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关键词： EMBR   Carbon nanotubes hollow fiber membranes   Membrane fouling   Transmembrane pressure   Electrochemical effect  

摘要： A novel electro-assisted membrane bioreactor (EMBR) was constructed by integrating conductive carbon nanotubes hollow fiber membranes (CNTs-HFMs) into an aerobic activated sludge system. Herein, the CNTs-HFMs served as anode and filtration core simultaneously. Contrasted with the other two MBRs (PVDF-HFMs and CNTs-HFMs without electro-assistance), the effluent COD and NH4+-N were lower than 40 mg/L and 3 mg/L at +1.0 V even HRT as short as 4 h. However, they were mostly over 50 mg/L (COD) and 5 mg/L (NH4+-N) under the same conditions in the other two MBRs. The hydraulic cleaning for electro-assisted CNTs-HFMs was carried out only once during 60-day operation, and the permeate flux recovered to 100% of the original status. While four and five times hydraulic cleaning were executed for other two MBRs (PVDF-HFMs and CNTs-HFMs), respectively. Furthermore, merely 50 min continuous electrochemical oxidation was enough to resume flux of the heavily fouled CNTs-HFMs, i.e. flux recovered to 2020.87 L/(bar.m(2).h) from 394.68 L/(bar.m(2).h) (pure water flux, similar to 2200 L(bar.m(2).h)). Simpson and Shannon indexes indicated enhanced microbial community stability in EMBR. Thus, electro-assisted CNTs-HFMs endow EMBR excellent anti-fouling ability and good effluent quality. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Sulfate reduction   Up-flow reactor   Copper   Nickel   Precipitation   Acid mine drainage  

摘要： Acid mine drainage is the outflow from a mining site which contains high sulfate and metal concentrations and low pH. Appropriate disposal of this drainage relies on the removal and preferably recovery of heavy metals and neutralizing pH. Sulfidogenic electron donor oxidation generates alkalinity which increases water pH. In this study, sulfate reduction was studied comparatively in two up-flow reactors fed with acetate and ethanol, respectively. Reactors were operated in parallel for 148 days and the influent 2000 mg/L sulfate was decreased to 51 +/- 7 and 31 +/- 6 mg/L in ethanol and acetate fed reactors, respectively. With the produced hydrogen sulfide, metal precipitation in a simulated AMD containing both copper and nickel was studied. Copper was precipitated at low pH (pH < 2) by the gaseous hydrogen. Cu precipitation was completed within 35 min and Ni did not precipitate during Cu removal. Nickel recovery was studied at higher pH values (pH = 8) using reactor effluent containing dissolved sulfide and alkalinity. Mineralogical characterization of the precipitates using X-ray diffraction indicated that CuS and NiS were precipitated selectively in the two metal removal stages.

关键词： Anaerobic membrane bioreactor   EEM   Low-grade coal wastewater   Methane production   Metagenomic analysis  

摘要： Demineralization is required in upgrading low-grade coal to serve as an alternative energy resource for the production of fuel and valuable chemicals but generates a large amount of low-grade coal wastewater (LCWW). The objective of this study was to investigate the effects of a co-substrate on an anaerobic membrane bioreactor (AnMBR) treating LCWW. CH4 was not produced during the operation fed by LCWW alone. When yeast wastes (YW) were supplemented, there was a gradual increase in the biodegradability of LCWW, achieving 182 CH4 mL/g COD with 58% COD removal efficiency. The analysis of physicochemical characteristics in the effluent of AnMBR, done by excitation-emission matrix (EEM) and size exclusion chromatography (SEC), showed that the proportion of soluble microbial products (SMPs) and aromatic group with high-molecular weight ( > 1 kDa) increased. Microbial analysis revealed that the increased dominance of bacteria Cornamonas, Methanococcus, and Methanosarcina facilitated biodegradation of LCWW in the presence of YW.

关键词： Petrochemical wastewater   COD removal   Industrial scale system   Microbial communities   EGSB   Aerobic activated sludge  

摘要： One industrial scale plant has been constructed for annual treatment of 657,000 m(3) real petrochemical wastewater of 4649 +/- 651 mg/l COD and more than 50 mg/l petrochemicals. The plant system is divided into four parts, and the treatment process mainly functions in a 2200 m(3) anaerobic expanded granular sludge bed (EGSB) bioreactor and a 10,000 m(3) aerobic activated sludge (AS) bioreactor with the hydraulic retention time (HRT) of 62.8 h and 133.3 h, respectively. The plant has been successfully operated for more than 450 days, and the overall COD and petrochemical removal efficiencies of the plant are 85.6 +/- 2.5% and 81.5 +/- 4.8%, respectively. The removal efficiency of the aerobic AS bioreactor was higher than that of the anaerobic EGSB bioreactor, and most COD and petrochemicals were removed in the aerobic AS bioreactor. Further microbial diversity analysis revealed that the dominant microbes in the EGSB and AS bioreactors were assigned to Proteobacteria and Firmicutes and 4 dominant OTUs related with COD or petrochemicals removal were enriched in the bioreactors, showing that the microbial communities had been adapted to the petrochemical wastewater treatment. Based on the results, the newly built industrial plant exhibited good performance in petrochemical wastewater treatment and enriched microbes towards petrochemical wastewater treatment during operation. This strategy also has potential applications for other industrial wastewater treatment in the future.

关键词： Tetrabromobisphenol A   Flame retardant   Microbial reductive debromination   Anaerobic sewage sludge   Acetate biostimulation  

摘要： The detection of increasing concentrations of tetrabromobisphenol A (TBBPA) in wastewater treatment plants is raising concerns as TBBPA has been identified as a potentially toxic flame retardant. The objectives of this study were to evaluate the effect of acetate biostimulation on TBBPA microbial reductive debromination, and the response of anaerobic sludge associated microbial communities repeatedly exposed to TBBPA. Results indicate that the bulk of the microbial community did not experience significant shifts as a result of TBBPA exposure, and that only a small fraction of the community responded to the presence of TBBPA. Taxa most likely responsible for TBBPA transformation affiliated to Clostridiales and the wastewater sludge group Blvii28. The biostimulating effect of acetate was only observed during reactor startup, when acetogenesis was likely not yet occurring. However, when acetate likely started to be microbially generated in the reactor, acetate addition resulted in a slight but significant inhibiting effect on TBBPA transformation. A significant increase of hydrogenotrophic methanogens in the TBBPA-spiked reactor overtime implies that TBBPA degraders were not in direct competition with methanogens for H-2. These results strongly suggest that TBBPA degrading taxa might have been primarily using acetate as an electron donor for the reductive debromination of TBBPA. (C) 2018 Elsevier B.V. All rights reserved.

关键词： Ananunox   Hydrogen sulfide   Inhibition kinetics   ASM   Modeling  

摘要： The inhibition effects of hydrogen sulfide (H2S) on anammox-enriched biomass from a laboratory membrane reactor were analyzed in a series of batch respirometric experiments. The determined half maximal inhibitory concentration (IC50) was 4.67 mg H2S-S L-1 at the constant pH = 7.0 and the total sulfide concentration varying between 1 and 15 mg TS-S L-1. In another test, the IC50 was found to be 4.25 mg H2S-S L-1 under a constant total sulfide concentration of 11 mg TS-S L-1 and the pH varying from 7.0 to 7.9. The decrease in the anammox activity was due to the pH-dependent un-ionized form of H2S. The results were simulated using Activated Sludge Model No. 1, extended with the two-step nitrification and anammox processes. The inhibition effect of pH and H2S concentration was determined using the Hultman pH function and inhibition switching function, respectively. The maximum specific growth rate of anammox bacteria at the optimum pH (pH(opt) = 7.2) was 0.075 d(-1) (at T = 35 degrees C), whereas the inhibition coefficient of H2S, (K-i,K-H2s) was 4.9 mg H2S-S L-1. The experimental and simulation results confirmed that even low H2S concentrations have a strong inhibitory effect on the anammox process.

关键词： Baculovirus-infected insect cell system   Sf9 cells   BTI-TN-5B1-4 (High Five) cells   Wave bioreactor   Oxygen transfer rate   Recombinant HPV 16L1  

摘要： Although the baculovirus expression vector system has been widely used to produce a variety of recombinant proteins, the shear sensitivity of insect cells besides their relatively high oxygen uptake rates have limited their large scale applicability. To address such issues, Wave bioreactor systems have been developed to provide the insect cells with sufficient dissolved oxygen in a bubble free medium of minimal shear stress. However, selection of rocking parameters, and the methods used to control the processes have not been well described in literature. Herein, oxygen transfer capacity of Wave bioreactor has been investigated at different combinations of rocking parameters. Considering the specific oxygen uptake rates (SOUR) and the assessed oxygen transfer capacity of the Wave bioreactor, rocking parameters were set to cultivate non-infected Spodoptera frugiperda 9 cells and infected/non-infected BTI-TN-5B1-4 cells in 2 L Cellbags. The obtained results were exploited to estimate the SOUR of the insect cells under actual condition of Wave bioreactor system. Furthermore, although Express Five medium was recommended by the supplier, the yield of the active soluble human papillomavirus (HPV) 16L1 protein expression was improved in Sf900 II medium. Using the obtained results, protein expression in BTI-TN-5B1-4 cells was finally scaled up to 50 L confirming that the obtained information could be successfully used to scale the Wave bioreactor by specifying the rocking parameters.

关键词： Denitrification   Phytotechnology   Greenhouse   Microbial community   nirS   Community-level physiological profiling  

摘要： The discharge from food production greenhouses (greenhouse effluent) contains high nutrient and salt concentrations, which, if directly released, can have adverse effects on the environment. Wood-chip bioreactors are increasingly popular passive water treatment systems favoured for their economical denitrification in treating agricultural field tile drainage. Microbial communities are central to denitrification;however little is known about the maturation of microbial communities in wood-chip bioreactors treating greenhouse effluents. In this study, multiple subsurface flow wood-chip bioreactors, each vegetated with a different plant species, together with an unplanted unit, received synthetic greenhouse effluent with elevated nitrate concentrations. The hybrid bioreactors were operated for over 2 years, during which time water samples were collected from the inlet, outlet and within the reactors. The increasing denitrification rate in the bioreactor planted with Typha angustifolia (narrowleaf cattail) correlated with increasing microbial activity and metabolic richness, measured by the carbon utilization patterns in Biolog (R) EcoPlates. Increased denitrifying gene (nirS) copies (determined by quantitative polymerase chain reaction, qPCR), and near-complete nitrate removal were observed in the T. angustifolia and unplanted reactors after 16 and 23 months of operation respectively. The findings suggested that an acclimation period of at least one year can be expected in unseeded bioreactors planted with T. angustifolia, while bioreactors without vegetation may require a longer time to maximize their denitrification capacity. These results are important for the design and operation of wood-chip bioreactors, which are expected to be more commonly applied in the future. (C) 2018 Elsevier B.V. All rights reserved.

关键词： Nutrient removal   sequencing batch hybrid membrane bioreactor   bacterial profile   specific phosphorus uptake rate   membrane fouling rate  

摘要： A conventional (SB-CMBR) and a hybrid moving-bed (SB-HMBR) sequencing batch membrane bioreactor treating municipal wastewater were compared during their start-up in terms of organic matter and nutrient removal, membrane fouling characteristics and microbial community. Both systems exhibited similar COD, ammonium, total nitrogen (TN) and phosphorus removal efficiency, amounting up to 96%, 99%, 70% and 85%, respectively. Results from cycle tests revealed that the contribution of attached biomass to the overall ammonium removal in the hybrid reactor was marginal. Moreover, higher despite the similar phosphorus removal efficiency attained in both reactors, nitrate-dosing activity batch assays specifically revealed that the anoxic phosphate uptake rate (PUR) in the SB-HMBR was 1.71 times higher than in the SB-CMBR. Moreover, a higher frequency of Candidatus Accumulibacter-related polyphosphate-accumulating organisms was observed in the biofilm carriers of the hybrid reactor. These findings may explain why the overall PUR was almost 50% higher in the SB-HMBR. By operating the reactors in sequencing batch mode, adhesion of particles on the membrane surface was reduced while fouling was mitigated as compared to continuous MBR systems. Better filterability conditions with lower fouling rate were found in the SB-HMBR, important features of the hybrid reactor for reducing membrane cleaning-related energy demand.

关键词： transparent liquid marble   embryonic stem cells (ESCs)   embryonic bodies (EBs)   "one pot" differentiation   nanoparticle-liquid interface  

摘要： Transparent liquid marbles coated with hydrophobic silica nanoparticles were used as micro-bioreactors for embryonic stem cell (ESC) culturing. The high transparency of silica liquid marbles enables real-time and in situ monitoring of embryonic body (EB) formation and differentiation. The experimental result shows that ESCs can aggregate with each other close to the bottom of the liquid marble and form EBs, while remaining suspended in the culture media. The differentiation of the suspending EBs into contractile cardiomyocytes has been demonstrated inside the transparent liquid marbles, which enable the in situ microscopic observation. It was also found, through comparison, that ESCs in a bare sessile drop placed on a superhydrophobic substrate tend to anchor onto the substrate and then differentiate following the normal way of cell spreading, i.e., withdrawal from the cell cycle, fusion with nascent myotubes, and final differentiation into cardiomyocytes. In contrast, liquid marble particle shells weaken the adhesion of spherical EBs to the substrate, encouraging them to differentiate in suspension into cardiomyocytes, without anchoring. The results of this study highlight the promising performance of liquid marbles as "one-pot" micro-bioreactors for EB formation and differentiation.