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关键词： Horizontal flow denitrification bioreactor   Folded plate denitrification bioreactor   Waste sawdust   Municipal sludge   Simulated agricultural surface runoff  

摘要： Nitrogen removal from agricultural surface runoff is of great significance to protect the water quality and safety of groundwater and drinking water. The denitrification bioreactor uses wood-particle products and municipal sludge as solid carbon sources to treat agricultural surface runoff and the rule of total nitrogen produced by wood-particle products is still blank. In this study, a type of denitrification bioreactor with municipal sludge (MS) and Cunninghamia lanceolata sawdust (CLS) as solid carbon source to denitrify simulated agricultural surface runoff is designed. Results show that CLS can release approximately 0.86 +/- 0.06 mg L-1 of nitrogen into the water, and the release process conforms to Non-Fickian transport (n = 0.46). The addition of MS is beneficial to increase the average degradation rate of NH4+-N (70.94%). Increasing the inflow rate is beneficial to increase the average degradation rate of NO2- -N, NO3- -N and TN. When the influent flow is 1.34 mL min-1, the average degradation rate of NO2- -N is as high as 61.61% while of TN is 86.04% in the CLS horizontal flow denitrification bioreactor. The average degradation rate of NO3- -N of CLS and MS (sludge-water volume ratio = 1:2) folded plate denitrification bioreactor is 95.72%, which is 17.46% higher than the horizontal flow type. Based on the principle of cleaner production, this study recycles waste CLS and MS as solid carbon sources in the bioreactor to continuously treat and simulate agricultural surface runoff. The device can not only degrade high-concentration nitrogen, but also prevent the generation of waste and waste of energy, which is a new surface runoff pollution control technology.

关键词： Anaerobic membrane bioreactor   energy   fouling   sewage sludge   sludge treatment  

摘要： Excess sewage sludge in wastewater treatment plants (WWTPs) is regarded the key energy source for achieving energy neutral WWTPs. The anaerobic digestion process transforms sludge-organic matter into methane, which subsequently can be used for heat and electricity production. Conventional anaerobic digesters (ADs) have been used for sludge treatment for many decades, requiring high energy and providing poor effluent quality. Anaerobic membrane bioreactor (AnMBR) technology exhibits a promising option for treatment of high solids concentration streams including sludge. AnMBRs result in an increase in digestion efficiency and enhancement in effluent quality at small footprints. AnMBRs have the potential to reduce capital and operational costs, and produce more energy in comparison to conventional ADs. Thus, energy neutral or positive operation can be achieved with AnMBRs. Besides, nutrient recovery or direct use of permeate will become more feasible in AnMBRs compared to use of sludge supernatant in ADs. However, membrane fouling can limit the feasibility of AnMBRs for sludge treatment, which requires further research. This review paper critically evaluates the current status of AnMBR technology for municipal sludge treatment discussing the effect of different factors on treatment and membrane filtration performances. Furthermore, future research opportunities to enhance applicability of this technology are addressed.

关键词： Decabromodiphenyl ethers   Anaerobic digestion   Thermophilic digestion   Degradation pathway  

摘要： Anaerobic digestion of decabromodiphenyl ether was carried out and compared in two continuously stirred anaerobic bioreactors for 210 days under thermophilic and mesophilic conditions. Results show that the degradation of decabromodiphenyl ether followed the first-order reaction kinetics, which exhibited a higher removal rate in the thermophilic reactor when compared to the mesophilic one, reaching its maximum of 1.1 mu ***-1. The anaerobic digestion of decabromodiphenyl ether was found to involve the replacement of bromines from polybrominated diphenyl ether by hydrogen atoms, gradually forming nona-, octa- and heptabrominated diphenyl ether, respectively. Under the thermophilic condition, the reactors were dominated by Bacillus sp. and Methanosarcina sp. with high bioactivity and high concentrations of debromination microorganisms.

关键词： Roofing rainwater treatment   Electrocoagulation   Gravity-driven membrane bioreactor   Roofing rainwater energy utilization   Stabilized flux   Biofilm  

摘要： A pilot-scale electrocoagulation method coupled with gravity-driven membrane bioreactor (EC-GDMBR) was conducted to roof rainwater cleaner production for long-term (120 days) operation. The utilization efficiency of roofing rainwater energy, water production efficiency, and water purification mechanism were systematically investigated. The permeate flux of the EC-GDMBR was stabilized at 17.0-20.0 L/(m(2).h), 24.6 L/(m(2).h) at given roofing rainwater heads of 0.4 and 0.6 m, respectively. Characterization of floc particle size showed that the large particle flocs (similar to 145 mu m) produced by the EC system enabled the stabilization flux improvement. A combined removal pathway (i.e., coagulation, adsorption, biodegradation, and coprecipitation) of the EC-GDMBR was found for particulate matter, ammonia nitrogen (NH3-N), total phosphorus (TP), organic substances, and heavy metal (i.e., Cr, Zn, and Cu) removal within synthetic or actual rainwater. In particular, EC could sweep the vast majority of bacteria deposited on the GDMBR, and the intensive biological activity of biofilms was demonstrated by analysis of bacterial abundance, extracellular polymeric substances (EPS), assimilable organic carbon (AOC), adenosine triphosphate (ATP), and confocal laser scanning microscopy (CLSM). Thus, a lower bacterial number (<100 cells/mL) within the effluent enabled us to ensure the biological safety of cleaner product water. Furthermore, a large amount of Nitrospira (10 %-12%) and Hyphomicrobium (2 %-3%) in the aggregates formed biofilms, clarifying the NH3-N and TP removal mechanism by microbial community analysis. In summary, the novel process is capable of roofing rainwater energy utilization considering building height and effective clean water purification.

关键词： Wastewater   Membrane bioreactor   Algae   Activated sludge   Electrochemical   Fouling  

摘要： The effect of addition of algae to activated sludge as active biomass in membrane bioreactors (MBRs) and electroMBRs (e MBRs) for wastewater remediation was examined in this study. The performances of Algae-Activated Sludge Membrane Bioreactor (AAS-MBR) and electro Algae-Activated Sludge Membrane Bioreactor (e-AASMBR) were compared to those observed in conventional MBR and e-MBR, which were previously reported and utilized activated sludge as biomass. The effect of application of electric field was also examined by the comparison of performances of e-AAS-MBR and AAS-MBR. Similar chemical oxygen demand (COD) reduction efficiencies of AAS-MBR, e-AAS-MBR, MBR, and e-MBR (98.35 +/- 0.35%, 99.12 +/- 0.08%, 97.70 +/- 1.10%, and 98.10 +/- 1.70%, respectively) were observed. The effect of the algae-activated sludge system was significantly higher in the nutrient removals. Ammoniacal nitrogen (NH3-N) removal efficiencies of AAS-MBR and e-AAS-MBR were higher by 43.89% and 26.61% than in the conventional MBR and e-MBR, respectively. Phosphate phosphorous (PO43--P) removals were also higher in AAS-MBR and e-AAS-MBR by 6.43% and 2.66% than those in conventional MBR and e-MBR. Membrane fouling rates in AAS-MBR and e-AAS-MBR were lower by 57.30% and 61.95% than in MBR and e-MBR, respectively. Lower concentrations of fouling substances were also observed in the reactors containing algae-activated sludge biomass. Results revealed that addition of algae improved nutrient removal and membrane fouling mitigation. The study also highlighted that the application of electric field in the e-AAS-MBR enhanced organic contaminants and nutrients removal, and fouling rate reduction. (C) 2021 Elsevier B.V. All rights reserved.

关键词： Bioreactors  

摘要： Retinal degeneration is a leading cause of vision impairment and blindness worldwide and medical care for advanced disease does not exist. Stem cell-derived retinal organoids (RtOgs) became an emerging tool for tissue replacement therapy. However, existing RtOg production methods are highly heterogeneous. Controlled and predictable methodology and tools are needed to standardize RtOg production and maintenance. In this study, we designed a shear stress-free micro-millifluidic bioreactor for nearly labor-free retinal organoid maintenance. We used a stereolithography (SLA) 3D printer to fabricate a mold from which Polydimethylsiloxane (PDMS) was cast. We optimized the chip design using in silico simulations and in vitro evaluation to optimize mass transfer efficiency and concentration uniformity in each culture chamber. We successfully cultured RtOgs at three different differentiation stages (day 41, 88, and 128) on an optimized bioreactor chip for more than 1 month. We used different quantitative and qualitative techniques to fully characterize the RtOgs produced by static dish culture and bioreactor culture methods. By analyzing the results from phase contrast microscopy, single-cell RNA sequencing (scRNA seq), quantitative polymerase chain reaction (qPCR), immunohistology, and electron microscopy, we found that bioreactor-cultured RtOgs developed cell types and morphology comparable to static cultured ones and exhibited similar retinal genes expression levels. We also evaluated the metabolic activity of RtOgs in both groups using fluorescence lifetime imaging (FLIM), and found that the outer surface region of bioreactor cultured RtOgs had a comparable free/bound NADH ratio and overall lower long lifetime species (LLS) ratio than static cultured RtOgs during imaging. To summarize, we validated an automated micro-millifluidic device with significantly reduced shear stress to produce RtOgs of comparable quality to those maintained in conventional static culture.

关键词： Membrane bioreactor   Humic acid   Biodegradation   Microbial community function   Water permeability  

摘要： A membrane bioreactor with humic acid substrate (MBR-H) was operated to investigate organic removal and membrane performance. Approximately, 60% of chemical oxygen demand removal was observed in MBR-H. The biosorption capacity reached to the maximum value of 29.2 mg g-1 in the experiments with various activated sludge concentrations and the amount adsorbed on the newly produced microbes was limited. To understand key functions of microorganisms in the biodegradation of humic acid, the microbial community was examined. The dominant phylum was changed from Actinobacteria at the raw sludge to Proteobacteria at the MBR-H. Especially, great increases of beta-, gamma-, and delta-Proteobacteria in the MBR-H indicated that those class of Proteobacteria played a vital role in humic acid removal. Investigation at the genus level showed enrichment of Stenotrophobacter in the MBR-H, which indicated the presence of metabolites in the proposed humic substance degradation pathway. In addition, the bacteria producing extracellular polymeric substances were increased in the MBR-H. Substantial variation of microbial community function was occurred in the MBR to degrade humic acid. Operational parameters in MBRs might be sought to maintain water permeability and to obtain preferable condition to evolution of microbial consortia for degradation of the refractory organic matter.

关键词： 含氰废水   复合厌氧生物滤池   流离生物反应器  

摘要： 利用复合厌氧生物滤池和流离生物反应器组合工艺处理含氰废水,研究了该系统的启动情况和对各污染物质的去除效果。结果表明,该系统在启动阶段逐渐按比例通入工业废水,COD容积负荷由0.1 kg/(m^(3)·d)增加到2.04 kg/(m^(3)·d)时,对COD、NH_(4)^(+)-N和CN^(-)都有较好的去除效果,说明系统具有较好的抗冲击负荷能力;在稳定运行阶段,系统对COD的去除率基本保持80%左右,对CN-的去除效果随进水CN-含量的变化而变化,但是出水CN-的质量浓度基本可以维持在5 mg/L。

关键词： 缺氧/好氧/缺氧-好氧膜生物反应器   污水处理   高盐废水   污泥性质  

摘要： 为了解决高盐榨菜废水厌氧膜生物反应器出水的处理问题,考察了缺氧/好氧/缺氧-膜生物反应器(anacrobic/oxic/anacrobic-membrane bioreactor,AOA-MBR)在不同水力停留时间(hydraulic retention time,HRT)下对高盐榨菜废水厌氧膜生物反应器出水的处理效果,并通过调整硝化液回流比(nitrification liquid reflux ratio,Ro)优化了反应器的运行参数。在进水COD值为3200 mg·L^(−1)、氨氮为400 mg·L^(−1)、盐度为35 g·L^(−1)、溶解氧(dissolved oxygen,DO)浓度为2~4 mg·L^(−1)、温度为25℃左右的条件下,AOA-MBR的最佳运行工况为HRT=4 d、Ro=200%。在此工况下,AOA-MBR的COD去除率为85.4%、氨氮去除率为96.4%,总氮去除率为89.1%。此外,仅依靠AOA-MBR无法实现出水总磷的达标排放,还需要与化学除磷相结合。在运行过程中,污泥浓度在初始高盐冲击下会出现短暂下降现象,随后在逐渐适应了高盐环境后再缓慢上升。长期的高盐环境驯化使体系内可溶性微生物产物(soluble microbial products,SMP)和胞外聚合物(boud extracellular polymeric substances,BEPS)的质量浓度由5.1 mg·g^(−1)和36.9 mg·g^(−1)(以MLVSS计)上升到18.3 mg·g^(−1)和62.5 mg·g^(−1),这可能有利于微生物在高盐环境下的生存。在AOA-MBR的运行过程中,膜组件共进行了5次清洗,而物理清洗+化学清洗的组合清洗方式对于膜污染有更好的清洗效果。

关键词： 植物   重组蛋白   生物反应器   表达系统  

摘要： 由于成本低廉、易于规模化生产、可减少污染哺乳动物病原的风险且能对表达蛋白进行翻译后修饰等优点,植物正逐渐成为一种重要的重组蛋白生产平台,而以转基因植物作为工业与化工产品生产的天然生物反应器也越来越受关注。植物生物反应器主要有稳定表达系统和瞬时表达系统,概述了这两种不同的表达系统的优缺点及其研究进展,并阐述了植物生物反应器的发展趋势,以期为植物生物反应器的发展和应用奠定理论基础。