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关键词： Membrane bioreactor   Membrane fouling   Soluble microbial product   Extracellular polymeric substance  

摘要： Membrane bioreactors (MBRs) are considered a promising tool for resource recovery in wastewater treatment. Nevertheless, membrane fouling is an inevitable phenomenon that deteriorates the MBR performance. Although many studies have attempted to elucidate the effect of sludge characteristics on MBR fouling, they posed certain limitations. Most of the previous studies focused on the initial sludge or employ the results of short-term batch tests without long-term transmembrane pressure (TMP) profiles in the interpretation of fouling behaviors. This study was conducted considering these limitations to determine the sludge characteristics most closely related to long-term TMP profiles and to identify their role in fouling behaviors. In long-term TMP profiles, critical time (t(c);time to TMP jump) and fouling rates (the increase in the TMP slope) were used as fouling indexes, which were used to correlate with average values of sludge characteristics before and after experiments. According to the results, the concentration of the total soluble microbial product (SMP) and extracted extracellular polymeric substance (eEPS) in sludge significantly increased by 1.9 times and up to 28 times after experiment. The increase in the SMP and eEPS caused early TMP jumps and resulted in low-fouling rates by increasing particle size. Owing to the increase in the SMP and eEPS concentration, the origin of fouling potential was shifted from suspended solids to colloids and soluble materials. Fouling resistance caused by soluble material increased by up to 11.38 times. (C) 2021 Elsevier Ltd. All rights reserved.

关键词： Bioreactor   Expansion   Antigen Specific T-lymphocytes  

摘要： 1218

关键词： Biohydrogen   Common reed   Invasive grass   Lignocellulose   Continuously anaerobic bioreactor  

摘要： This study aims to investigate the effect of substrate concentration and hydraulic retention time (HRT) on hydrogen production in a continuous anaerobic bioreactor from unhydrolyzed common reed (Phragmites australis) an invasive wetland and perennial grass. The bioreactor has capacity of 1 L and working volume of 600 mL. It was operated at pH 5.5, temperature at 37 degrees C, hydraulic retention time (HRT) 12 h, and variation of substrate concentration from 40, 50, and 60 g COD/L, respectively. Afterward, the HRT was then varied from 12, 8, to 4 h for checking the optimal biohydrogen production. Each condition was run until reach steady state on hydrogen production rate (HPR) which based on hydrogen percentage and daily volume. The results were obtained the peak of substrate concentration was at the 50 g COD/L with HRT 12 h, average HPR and H-2 concentration were 28.71 mL/L/h and 36.29%, respectively. The hydrogen yield was achieved at 106.23 mL H-2/g CODre. The substrate concentration was controlled at 50 g COD/L for the optimal HRT experiments. It was found that the maximum of average HPR and H-2 concentration were 43.28 mL/L/h and 36.96%, respectively peak at HRT 8 h with the corresponding hydrogen yield of 144.35 mL H-2/g CODre. Finally, this study successful produce hydrogen from unhydrolyzed common reed by enriched mixed culture in continuous anaerobic bioreactor. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

关键词： Aeration   biofilms   bioreactor   water quality   microbial community  

摘要： Biofilms play an important role in degradation, transformation and assimilation of anthropogenic pollutants in aquatic ecosystems. In this study, we assembled a tubular bioreactor containing a biofilm substrate and aeration device, which was introduced into mesocosms to explore the effects of bioreactor on physicochemical and microbial characteristics of a hypereutrophic urban river. The biofilm bioreactor greatly improved water quality, especially by decreasing dissolved inorganic nitrogen (DIN) concentrations, suggesting that biofilms were the major sites of nitrification and denitrification with an oxygen concentration gradient. The biofilm bioreactor increased the abundance of planktonic bacteria, whereas diversity of the planktonic microbial community decreased. Sequencing revealed that Proteobacteria, Bacteroidetes, Planctomycetes, and Actinobacteria were the four predominant phyla in the planktonic microbial community, and the presence of the biofilm bioreactor increased the relative abundance of Proteobacteria. Variations in microbial communities were most strongly affected by the presence of the biofilm bioreactor, as indicated by principal component analysis (PCA) and redundancy analysis (RDA). This study provides valuable insights into changes in ecological characteristics associated with self-purification processes in hypereutrophic urban rivers, and may be of important for the application of biofilm bioreactor in natural urban river.

关键词： Forward osmosis   Osmotic anaerobic bioreactors   Draw solutions   Techno-economic preferability   Analytic hierarchy process  

摘要： Cost and performance efficient integrations of biological treatments with membrane processes are very worthy for water and resource recovery among of which osmotic anaerobic digestion suffers from exactly elucidating desirable techno-economic features of key operating factors. Cost-performance effective draw solutions (DSs) were ascertained for forward osmosis (FO) and its anaerobic bioreactor (AnBR) configurations, anaerobic osmotic membrane bioreactor (AnOMBR) and [FO/AnBR]. In case study comprising literature data pre-screening, selected DS experiments, and preferability analysis, dual modeling was executed for prioritizing DSs eligible to osmotic AnBRs by analytic hierarchy process (AHP). Through AHP screening of 29 DSs' FO data, NaNO3, NaCl, MgCl2, CaCl2, NH4H2PO4, HCOONa and CH3COONa were established between the best 10% worth researching for osmotic AnBRs. Experiments showed that isothermally varied temperatures hardly affected DS performances in submerged, but DS concentration raises led to those distinguished by reverse solute fluxes. Reverse solute flux selectivity was differed significantly by DS kinds and FO configurations because of varying interactions among predominant inorganic ion and soluble organics. Submerged FO fed by distilled water provided better performance than sidestream but not by wastewater. Anaerobic bioactivities showed longer acclimation times increased by alkalinity unlike seawater (SW) and better CH4 productivity of organics enhanced by DS concentration. Upon AHP analyses, CaCl2, MgCl2, both organics, and SW were more techno-economically favorable DS kinds. Irrespective of technological alternatives, CaCl2 and MgCl2 were found as top two except just SW was the best for AnOMBR by low-cost supply. It was finally proved that eligible DSs should be designated technology dependently due to their distinctive performances and replenishment costs, and topmost priority to SW should be attributed in sustainable wastewater reclamations by AnOM

关键词： Pharmaceuticals   Fungi   Wastewater treatment   Toxicity   Bioreactor  

摘要： Hospital wastewater is loaded with pharmaceutically active compounds (PhACs), which sometimes end up in the environment unaltered due to the lack of effective and specific treatments. The use of white rot fungi, specifically Trametes versicolor, as a biological treatment has proven to be an effective and environmentally friendly technology to tackle this problem. However, only a few studies have dealt with the removal of pharmaceuticals from wastewater by immobilizing white rot fungi in a lignocellulosic substrate. In this work, two bioreactor configurations are utilized to treat both synthetic and real hospital wastewater by the use of T. versicolor. The stirred tank bioreactor (STB) was able to remove to a great extent 16 pharmaceuticals spiked in the synthetic wastewater (95.7%) and those naturally present in the hospital wastewater (85.0%). Nonetheless, acute toxicity tests with Daphnia magna and germination index with Lactuca sativa showed an increase in the general toxicity of both wastewater matrices after the treatment. On the other hand, a trickle-bed bioreactor (TBB), using fungal biomass immobilized on rice husks, achieved an elimination of 88.6% and 89.8% in synthetic and real wastewater, respectively. However, 73.3% of the removal was ascribed to adsorption to the bed's biomass. Additionally, toxicological tests showed a decrease in the hospital wastewater's toxicity after the treatment in the TBB. These findings suggest that the fungal fixed-bed reactor could be more suitable than the stirred tank reactor to remove pharmaceutical compounds from wastewater, since it was able to remove PhACs to a great extent and simultaneously detoxify real wastewater.

关键词： Hospital wastewater   Submerged membrane bioreactor   Membrane fouling   Modeling   Simulation  

摘要： This article presents the modeling of a submerged membrane bioreactor (SMBR) using experimental values at laboratory and pilot scale for urban and hospital wastewater treatment, respectively. The main objective of this work is to develop an improved model integrating a biological model with a membrane fouling model, with upgraded precision, consistency and calibration in the description of the functioning of SMBR. For this, con-cerning the biological model, an evolution of the Activated Sludge Model 3 (ASM3), including the simultaneous growth and substrate storage, and the soluble and bound extracellular polymeric substances (EPS) production was proposed. The concentration of EPS and the mixed liquor suspended solids are the variables of connection with the new version of the membrane fouling model that takes into account the influence of EPS on the sludge cake and membrane porosity. A new procedure was developed to calibrate the parameters considering their influence on the model and parameters uncertainty. It allowed the calibration and successful validation of the developed model. The high correspondence obtained between numerical and experimental results evidences the relevance of the phenomena considered in the model.

关键词： Anaerobic membrane bioreactor (AnMBR)   Irrigation   Life cycle assessment (LCA)   Life cycle cost (LCC) analysis   Tertiary wastewater treatment   Reclaimed water reuse  

摘要： Reuse of treated wastewater for irrigation purposes is a measure to reduce water stress and over exploitation of freshwater resources. This study aims to investigate the environmental and economic impacts of a current conventional wastewater treatment plant (WWTP) in Peschiera Borromeo (Milan, Italy), and compare possible scenarios to enable reclaimed water reuse for agriculture. Accordingly, we propose alternative disinfection methods (i.e. enhanced UV, peracetic acid) and replace conventional activated sludge (CAS) with upflow anaerobic sludge blanket (UASB) for biological treatment and use anaerobic membrane bioreactor (AnMBR) as the tertiary treatment. Life cycle assessment (LCA) and life cycle costing (LCC) were implemented on the existing full-scale wastewater treatment line and the hypothetical scenarios. In most cases, the impact categories are primarily influenced by fertilizer application and direct emissions to water (i.e. nutrients and heavy metals). The baseline scenario appears to have the largest environmental impact, except for freshwater eutrophication, human ecotoxicity and terrestrial ecotoxicity. As expected, water depletion is the most apparent impact category between the baseline and proposed scenarios. The UASB + AnMBR scenario gives relatively higher environmental benefits than the other proposed scenarios in climate change (-28%), fossil fuel depletion (-31%), mineral resource depletion (-52%), and terrestrial ecotoxicity compared to the baseline. On the other hand, the highest impact on freshwater eutrophication is also obtained by this scenario since the effluent from the anaerobic processes is rich in nutrients. Moreover, investment and operational costs vary remarkably between the scenarios, and the highest overall costs are obtained for the UASB + AnMBR line mostly due to the replacement of membrane modules (24% of the total cost). The results highlighted the importance of the life cycle approach to support decision making when consider

关键词： 肉牛   基质金属蛋白酶   抗氧化指标   肉品质   相关关系  

摘要： 本研究旨在揭示肉牛血清基质金属蛋白酶(MMP)2、9、13浓度与血清抗氧化指标和肉品质指标的相关关系。试验选取健康状况良好、体重相近的杂交育肥公牛[西门塔尔牛×延边黄牛,初始体重(436±35)kg]52头,饲喂相同的全混合日粮(TMR)。饲养试验结束前1天在晨饲前采集每头牛的血液,制备血清,测定MMP2、9、13浓度以及抗氧化指标;饲养145 d后全部屠宰,测定屠宰性能、胴体性状及肉品质指标。结果显示:肉牛血清MMP2浓度与血清活性氧自由基(ROS)、丙二醛(MDA)含量,谷胱甘肽过氧化物酶(GSH⁃Px)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、谷胱甘肽还原酶(GR)活性及总抗氧化能力(T⁃AOC)均无显著相关关系(P>0.05);肉牛血清MMP9浓度与血清ROS含量显著负相关(r=-0.358,P=0.011),与血清其他抗氧化指标无显著相关关系(P>0.05);肉牛血清MMP13浓度与血清ROS含量显著负相关(r=-0.292,P=0.040),与血清其他抗氧化指标也无显著相关关系(P>0.05)。肉牛血清MMP2浓度与牛肉大理石花纹评分(r=0.352,P=0.012)和肌内脂肪含量(r=0.307,P=0.036)显著正相关;肉牛血清MMP9浓度与牛肉剪切力显著负相关(r=-0.430,P=0.002);肉牛血清MMP13浓度与牛肉剪切力显著负相关(r=-0.281,P=0.048);肉牛血清MMP2、9、13浓度与牛肉饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)、多不饱和脂肪酸(PUFA)、n⁃3 PUFA、n⁃6 PUFA比例以及n⁃6/n⁃3、PUFA/SFA、C18∶2n6/C18∶3n3均无显著相关关系(P>0.05)。由此可见,肉牛血清MMP2浓度与牛肉大理石花纹评分显著正相关,血清MMP9、13浓度与血清ROS含量及牛肉剪切力显著负相关,血清MMP2、9、13浓度可成为潜在的生物标记物用于肉牛肉质性状的遗传选择或肉品质调控策略。