The Experts below are selected from a list of 18597 Experts worldwide ranked by ideXlab platform
Tzyy Haur Chong - One of the best experts on this subject based on the ideXlab platform.
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recycling rainwater by submerged gravity driven membrane gdm reactors effect of Hydraulic Retention Time and periodic backwash
Science of The Total Environment, 2019Co-Authors: Genevieve Soon, Tzyy Haur ChongAbstract:Abstract Rainwater recycling has been considered as an alternative cost-effective decentralized water supply. The low cost and effective gravity-driven membrane (GDM) filtration technology has been introduced to treat the rainwater prior use. In this study, we investigated the effects of Hydraulic Retention Time (HRT; 27 h, 51 h, and 156 h) and periodic backwash durations (2 min, 5 min, 10 min, and 30 min per 2–3 days' filtration) on the permeate quality, flux and fouling mechanism in lab-scale submerged GDM reactors. Compared to the performance at HRT of 51 h (40% of DOC removal and ~2.9 L/m2 h), better permeate quality and higher membrane flux were achieved at HRT of 27 h (51% of DOC removal and ~4.2 L/m2 h) and 156 h (48% of DOC removal and ~5.0 L/m2 h). Although the Hydraulically reversible resistance was predominant (up to 90% of the total fouling resistance), the permeate flux could not be fully recovered by periodic backwash, regardless of the backwash durations. After several filtration-backwash cycles, the stabilized flux of GDM reactor with backwash was even worse than those without backwash. However, no correlation can be established between the stabilized flux (i.e., cake layer resistance) and the soluble organics and microbial cells in the cake layer of the GDM system during rainwater treatment.
Jianzheng Li - One of the best experts on this subject based on the ideXlab platform.
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modeling the dynamic volatile fatty acids profiles with ph and Hydraulic Retention Time in an anaerobic baffled reactor during the startup period
Bioresource Technology, 2016Co-Authors: Jianzheng Li, Philip AntwiAbstract:To predict the dynamic profiles in volatile fatty acids (VFAs) with pH and Hydraulic Retention Time (HRT) during the startup of a 4-compartment ABR, a mathematical model was constructed by introducing pH and thermodynamic inhibition functions into the biochemical processes derived from the ADM1. The calibration of inhibition parameter for propionate uptake effectively improved the prediction accuracy of VFAs. The developed model could simulate the VFAs profiles very well no matter the observable change of pH or/and HRT. The simulation results indicated that both H2-producing acetogenesis and methanogenesis in the ABR would be inhibited with a pH less than 4.61, and the propionate oxidation could be thermodynamically restricted even with a neutral pH. A decreased HRT would enhanced the acidogenesis and H2-producing acetogenesis in the first 3 compartments, but no observable increase in effluent VFAs could be found due to the synchronously enhanced methanogenesis in the last compartment.
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performance 5 aminolevulinic acid ala yield and microbial population dynamics in a photobioreactor system treating soybean wastewater effect of Hydraulic Retention Time hrt and organic loading rate olr
Bioresource Technology, 2016Co-Authors: Jie Zhang, Xiangkun Li, Jianzheng LiAbstract:Abstract Effects of Hydraulic Retention Time (HRT) and influent organic loading rate (OLR) were investigated in a photobioreactor containing PNSB ( Rhodobacter sphaeroides )-chemoheterotrophic bacteria to treat soybean wastewater. Pollutants removal, biomass production and ALA yield in different phases were investigated in together with functional microbial population dynamics. The results showed that proper HRT and OLR increased the photobioreactor performance including pollutants removal, biomass and ALA productions. 89.5% COD, 90.6% TN and 91.2% TP removals were achieved as well as the highest biomass production of 2655 mg/L and ALA yield of 7.40 mg/g-biomass under the optimal HRT of 60 h and OLR of 2.48 g/L/d. In addition, HRT and OLR have important impacts on PNSB and total bacteria dynamics.
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performance carotenoids yield and microbial population dynamics in a photobioreactor system treating acidic wastewater effect of Hydraulic Retention Time hrt and organic loading rate olr
Bioresource Technology, 2016Co-Authors: Jie Zhang, Xiangkun Li, Jianzheng LiAbstract:Abstract Effects of Hydraulic Retention Time (HRT) and influent organic loading rate (OLR) were investigated in a photobioreactor containing PNSB ( Rhodopseudomonas palustris )-chemoheterotrophic bacteria to treat volatile fatty acid wastewater. Pollutants removal, biomass production and carotenoids yield in different phases were investigated in together with functional microbial population dynamics. The results indicated that properly decreasing HRT and increasing OLR improved the nutrient removal performance as well as the biomass and carotenoids productions. 85.7% COD, 89.9% TN and 91.8% TP removals were achieved under the optimal HRT of 48 h and OLR of 2.51 g/L/d. Meanwhile, the highest biomass production and carotenoids yield were 2719.3 mg/L and 3.91 mg/g-biomass respectively. In addition, HRT and OLR have obvious impacts on PNSB and total bacteria dynamics. Statistical analyses indicated that the COD removal exhibited a positive relationship with OLR, biomass and carotenoids production. PNSB/total bacteria ratio had a positive correlation with the carotenoids yield.
Genevieve Soon - One of the best experts on this subject based on the ideXlab platform.
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recycling rainwater by submerged gravity driven membrane gdm reactors effect of Hydraulic Retention Time and periodic backwash
Science of The Total Environment, 2019Co-Authors: Genevieve Soon, Tzyy Haur ChongAbstract:Abstract Rainwater recycling has been considered as an alternative cost-effective decentralized water supply. The low cost and effective gravity-driven membrane (GDM) filtration technology has been introduced to treat the rainwater prior use. In this study, we investigated the effects of Hydraulic Retention Time (HRT; 27 h, 51 h, and 156 h) and periodic backwash durations (2 min, 5 min, 10 min, and 30 min per 2–3 days' filtration) on the permeate quality, flux and fouling mechanism in lab-scale submerged GDM reactors. Compared to the performance at HRT of 51 h (40% of DOC removal and ~2.9 L/m2 h), better permeate quality and higher membrane flux were achieved at HRT of 27 h (51% of DOC removal and ~4.2 L/m2 h) and 156 h (48% of DOC removal and ~5.0 L/m2 h). Although the Hydraulically reversible resistance was predominant (up to 90% of the total fouling resistance), the permeate flux could not be fully recovered by periodic backwash, regardless of the backwash durations. After several filtration-backwash cycles, the stabilized flux of GDM reactor with backwash was even worse than those without backwash. However, no correlation can be established between the stabilized flux (i.e., cake layer resistance) and the soluble organics and microbial cells in the cake layer of the GDM system during rainwater treatment.
Seokhwan Hwang - One of the best experts on this subject based on the ideXlab platform.
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mesophilic acidogenesis of food waste recycling wastewater effects of Hydraulic Retention Time ph and temperature
Applied Biochemistry and Biotechnology, 2016Co-Authors: Gyuseong Han, Seung Gu Shin, Joonyeob Lee, Changsoo Lee, Seokhwan HwangAbstract:The effects of Hydraulic Retention Time (HRT), pH, and operating temperature (T OP) on the degradation of food waste-recycling wastewater (FRW) were investigated in laboratory-scale hydrolysis/acidogenesis reactors. Response surface analysis was used to approximate the production of volatile organic acids and degradation of volatile suspended solids (VSS), carbohydrate, protein, and lipid with regard to the independent variables (1 ≤ HRT ≤ 3 days, 4 ≤ pH ≤ 6, 25 ≤ T OP ≤ 45 °C). Partial cubic models adequately approximated the corresponding response surfaces at α < 5 %. The physiological conditions for maximum acidification (0.4 g TVFA + EtOH/g VSadded) and the maximal degradation of VSS (47.5 %), carbohydrate (92.0 %), protein (17.7 %), and lipid (73.7 %) were different. Analysis of variance suggested that pH had a great effect on the responses in most cases, while T OP and HRT, and their interaction, were significant in some cases. Denaturing gradient gel electrophoresis analysis revealed that Sporanaerobacter acetigenes, Lactobacillus sp., and Eubacterium pyruvivorans-like microorganisms might be main contributors to the hydrolysis and acidogenesis of FRW. Biochemical methane potential test confirmed higher methane yield (538.2 mL CH4/g VSadded) from an acidogenic effluent than from raw FRW.
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effect of temperature and Hydraulic Retention Time on volatile fatty acid production based on bacterial community structure in anaerobic acidogenesis using swine wastewater
Bioprocess and Biosystems Engineering, 2013Co-Authors: Woong Kim, Seung Gu Shin, Juntaek Lim, Seokhwan HwangAbstract:To investigate the effect of Hydraulic Retention Time (HRT) and temperature (T) on bacterial community structure and volatile fatty acids (VFAs) production of an acidogenic process, and VFA production and changes in the bacterial community in three identical automated anaerobic continuously-stirred tank reactors were analyzed using response surface analysis (RSA) and nonmetric multidimensional scaling (NMDS). For RSA, 11 trials were conducted to find the combination of T and HRT under which VFA production was greatest; VFA production was affected more by HRT than by T. To identify the bacterial community structure in each trial, DNA from each experimental point of the RSA was analyzed using denaturating gradient gel electrophoresis (DGGE), and eight bacteria species were detected. NMDS was conducted on band intensities obtained using DGGE, and bacterial community structure was affected more by T than by HRT. Taken together, these results suggest that VFA production during acidogenesis was more dependent on the physicochemical properties of acidogens, such as their specific growth rate or contact Time with of substrates, than on changes in the microbial community.
Byoungin Sang - One of the best experts on this subject based on the ideXlab platform.
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continuous hydrogen and butyric acid fermentation by immobilized clostridium tyrobutyricum atcc 25755 effects of the glucose concentration and Hydraulic Retention Time
Bioresource Technology, 2009Co-Authors: Robert J Mitchell, Ji Seong Kim, Byung Seung Jeon, Byoungin SangAbstract:The effects of the Hydraulic Retention Time (HRT = 8, 10, 12 or 16.7 h) and glucose concentration (30, 40 or 50 g/L) on the production of hydrogen and butyrate by an immobilized Clostridium tyrobutyricum culture, grown under continuous culturing conditions, were evaluated. With 30 g/L glucose, the higher HRTs tested led to greater butyrate concentrations in the culture, i.e., 9.3 g/L versus 12.9 g/L with HRTs of 8 h and 16.7 h, respectively. In contrast, higher biogas and hydrogen production rates were generally seen when the HRT was lower. Experiments with different glucose concentrations saw a significant amount of glucose washed out when 50 g/L was used, the highest being 22.7 g/L when the HRT was 16.7 h. This study found the best conditions for the continuous production of hydrogen and butyric acid by C. tyrobutyricum to be with an HRT of 12 h and a glucose concentration of 50 g/L, respectively.
