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This study considers peroxymonosulfate (PMS)-assisted iron electrolysis for electro-oxidation/coagulation (EO/EC) pretreatment combined with a ceramic ultrafiltration (UF) membrane for simultaneous manganese (0–1.0 mg/L) and phosphorus (0–0.8 mg/L) removal from surface water. The results indicated that the optimum EO/EC operation conditions appear to be current(I) of 0.2 A with an electrolysis time of 60 s at pH 7.5 (corresponding to nearly 0.5 mg/L Fe2+) under a PMS dosage of 100 µM. Electron paramagnetic resonance (EPR) spectroscopy suggested that sulfate radicals (SO4 −) or hydroxyl radicals ( OH) were produced during the PMS activation process, and manganese oxide formation after the EO/EC process was elucidated on the basis of the results of X-ray photoelectron spectroscopy (XPS). In addition, EO/EC pretreatment might favour the generation of large flocs and significantly decrease the UF fouling, and SEM-EDS indicated the existence of Mn, P and Fe in the flocs. In real applications, the combined process achieved trace levels of manganese and phosphorous, and membrane fouling was caused by the remaining manganese/ferric oxide. This combined process could treat pollutants in remote regions where electricity supplies are not available.

The possibility of utilizing blended wastewaters from raw anaerobic digestion effluent (RADE) and rainwater (RW) was investigated for cost-efficient Chlorella vulgaris (C. vulgaris) cultivation in photobioreactor (PBR). Two-sequencing batch PBRs were started-up with RADE and mixed wastewater (40% ADE + 60% RW). The result indicated that C. vulgaris growth and contaminants removals were inhibited due to the high concentration of nutrient and organic pollutants in PBR (RADE). Comparatively, PBR (ADE + RW) obtained satisfying treatment efficiencies with the maximum removals of NH4+-N (94.61 ± 1.83%), PO43−-P (95.71 ± 1.73%) and COD (86.72 ± 1.72%). RW supplemented trace elements (Fe, Mn, Zn, Cu), which accelerated C. vulgaris photosynthesis with high lipid productivity accumulation (65.72 ± 1.98 mg/L⋅day) in PBR (ADE + RW). This study firstly demonstrated the potential of using mixed wastewater (ADE + RW) for cost-efficient C. vulgaris cultivation with simultaneous actual ADE wastewater treatment in PBR.

In this study, cellulose nanocrystals (CNCs) were incorporated into a polyamide (PA) layer to prepare novel thin film composite (TFC) nanofiltration membranes (CNC-TFC-Ms). Scanning electron microscopy (SEM) results revealed differences in the surface morphologies of the CNC-TFC-Ms compared with that of a control membrane (TFC-control-M). The pore size distribution (PSD) results showed that the CNC-TFC-Ms exhibited smaller pore sizes and narrower PSD curves as the CNC content in the PA layer increased. Continuous potential measurements showed that the negativity of the surface charge of the CNC-TFC-Ms decreased as the CNC concentration increased. The CNC-TFC-Ms showed great rejection performance for divalent salts with rejection rates over 98.0% and 97.5% for Na2SO4 and MgSO4, respectively. Meanwhile, the filtration flux of salts was dramatically enhanced compared with that of TFC-control-M. Additionally, the permeate flux and rejection of NaCl were simultaneously enhanced as the CNC content increased, demonstrating that CNC-TFC-Ms can overcome the trade-off limitation. In addition, the NaCl/Na2SO4 selectivity of the CNC-TFC-Ms reached as high as 60, suggesting their distinguished divalent/monovalent separation characteristics. The CNC-TFC-Ms exhibited greater dye removal for both anionic and cationic dyes due to their decreased negative charge and smaller pore size than the control membrane.

The anaerobic digestion effluent (ADE) generated from biogas projects has raised increasing environmental concerns. In this study, the algal cells integrity, pollutants degradation and the community compositions shifts were evaluated during the ADE treatment with simultaneous biodiesel accumulation in photobioreactors (PBR). The operation of six PBRs was initiated with diluted ADE (625, 393, 272, 193, 178 and 167 mg/L SCOD). The results showed that the high concentration of ADE (625 mg/L SCOD) led to considerable inhibition of algal cells growth. By comparison, the PBR (272 mg/L SCOD) attained the maximum lipid productivity (59.13 mg/L·d), and complete nutrient (nitrogen and phosphorus) removal was observed in PBR (167 mg/L SCOD). Moreover, the highest viable algal cells (86.2%) was attained in PBR (272 mg/L SCOD). Therefore, this study provides a feasible technology for microalgal cultivation with simultaneous treatment of ADE in PBRs. In addition, the approach of excitation-emission matrices with parallel factor (EEMs-PARAFAC) was utilized to further understand the organics degradation. The removals of component 1 (humic-like) and component 2 (protein-like, biological production) were ascended by the increased algal and bacteria activity in the microalgal-bacterial consortium. Additionally, the community composition analysis illustrated that bacterial diversity was reduced by the inoculation with microalgae, which was attributed to the formation of stable function groups with satisfactory contaminant degradation abilities and good algal cell growth; and Chlorella species were dominant, which benefited biodiesel accumulation in PBRs. These findings demonstrated the potential of using a bacterial-microalgal consortium for ADE purification simultaneous biodiesel production.

Utilization of g-C3N4 as a single photocatalyst material without combination with other semiconductor remains challenging. Herein, we report a facile green method for synthesizing a metal free modified g-C3N4 photocatalyst. The modification process combines four different strategies in a one-pot thermal reaction: non-metal doping, porosity generation, functionalization with amino groups, and thermal oxidation etching. The as-prepared amino-functionalized ultrathin nanoporous boron-doped g-C3N4 exhibited a high specific surface area of 143.2 m2 g−1 which resulted in abundant adsorption sites for CO2 and water molecules. The surface amino groups act as Lewis basic sites to adsorb acidic CO2 molecules, which can also serve as active sites to facilitate hydrogen generation. Besides, the simultaneous use of ammonium chloride as a dynamic gas bubble template along with thermal oxidation etching efficiently boosts the delamination of the g-C3N4 layers to produce ultrathin sheets; this leads to stronger light–matter interactions and efficient charge generation. Consequently, the newly modified g-C3N4 achieved selective gas-phase CO2 reduction into CO with a production yield of 21.95 µmol g−1, in the absence of any cocatalyst. Moreover, a high hydrogen generation rate of 3800 µmol g-1h−1 and prominent apparent quantum yield of 10.6% were recorded. This work opens up a new avenue to explore different rational modifications of g-C3N4 nanosheets for the efficient production of clean energy.

This study describes some results concerning the hybrid process of ultraviolet/chlorine (UV/chlorine) as a pre-oxidation strategy prior to ultrafiltration for the treatment of natural organic matter (NOM)-contaminated surface water. Chlorine has been extensively used in water treatment since it can act as disinfectant or coagulant aid. In addition, the combination of UV and chlorine, compared to the other oxidants generally used in water treatment, offers a potentially effective and cheaper alternative for pre-oxidation process. Parallel tests with or without the application of chlorine were conducted to evaluate the effect of chlorine dosage on the increase of trans-membrane pressure under low dosage of UV irradiation. The results showed that UV/chlorine pre-oxidation achieved remarkable reduction of both total membrane fouling (49%) and reversible membrane fouling (59%) at 4 mg/L dose of chlorine as a result of the removal of both high molecular weight (MW) (1–20 kDa) humic substances and lower MW compounds. Hybrid process of UV/chlorine and UF membrane achieved significant removal of DOC (34%) and UV254 (49%) at chlorine dosage of 4 mg/L and a UV dosage of 180 mJ/cm2. Modeling fit results indicated that the NOM-related membrane fouling mitigation was probably attributed to the alleviation of intermediate pore blocking and standard pore blocking with intermediate pore blocking playing a more important role. Additionally, the UV/chlorine unit could have a bright prospect for engineering application as it performed better in cost control as pretreatment prior to UF membrane compared to other pre-oxidation processes.

An integrated gravity-driven membrane (GDM) and granular activated carbon (GAC) filtration process was operated for 193 days to investigate the influence of integrated GAC on the flux stabilization, permeate quality, composition of the biofouling layer and eukaryotic community compared with a GDM control system. The results revealed that the presence of GAC resulted in a strongly increased stable flux (6 L m −2 h −1 , compared to 2 L m −2 h −1 in the GDM control). Furthermore, the GAC/GDM system exhibited a significant removal of dissolved organic compounds (DOC) (50–70%) due to the adsorption and biodegradation process. By contrast, the DOC in the permeate of the control was approximately 20–30% higher than in the raw water, which was attributed to the hydrolysis of high-MW compounds. Furthermore, the composition of the biofouling layer attached on the membrane surface was significantly influenced by the presence of GAC, leading to a reduction of accumulated organic compounds by 60%. Likewise, the extracellular polymeric substances (EPS) were obviously reduced in the GAC/GDM system, especially the tightly bound EPS in the biofilm and EPS deposited in membrane pores. Additionally, the GAC could function as a eukaryotic pre-incubator, resulting in a higher diversity of the eukaryotic community and improving predation in the biofouling layer. Furthermore, a more porous, heterogeneous and permeable biofouling layer was observed in GAC/GDM. The higher flux in GAC/GDM system was attributed to (i) lower organic foulants (especially EPS) accumulated in the biofouling layer and membrane pores and (ii) highly heterogeneous structures due to improved activity of eukaryotes in the biofouling layer. These results are essential to develop robust maintenance-free, cost-effective and energy-efficient drinking water treatments.

The aim of present study was to evaluate the effects of the interaction between ferric coagulant and natural organic macromolecules (NOMs) on gypsum scaling during nanofiltration. Both crystallization process and membrane flux behavior were taken into consideration. Although bulk crystallization could be enhanced by ferric coagulant and humic acid (HA), it was hindered by the mixture of these coexisting pollutants due to their interaction in aqueous solution. According to the variation in zeta potential and the prediction with the NICA-Donnan model, Fe3+ could compete with Ca2+ for binding to HA, while the interaction between coagulant and HA reduced the concentration of active ingredients in the coagulant which could enhance scaling development. FTIR-ATR spectra showed that ferric coagulant and NOMs could promote the attachment of each other on membranes. Unlike bulk crystallization, surface crystallization could be enhanced by the combination of HA and ferric coagulant on nanofiltration membranes. Therefore, both ferric coagulant and HA could increase scaling layer resistance, and there were synergistic effects on aggravating the flux decline between them. Moreover, the effects of salt saturation and system pressure on coagulant-influenced gypsum scaling in nanofiltration were also investigated. Modified Hermia’s models were applied to theoretically verify the membrane fouling mechanisms. In addition, ferric coagulant was found to decrease the retention efficiency of ions and atrazine by nanofiltration membranes by weakening the steric hindrance.

In this study, the effect of bubbly flow on the performance of water flux of forward osmosis (FO) membranes was investigated, in terms of membrane biofouling causing by treating wastewater under a lower flow rate operation (cross flow velocity = 0.04 m/s) in feed channel. It was found that water flux exhibited a better performance through bubbly flow (aeration rate = 0.4 L/min) in the feed channel compared to that under single-phase flow. After a 20-circle operation, the period of time required for collecting a total of 7000 ml water under bubbly flow condition was approximately half (17 d) of that under single-phase flow (36 d). Water flux dropped from 11.0 to 4.5 LMH with the presence of air bubbles, and to 2.0 LMH in the absence of air bubbles in the feed channel. In addition, it was found that the biofilm under bubbly flow condition was more homogeneous than that under single-phase flow. This finding has suggested that shear stress created by the bubbly flow has affected total biomass loading. Analysis of the characteristics of the fouling layer indicated that the fouling layer was composed of bacterial cells surrounded by scaling-like foulant, protein, polysaccharide, humic-like substances and inorganic particulates. The biofilms exhibited the dissimilarity of certain bacterial populations in the absence and presence of air bubbles. Larger molecular weight humic-like substances and inorganic particulates were present in the biofilm under single-phase flow condition. Results from this work indicated that bubbly flow condition within the feed channel can lead to intense tangential flow and uniform shear stress distribution on the vicinity of the membrane surface, and reduce the accumulation of biofoulants with higher molecular weight.

Mn oxide incorporated membranes were fabricated by incorporation of MnO2 particles prepared using different methods (C-MnO2, M-MnO2 and S-MnO2) on the surface of ceramic ultrafiltration membranes. Initially, the physicochemical properties of prepared MnO2 particles were systematically analyzed, and S-MnO2 exhibited the best dispersibility and smallest particle size. Scanning electron microscopy and atomic force microscopy analyses demonstrated that the morphologies and topographies of the fabricated membranes were significantly affected by the preparation method of MnO2 particles. Subsequently, sodium alginate was employed to investigate the antifouling properties of the fabricated membranes. Although the incorporation of MnO2 particles increased membrane intrinsic resistance to varying degrees, M-MnO2 and S-MnO2 apparently mitigated both reversible and irreversible fouling in the presence of ozone, whereas C-MnO2 exerted a minor influence. Further, p-chloronitrobenzene was used to study the activity of fabricated membranes in catalytic ozonation. C-MnO2, M-MnO2 and S-MnO2 incorporated membranes exhibited enhanced activities with the removal efficiencies of 51.7%, 61.5% and 68.0%, respectively. The results indicated that the preparation method of S-MnO2 was most appropriate for the preparation of highly dispersive MnO2 particles to incorporate with ceramic membranes. Results in this study contribute to the fabrication of Mn oxide incorporated membranes with an efficient and convenient way, and provide relevant information on their actual application.

Severe membrane fouling caused by iron and manganese limited the intensive application of ultrafiltration (UF) technologies. In the present study, an innovative biofilm based UF process, gravity driven membrane (GDM) filtration, was employed to evaluate its possibility to directly treat manganese-contaminated surface water at high concentration. Surprisingly, an extremely short and stable ripening period (less than 10 d) of iron and manganese removal was achieved in GDM filtration, with average removals of 90% and 58%, respectively, attributing to the effective rejection of active catalytic manganese oxides and fast colonization of iron- and manganese-oxidizing bacteria (e.g Acinetobacter and Lysobacter) within the biofilm due to the efficient rejection by UF membrane. Importantly, the presence of iron and manganese did not influence the occurrence of flux stabilization, and fluxes stabilized at 7–9 L m−2 h−1 during long-term filtration. Furthermore, a highly rough, porous and heterogeneous biofilm was observed on the membrane surface, which was potentially responsible for the flux stabilization. Additionally, pre-coating manganese oxides on the membrane surface can efficiently enhance the removals of manganese and iron, and engineer even highly heterogeneous structures of biofilm to improve the stable flux. Therefore, the findings are relevant to develop new strategies for the treatments of manganese-contaminated water resource at high concentration, and to encourage extensive applications of membrane technologies for decentralized drinking water supply.

The goal of this study was to quantify and demonstrate the combined effects of powdered activated carbon (PAC) adsorption and in situ chlorination on the performance of a coagulation and submersed hollow-fiber ultrafiltration (UF) membrane system at the pilot scale. The real-time levels of natural organic matter (NOM), including dissolved organic carbon (DOC) and trichloromethane formation potential (TCMFP), were quantified to evaluate NOM removal in different hybrid UF systems. The fouling behavior of the UF membranes after combined adsorption pre-treatment and in situ chlorination was systematically investigated in terms of membrane filtration resistance. The results showed that the presence of PAC during the coagulation–flocculation process increased the removal of NOM, particularly the fractions of proteinaceous substances and humic-like substances, as indicated by excitation emission matrix (EEM) spectroscopy, which contributed to the retardation of membrane fouling. In situ chlorination postponed membrane fouling to some extent owing to small modifications to the molecular structure of NOM, which demonstrated that the portion of humic acid (HA) that reacted with sodium hypochlorite penetrated the UF membrane, avoiding adsorption to the membrane pores. Combining adsorption enhancing coagulation pre-treatment and in situ chlorination in the hybrid UF system led to further alleviation of membrane fouling.

As Microcystis cell breakage may decrease the water quality, the accurate evaluation of cell breakage is of concern in drinking water production. Well-known cell breakage indicators such as dissolved organic carbon (DOC) release and potassium release were investigated in comparison with flow cytometry coupled with a fluorescence probe. DOC release, potassium release and ratios of SYTOX Green positive cells (ruptured cells) were calibrated using known degrees of cell breakage (mixtures of live and heated cells). Good linear relationships were observed between the indicators and the known ratios of ruptured cells, with R 2 values larger than 0.925. Flow cytometry coupled with a fluorescence probe had the best overall performance, followed by potassium release and then DOC release. Moreover, the influence of factors such as extracellular organic matter (EOM), cell intake, sample conservation and strong oxidants was also studied. EOM and strong oxidants caused the overestimation and underestimation, respectively, of the cell breakage by DOC release. Potassium release had a more extensive application scope than DOC release and was only influenced by intake by residual live cells. Flow cytometry was generally not affected by EOM, cell intake or strong oxidants except during long-term storage.

Control of the ultrafiltration (UF) membrane fouling caused by Microcystis cells using permanganate preoxidation was investigated with lab-cultured Microcystis aeruginosa. The contributions of two widely considered mechanisms, i.e. potassium permanganate (KMnO4) oxidation and in situ formed manganese dioxide (MnO2) adhesion, to the Microcystis cell fouling control were compared and discussed. Initially, effects of KMnO4 oxidation and in situ formed MnO2 adhesion on the characteristics of Microcystis cells, including viability, zeta potential, size distribution and settleability, were compared. Subsequently, filtration tests were undertaken to investigate the flux decline and fouling reversibility during UF of the untreated and treated cell solutions. The results indicated that KMnO4 oxidation exhibited a minor effect on the characteristics of Microcystis cells as well as the cell integrity under the tested KMnO4 exposure (1.0 and 2.0 mg/L). The adhesion of in situ formed MnO2 particles could promote the aggregation of the cells, apparently improving their settleability. With regards to membrane fouling, the in situ formed MnO2 particles displayed a superior capacity in alleviating both the flux decline and the irreversible fouling associated with Microcystis cells than KMnO4 oxidation did, owing to the reinforced aggregation of the cells and the adsorption of released extracellular organic matter (EOM). Moreover, the effect of membrane precoating with in situ formed MnO2 particles on the cell fouling was also studied. The precoating layer seldom reduced the flux decline by Microcystis cells, but improved the fouling reversibility probably by inhibiting the direct membrane-cell contact and retaining the released EOM.

After cow manure undergoes anaerobic fermentation process, it still contains several pollutants such as nitrogen, phosphorus, and organic matter. If not treated properly, these pollutants would cause secondary pollution. Membrane-aerated biofilm reactor (MABR) has been widely used to handle the wastewater with high concentration contaminants. In this study, MABR was utilized to treat the cow manure anaerobic fermentation effluence (CMAFE). In order to avoid incomplete biofilm being affected by high concentration of CMAFE, a gradient dilution of CMAFE was employed. The removal rates of NH4+-N and COD were achieved up to 90% and 85%, respectively, in different dilution ratios. RDA demonstrated that NH4+-N removal was in a full-nitrification process in higher dilution ratio (Stage 1 and 2) but in short-nitrification in lower dilution ratio (Stage 4). The gradient dilution did not affect the biofilm growth. The Inner biofilm contained higher amounts of extracellular polymeric substance (EPS) than the Outer biofilm, which reduced the impact of high-concentration CMAFE on the internal aerobic bacteria, especially nitrifying bacteria. Concerning bacteria abundance, a significant modification occurred in the biofilm compared to raw sludge, demonstrating that MABR had a great potential in CMAFE treatment.

Though microalgal-bacterial consortium in photobioreactor (PBR) has been investigated to the anaerobically digested centrate (ADC) treatment, the impact and degradation of micropollutant sulfamethoxazole (SMX) in this system has never been reported. In this research, three microalgal-bacterial consortiums were parallel operated with suspended Chlorella vulgaris (C. vulgaris), immobilized C. vulgaris and immobilized C. vulgaris-powdered activated carbon (PAC), namely PBR (SCV), PBR (ICV) and PBR (ICV + PAC), respectively. The impact of SMX on the ADC treatment performance, C. vulgaris growth and microbial community shifts were investigated. The performance of SMX removal and potential SMX degradation mechanism by the microalgal-bacterial consortium were explored. The results showed that SMX significantly inhibited PBR (SCV) with unsatisfactory C. vulgaris growth, ADC treatment and SMX removal. Comparatively, immobilized microalgae beads protected microalgae in PBR (ICV) and PBR (ICV + PAC) obtaining higher proportion of living C. vulgaris of 85.1% and 86.2%, respectively, comparing to that of 74.6% in PBR (SCV) (p

In this study, the sludge activated carbon-based CoFe2O4 (CoFe2O4-SAC) nanocomposites were prepared by a simple hydrothermal method, which were subsequently applied in degrading the antibiotic norfloxacin (NOR) through heterogeneously activating peroxymonosulfate (PMS). Due to its porous structure and more reactive oxygen species (ROS), various characterizations of the CoFe2O4-SAC composite, such as XRD, FTIR, SEM and XPS, showed that the composite had more efficient catalytic activity than CoFe2O4. The application potential of SAC derived sewage sludge as the support enhanced the catalytic activation performance of the CoFe2O4. NOR could almost be fully degraded within 60 min at pH = 5–9 in the CoFe2O4-SAC/PMS system. The degradation efficiency of NOR was impeded by the strong acidic or alkaline environment. The influences of coexisting anions on the catalytic reaction, such as Cl−, HCO3−, and NO3− were also investigated. After five consecutive cycles, CoFe2O4-SAC could still maintain its good catalytic efficiency, with the NOR removal rate of >90%. Additionally, the reaction mechanism was also examined on the basis of radical quenching study and XPS results. Our findings suggested that, sulfate (SO4− ) and hydroxyl ( OH) radicals had facilitated the degradation of NOR. The oxygen groups linked to the surface of composited were the primary reactive oxygen species, which developed the oxidation degradation of NOR.

Utilizing additional aeration to enhance the pollutants removal in the ABS system has been extensively studied. It is widely accepted that that higher aeration rate poses limitations in algae growth. However, this phenomenon is always attributed the phenomenon to the high dissolved oxygen (DO), and the CO2 blow-off that results in inorganic carbon (IC) deficiency is often ignored. In this research, different aeration rates were set under the same DO condition to prove that CO2 stripping, and not DO, is the main cause of algae growth limitation. It was apparent that ideal algae growth conditions, at an aeration intensity of 100 mL/min, was deteriorated due to CO2 stripping, leading to a large amount (15.62 mg/L) of unused NO2− and NO3−. Meanwhile, algae death caused by CO2 stripping damaged the phosphate assimilation process. Furthermore, insufficient IC resulted in competition between autotrophic bacteria and algae, inducing the drastic decline of nitrifying bacteria (whose growth cycle is especially long) numbers. For the relatively lower aeration rate (20 mL/min), the ABS system presented a more stable condition and higher pollutants removal efficiency than both the non-aerated group (0 mL/min) and the high-aeration group (50 mL/min and 100 mL/min). This finding demonstrates that CO2 stripping in the aeration process is the main cause of damage to the ABS system, which guides the ABS application.

This work is a contribution to understand the interaction of biological and chemical auto-catalytic oxidation processes for the removal of manganese (Mn) (0–1.8 mg/L) using the ripened sand filter. Here, penicillin, sodium chloride (NaCl), autoclave sterilization and sodium hypochlorite (NaClO) were chosen as the four inactivation methods to distinguish biological and chemical oxidation processes on the removal of Mn in the ripened sand filter. The amounts of manganese-oxidizing bacteria (MnOB) in the filters before inactivation, right after inactivation and after 150 days of recuperation were found to be 104 CFU/g, 0 CFU/g and merely 102 CFU/g. The data suggested that autoclave sterilization and NaClO inactivated filters were less effective for 36% removal of Mn compared to penicillin and NaCl inactivated filters for which over 98% was possible to be removed, and the chemical oxidation ratio was 81%. Characterization of manganese oxides (MnOx) was carried out by scanning electron microscopy energy dispersive spectroscopy (SEM-EDS), Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results showed that active MnOx present on the ripened media were poorly crystalline and belonged to birnessite. Compared with penicillin and NaCl inactivation, MnOx were oxidized during NaClO and autoclave sterilization inactivation process, which caused a great influence on the crystal structure. The removal of Mn in the ripened sand filter after inactivation was predominantly achieved by chemical auto-catalytic oxidation of active MnOx although biological oxidation also existed overall the process.

To prevent membrane fouling caused by natural organic matter (NOM), cellulose nanocrystals (CNCs) were blended with inherently hydrophobic polyethersulfones (PES) by the phase inversion method to fabricate nanocomposite membranes. Characterization of the membrane surface morphology indicated that the CNC-containing nanocomposite membranes exhibited homogeneous surfaces. Compared to the neat PES membrane, the nanocomposite membranes had higher porosity and zeta potentials. The static contact angle and pure water flux of the nanocomposite membranes indicated an increase in hydrophilicity of the modified membranes. However, the porosity and permeability of the nanocomposite membranes decreased at 5.0 wt% CNC loading. The NOM removal and fouling experiments were performed using humic acids (HAs), bovine serum albumin (BSA) and sodium alginate (NaAlg) as surface water pollutants. The removal rates of hydrophobic HA and BSA were significantly increased by the developed membranes. The nanocomposite membranes exhibited enhanced anti-NOM fouling properties, increased cleaning efficiency and effective control of both reversible and irreversible fouling. This study provides insight into the utilization of high-performance nanocomposites for a wide range of water treatment applications.

Antimony is a pollutant that is classified as high priority by the United States Environmental Protection Agency (USEPA) and the European Union (EU). In this work, a hybrid coagulation–flocculation–ultrafiltration (CF–UF) process was developed to remove antimony (III) from polluted surface water, and the process parameters, including the ferric coagulant (FC) dose, pH and initial contaminant loading, were systematically optimized. The results indicated that the optimum FC dose and solution pH range were 0.4 mM and 7.1–9.0, respectively. Under these conditions, the antimony (III) concentrations in the CF–UF effluent were as low as 1.0–2.0 μg L−1, which is significantly lower than drinking water standards (USEPA

A novel integrated vertical membrane bioreactor (IVMBR) composed of both anoxic and oxic zones based on the installation of a three-phase separator was developed to simultaneously remove organic matter and nitrogen. The three-phase separator could successfully create favorable conditions for both denitrifying and nitrifying process, which occurred in upper part (anoxic zone) and lower part (oxic zone) of the reactor, respectively. A lab-scale IVMBR was operated in parallel with a controlled MBR (without the three-phase separator), and their performance on the removal of organics and nitrogen was compared. The results show that both IVMBR and controlled MBR were efficient in removal of COD and NH 4 + –N when fed with synthetic wastewater or domestic sewage. IVMBR performed a better removal performance of NH 4 + –N and TN when the volume ratio of anoxic zone and oxic zone and internal recycle rate were around 1% and 400%, respectively. However, the TN removal performance of controlled MBR was quite poor due to the lack of anoxic condition. Additionally, it was found that IVMBR could save half of alkalinity compared to the controlled one. Overall, the IVMBR has the potential of being applied in the treatment of domestic sewage and ammonium industrial wastewater.

Operation conditions such as reflux, sludge retention time (SRT), aeration intermediate, hydrogen retention time (HRT) and powder active carbon (PAC) dosing were optimized to start up a CANON-like MBR. Reflux can give the MBR system a good mixture. SRT did not have much effect on washout of nitrite oxidized bacteria (NOB) but related to membrane fouling. Decreasing aeration intermediate reduced ammonium removal rate to 50% due to the limited oxygen, but nitrification was dominant. HRT did not have much influence on ammonium removal rate, whereas reduce the NO 3 produced - / NH 4 totalremoval + value to 0.8. PAC played a great role in ammonium removal and reduced the NO 3 produced - / NH 4 totalremoval + value to 0.55. Under the optimized operation conditions such as reflux of 1 m3/L, SRT of 20 days, aeration intermediate of 11 h 50 min off and 10 min on, 20 mg/L of PAC, one column (8#) and a membrane reactor (9#), ammonium removal rate was increased to 99% while the NO 3 produced - / NH 4 totalremoval + value was around 0.55. Increasing the ammonium concentration to 6 mg/L can reduce the NO 3 produced - / NH 4 totalremoval + value to 0.13. On a whole, Dissolved oxygen (DO) is the key to start up the CANON-like MBR treating surface water even under low temperature and sustainable flux increased the sustainability of the system.

The mini-pilot experiments of submerged membrane bioreactor (sMBR) for the drinking water treatment from a slightly polluted surface water supply was conducted for more than 110 days, with a hydraulic retention time of 0.5 h. Perfect ammonia removal (by 89.4%) were achieved by the sMBR through the biological nitrification. However, the capacity of the sMBR for organic matter removal was demonstrated to be low. The average removal efficiencies for TOC, COD Mn , DOC, UV 254 , and corresponding THMFP and HAAFP were 28.6%, 33.5%, 21.5%, 15.1%, 34.1% and 24.7%, respectively, though much higher removal of 51.7% and 54.9% were obtained for BDOC and AOC, respectively. A sludge layer was observed on the UF membrane surface in the sMBR. The sludge layer could provide additional filtration for dissolved organic matter (DOM) in the mixed liquor, especially for organic molecules in the range of 5000–500 Da. Fractionation of DOM indicated that the sludge layer together with the UF membrane had the ability to reject hydrophobic neutrals, hydrophobic acids, and weakly hydrophobic acids by 45.0%, 42.7% and 48.1%, respectively; whereas hydrophobic bases and hydrophilic organic matter were separated mainly by the UF membrane, with the efficiencies of 11.3% and 14.6%, respectively.