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关键词： Piezoelectric membrane   β-PVDF membrane   AnMBR   Anti-fouling  

摘要： Membrane fouling is a common phenomenon in anaerobic membrane bioreactor (AnMBR), deteriorating membrane performance and increasing the operation costs of AnMBR. In this study, β-phase polyvinylidene fluoride (PVDF) flat sheet membranes were successfully prepared by first mixing PVDF powder with ionic liquid [BMIM]PF₆ and subsequently casting them using thermally induced phase separation (TIPS), followed by high voltage polarization treatment to endow the PVDF membranes with piezoelectric properties. For the first time in AnMBR, we reported in this study on the piezoelectric PVDF membrane that generates in-situ vibrations to reduce membrane fouling by applying a given frequency and alternating voltage (AV). The results suggested that the steady-state water flux through the piezoelectric membrane in AnMBR operation increased along with the AV, enhancing it by up to 72.6% (at 20 V) compared to that of the membrane without applying AV. In addition, high water flux was obtained at the optimal operating frequency of 10 kHz when the cross-flow mode was taken into consideration in AnMBR operation in this study, although the resonance frequency with maximum amplitude of the membrane was 600 kHz. These results indicate that the piezoelectric β-PVDF membrane is effective at minimizing or alleviating the membrane fouling when the electric field simultaneously applied during AnMBR operation. During the 30-day operation of AnMBR with the β-PVDF membrane with poling, the COD removal rate was maintained at over 90%, even if the applied frequencies and voltages were changed during the operation.

关键词： Bacterial consortium   BTXP contaminated sites   Petrochemical wastes   Xenobiotics   Polyurethane bioreactor  

摘要： Polyurethane (PU) tubular coil-based bioreactor was constructed and evaluated for the effective biodegradation of benzene, toluene, xylene and phenol (BTXP). Herein, the removal of BTXP was done with a formulated bacterial consortium adsorbed on the inner surface of the PU coil. The formulated consortium consisted of four bacterial strains namely, Alcaligenes sp. d(2), Enterobacter aerogenes, Raoultella sp. and Bacillus megaterium. The adsorption ability of the bacterial cells onto the coil surface was assessed by spectrophotometric and Scanning Electron Microscopic (SEM) analysis. BTXP degradation performance was evaluated by Ultra-Violet spectroscopy and the degradation was confirmed by Fourier Transform Infrared Spectroscopy (FT/IR). The bioreactor constructed using polyurethane (PU) tubular coil with adsorbed bacterial cells exhibited 70% degradation capacity of 250 mu L of 5% benzene, toluene, xylene and phenol (BTXP) at a pH of 6 within 8 h of treatment. FT/IR spectra of the treated sample indicated the production of ketonic, carboxylic acid/esters during biodegradation. The innovative technology proposed in the current study with the formulated bacterial consortium and the novel bioreactor opens up new possibilities for the better removal of BTXP mixture from contaminated sites and industrial effluents.

关键词： Landfill leachate   Organic pollution control   Anaerobic membrane bioreactor (AnMBR)   Membrane fouling   Bioenergy  

摘要： Most of the municipal solid wastes (MSW) produced daily in the world are being buried in landfllling sites without any prior treatment particularly in developing countries. These landfills yield leachate which is a highly contaminated wastewater. Thus, a proper treatment of leachate is highly recommended before the final discharge. Recently, the use of membrane separation technology alongside bioreactors have opened a new gateway in treating refractory wastewater such as landfill leachate. Anaerobic membrane bioreactor (AnMBR) is a promising technique for leachate treatment due its substantial benefits over other conventional anaerobic and aerobic technologies. Thus, this study provides a comprehensive review and assessment on the potential practice of AnMBR in treating landfill leachate and its technological advancements in the recent past. A critical review on the performance of a lab-scale AnMBR on landfill leachate with the biogas production is also included in the current work. Moreover, this study inspects various factors affecting the performance of AnMBR along with its limitations and future perspectives. The simultaneous treatment of landfill leachate anaerobically to produce bioenergy complies with the principles of circular economy and sustainable growth. (C) 2020 Published by Elsevier Ltd.

关键词： Biofilms   Bacteria   Membranes   Deposition   Fluoropolymers  

摘要： Membrane biofouling constitutes a great challenge in anaerobic membrane bioreactor (AnMBR). Here, we studied the initial deposition of anaerobes, the first step in biofilm formation, with a consortium isolated from an AnMBR on membranes with different surface properties and under two shear rate conditions without filtration. We found that the cell transfer coefficient, calculated from the initial deposition experiments, was similar under the two shear rates for the hydrophobic membranes, but much higher under low shear rate and much lower under high shear rate, for the hydrophilic membrane. The cell transfer coefficient measured under filtration mode and at a higher shear rate showed a similar trend. The pioneer bacteria and archaea (without filtration) were identified by next-generation sequencing. The results showed that the selective force for the dissimilarity of the pioneer bacterial and archaeal diversity was the shear rate and the membrane surface properties, respectively. However, statistical analyses revealed minor changes in the pioneer bacteria (class level) and archaea (order level) populations under the various conditions. These results shed light on the first step of biofilm formation on the membranes in AnMBRs and emphasize the importance of hydrodynamic shear and membrane surface properties on the initially deposited anaerobes.

关键词： Algae   biohydrogen   decentralized reactors   hydrogen   hydrogen cars   hydrogen economy  

摘要： New options are needed to reduce the impact of motor vehicles on climate change and declining fossil fuel resources. Cars which are fueled by hydrogen could be a sustainable method of transportation if suitable technologies can be devised to produce hydrogen in an environmentally benign manner along with the provision of the necessary fueling infrastructure. This paper assesses size, space, and cost requirements of bioreactors as a decentralized option to supply hydrogen powered cars with biohydrogen produced from algae or cyanobacteria on a theoretical basis. Decentralized supply of biohydrogen could help to reduce the problems that hydrogen cars face regarding market penetration. A feasibility study for decentralized biohydrogen production is conducted, taking the quantity of hydrogen which is needed to fuel current hydrogen cars into account. While this technology is, in theory, feasible, sizes, and costs of such reactors are currently too high for widespread adoption. Thus, more R&D is needed to close the gap and to approach marketability.

关键词： 真菌性角膜炎   伏立康唑   角膜基质内注射  

摘要： 目的观察角膜基质内注射不同浓度伏立康唑治疗真菌性角膜炎的临床疗效。方法前瞻性病例对照研究。87例(87眼)真菌性角膜炎患者随机分为三组,均行KOH湿片检查和真菌培养,A组(28眼)给予5 g·L^-1氟康唑和50 g·L^-1那他霉素滴眼液滴眼,B组(30眼)和C组(29眼)在A组治疗的基础上再分别给予0.25 g·L^-1和0.50 g·L^-1的伏立康唑行角膜基质内注射。术后随访4个月,观察三组患者的疗效及并发症情况。结果KOH湿片检查阳性率为86.2%(75/87),真菌培养阳性率为93.1%(81/87);前三位的致病菌依次是镰刀菌40例(46.0%),曲霉菌19例(21.8%),链格孢霉菌13例(15.0%),三组患者致病菌分布差异无统计学意义(χ^2=0.932,P=0.988)。A组的治愈率为42.9%(12/28),明显低于B组的76.7%(23/30)和C组的86.2%(25/29),差异均有统计学意义(P=0.009、0.000);B组和C组治愈率比较差异无统计学意义(P=0.347)。A、B、C三组的治愈时间依次为(31.96±10.20)d、(26.17±7.23)d和(21.50±7.32)d,两两相比差异均有统计学意义(均为P<0.05)。A组治疗前后视力比较差异无统计学意义(P=0.905);B、C两组治疗前后视力比较差异均有统计学意义(P=0.027、0.022)。B、C两组的注射次数分别是(3.93±1.26)次和(3.41±1.12)次,差异无统计学意义(P=0.099)。未愈者A组16眼、B组7眼、C组4眼。结论对轻度、中度真菌性角膜炎患者可选择0.25 g·L^-1伏立康唑角膜基质内注射治疗,对于0.25 g·L^-1伏立康唑角膜基质内注射治疗效果不理想或病情较重者可考虑用0.50 g·L^-1伏立康唑行角膜基质内注射治疗。

关键词： 两相分配生物反应器   有机废气   疏水性   非水相   生物降解  

摘要： 通过研究国内外关于两相分配生物反应器治理有机废气进展,介绍了搅拌釜生物反应器、生物滴滤塔等多种两相分配生物反应器的结构及其工作原理;分析了硅油、十六烷等不同非水相对于不同目标污染物的去除效果;研究了两相分配生物反应器对有机废气的处理性能;最后指出如何消除液态非水相的泡沫化和反应器的堵塞问题是今后研究的关键。

关键词： Municipal solid waste   Unsaturated hydraulic conductivity   Water retention curve   Bioreactor   Recirculation   Decomposition   Sustainability   Compression  

摘要： The effects of compression and decomposition on the water retention curve (WRC) and unsaturated hydraulic conductivity (K theta) of municipal solid waste (MSW) were evaluated in the laboratory and field. Laboratory measurements of the WRC and K theta were made using the multistep outflow (MSO) method. Numerical inversion of data collected during the Deer Track Bioreactor Experiment (DTBE) was used to estimate field-scale unsaturated hydraulic properties. For the MSW tested in this study, data indicated that increasing dry unit weight resulted in an increase of the air-entry suction. Increasing levels of decomposition had the opposite effect, reducing air-entry suction for MSW at constant dry unit weight. Multiple mechanisms likely resulted in the observed changes in air-entry suction, including reduction in pore size during compression and changes in overall MSW hydrophobicity during decomposition. At field-scale, air-entry suction tended to remain constant as MSW compressed and decomposed simultaneously indicating that the two processes, which had opposite effects in the laboratory, also may have opposing effects the field. For fresh MSW, van Genuchten's n, which is inversely related to the variance of the pore size of a porous medium, ranged between 1.3 and 2.5 and decreased as the dry unit weight increased in laboratory-scale tests. For decomposed MSW, n ranged from 1.1 to 1.3 and did not vary systematically with dry unit weight. This indicated that for degraded MSW, the variance of the pore-size distribution did not change substantially with increasing dry unit weight. The value of K theta decreased with increasing dry unit weight for MSW in this study, consistent with observations for saturated hydraulic conductivity in MSW. However, K theta tended to increase in laboratory tests with increasing levels of decomposition at constant dry unit weight, consistent with observed increases in void ratio. At field scale, observed changes in K theta varied consistently w

关键词： mass spectrometry   polymer contaminants   alkylation   sample preparation   bottom-up proteomics   bioreactor samples  

摘要： Proteomic analysis of bioreactor supernatants can inform on cellular metabolic status, viability, and productivity, as well as product quality, which can in turn help optimize bioreactor operation. Incubating mammalian cells in bioreactors requires the addition of polymeric surfactants such as Pluronic F68, which reduce the sheer stress caused by agitation. However, these surfactants are incompatible with mass spectrometry proteomics and must be eliminated during sample preparation. Here, we compared four different sample preparation methods to eliminate polymeric surfactants from filtered bioreactor supernatant samples: organic solvent precipitation;filter-assisted sample preparation (FASP);STrap;and single-pot, solid-phase, sample preparation (SP3). We found that SP3 and S-Trap substantially reduced or eliminated the polymer(s), but S-Trap provided the most robust cleanup and highest quality data. Additionally, we observed that SP3 sample preparation of our samples and in other published data sets was associated with partial alkylation of cysteines, which could impact the confidence and robustness of protein identification and quantification. Finally, we observed that several commercial mammalian cell culture media and media supplements also contained polymers with similar mass spectrometry profiles, and we suggest that proteomic analyses in these media will also benefit from the use of S-Trap sample preparation.

关键词： Dichloromethane   Toluene   Airlift packing bioreactor   Airlift bioreactor   Factorial design  

摘要： Biotechnology has proven effective in removing a wide variety of VOCs. In this study, the effects of pH (from 3 to 7), operating temperature (20 - 30 degrees C), empty bed residence time (EBRT, 10 - 40 s) and transient inlet concentration (400 - 4000 mg m(-3)) on the removal performance of an airlift packing bioreactor (ALPR) was investigated. The removal efficiency (RE) and stability of the ALPR was evaluated and compared with the conventional airlift bioreactor (ALR). The results showed that under the influence of single factor variation, the ALPR showed significant higher RE and better stability than the ALR in removing dichloromethane (DCM) and toluene. Besides, a factorial design was used to analyses the interaction of multiple factors and their influence on the removal of DCM and toluene in the ALPR and ALR. It shows that pH value has the most significant influence, and plays a crucial role in maintaining high RE of DCM and toluene in both of the ALPR and ALR. Temperature has a great effect on the removal of toluene. EBRT has certain effect on the removal of DCM in the ALPR. The transient concentration of a single substrate has a significant negative effect on the RE of this substrate, while it does not significantly affect the removal of another substrate in the ALPR. However, the steep increase of DCM concentration has an adverse effect on the RE of high concentration toluene in the ALR. The overall RE and degradation capacity of both toluene and DCM by the ALPR are much higher than that of the conventional ALR.