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关键词： Sponge   Anaerobic submerge membrane bioreactor   Membrane fouling   Treatment efficiency   Municipal wastewater  

摘要： This paper investigated a strategy to minimize membrane fouling and increase treatment efficiency through an investigation of a specific approach by adding sponges into a conventional submerged anaerobic membrane bioreactor (CAnSMBR). During the operation, the protein-based soluble microbial products as the main factor affecting the membrane fouling could be reduced by sponge addition in the CAnSMBR (SAnSMBR). Furthermore, reducing HRT from 18 h to 12 h could shorten the membrane fouling cycle to 62% and 87% in CAnSMBR and SAnSMBR, respectively. At the initial of COD/NO 3 ratio ranges from 5 to 4, only 88% of nitrogen in CAnSMBR was removed, while the SAnSMBR could remove more than 90%. TOC removal efficiency could reach more than 95% under a good stirring scenario. It is evident that the SAnSMBR is a promising solution for improving overall CAnSMBR performance and substantially mitigating membrane fouling.

关键词： Cake layer   Membrane fouling   Optical coherence tomography (OCT)   Membrane autopsy   Microbial community  

摘要： Non-invasive analysis and a final destructive analysis were employed to study the fouling formation during the initial days of AS-MBR operation. The fouling layer development was quantified in-situ non invasively with Optical Coherence Tomography (OCT). The increase in biomass thickness was related to the transmembrane pressure (TMP) and to the increase in concentration of soluble microbial products (SMP) in the reactor The OCT non-destructive analysis allowed normalizing the final autopsy values for the amount of biomass deposited on the membrane. After 8 days of operation, the cake layer presented a biomass activity of 400 pg/mm(3) of intra-ATP and EPS concentration of 9.8 mg/mm(3). The microbial community analysis of sludge and biofouling on the membrane surface revealed the abundance of Proteobacteria. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

关键词： Bioethanol   Vacuum membrane distillation   Bioreactor   Permeate fractional condensation   Mechanical vapor compression  

摘要： A vacuum membrane distillation bioreactor (VMDBR) by permeate fractional condensation and mechanical vapor compression with PTFE membrane was developed for bioethanol production. Cell concentration of 11.5 g/L, glucose consumption rate of 5.2 g/L/h and ethanol productivity of 2.3 g/L/h could be obtained with fermentation continues lasting for 140 h. Membrane flux of over 10 kg/m(2)/h could be obtained for model solution separation. Higher temperature and flow rate could promote membrane separation. Membrane flux could be reduced to about 2000 g/m(2)/h with fermentation proceeding owing to the deposited cell on membrane surface. The membrane separation performance could be resumed by water rinse. High ethanol concentration of 421 g/L could be obtained by permeate fractional condensation with the process separation factor increased to 19.2. Energy of only 14 MJ/kg was required in VMDBR and the energy consumption would be reduced further if the compressed vapor could be used to heat the feed.

关键词： Acclimation   Koliella antarctica   Photobioreactor   Photosynthesis   Psychrophilic microalgae   Respiration  

摘要： Effect of temperatures and illumination of temperate winter on photosynthesis and respiration was studied in the psychrophilic microalgae, Koliella antarctica (Tre-bouxiophyceae). Outdoor and indoor algal cultures were compared. Photosynthetic as well as respiration rates increased as light and temperature increased, until 35 degrees C, more in outdoor than in indoor cells, in agreement with the calculated Q(10) values. K. antarctica showed important strategy mechanisms of adaption to the several temperature and light conditions. These significant photo-acclimation and thermo-acclimation abilities make it possible to cultivate Koliella for different uses, under less expensive outdoor conditions. Therefore, K. antarctica shows important strategy mechanisms of adaption to various temperature and light conditions;moreover, by varying the culture conditions, it is possible to modulate and optimize the growth and accordingly the biomass production. This is a very interesting point since it has been proved that this microalga is a promising potential source of functional ingredients, such as polyunsaturated fatty acids and carotenoids, suitable for industrial purposes.

关键词： Denitrification   Nitrate   End-of-pipe  

摘要： The aquaculture industry needs new cost-effective solutions for removing effluent nitrogen to reduce their environmental impact. Recent studies have shown that laboratory and pilot-scale woodchip bioreactors can remove nitrate from aquaculture effluent. Encouraged by these results, several Danish fish farmers recently constructed commercial scale woodchip bioreactors prior to- or integrated into existing free water surface constructed wetlands without knowing the effects of design and upscaling on removal performance. The objective of the current study was to monitor initial performance (first 28-52 weeks of operation) of three such custom-designed denitrifying woodchip bioreactors installed in full-scale (350, 650, and 1250 m(3) woodchips) for effluent treatment at three commercial recirculated rainbow trout (Oncorhynchus mykiss) farms. All three woodchip bioreactors removed nitrogen (essentially nitrate-nitrogen) continuously from the start and at relatively stable rates (5.3-8.5 g N/m(3)/d;4.5-7.8 g NO3-N/m(3)/d) during the investigation period. Leaching of dissolved organic matter continued for up to half a year whereas there was no similar leaching of dissolved phosphorus. A net production of dissolved organic matter was observed under nitrate-limited conditions in one of the bioreactors characterized by a loading of 5.5 compared to 16.4-16.8 g NO3-N/m(3)/d at the other sites, and an empty bed contact time (EBCT) of 26 h compared to 15-16 h at the other sites. An increase in water level difference between inlet and outlet indicated that accumulation of particulate organic matter and associated bacterial growth may lead to head loss potentially reducing the long-term performance of the bioreactors. In conclusion, the study confirms that woodchip bioreactors can be applied at full-scale for removing NO3-N from fish farm effluent. Woodchip bioreactors should be designed to minimize head loss and the risk of clogging, and loading and retention time should ensure th

关键词： Biosolubilization   Rock phosphates   Microbial community  

摘要： In recent years, the biosolubilization of rock phosphates by phosphate-solubilizing microorganisms has become a major topic of research studies. However, the microorganisms used in previous studies were mostly single and known species, and studies seldom focused on mixed communities of microorganisms or microbial consortia from natural environments. In this study, a microbial consortium from rhizospheric soil was used to solubilize two different compositions of medium- to low-grade rock phosphates - designated as ore samples 1 and 2 - in a laboratory-scale bioreactor. The microbial consortium showed good growth in the bioreactor, reduced the suspension pH and released soluble phosphates from the ores. Scanning electron microscopy with energy-dispersive X-ray spectroscopy showed the action of the microbial consortium on the ore surface. There was considerable corrosion on the ore surface, and 3.42 and 4.93 percent of the element phosphorus was removed from ore samples 1 and 2, respectively. Microorganisms were sampled from the bioreactor for the analysis of their community structures by Illumina MiSeq high-throughput sequencing. The analysis show that the suspensions added with different ore samples had different microbial diversities and richness. This study provides new insight into the biosolubilization of rock phosphates by a microbial consortium directly taken from rhizospheric soils.

关键词： Dynamic membrane   Mesh   MBR   IFAS   Wastewater  

摘要： Two lab-scale Self Forming Dynamic Membrane BioReactors (SFD-MBR), equipped with 50 mu m nylon meshes were set up and operated for the treatment of real municipal wastewater. Plastic carriers were added in one of the two bioreactors to generate a combination of the Integrated Fixed-film Activated Sludge (IFAS) and the SFD-MBR technologies. Overall, the two systems performed very well, achieving excellent effluent quality under steady state conditions and showing good resilience to extreme organic loading conditions. Continuous air scouring and periodical mesh cleaning by jet rinsing with tap water were effective in maintaining stable and high productivity (membrane flux around 67 L m(2)h(-1)) over a period of 140 days. The application of the IFAS process resulted in lower production of excess sludge and improved denitrification. On the other hand, under the tested conditions the combined IFAS-SFD-MBR showed a higher tendency to mesh clogging with respect to the SFD-MBR.

关键词： Eclipta prostrata   greywater   SHEFROL (R) bioreactor   vascular plants   wastewater treatment  

摘要： In a first report of its kind, it is shown that the weed Eclipta prostrata is able to treat sewage rapidly and effectively when used in the novel sheet-flow-root-level (SHEFROL (R)) bioreactor developed earlier by the authors. Besides extensive primary and secondary treatment in terms of removal of suspended solids, chemical oxygen demand and biological oxygen demand, E. prostrata was also able to substantially remove the excess nutrients which cause eutrophication (nitrogen and phosphorous) and the heavy metals copper, nickel and manganese. In this manner extensive secondary treatment was achieved along with significant primary and tertiary treatment. Equally significantly it was all accomplished in a single step and at hydraulic retention times (HRTs) of 6 h or less. The system promises to be highly inexpensive and efficient in treating sewage.

关键词： Nutrient removal   Moving bed membrane bioreactor   Sequencing batch reactor   Hydraulic retention time   Microbial community   Wastewater treatment  

摘要： A sequencing batch conventional membrane bioreactor (SB-CMBR) and sequencing batch hybrid membrane bioreactor (SB-HMBR) were operated in parallel under two different hydraulic retention times (HRTs) (namely 12h and 6h), and their chemical oxygen demand (COD) and nutrient removal performance, membrane fouling behavior, and microbial community characteristics were compared. Both systems exhibited high organic matter (>95%) and ammonium (>98%) removal performance regardless of the HRT applied. As the HRT was reduced from 12 to 6h, total nitrogen removal slightly increased in both reactors, being higher in the carrier-based MBR, where anoxic zones may have been established within the biofilm. Conversely, total phosphorus removal improved only in the SB-CMBR at the shorter HRT. Moreover, activity batch assays have shown a faster P uptake rate in the SB-CMBR than in the SB-HMBR, a result likely associated with the lower relative abundance of phosphate-accumulating organisms in both adhered and suspended biomass fractions in the hybrid MBR. The results also revealed that more pronounced increases in the transmembrane pressure and, consequently, in the membrane fouling rate at higher COD loading rates were observed in the SB-CMBR, where the soluble microbial products (proteins, polysaccharides, and especially, transparent exopolymer particles), supernatant turbidity, and filamentous bacteria were more significant. Overall, as compared to the conventional MBR, the plastic media-based SB-HMBR showed a lower fouling propensity at all hydraulic conditions tested.

关键词： scale up   Ambr bioreactor   CFD   k(L)a  

摘要： It is known that process scaling-up has always been a challenge in biopharmaceutical and food industry. In recent years, newly emerging microscale bioreactors like Ambr15 and Ambr250 have attracted significant attention for that they can provide high throughput and accelerate upstream process development. In this work, we developed the first multiphase Computational Fluid Dynamics (CFD) model for an in-depth characterization of Ambr bioreactor systems. A number of advanced computational methods, including Reynolds stress turbulence model, population balance model, multiple reference frame (MRF), sliding mesh (SM) and user defined functions (UDFs), were integrated for the first time to systematically study the gas-liquid mixing in Ambr250 bioreactor. We provided detailed comparison between MRF and SM method, demonstrated the limitation of MRF for predicting bubble distribution in asymmetric reactors. Characteristics of hydrodynamics, mass transfer, turbulent dissipation and bubble size distribution were predicted from our CFD models and validated by existing experimental data for a variety of operating conditions for both the Ambr15 and Ambr250 bioreactors. The predicted k(L)a value ranges are 0.18-7.90 h(-1) and 2.15-11.52 h(-1) for Ambr250 and Ambr15, respectively. This work thus provides a superior framework for the computational modeling of microscale stirred bioreactors.