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关键词： Driving force   Forward osmosis   Membrane fouling   Osmotic membrane bioreactor   Anaerobic reactor  

摘要： Anaerobic osmotic membrane bioreactor (AnOMBR) has shown great promise for wastewater treatment and energy recovery. One of the major obstacles limiting the performance of the AnOMBR is the low water flux of forward osmosis (FO) membrane. Here, impacts of draw solution (DS) concentration on the performance of the AnOMBR were investigated for enhancing the water flux of FO membrane via controlling the driving force. The results indicated that the flux variations of FO membrane in the AnOMBR included two stages of a rapid and a mild flux declines at all DS concentration conditions. In addition, the FO membrane fouling correlated well with the flux variations for all DS concentration levels, i.e., a severe fouling in Stage 1 and a slight fouling in Stage 2. When the driving force or DS concentration exceeded a critical value, a worse FO membrane performance especially a severer flux decline in Stage 1 was observed. It could be attributed to an aggravated membrane fouling in Stage 1 owing to an increased initial flux with the rise of the driving force, implying that a critical initial flux exists in the AnOMBR except for a critical driving force. Inspired by the critical initial flux and the significant role of the membrane fouling in Stage 1, this study provides a novel method to enhance flux performance of FO membrane via controlling the driving force in a two-stage pattern. It utilizes a low driving force in Sage 1 to form a thin and loose fouling layer on the FO membrane surface and then a high driving force in Sage 2 to alleviate the flux drop. Compared with the stable driving force, the two-stage pattern obtained a better flux performance owing to a mitigation of membrane fouling with thinner layer thickness and less deposited foulants.

关键词： Suspended AnaEG reactor   Starch processing wastewater   High-throughput sequencing   High microbial diversity   Core species  

摘要： In this study, a novel type of mesophilic anaerobic bioreactor-an expanded granular sludge bed (EGSB)-was utilized to explore the effect of suspending reactor operation on the treatment performance and the microbial community structure. The parameters of performance and bacterial community before and after a four-week suspension were compared for the starch processing wastewater treatment bioreactor. The results indicate that the removal rate of the organic matter remained higher than 90%, although the biomass significantly decreased after restarting the reactor. However, the relatively stable microbial community structure before the suspension was altered significantly during the restart and post-running stages. This change was primarily due to variability in satellite species and the substitution effect of different dominant bacteria. For example, some non-major carbohydrate-degrading bacteria that were sensitive to nutrition deficiency, such as Desulfovibrio and Geobacter, were dramatically reduced after the suspension. In contrast, the stress of starvation stimulated the reproduction of hydrolytic bacteria, such as Macellibacteroides. However, the high bacterial diversity index (6.12-6.65) and the longstanding core species, including Chloroflexi, Cloacimonetes, Ignavibacteriae, Thermotogae and Euryarchaeota, maintained the functional stability of the reactor. Consequently, although the total bacteria decreased significantly after reactor operation was suspended, sufficient functional bacteria supported by the high diversity, as well as the longstanding core species, guaranteed the effective degradation after suspension. (c) 2018 Elsevier B.V. All rights reserved.

关键词： Membrane bioreactor   Microbial community   Nanofiltration   Produced water   Reverse osmosis   Salinity  

摘要： Biomass characteristics may change subject to a salinity increase when treating high strength wastewater. In this study, the impact of salinity in a membrane bioreactor (MBR) was investigated for the treatment of produced water (PW). MBR was operated as a pre-treatment prior to nanofiltration (NF) and reverse osmosis (RO). Mixed PW, that was originated from different oil, gas, and oil-gas wells, were subjected to pre-treatment for 146 days including three different operational phases: Low-salinity (similar to 10 mS/cm), gradual increased salinity (10-40 mS/cm) and high salinity (similar to 40 mS/cm). The results of this study showed that microorganisms could adapt using real wastewater and treat PW up to a certain level of the salinity. At high salinity levels of PW, the floc structure started to be disrupted and membrane fouling was accelerated. PCR-DGGE analysis confirmed the changes in microbial communities' composition in relation with high salinity. The results of the final treatment experiments presented that NF and RO treatment produced high-quality effluents that could be suitable for reuse. (C) 2018 Published by Elsevier B.V.

关键词： 生物反应器   耦合系统   电性能   废水   还原   沉积物  

摘要： 以厌氧活性污泥为阳极菌种,乙酸钠为阳极底物,硫酸铜和重铬酸钾溶液为微生物燃料电池(MFC)阴极液,人工模拟含镉重金属废水为微生物电解池(MEC)阴极液,构建MFC-MEC耦合系统,利用MFC的产电驱动MEC运行,在不消耗外部能源的情况下,实现含镉重金属废水中Cd^(2+)的去除。实验研究了MFC反应器容积、MFC堆栈、MEC电极材料、MEC阴极液pH对MFC-MEC耦合系统电性能及含镉重金属废水处理效果的影响。结果表明:MFC反应容积的扩大可以提高其产电性能,但与此同时会造成MFC的内阻升高,随着MFC容积的增加,MEC中Cd^(2+)去除率逐渐增加,但同时MFC阴极Cr6+去除率逐渐下降;MFC堆栈可以提高工作组两端电压,串联时最大输出电压为1509 mV,Cd^(2+)去除率为69.3%;以钛板作为MEC电极时,微生物能有效附着在阳极表面,MFC阳极COD去除率为85%,MEC中Cd^(2+)去除率为51.5%;MEC阴极液pH在3～5时,有利于含镉重金属废水的处理,Cd^(2+)去除率80%以上。经XRD分析,MEC阴极还原产物为CdCO3。

关键词： 龙眼   细胞培养   生物反应器   光照   柯里拉京  

摘要： 【目的】研究不同光照条件对龙眼胚性悬浮细胞培养及柯里拉京代谢合成的影响,以期为龙眼胚性悬浮细胞大规模培养、工业化生产柯里拉京奠定理论基础。【方法】基于龙眼胚性悬浮细胞体系的建立,采用5 L新型搅拌式生物反应器放大培养龙眼胚性悬浮细胞,探讨黑暗和光照处理对龙眼胚性悬浮细胞生长、柯里拉京含量、蔗糖消耗以及培养体系中pH和DO(溶氧)的动态变化规律。【结果】龙眼胚性悬浮细胞在黑暗和光照条件下其生长动态大致均呈"S"形曲线,最大增重分别为4.74 g·L^(-1)和3.71 g·L^(-1);黑暗培养到第7 d龙眼胚性悬浮细胞体内柯里拉京含量达到最大值8.72 mg·g^(-1),是光照条件下的2.8倍,但在细胞培养液中柯里拉京含量明显低于光照条件(P<0.05)。光照加快了龙眼胚性悬浮细胞对蔗糖的消耗速度,但对培养体系中的pH和DO无明显影响。【结论】生物反应器大规模培养过程中,黑暗条件利于龙眼胚性悬浮细胞生长及细胞内柯里拉京含量的积累,蔗糖消耗、pH和DO是龙眼胚性悬浮细胞生长及柯里拉京合成的重要调控因子。

关键词： 矽藻   半連續式培養   褐藻黃素   抗氧化   抗癌  

摘要： 矽藻(Diatom)是海洋中物种最丰富及多样化的单细胞真核生物。矽藻生产的天然产物中，褐藻黄素(fucoxanthin)，是具有多种生物活性的化合物，例如:抗癌及免疫调节等生物活性。本研究执行了6种不同培养条件，结果显示在提供充裕的矽酸盐及额外多添加0.016 mole Na2CO3且在较短的时间进行收获可以得到最高的乾藻浓度(g/L)及褐藻黄素单位体积产率(mg/L/Day)。将收获的矽藻冷冻乾燥後以95%乙醇进行萃取，可以得到叶绿体中的总色素粗萃物。根据色素的极性高低，将萃取之总色素粗萃物利用正相管柱层析法进行纯化，并利用薄层层析法(TLC)找出最有效率之移动相组合。结果显示，以乙酸乙酯:正己烷(2:3)为管柱层析最佳移动相，可将褐藻素有效地从总色素粗萃物中分离出来，将纯化後的收集管经由薄层层析法初步分析目标产物的纯化效率，再经由高效能液相层析仪(HPLC)、液相色谱法-质谱联用(LC-MS)、傅里叶转换红外光谱(FTIR)和核磁共振(NMR)分析，监定分子结构与化合物纯度。纯化後的褐藻黄素进行生物活性测试，以DPPH来分析褐藻素对於自由基的清除能力，後续针对巨噬细胞RAW 264.7、胰腺癌细胞Panc-1与前列腺癌细胞LNCaP进行细胞毒性的测试，结果显示，在投药後的72小时，褐藻黄素对毒杀胰腺癌细胞有较好的效果，IC50为30 M，而对於巨噬细胞而言，在投药後72小时IC50仅为90 M，这说明了在低剂量的褐藻黄素可以毒杀癌细胞甚至影响其生长，且对於免疫细胞不会有太高的毒性，因此，褐藻黄素以低剂量作为抗癌药物有着优秀的潜力。盼望未来能研发新的剂型来针对一些慢性病的治疗或辅疗药物。

关键词： 间歇式   膜生物反应器   垃圾渗滤液   实验过程  

摘要： 为了顺应环保管理要求,有效处理垃圾渗滤液,相关部门要积极建立健全完整且有效的监管机制,并且发挥新技术的优势,夯实管控流程和监督规划,确保能对滤液予以综合处理。文章分析了基于间歇式膜生物反应器的垃圾渗滤液处理实验,从COD的结果,从而提出了膜污染及处理措施的建议,仅供参考。

关键词： Nitrates  

摘要： Woodchip bioreactors are widely used to control nitrogen export from agriculture using denitrification. There is abundant evidence that drying-rewetting (DRW) cycles can promote enhanced metabolic rates in soils. A 287-d experiment investigated the effects of weekly DRW cycles on nitrate (NO3) removal in woodchip columns in the laboratory receiving constant flow of nitrated water. Columns were exposed to continuous saturation (SAT) or to weekly, 8-h drying-rewetting (8 h of aerobiosis followed by saturation) cycles (DRW). Nitrate concentrations were measured at the column outlets every 2 h using novel multiplexed sampling methods coupled to spectrophotometric analysis. Drying-rewetting columns showed greater export of total and dissolved organic carbon and increased NO3 removal rates. Nitrate removal rates in DRW columns increased by up to 80%, relative to SAT columns, although DRW removal rates decreased quickly within 3 d after rewetting. Increased NO3 removal in DRW columns continued even after 39 DRW cycles, with similar to 33% higher total NO3 mass removed over each weekly DRW cycle. Data collected in this experiment provide strong evidence that DRW cycles can dramatically improve NO3 removal in woodchip bioreactors, with carbon availability being a likely driver of improved efficiency. These results have implications for hydraulic management of woodchip bioreactors and other denitrification practices.

关键词： Volatile fatty acids   Anaerobic membrane bioreactor   Low strength wastewater   Hydraulic retention time   Organic loading rate  

摘要： This study aims to investigate the production of volatile fatty acids (VFAs) from low strength wastewater at various hydraulic retention time (HRT) and organic loading rate (OLR) in a continuous anaerobic membrane bioreactor (AnMBR) using glucose as carbon source. This experiment was performed without any selective inhibition of methanogens and the reactor pH was maintained at 7.0 +/- 0.1. 48, 24, 18, 12, 8 and 6 h-HRTs were applied and the highest VFA concentration was recorded at 8 h with an overall VFA yield of 48.20 +/- 1.21 mg VFA/100 mg CODfeed. Three different ORLs were applied (350, 550 and 715 mg CODfeed) at the optimum 8 hHRT. The acetic and propanoic acid concentration maximums were (1.1845 +/- 0.0165 and 0.5160 +/- 0.0141 mili-mole/l respectively) at 550 mg CODfeed. The isobutyric acid concentration was highest (0.3580 +/- 0.0407 mili-mole/l) at 715 mg CODfeed indicating butyric-type fermentation at higher organic loading rate.

关键词： Haldane model   immobilized cell   mass transfer limitations   microbial decolorization   Ralstonia eutropha  

摘要： Aerobic degradation of methylene blue by a pure culture of Ralstonia eutropha was studied by both freely suspended cells and kissiris-immobilized packed bed reactors. Kissiris as a cell support matrix favored the retention of the cells in the packed bed reactor during of the methylene blue biodegradation process. The biodegradation experiments showed that the kissiris-packed bed reactor had higher performance in removal of the dyestuff for initial concentrations equal or higher than 150 mg L-1 when compared with the freely suspended cells. To evaluate the effect of mass transfer phenomena in the immobilized system, mass balance of methylene blue for a single kissiris piece was applied to derive expressions correlating the methylene blue concentration in the bulk liquid medium and inside of the bioparticle. Kinetics studies revealed a self-inhibitory effect of methylene blue on its biodegradation at concentrations higher than 85.76 mg L-1 in the free cell and 190.1 mg L-1 for immobilized system. The mass transfer modeling indicated the protective role of the support from cells against the inhibitory role of methylene blue is related to both external and internal mass transfer limitations in the immobilized system. In the kissiris packed bed reactor, the effectiveness value was higher than unity for initial methylene blue concentration of 150 mg L-1.