophosphate (PO4-P) and ammonia nitrogen (NH4-N) removal efficiencies up to 96.06 and 69.34 %, respectively. A reduction of membrane fouling was also observed with an increase of floc hydrophobicity to 71.72 %, a decrease of membrane fouling precursor concentrations, and, thus, of membrane fouling rates up to 54.33 %. The relationship found between TEP concentration and membrane fouling rate after the application of electrochemical processes confirms the applicability of this parameter as a new membrane fouling indicator.

In this study, an electro-replacement/precipitation/deposition/direct reduction (ERPDD) process with scrap iron packed in a Ti mesh cage as a sacrificial anode was investigated for the treatment of wastewater containing CuEDTA complexes. The ERPDD mechanisms were responsible for the removal of Cu from CuEDTA complexes and were verified by a series of experiments using either iron or carbon plates as anodes for the Cu-containing solutions with and without EDTA. A complete Cu removal was achieved with electrical current density applied (1.18–2.36 mA/cm2), whereas only 60% of the Cu was removed without electricity. Dissolved oxygen (DO) was found to have a significant impact on Cu removal. Aeration reduced Cu removal (i.e., only 60% of the Cu was removed), whereas complete Cu removal was achieved with negligible DO concentration under mechanical mixing and N2 purging conditions. Compared to chemical replacement/precipitation (CRP) process, the ERPDD was able to save approximately 60–75% of the total operational costs during the treatment of CuEDTA-containing wastewater, due to the electrochemically controlled dosing of inexpensive sacrificial scrap iron and additional removal mechanisms not found in the CRP process.

Global consideration has been growing recently to tackle the toxic and carcinogenic effects of heavy metal presence in water streams. In this work, novel polyvinylidene fluoride (PVDF)/tin(IV) oxide (SnO2) ion exchange membranes were prepared via the phase inversion method and their performance and properties were analyzed. The results showed that the addition of SnO2 nanoparticles (SnNPs) led to an improvement in the pure water flux from 25.5 ± 1.5 L/m2.h in the pristine PVDF membrane to 250.5 ± 12.5 L/m2·h in the 1.00 wt% PVDF/SnNPs membranes. This was related to the increase in the overall porosity and hydrophilicity of the membranes. Additionally, the 0.25 wt% PVDF/SnNPs membrane reported the highest tensile strength equal to 21.3 ± 0.6 MPa compared to only 14.3 ± 0.4 MPa in the pristine PVDF membrane. Lastly, the maximum removal of Pb2+, Cu2+, Zn2+, Cd2+, and Ni2+ was achieved by the 0.25 wt% PVDF/SnNPs membrane with around 93.9 ± 1.7, 92.8 ± 1.3, 82.3 ± 2.0, 70.7 ± 1.1, and 63.9 ± 1.5%, respectively, compared to 93.5 ± 1.3, 92.9 ± 1.7, 68.3 ± 2.1, 50.3 ± 1.8, and 50.3 ± 1.4% in the pristine PVDF membrane. The mechanism of removal was predicted to be a combination of ion exchange/adsorption, inner-sphere complexations and electrostatic attraction between the metal ions and the SnNPs. Such a PVDF/SnNPs membranes have great potential in the field of wastewater treatment.

Ti-based Sb-SnO2 electrodes are attractive due to their excellent catalytic activity but have a short service life. Here, we report a highly stable and efficient Ti/TiONC/Sb-SnO2 electrode, which was fabricated through hydrothermal reactions using urea to form TiONC interlayers and electrodeposition-annealing to coat the active Sb-SnO2 catalysts. The triple-layered anode was characterized by highly crystalline structures, high oxygen evolution potentials, and corrosion-resistance properties. The structural arrangement yielded better electrocatalytic performances than that using the control electrode (Ti/Sb-SnO2), showing enhanced organics degradation efficiencies. This new electrode’s lifetime was significantly (~25 times) longer than that of either the control or any Sb-SnO2 electrode modified with non-precious materials reported in the literature. The electrode’s enhanced stability was attributed to the insertion of the mixed C and N interlayers that are resistant to oxidants and corrosive ions. The Ti/TiONC/Sb-SnO2 anode holds promise for use in electrochemical water treatment.

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.

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.

Three different advanced oxidation processes (AOPs) were applied to investigate the removal of emerging contaminants (ECs) i.e. sulfamethoxazole (SMX), diclofenac (DCF) and carbamazepine (CBZ) in synthetically prepared solutions. The degradation of these substances was carried out by ozonation, sonolysis and photocatalytic oxidation, as well as by different combinations of these processes. The objectives of this work were to evaluate the removal efficiency in each AOP and to assess the performance variation of sonolysis in combination with other AOPs. The best performances were achieved by sonocatalysis, which resulted in the removal of the selected pharmaceuticals in the range between 37% and 47%. Under similar experimental conditions, the removal of the selected ECs by single compounds by ozonation was slightly lower than the removal of respective compounds in the mixture. Moreover, pseudo first-order removal rate constants of photocatalytic mineralization were determined as 9.33×10-2, 4.90×10-3, 1.06×10-2 min-1 for SMX, DCF and CBZ, respectively.

In this study, a Fenton-activated persulfate (Fe2+/PS) system was introduced for the efficient degradation of Mordant Blue 9 (MB 9) as a textile dye in an aqueous solution. Results showed that the degradation of MB 9 was markedly influenced by operational parameters, such as initial pH, PS concentration, Fe2+ concentration, and initial dye concentration. Optimal reaction conditions were then determined. Inorganic anions, such as Cl&minus, and HCO3&minus, enhanced the degradation efficiency of MB 9 under optimal conditions. Addition of HCO3&minus, reduced the degradation performance of MB 9, whereas the addition of Cl&minus, increased the degradation percentage of MB 9. In addition, quenching experiments were conducted using methanol and tert-butyl alcohol as scavengers, and methanol was identified as an effective scavenger. Thus, the degradation of MB 9 was attributed to S O 4 &bull, &minus, and &bull, OH radicals. The degradation and mineralization efficiency of MB 9 was significantly reduced using the conventional Fenton process i.e., Fe2+/ hydrogen peroxide (HP) because of the formation of a Fe complex during degradation. Meanwhile, the Fe2+/persulfate (PS) system improved the degradation and mineralization performance.

Outdoors, radon is quickly diluted to very low, not problematic concentrations but indoors, it can concentrate significantly. Places that are particularly exposed to an increased radon concentration from water sources are places where water is dispersed, e.g. bathrooms or areas in water treatment facilities. The aim of the paper is to present the calculation of radon escaping from water into the indoor area at home on the example of Mokre village. Mokre is supplied with water from an underground source containing radon 222 Rn in concentration of about 200 Bq/L. The obtained data has been compared with WHO recommendation (WHO, 2009) and literature review. Considering that 300 Bq·m-3 are equivalent to 10 mSv per year, which is equal to receiving approximately an annual full chest CT (computed tomography), the risk resulting from the emission of radon from tap water in Mokre has been assessed to be insignificant.

In this study, the viability of using electrocoagulation process as a method for pharmaceuticals removal from real municipal wastewater was demonstrated. Batch experimental runs were performed using a simple laboratory scale electrochemical reactor with aluminium and stainless steel as anode and cathode, respectively. Diclofenac (DCF), carbamazepine (CBZ) and amoxicillin (AMX) were selected as representative of pharmaceuticals frequently detected in the aquatic environment. The effects of varying experimental parameters namely current density (0.3, 0.5 1.15 and 1.8 mA cm−2), initial pharmaceutical concentration (0.01, 4 and 10 mg L-1), electrolysis duration (3, 6 and 19 h) and application mode (continuous vs. intermittent) on pharmaceutical removal efficiencies were evaluated. High pharmaceutical abatement was recorded at elevated current density and prolonged electrolysis duration due to additional electro-generated coagulant species in solution.

The present study investigated the influence of electric field on the removal of quorum sensing (QS) and emerging contaminants using an electrochemical membrane bioreactor (eMBR). A significant reduction of N-octanoyl-L-homoserine lactone signal molecules (∼76%) was achieved in the eMBR, with respect to the level observed in the conventional MBR as the control. Furthermore, the intermittent electric current supply (0.5 mA/cm2) was found to be effective for the removal of atrazine and estrone. The degradation of key pharmaceutical compounds, such as diclofenac, carbamazepine, and amoxicillin, was also possible, confirming the applicability of the eMBR system for removing the priority chemical compounds of public health concern.

The negative effects of volatile organic compounds (VOCs) on humans’ health and the environment have boosted the enforcement of regulations, resulting in the need of effective and environmentally friendly off-gas treatment technologies. In this work, the synergism between microalgae and bacteria was investigated as a sustainable platform to enhance the biological degradation of toluene, herein selected as a model VOC. An innovative algal-bacterial tubular photobioreactor (TPBR) was systematically compared with a conventional biotrickling filter (BTF). The BTF supported average removal efficiencies close to those obtained in the TPBR (86 ± 9% and 88 ± 4%, respectively) at the highest inlet load (∼23 g m 3 h −1 ) and lowest gas residence time (0.75 min). However, the BTF was more sensitive towards the accumulation of secondary metabolites. In this regard, photosynthetic O 2 supplementation (resulting in dissolved oxygen concentrations of ∼7.3 mg O 2 L −1 ) and CO 2 consumption by microalgae (which reduced the impact of acidification) enhanced toluene abatement performance and process stability.

Advanced wastewater treatment is necessary to effectively remove emerging contaminants (ECs) with chronic toxicity, endocrine disrupting effects, and the capability to induce the proliferation of highly resistant microbial strains in the environment from before wastewater disposal or reuse. This paper investigates the efficiency of a novel hybrid process that applies membrane ultrafiltration, activated carbon adsorption, and ultrasound irradiation simultaneously to remove ECs. Diclofenac, carbamazepine, and amoxicillin are chosen for this investigation because of their assessed significant environmental risks. Removal mechanisms and enhancement effects are analysed in single and combined processes. The influence of adsorbent dose and ultrasonic frequency to EC removal are also investigated. Results suggest that adsorption is probably the main removal mechanism and is affected by the nature of ECs and the presence of other components in the mixture. Almost complete removals are achieved in the hybrid process for all ECs.

The occurrence and fate of pharmaceuticals in the environment, and in aquatic media in particular, have received considerable attention by the scientific community during the last two decades. Pharmaceuticals, which are designed to be biologically active substances, are usually lipophilic and resistant to biodegradation, thus having the potential for accumulation and persistence in the environment. Although they are usually present at relatively low concentrations, ranging between ng/L and μg/L levels, they may cause serious effects on the environment. In this study, the removal efficiency of sonolysis has been tested on a mixture of 23 pharmaceuticals. Diclofenac and carbamazepine degradations were tested at different power densities (100–400 W/L) using low frequency. These compounds were spiked separately in wastewater at high concentrations (mg/L). Subsequently, low-frequency ultrasound-induced degradation of a mixture of 23 emerging contaminants with low concentration (μg/L) in urban wastewate...

Recently, microbial fuel cells (MFCs) have been integrated with membrane bioreactors (MBRs), either in an internal or an external configuration, for wastewater treatment and energy recovery. In an external configuration, MFCs could be applied for an efficient sludge reduction since they can simultaneously address energy issue and environmental concerns associated with sludge treatment. In the present study, a potentiostatic controlled microbial fuel cell (MFC) was fed with activated sludge from a membrane bioreactor (MBR) at different total suspended solid (TSS) concentrations (1–10 gTSS L −1 ) in order to assess the electrochemical response of the system and the impact of the bioelectrochemical treatment on sludge characteristics and membrane fouling parameters. The MFC showed COD removals 30% higher than the control test and a reduction of volatile suspended solids (VSS) up to 43% with concomitant production of energy (maximum current density of 2.0 A m −2 ). The electricity production increased with the increase of TSS content. In both MFC and the control test, an increase of soluble microbial products (SMP) ratio in terms of proteins and carbohydrates (SMPp/SMPc) and an average 50% increase of sludge hydrophobicity were observed. This could limit membrane fouling in the case that the sludge is recirculated to the MBR. The electrochemical characterization indicated that both, acetate and sludge oxidation took place at a similar formal potential of −0.2 V vs. SHE indicating that both used the same electron transfer mechanism. Hence, this study shows that a MFC could oxidize, reduce and stabilise MBR sludge producing electricity and affecting membrane fouling parameters The authors would like to thank the Spanish Ministry (CTQ2014-53718-R and CTM2015-71982-REDT) and the University of Girona (MPCUdG2016/137) for their financial support. LEQUIA has been recognised as consolidated research groups by the Catalan Government (2014-SGR-1168)

The continuous release of emerging contaminants (ECs) in the aquatic environment, as a result of the inadequate removal by conventional treatment methods, has prompted research to explore viable solutions to this rising global problem. One promising alternative is the use of electrochemical processes since they represent a simple and highly efficient technology with less footprint. In this paper, the feasibility of treating ECs (i.e., pharmaceuticals) using an intermittent electrocoagulation process, a known electrochemical technology, has been investigated. Diclofenac (DCF), carbamazepine (CBZ) and amoxicillin (AMX) were chosen as being representative of highly consumed drugs that are frequently detected in our water resources and were added in synthetic municipal wastewater. The removal efficiencies of both individual and combined pharmaceuticals were determined under different experimental conditions: hydraulic retention time (HRT) (6, 19 and 38 h), initial concentration (0.01, 4 and 10 mg/L) and intermittent application (5 min ON/20 min OFF) of current density (0.5, 1.15 and 1.8 mA/cm2). Results have shown that these parameters have significant effects on pharmaceutical degradation. Maximum removals (DCF = 90%, CBZ = 70% and AMX = 77%) were obtained at a current density of 0.5 mA/cm2, an initial concentration of 10 mg/L and HRT of 38 h.

The combination of chemical and biological treatment is a promising solution to remove emerging contaminants, e.g., pharmaceuticals, from wastewater for its future reuse. In this study, the combination of ozonation and ultrasound (O3/US) was examined as a pretreatment prior to membrane bioreactor (MBR). The effects of O3/US on the removal of selected pharmaceuticals, including diclofenac (DCF), sulfamethoxazole (SMX) and carbamazepine (CBZ), and MBR fouling control were investigated. The variation of the toxicity potential of the MBR influent was also assessed. The O3/US treatment was effective in reducing fouling, mainly due to its effects on the microbial metabolism products in the MBR. Extracellular polymeric substance (EPS) concentration was reduced by 50%. Improved operating conditions resulted in higher removal rates for pharmaceuticals in the MBR effluent, with removal efficiency in the range of 80–84%. However, the O3/US treatment alone was not efficient in removing the toxicity of wastewater. This was likely due to the formation of intermediate products that are more toxic than the parent compounds. These intermediate products were observed to be biologically oxidized by MBR, with a 80% reduction of the toxicity potential in the MBR permeate compared to the influent.

This study investigates the removal of selected pharmaceuticals, as recalcitrant organic compounds, from synthetic wastewater using an electro-membrane bioreactor (eMBR). Diclofenac (DCF), carbamazepine (CBZ), and amoxicillin (AMX) were selected as representative drugs from three different therapeutic groups such as anti-inflammatory, anti-epileptic, and antibiotic, respectively. An environmentally relevant concentration (10 μg/L) of each compound was spiked into the synthetic wastewater, and then, the impact of appending electric field on the control of membrane fouling and the removal of conventional contaminants and pharmaceutical micropollutants were assessed. A conventional membrane bioreactor (MBR) was operated as a control test. A reduction of membrane fouling was observed in the eMBR with a 44% decrease of the fouling rate and a reduction of membrane fouling precursors. Humic substances (UV254), ammonia nitrogen (NH4-N), and orthophosphate (PO4-P) showed in eMBR removal efficiencies up to 90.68 ± 4.37, 72.10 ± 13.06, and 100%, respectively, higher than those observed in the MBR. A reduction of DCF, CBZ, and AMX equal to 75.25 ± 8.79, 73.84 ± 9.24, and 72.12 ± 10.11%, respectively, was found in the eMBR due to the enhanced effects brought by electrochemical processes, such as electrocoagulation, electrophoresis, and electrooxidation.

This paper examines the effectiveness of sonolysis in improving the anaerobic biodegradability of the organic fraction of municipal solid waste coming from mechanical selection, thus enhancing biogas production and energy recovery as well. Methane yield of solid organic material anaerobic digestion is significantly affected by substrate availability that was evaluated, in this investigation, through organic matter solubilisation tests carried out at different conditions of ultrasound treatment. Results show that sonolysis can significantly improve the solubilisation of organic solid waste, thus allowing higher biogas production from anaerobic treatment of sonicated substrates. After 45 days, the biogas produced during anaerobic codigestion tests for the sonicated mixture was 24% higher than untreated one. Therefore, these results can lay the basis for the development of technologies useful to produce high biogas quantities, in order to improve clean energy generation from biowaste.

Activated sludge processes are key technologies in wastewater treatment. These biological processes produce huge amounts of waste activated sludge (WAS) or otherwise biosolids. Mechanical, thermal, and/or chemical WAS conditioning techniques have been proposed to reduce the sludge burden. Among the WAS treatments, the pre-treatment with ultrasound (US) is one of the most innovative processes. In many anaerobic digestion processes for the treatment of the sludge produced in wastewater treatment plants, the hydrolysis of the organic matter has been identified as the rate limiting step. This study is focused on the effect of US pre-treatment of WAS to the anaerobic digestion. Particle size reduction, Chemical Oxygen Demand (COD) solubilization and biodegradability by anaerobic digestion were monitored in order to find the optimal dose in US pre-treatment. The results show the better sonolysis conditions (US density, sonication time, specific energy) which can significantly improve the COD solubilisation and the anaerobic biodegradability.