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Ensuring the effluent quality despite fluctuations in influent flow rate and organic load to municipal wastewater treatment plants is critical. This study investigated the performance of a membrane bioreactor (MBR) in handling hydraulic and organic loading shocks during wastewater treatment. The ability of the MBR to remove COD, BOD5, and turbidity from synthetic wastewater was evaluated at steady-state and after applying five levels of organic shock loads (1.5×-4×) and four levels of hydraulic shocks (1.2×-4.7×). Due to the short-term shock-loadings no discernible effect was observed on the mixed liquor suspended solids implying biological stability. The average COD removal in MBR exposed to organic and hydraulic shock loads was 93.8% and 94%, respectively, similar to average BOD5 removals of 94.4% and 93.6%. The membrane retained suspended particles well throughout the process. However, it became quickly fouled only by applying a strong hydraulic shock. The MBR guaranteed the quality of the effluent. [ABSTRACT FROM AUTHOR]

In this study, the morphology of the nanostructures is evaluated on the surface characterization and performance of the polyacrylonitrile (PAN) ultrafiltration mixed matrix membranes (MMM). To this end, silica nanoparticles (NPs) such as spherical (SiO2) and hexagonal mesoporous (MCM‐41) with high hydrophilicity were incorporated at 0.5, 1, and 2 wt%. Attenuated total reflectance‐Fourier transform infrared analysis illustrated the placement of NP on the surface of the MMM. Atomic force microscopy studies also showed that SiO2 NP added to PAN exhibited a smoother surface than MCM‐41 NP. Field‐emission scanning electron microscope analysis of the MMM identified that all membranes are composed of a finger‐like porous structure. Contact angle measurements indicate that the morphology of the NPs has no significant effect on MMM hydrophilicity. Moreover, the performance of the MMM was evaluated, and regardless of NP morphology, the MMM showed better permeate flux with increased loading. A higher pure water flux was observed in the PAN‐MCM41‐1% membrane (237 L/m2 h), possibly because of inherent porosity and high hydrophilicity of MCM‐41 compared to SiO2 NP. Further, the PAN‐SiO2‐1% membrane exhibited superior antifouling properties due to a lower surface roughness. The present studies reveal that the morphology of the NP greatly influence on the structure, permeation, and antifouling properties of PAN membranes. [ABSTRACT FROM AUTHOR]

Novel mixed matrix membranes (MMMs) were fabricated using Fe3O4, and Al2O3 nanoparticles (NPs) were added to the polysulfone (PSf) and N‐methylpyrrolidone (NMP) solution. The nanocomposite membranes were fabricated using the NIPS (non‐solvent induced phase separation) method. In order to create preferential permeation pathways for water across the MMMs, membrane formation is accomplished with an external magnetic field. Using magnetic casting cause the targeted placement of NPs in the best location and orientation. The performance of the prepared membranes was examined in terms of pure water flux and fouling parameters. Magnetic casting considerably increased pure water flux and decreased the total resistance of the optimum mixed matrix membrane, which contains 0.2% wt. of Fe3O4 NPs to 1175 L/m2h and 13.4 * 1011 (m−1), respectively. This is explained by the ordering of magnetic nanoparticles on the membrane sub‐layer cast under the magnetic field of 500 mT, which changed the sub‐layer structure. Less rough membrane surface of the mixed matrix membranes offered preferable anti‐fouling properties against fouling by BSA proteins. The characterization of fabricated membranes was carried out using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), energy dispersive X‐ray (EDX), and water contact angle measurement methods. [ABSTRACT FROM AUTHOR]

The goal of the current research is to simultaneously improve the fouling resistance and mechanical properties of polyacrylonitrile ultrafiltration membrane for membrane bioreactors (MBR) applications by a relatively easy method. For this purpose, amino‐functionalized carbon nanotubes (NH2‐MWCNTs) were employed, which have exceptional mechanical properties, hydrophilic functions, and good interaction with polyacrylonitrile. It was used to fabricate nanocomposite membranes with different MWCNTs contents. The rheological and thermodynamical aspects of the phase separation process were investigated to understand the mechanism of the membrane formation. The related characteristics including morphological, mechanical, and chemical properties of the membrane as well as its performance were studied. In the end, the synthesized membranes were used in an MBR setup for further investigations. The Pure water flux data shows considerable improvement from 810 LMH for the neat membrane to 1055 LMH for the 0.3 wt% NH2‐MWCNTs nanocomposite membrane. Mechanical enhancement was confirmed with about a 24% increase in the tensile strength and 61% for elongation at break. The membrane with 0.3 wt% NH2‐MWCNTs revealed the best porosity, fouling resistance, and performance in MBR with 95% flux recovery ratio and 64% improvement in permeated flux compared to the neat membrane. [ABSTRACT FROM AUTHOR]

Membrane costs and biofouling limit applications of membrane bioreactors (MBRs) for wastewater treatment. Here, powdered activated carbon (PAC) utilization in the formation and performance of a self-forming dynamic membrane consisting of activated sludge and PAC during hybrid wastewater treatment process was studied. Short-term agitation helped (non)biological particles to quickly uniformly settle on mesh filter, forming more uniform PAC-containing dynamic membranes (PAC-DMs). PAC adsorbed adhesive materials, resulting in an increase in average floc size and DM permeability while decreasing biofouling. The most efficient PAC concentration was 4 g L−1 considering techno-economics, i.e. the highest effluent quality (turbidity of 19.89 NTU) and the lowest biofouling (transmembrane pressure rise of 2.89 mbar). Short-term performance of hybrid PAC-DM bioreactor (PAC-DMBR) showed stability in effluent quality improvement including 92%, 95%, 83%, 84% and 98% reductions in turbidity, chemical oxygen demand, total dissolved solids, total nitrogen, and total phosphorous, respectively. Accordingly, adopting hybrid PAC-DMBR has potential to alleviate biofouling and capital cost. [ABSTRACT FROM AUTHOR]

The aim of this research is benefiting from the synergistic effect of the simultaneous presence of Fe3O4 and ZrO2 in the form of Fe3O4-coated ZrO2 (Fe3O4@ZrO2) nanoparticles within the structure of PAN membrane to reduce membrane fouling. The role of Fe3O4 nanoparticles in increasing the pore size and magnetic saturation as well as the role of ZrO2 in decreasing surface roughness and hydrophobicity can mitigate membrane fouling in magnetic-assisted membrane bioreactors. For this purpose, Fe3O4, ZrO2, and Fe3O4@ZrO2 nanoparticles were embedded into PAN membrane structure and magnetic (MnM), hydrophilic (HnM), and magnetic-hydrophilic (HMnM) membranes were synthesized. H1M (1ZrO2/PAN) membrane with a contact angle of 31 degrees, M1N (1Fe3O4/PAN) with a pore size of 90 nm, and H3M (3ZrO2/PAN) membrane with an RMS roughness of 13.5 nm were the most hydrophilic, porous, and smoothest membranes, respectively. High sensitivity to magnetic field along with high porosity, high hydrophilicity and low surface roughness simultaneously exist within the structure of MHMs membranes, such that MH1M (1Fe3O4@ZrO2/PAN) indicated 116% greater flux, 121% greater flux recovery, and 85% less total filtration resistance in comparison with the blank membrane in magnetic membrane bioreactor, at a magnetic field intensity of 120 mT and MLSS = 10,000 mg/l. As an overall conclusion, the output of this research was compared with other research in term of normalized flux. Results reveal that at MLSS = 10,000 mg/l, HRT = 8 h and TMP = 0.3 bar, MH1M membrane has normalized flux equal to 1.56 g/m2 h bar which is an acceptable value compared to normalized flux reported by other researchers. [ABSTRACT FROM AUTHOR]

In this work the influence of fabrication conditions (ion strength, surfactant utilization) on the macro- (particle size distribution, PSD) and microscopic [pore size distribution (PoSD), specific surface area] structure of agarose beads was investigated. The main purpose was achieving uniform sized and porous beads with improved mechanical strength for bioseparation and chromatography applications. Therefore, PSD, PoSD, mechanical resistance, and flux through packed bed of the fabricated beads (4, 6, and 8% wt/wt) were analyzed. Based on porosimetry results, it was found that increasing ion concentration or presence of surfactant (the key variable for narrowing PSD) decreases the span value of PSD (p-value <0.05); thus, leading to a more uniform distribution. Moreover, as a result of controlling PSD, the PoSD changes from micro- to meso- and macropores in higher ion charged solutions. Furthermore, the obtained PoSD affects mechanical resistance of the prepared microspheres either as single beads or packed in a column. Mesoporous 6%-agarose beads showed the highest flux due to elevated mechanical resistance and elastic characteristic. Mesoporous 4%-beads showed the highest elasticity, and thus lower flux through column. These results demonstrate that manipulation of both macro- and microscopic characteristics of the beads should be commensurate with the intended application i.e., bioadsorption chromatography. [ABSTRACT FROM AUTHOR]

The aim of this work was to synthesize nanocomposite membranes based on chitosan (CS) and cellulose acetate (CA) blends containing titanium dioxide (TiO2) nanoparticles and investigate their morphological, structural, mechanical, and thermal properties along with dye affinity ligand content for using potentially as bioadsorption applications. The samples were characterized by means of scanning electronic microscopy (SEM), energy dispersive X‐ray (EDX), Fourier transform infrared spectroscopy (FTIR), tensile, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and water contact angle (WCA). The SEM micrograph images showed a uniform and microporous morphology of the prepared membranes. FTIR analysis confirmed the presence of CA and TiO2 nanoparticles through the CS matrix in which the components used had good compatibility. The mechanical and thermal studies emphasized that strong interactions occurred between CS, CA, and TiO2 nanoparticles. Blending CS with CA and the addition of TiO2 nanoparticles enhanced the hydrophilic property of CS membranes, significantly. The CS/CA based nanocomposite containing 1.5 wt% of TiO2 nanoparticles showed the remarkable improvements in ultimate tensile strength values and an increase in stiffness more than three times compared to the neat CS membrane sample. Finally, considering the results of tensile test and immobilized Cibacron Blue F3G‐A (CB) content measurement, the nanocomposite samples denoted by (50/50) CS/CA/TiO2 (1.5%) were nominated as the promising material used for potentially bioadsorptive membrane. POLYM. COMPOS., 39:4452–4466, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Abstract The present study examined fouling in a microalgal membrane bioreactor under mixotrophic, heterotrophic and photoautotrophic conditions. N-enriched wastewater, containing nitrate source, was used as a nutrient source for cultivation of microalgae. The results confirmed that the membrane fouling rates increased under mixotrophic cultivation through enhanced production of carbohydrates in soluble microbial products (SMP c) and protein in extracellular polymeric substances (EPS p). The transmembrane pressure (TMP) jumping was observed under mixotrophic and photoautotrophic cultivation after 31 and 47 days of operation, respectively, while the TMP of heterotrophic cultivation did not exceed 10 kPa throughout 51 days. The highest EPS p was produced under mixotrophic condition due to high nitrogen removal rate. Also, the results of resistance analysis indicated that cake resistance was the main fouling resistance in all cultivation types and the latter result was confirmed by SEM analysis. In addition, higher protein fraction of cake layer on membrane foulants in comparison to carbohydrates fraction increased the hydrophobicity of membrane's surface in all cultivations (except heterotrophic culture). Compared to mixotrophic and photoautotrophic cultures, hydrophobic properties and cell size of heterotrophic microalgae increased and resulted in low membrane fouling rates. Graphical abstract Unlabelled Image Highlights • Chlorella cultured under different trophic conditions in membrane bioreactor. • Fouling rate increased under mixotrophic and photoautotrophic cultivations. • High nitrogen removal resulted in increasing extracellular polymeric substances. • Increased soluble microbial products were responsible for higher membrane fouling. • Hydrophobicity and cell size of microalgae depended on soluble microbial products. [ABSTRACT FROM AUTHOR]

The main purpose of this research is to use aluminum oxide nanoparticles in order to manipulate the formation mechanism of poly acrylonitrile (PAN) UF membranes with the aim of improving their performance in separating biological macromolecules including sodium alginate, humic acid, bovine serum albumin (BSA). For this purpose, alumina nanoparticles with the approximate size of 40 nm and high hydrophilicity properties were placed within the structure of the PAN membrane to engineering design of pores. Viscometry analysis and determination of cloud point were performed in order to investigate the formation mechanism of the nanocomposite membrane. Chemical, surface, and morphological variations of the nanocomposite membrane were evaluated using FTIR, zeta potential, contact angle, DLS, porosity metering, SEM, and AFM analyses. Eventually, investigation of the filtration performance of the nanocomposite membranes showed that the membranes containing 1 wt% of alumina nanoparticles have a water flux 57% more than that of raw membrane. Further, in terms of flux recovery parameter, this membrane indicated 22, 9, and 14% increase for sodium alginate, humic acid, and BSA, respectively. Regarding extent of dye separation, sodium alginate separation, humic acid separation, and BSA separation, 12, 7, 9, and 7% increase was observed for the nanocomposite membrane containing 3 wt% of alumina nanoparticles. [ABSTRACT FROM AUTHOR]

In this study, the effect of mixotrophic, heterotrophic, photoautotrophic (CO2 of air source), and photoautotrophic (bicarbonate source) cultivation of Chlorella vulgaris was investigated on microalgae growth rate and nutrient removal under different kinds of nitrogen sources. The highest N-NH3+, N-NO3−, P-PO43− (in ammonium source), and P-PO43− (in nitrate source) removal efficiency (87.28 ± 0.89, 70.00 ± 1.20, 87.00 ± 3.10, and 78.10 ± 1.95%, respectively) was reached in the mixotrophic culture. In all cultivations, when nitrate was used as the nitrogen source, specific growth rate, biomass productivity, and specific oxygen production rate (SOPR) were higher than the one with ammonium source due to decreased pH. However, in all cultures except for photoautotrophic cultivation (in the CO2 of the air), nitrogen removal rates improved in the ammonium source. In addition, in both ammonium and nitrate source, the respiration activity of mixotrophic microalgae was higher than the photosynthetic activity of the cells. When CO2 was used as inorganic carbon, the specific growth rate of microalgae was lower than with the bicarbonate source. Based on the obtained results, mixotrophic conditions would be the most useful cultivation for application in N-rich wastewater treatment systems. [ABSTRACT FROM AUTHOR]

This study investigates the effectiveness of zeolite for controlling the membrane fouling in a hybrid membrane bioreactor. A control membrane bioreactor without zeolite (CMBR) and a hybrid MBR with zeolite were studied, which were called 4 g L–1 zeolite (Z4-MBR), 8 g L–1 zeolite (Z8-MBR) and 12 g L–1 zeolite (Z12-MBR) within long- and short-term filtration experiments. On average, the Z4-MBR, Z8-MBR and Z12-MBR reduced soluble microbial products (SMPC) by 18.96%, 42.11% and 19.44%, respectively. Furthermore, the ZMBR systems developed lower operational trans-membrane pressure (TMP), lower zeta potential, increased the relative hydrophilicity of sludge and enhanced the concentration of EPS. Reduced membrane fouling and ease of membrane operation are concluded from this study. [ABSTRACT FROM AUTHOR]

In this research membrane bioreactor (MBR) technology as a novel and practical technology was studied for treatment of saline petrochemical wastewater. Membrane fouling and permeability, mixed liquor properties such as change of flock size, and effluent characteristics of MBR were measured in presence of various salt concentrations in the feed. The results showed that the increasing the salinity reduced cake layer, total membrane resistances and increased the membrane permeability and sludge particle size. Also, COD removal efficiencies were up to 91% in all trials. These results indicate that the MBR was highly efficient for treating saline petrochemical wastewater. [ABSTRACT FROM PUBLISHER]

The aim of this study was to evaluate the potential use of ozonation with pharmaceutical compounds on membrane bioreactor (MBR). The result has shown that high concentrations of pharmaceutical contaminants have caused destruction of cell wall, thereby reducing mixed liquor suspended solids (MLSS). It also resulted in high amounts of biopolymers in the presence of non-biodegradable pharmaceutical compound in MBR. As a result, biological removal decreased and membrane fouling happened. Ozonation treatment reached a chemical Oxygen Demand (COD) removal of 99.9% and caused better effluent quality. The MBR-ozonation process could achieve an acetaminophen and fluoxetine removal of around 98.4 and 57.83%, respectively. [ABSTRACT FROM AUTHOR]

Dynamic membranes (DMs) formed upon cost-effective mesh filters are considered as convenient alternatives to conventional membranes in membrane bioreactors (MBRs). This novel study investigates how hydrodynamics resulting from aeration rates of 2.5, 5, 10, and 15 L/min and agitation speeds of 100, 200, 300, and 400 rpm affect the sludge particle size, soluble microbial product (SMP), accumulation of sludge upon filter media, fouling propensity, effluent turbidity, and separation properties of DMs. The results conveyed that mixing flow and mixing intensity affect sludge properties considerably as well as DMs formed in the MBR. Despite fouling propensity, sludge mean particle size and dry weight of DMs decreased by increasing aeration rate and agitation speed. Optimum performance in terms of turbidity removal and blue pigment separation was obtained at the aeration rate of 5 L/min and the agitation speed of 300 rpm. In addition, more uniform DMs were formed by the flow pattern created by agitation which improved the performance. The DM formed by the agitation speed of 300 rpm could remove approximately 82% of blue pigments with a mean particle size of 0.9 μm which performs similar to microfiltration. [ABSTRACT FROM AUTHOR]

This study investigated the long-term filtration of mesh filter with the formed dynamic membrane in bioreactor. The trend of transmembrane pressure (TMP) variations highly corresponded to the thickness and compactness index of dynamic membrane. The dynamic membrane was fractionated by applying two cleaning protocols, that is, rinsing and chemical cleaning. The desorbed fraction, consisting of soluble microbial products (> 70%), provided a stickiness surface for formation of consecutive biomass layer which featured a high concentration of extracellular polymeric substances (> 75%). The chemical oxygen demand (COD) removal was 70%, 89%, and 92% for period of 0–26, 26–49, and 49–67 day, respectively, which indicated that further development of dynamic membrane increased the TMP without improvement in the effluent quality (TMP: 50–200 mbar, COD removal: 89%; TMP: 200–600 mbar, COD removal: 92%). The averageand TN removal was about 76% and 21%, respectively. The effluent turbidity fell less than 2 NTU after 26 days of filtration. [ABSTRACT FROM PUBLISHER]

This study presents a closed-loop process for forming pre-coated dynamic membrane used in membrane bioreactor. Powder-activated carbon (PAC) particles are suspended by using axial-flow agitator whilst simultaneously deposited upon the filter medium by cross-flow filtration. The revolution speed of agitator is varied in the range of 150–450 rpm. Computational fluid dynamic is used to calculate velocity and shear rate adjacent to membrane surface. The force balance of the particles considers the driving force of dynamic membrane formation, drag force due to negative pressure-driven of suction pump, lift force due to mechanical mixing, and adhesive force due to particle–particle interactions. The effect of two major terms including drag and lift forces on the porosity of dynamic membrane is systematically investigated. The lower drag force results in the higher porosity of dynamic membrane. The results also show that the denser dynamic membrane is formed when the lift force becomes lower. The porosity of dynamic membrane is ranged from 0.38 to 0.46 while the thickness of dynamic membrane is altered between 100 and 500 μm. A dimensionless immobilized parameter is derived to predict the formation of pre-coating dynamic membrane. The results obtained from modeling show that dynamic membranes formed at higher values of immobilization parameter have a more cohesive structure. The results obtained from the experiments and the model reveal that the thickness of 400 μm of PAC layer is considered as a stability threshold thereafter the structure of dynamic membrane becomes loose and unstable. The rejection capacity of dynamic membrane is also evaluated at different thicknesses by using Formazin solution. The results reveal that the turbidity of filtrate decreases with increasing the thickness of dynamic membrane. The results display that rejection capacity of pre-coating dynamic membrane is comparable to that of microfiltration membrane. [ABSTRACT FROM PUBLISHER]

In this work, separation of disperse dyes and polyethylene glycol (PEG) as organic contaminant by nanocomposite membrane was investigated. The main goal of this study is to achieve more efficient separation of contaminant from water at high fluxes. For this purpose, iron oxide nanoparticles (NP) were synthesized through co-precipitation, blended with polysulfone/N-methylpyrrolidone solution, and finally, dispersed in membrane structure after coagulation of casted polymeric solution. Effect of magnetic nanoparticle concentration on membrane structure and filtration performance was studied. According to filtration experiments, the increasing of nanoparticle concentration in membrane matrix cause permission flux to raise. On the other side, any increases in magnetic nanoparticle content improved disperse dyes and PEG rejection as organic contaminant. Iron oxide NP in polymeric solution act as an agent to increase viscosity and cause a delay in phase inversion, decrement in membrane pore size, and finally, solute rejection enhancement. The Fourier transform infrared spectroscopy confirmed nanoparticle existence in membrane matrix. Furthermore, the magnetic properties of nanocomposite membranes were measured by Vibrating Sample Magnetometer. Scanning electron microscopy images showed the effect of nanoparticle concentration on membrane porosity. The cross section of which confirmed the role of NP as a delay agent in membrane formation. [ABSTRACT FROM PUBLISHER]

In this study, the amount of ozone which is adsorbed by the activated sludge system and the effect of ozonation on the sludge properties were investigated. Two batch reactors, one control and one ozonated were used. During the test, the ozonation time was increased from 15 to 185 s, the ozone concentration was 0.73–4.83 mgO3 g−1MLSS and the mixed liquid suspended solid (MLSS) was 11–14 g L−1. In an ozonated reactor, with increasing the ozonation time the ozone concentration was determined in order to calculate how much ozone adsorbed in sludge system. It was found that the ozone concentration increased in the activated sludge system with time and after it reached to the maximum level in 40 s, it decreased. Based on the result, MLSS was not affected by ozonation. When ozone dose was less than 3.8 mgO3 g−1MLSS, soluble chemical oxygen demand (SCOD) decreased or did not change but while applying dosages higher than 3.8 mgO3 g−1MLSS, SCOD increased. In addition, protein and polysaccharide which are the main parameter in fouling in membrane bioreactors decreased when ozone dosage was less than 3.8 mgO3 g−1MLSS while they increased when ozone dose is higher than 3.8 mgO3 g−1MLSS which showed that ozone could disrupt the cell walls and release the soluble microbial product. [ABSTRACT FROM PUBLISHER]

This work aimed to investigate the efficiency of nutrient removal in a modified membrane bioreactor (MBR) used for treatment of wastewater containing high level of ammonium. Due to high selectivity of ammonium for clinoptilolite (a natural kind of zeolite) and its unique characteristics, this sort of clay was studied in combination with MBR. Experiments were in two parallel simultaneous MBRs with an hydraulic retention time (HRT) of 8 h within 33 days. Then, the control membrane bioreactor without clinoptilolite (CMBR) and the zeolite membrane bioreactor with clinoptilolite (ZMBR) were studied. Thereafter, nutrient removal from synthetic wastewater in the CMBR and ZMBR were compared. In ZMBR, about 24% more N-NH4removal was achieved owing to combination of nitrification and cation exchange. It was also found that ZMBR application resulted in 10% increase in TN removal in comparison with CMBR. In contrast, no significant difference was observed in chemical oxygen demand (COD) removal. Only low amounts of nitrate and phosphate were removed during the first days of experiments. The results demonstrated that clinoptilolite is highly effective in reducing ammonium content of wastewaters. [ABSTRACT FROM PUBLISHER]

• The performance of submerged membrane bioreactor (SMBR) for the removal of personal care products from greywater was investigated. • The influence of different hydraulic retention time (HRT) values on the operation of SMBR within 150 days of continuous operation was studied. • Triclosan, methylparaben and propylparaben were considered as the main contaminants in the PCP-rich greywater. • In terms of effluent quality, the SMBR reached as high contaminant removal efficiency as 99.97 % at ambient conditions. The rising trend of depletion in global water supplies and the consistent accumulation of emerging environmental contaminants in water, soil and plant have become an international concern during the past decade. In recent years, the removal of personal care products (PCPs) from greywater has inspired a great attention for facile water recycling. In this study, the performance of a specially designed submerged membrane bioreactor (SMBR) system toward high-efficiency degradation of PCPs released through household greywater was investigated. The influent PCP-rich greywater was prepared by mixing commercial PCPs and the SMBR operated under different hydraulic retention time (HRT) values for 150 days of continuous operation. The results revealed that HRT has a striking influence on the treatment performance of the SMBR for PCP contaminants while the SMBR displayed a superior degradation capability for all categories of PCP contaminants (including antimicrobial agent, preservative, fragrance and UV Filter) at the effluent stream. Triclosan, methylparaben and propylparaben as the contaminants with the highest concentration at prepared PCP-rich greywater were removed up to 98.20%, 99.96% and 99.97%, respectively and other ones had more than 64% removal efficiency at HRT of 16 h. The chemical oxygen demand (COD) and biological oxygen demand (BOD) at the optimum HRT value were negligible. [ABSTRACT FROM AUTHOR]

Photobiological hydrogen production by green microalgae is considered as a promising alternative for renewable biofuel production. We have evaluated hydrogen production in the model microalga Chlamydomonas reinhardtii in co-cultures with different bacteria, including Pseudomonas spp., Escherichia coli and Rhizobium etli cultured in acetate-containing nutrient-replete media at three different light intensities (12, 50 and 100 PPFD). Co-culturing Pseudomonas spp. with Chlamydomonas can significantly improve algal hydrogen production, especially at moderate to high light intensities (50–100 PPFD). Enhancement of hydrogen production in co-cultures was clearly related to the lower capacity of these co-cultures to consume the acetic acid from the media. The longer the acetic acid remained in the media, the longer the cultures were able to sustain hypoxia and support hydrogen production. • Co-culturing Chlamydomonas with Pseudomonas in TAP medium improves H 2 production. • Presence of acetate is the key to allow H 2 production in Chlamydomonas co-cultures. • Reduced acetate uptake rate in co-cultures improves algal H 2 production. [ABSTRACT FROM AUTHOR]

In this research, to benefit from the hydrophilic properties of zirconia nanoparticles as well as the role of iron oxide nanoparticles in improving porosity of polymer membranes simultaneously, Fe 3 O 4 @ZrO 2 /PAN nanocomposite membrane was synthesized and its performance was examined in reducing biological fouling of the membrane. FESEM analysis confirmed a size distribution of 35–55 nm, and TEM analysis confirmed a core-shell structure for Fe 3 O 4 @ZrO 2 nanoparticles. FTIR analysis identified the functional groups in the Fe 3 O 4 @ZrO 2 nanoparticles and confirmed their presence in the matrix of 1 Fe 3 O 4 @ZrO 2 /PAN NCM membrane. Contact angle analysis confirmed the role of zirconia nanoparticles in enhancing the membrane hydrophilicity by 51%, and porosimetry analysis confirmed the role of iron oxide nanoparticles in improving porosity of nanocomposite membranes by 47%. Usage of 1 wt% of Fe 3 O 4 @ZrO 2 nanoparticles in the PAN membrane matrix brought about 40% increase in water flux and 37% growth in dye rejection for 1Fe 3 O 4 @ZrO 2 /PAN NCM membrane. Investigation of the role of Fe 3 O 4 @ZrO 2 nanoparticles in the filtration of biological macromolecules indicated that 1 Fe 3 O 4 @ZrO 2 /PAN NCM membrane has 60%, 51%, and 56% less resistance to filtration of humic acid, sodium alginate, and BSA, respectively, when compared with raw membranes. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the applicability of the adsorption process for the removal of organophosphorus pesticide malathion 57% from water by using multi-walled carbon nanotubes (MWCNTs). The impact of various experimental conditions such as pH, quantity of adsorbent, concentration of pesticides, contact time and temperature was studied and optimized for the maximum removal of malathion. Unlike conventional optimization, a limited number of experiments (26 steps) were performed in a cost-effective manner for different independent variables such as MWCNTs concentration (0.1–0.5 g/L), the malathion (57%) concentration (6 mg/L and 10 mg/L), contact time (2–30 min) and pH (neutral range). Based on the experimental data obtained in a lab-scale batch study, a three-factor response surface modeling (RSM) approach was implemented in order to optimize the conditions for maximum removal of malathion, and compare experimental results with standardized malathion samples. The optimized conditions to achieve the maximum removal of malathion (100%) were determined to be a malathion concentration of 6 mg/L, an initial MWCNTs concentration of 0.5 g/L, and a contact time of 30 min. Findings of this study clearly indicated that 100% of the malathion could be cost-effectively removed by MWCNTs in conditions predicted by the proposed optimization methodology. [ABSTRACT FROM AUTHOR]

About half a century after antibiotics discovery, multi-antibiotic-resistant bacteria posed a new challenge to medicine. Attempts to discover new antibiotics have drawn the attention to Antimicrobial Peptides (AMPs). The rapid growth, besides its known genetic and manipulation systems, makes E. coli the preferred host system for production of recombinant proteins on an industrial scale. To produce AMPs in E. coli , the application of fusion-tags with the aim of stability, solubility, and prevention of antimicrobial activity is one of the best practices in this regard. In this study, we presented two different expression systems for the production of PR-39 in E. coli ; one in fusion with intein-Chitin binding domain (CBD) and another in fusion with SUMO accompanied by polyhistidine affinity tag. Both were cloned in the NdeI-XhoI sites of pET-17b and transformed to E. coli BL21 (DE3) pLysS. Recombinant bacteria were cultured and induced with 0.4 mM IPTG at 30 °C. Expression and purification of target proteins were confirmed by Tricine- SDS-PAGE and dot blot analysis. Recovery of 250 μg PR-39/L from SUMO fusion system and 280 μg PR-39/L from the intein fusion system was achieved. Both purified peptides showed antibacterial activity using MIC/MBC demonstrating their functionality after SUMO and intein mediated purification. • Utilizing SUMO and intein fusion systems for production of PR-39, a porcine cathelicidin antimicrobial peptide, in E. coli. • SSuccessful expression of both constructs in E. coli Bl21 (DE3) pLysS • One step purification of PR-39 peptide in the case of fusion with intein-chitin binding domain. • SUMO-fused peptide purification and tag removal in two steps with Ni-NTA column and the use of SUMO protease. [ABSTRACT FROM AUTHOR]

Coupling chemical oxidation and biodegradation to remediate polycyclic aromatic hydrocarbon (PAH)-contaminated sediment has recently gained significant attention. In this study, calcium peroxide nanoparticles (nCaO 2 ) were utilized as an innovative oxygen-releasing compound for in-situ chemical oxidation. The study investigates the bioremediation of phenanthrene (PHE)-contaminated sediment inoculated with Sphingomonas sp. DSM 7526 bacteria and treated with either aeration or nCaO 2 . Using three different culture media, the biodegradation efficiencies of PHE-contaminated anoxic sediment, aerobic sediment, and sediment treated with 0.2% w/w nCaO 2 ranged from 57.45% to 63.52%, 69.87% to 71.00%, and 92.80% to 94.67%, respectively. These values were significantly higher compared to those observed in non-inoculated sediments. Additionally, the type of culture medium had a prominent effect on the amount of PHE removal. The presence of minerals in the culture medium increased the percentage of PHE removal compared to distilled water by about 2-10%. On the other hand, although the application of CaO 2 nanoparticles negatively impacted the abundance of sediment bacteria, resulting in a 30-42% decrease in colony-forming units after 30 days of treatment, the highest PHE removal was obtained when coupling biodegradation and chemical oxidation. These findings demonstrate the successful application of bioaugmentation and chemical oxidation processes for treating PAH-contaminated sediment.