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关键词： Anaerobic membrane bioreactor   Beet molasses   Calcium precipitation   Melanoidins   Vinasse  

摘要： Baker's yeast industries (BYI) generate highly polluted effluents, especially vinasse from yeast separators, with very high chemical oxygen demand (COD), nitrogen, sulphate and salts, mainly potassium and calcium. Anaerobic treatment is the most commonly applied method for treating BYI wastewaters. However, it is quite challenging to obtain a high performance due to the difficulties in biomass retention. Moreover, it does not provide compliance with COD and color discharge limits when used as a sole treatment process. In this context, a pilot scale anaerobic membrane bioreactor, which provides excellent biomass retention, was operated to investigate its treatment performance for vinasse from a BYI. The reactor achieved a COD removal between 48% and 92% up to a volumetric load of 10 kg COD m(3) d(-1). A specific methane production of 0.37 m(3) CH4 kg(-1) CODremoved was observed in the study. On the other hand, passage of inert organic compounds through membrane deteriorated permeate quality and treatment efficiency. High alkalinity and pH led to the accumulation of calcium precipitates, which reduced volatile solids fraction of sludge and biomass activity in the reactor. The present study showed the operational challenges and potential drawbacks of AnMBR systems for BYI wastewater treatment. The experience gained in the pilot system can be utilized in the design and operation of full scale AnMBRs for high strength industrial effluents.

关键词： Solution chemistry   Liquid liquid equilibrium   Chromatography   Vapor pressure   Water  

摘要： Because of the depletion of fossil fuels and associated environmental problems, the biotechnological production of 1-butanol used as a gasoline blend is of renewed interest. Biobutanol from biomass is obtained in aqueous solution at low concentration with impurities in the fermentation broth. To perform extraction of biobutanol from the aqueous solution, liquid-liquid (LLE) and vapor-liquid equilibria (VLE) are necessary. With this aim, we determined VLE of two pure compounds (1-butanol and 1,3,5-trimethylbenzene) and two binary systems (n-dodecane + 1-butanol and 1,3,5-trimethylbenzene + 1-butanol) as well as carried out LLE measurements at atmospheric pressure of water + butanol (2, 4, and 6% weight in water) + 1,3,5-trimethylbenzene and water + butanol (6% weight in water) + dodecane and the system (1,3,5-trimethylbenzene + water) at 283.15, 303.15, and 333.15 K. Comparison of the two extraction solvents (1,3,5-trimethylbenzene and n-dodecane) shows that the content of butanol in the aqueous phase is very close and the mole fraction for butanol is twice higher in 1,3,5-trimethylbenzene than in n-dodecane. VLE and LLE results were compared with the literature data, a good agreement is observed in both cases. The non-random two liquid (NRTL) model was used for predicting the ternary systems. The adjustable parameters of the model were determined by regression of the binary data (VLE and LLE). Experimental and predicted mutual solubility values are in good agreement.

关键词： Dynamic membrane bioreactor   Anaerobic membrane bioreactor   Textile wastewater   Cake layer   Membrane fouling  

摘要： The robustness of anaerobic dynamic membrane bioreactor (AnDMBR) for synthetic textile wastewater treatment was investigated. Textile wastewatermay contain high concentrations of NaCl and sulfate, hence their impact on the AnDMBR performancewas investigated in detail. A dynamic membrane was formed on a 20-mu m pore sized nylon support layer at a constant flux of around 8 LMH. In the absence of sulfate addition, total and filtered (soluble) COD averaged 96 +/- 49 mg/L (91% removal) and 75 +/- 35 mg/L (93% removal), respectively. Sulfate addition increased total CODin the permeate to 222 +/- 68 mg/L (79% removal). Average SS concentrationwas lower than 30 mg/L in the permeate although its concentration in the bioreactor reached 10 g/L. Throughout the AnDMBR operation dye removal averaged >97%. Sludge filterability, which was assessed by specific resistance to filtration, supernatant filtration, capillary suction time and viscosity, decreased after sulfate addition. Organic and inorganic matters in the dynamic layer were characterized by SEM-EDS and FTIR analyses. (C) 2020 Elsevier B.V. All rights reserved.

关键词： MBR   Membrane fouling control   Quorum quenching   APQ strategy   AHL  

摘要： Microbial quorum quenching (QQ) has been shown as a promising technology for biofouling control in membrane bioreactors (MBRs). However, QQ technology has never been applied in the industrial wastewater MBR due to the complex water properties. In this study, a type of novel alginate (polyvinyl alcohol)-powdered activated carbon-quorum quenching bacteria beads (APQ beads) was introduced, and the anti-biofouling potential was investigated in an MBR treating semi-conductor wastewater (rich in ethanolamine and diethylene glycol butyl ether). The results show that APQ strategy could significantly alleviate MBR biofouling by extending 4.5 times operating period as compared to the Control-MBR (R1) without APQ beads. The APQ strategy effectively reduced the extracellular polymeric substance (EPS) content and N-acyl homoserine lactones (AHL) concentration in biocake. EPS concentration was reduced by 33.8% and AHLs almost disappeared, probably retarded the adhesion rate of biofilm on the membrane surface, thus displayed a high biofouling mitigation potential. With APQ addition, cake layer membrane resistance was also greatly reduced by 37.22% compared to that of Control-MBR (R1). The QQ activity batch tests confirmed that the used APQ beads still displayed a high AHL-degrading activity and can be employed for long-term operation. (c) 2020 Elsevier Ltd. All rights reserved.

关键词： Lipids   Electrolytic cells   Membranes   Biotechnology   Electrolysis  

摘要： Medium-chain carboxylic acids (MCCAs) are valuable platform chemicals and can be produced from waste biomass sources or syngas fermentation effluent through microbial chain elongation. We have previously demonstrated successful approaches to separate >90% purity oil with different MCCAs (MCCA oil) by integrating the anaerobic bioprocess with membrane-based liquid-liquid extraction (pertraction) and membrane electrolysis. However, two-compartment membrane electrolysis unit without pertraction was not able to separate MCCA oil. Therefore, we developed a five-compartment electrodialysis/phase separation cell (ED/PS). First, we tested an ED/PS cell in series with pertraction and achieved a maximum MCCA-oil flux of 1.7 x 10(3) g d(-1) per projected area (m(2)) (19 mL oil d(-1)) and MCCA-oil transfer efficiency [100% x moles MCCA-oil moles electrons(-1)] of 74% at 15 A m(-2). This extraction system at 15 A m(-2) demonstrated a similar to 10 times lower electric-power consumption (1.1 kWh kg(-1) MCCA oil) than membrane electrolysis in series with pertraction (9.9 kWh kg(-1) MCCA oil). Second, we evaluated our ED/PS as a stand-alone unit when integrated with the anaerobic bioprocess and demonstrated that we can selectively extract and separate MCCA oil directly from chain-elongating bioreactor broth with just an abiotic electrochemical cell. However, the electric-power consumption increased considerably due to the lower MCCA concentrations in the bioreactor broth compared to the pertraction broth.

关键词： Biogas   Elemental sulfur   CSTBR   Hydrogen sulfide   Autotrophic denitrification   Feedback control  

摘要： Biological desulfurization of biogas has been extensively studied using biotrickling filters (BTFs). However, the accumulation of elemental sulfur (S) on the packing material limits the use of this technology. To overcome this issue, the use of a continuous stirred tank bioreactor (CSTBR) under anoxic conditions for biogas desulfurization and S production is proposed in the present study. The effect of the main parameters (stirring speed, N/S molar ratio, hydraulic residence time (HRT) and gas residence time (GRT)) on the bioreactor performance was studied. Under an inlet load (IL) of 100 g S-H2S m(-3) h(-1) and a GRT of 119 s, the CSTBR optimal operating conditions were 60 rpm, N/S molar ratio of 1.1 and a HRT of 42 h, in which a removal efficiency (RE) and S production of 98.6 +/- 0.4 % and 88 % were obtained, respectively. Under a GRT of 41 s and an IL of 232 g S-H2S m(-3) h(-1) the maximum elimination capacity (EC) of 166.0 +/- 7.2 g S-H2S m(-3) h(-1) (RE = 71.7 +/- 3.1 %) was obtained. A proportional-integral feedback control strategy was successfully applied to the bioreactor operated under a stepped variable IL.

关键词： 膜生物反应器   工艺   污水处理  

摘要： 膜生物反应器出水污染物浓度低且水质稳定、膜组件可紧凑拼接占地面积小和微滤膜作用污泥产率低等优点,同时我国当前的水资源现状和膜生物反应器的特点以及相关政策的出台为MBR技术的广泛应用提供了巨大机会本文主要阐述膜生物反应器在污水处理中的应用,供相关人员参考.

关键词： 生物反应器   农村   生活污水   处理   实践研究  

摘要： 农村随意排放的生活污水对水环境造成严重的影响,怎样根据不同的生活污水特征和污染状况,制定科学合理地处理措施、寻求与之相符合的污水处理设备,是解决我国农村生活用水污染的关键所在。生物反应器是一种新型的水处理系统,在污水处理中应用取得了良好的效果。本文将以该型生物反应器为例,进行生物反应器处理污水的实践研究。

关键词： 膜生物   反应器   工艺技术   膜污染   PTA废水  

摘要： 本文将采取膜生物反应器作为主要中心组合工艺对PTA废水予以处置,如此一来,进一步分析组合工艺呈现出的处理效果。根据本次研究不难看出,该工艺对于处置PTA废水来说效果显著,系统抗负荷冲击性高,同时,其出水的品质较高。

关键词： 粉末活性炭   膜生物反应器   印染废水  

摘要： 开展了粉末活性炭膜生物反应器深度处理印染废水的中试研究,探讨了其对出水CODCr、色度、悬浮物的去除效果。结果表明,在粉末活性炭投加量为400~500 mg·L-1的条件下,CODCr、色度、悬浮物的去除率分别达到了55%~68%、80%~92%、74%~92%,出水水质可满足GB 4287-2012《纺织染整工业水污染物排放标准》中表3规定的特别排放限值。中试工程直接运行成本为1.35元·m-3,对于有迫切提标需要的印染工业园区,粉末活性炭膜生物反应器深度处理印染废水在经济上是可行的。