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A. Martin - One of the best experts on this subject based on the ideXlab platform.
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effect of the organic loading rate on the performance of anaerobic Acidogenic Fermentation of two phase olive mill solid residue
Waste Management, 2008Co-Authors: B Rincon, L Travieso, Francisco Raposo, M A Martin, Enrique Garcia Sanchez, Rafael Borja, A. MartinAbstract:A study of the effect of the organic loading rate (OLR) on the anaerobic Acidogenic Fermentation of two-phase olive mill solid residue (OMSR) derived from fruits with a low ripening index was carried out in a laboratory-scale completely stirred tank reactor at mesophilic temperature (35 degrees C). Eight experimental runs were carried out at OLRs of 3.2, 5.6, 7.4, 9.6, 11.0, 12.9, 14.0 and 15.1g T-COD/ld, which were equivalent to hydraulic retention times of 50.0, 28.8, 21.8, 16.9, 14.7, 12.4, 11.5 and 10.7d, respectively. The experimental results obtained demonstrated that the optimum value of OLR for the Acidogenic Fermentation process was 12.9 g T-COD/ld, for which a maximum production of acetic acid was achieved. It was found that inhibition of the process occurred at OLRs higher than 12.9 g T-COD/ld. This was characterized by a significant decrease in the acetic acid concentration in the effluent and an increase in the concentration of other volatile acids that may affect the methanogenic step. The process inhibition was also characterized by the plateau in the curves of the effluent substrate concentration versus the OLR applied. It was found that a first-order kinetics satisfactorily described the influence of non-acetic acid soluble organic matter concentration (S-COD( *)) on the rate of soluble organic matter conversion to acetic acid (R(S-COD)( *)), and the influence of acetic acid concentration (AcH) on the rate of acetic acid production (R(AcH)), while a potential equation type adequately described the influence of acetic acid concentration on the volumetric hydrogen production (R(ACH) ). The kinetic constant for soluble organic matter removal was 0.145 d(-1), while the constant for acetic acid formation was found to be 0.075 d(-1).
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effect of the organic loading rate on the performance of anaerobic Acidogenic Fermentation of two phase olive mill solid residue
Waste Management, 2008Co-Authors: B Rincon, L Travieso, Francisco Raposo, M A Martin, Rafael Borja, E Sanchez, A. MartinAbstract:A study of the effect of the organic loading rate (OLR) on the anaerobic Acidogenic Fermentation of two-phase olive mill solid residue (OMSR) derived from fruits with a low ripening index was carried out in a laboratory-scale completely stirred tank reactor at mesophilic temperature (35 degrees C). Eight experimental runs were carried out at OLRs of 3.2, 5.6, 7.4, 9.6, 11.0, 12.9, 14.0 and 15.1g T-COD/ld, which were equivalent to hydraulic retention times of 50.0, 28.8, 21.8, 16.9, 14.7, 12.4, 11.5 and 10.7d, respectively. The experimental results obtained demonstrated that the optimum value of OLR for the Acidogenic Fermentation process was 12.9 g T-COD/ld, for which a maximum production of acetic acid was achieved. It was found that inhibition of the process occurred at OLRs higher than 12.9 g T-COD/ld. This was characterized by a significant decrease in the acetic acid concentration in the effluent and an increase in the concentration of other volatile acids that may affect the methanogenic step. The process inhibition was also characterized by the plateau in the curves of the effluent substrate concentration versus the OLR applied. It was found that a first-order kinetics satisfactorily described the influence of non-acetic acid soluble organic matter concentration (S-COD( *)) on the rate of soluble organic matter conversion to acetic acid (R(S-COD)( *)), and the influence of acetic acid concentration (AcH) on the rate of acetic acid production (R(AcH)), while a potential equation type adequately described the influence of acetic acid concentration on the volumetric hydrogen production (R(ACH) ). The kinetic constant for soluble organic matter removal was 0.145 d(-1), while the constant for acetic acid formation was found to be 0.075 d(-1).
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study and optimisation of the anaerobic Acidogenic Fermentation of two phase olive pomace
Process Biochemistry, 2005Co-Authors: Rafael Borja, B Rincon, Francisco Raposo, M A Martin, E Sanchez, A. MartinAbstract:A study of the effect of hydraulic retention time (HRT) on the anaerobic Acidogenic Fermentation of two-phase olive pomace (TPOP) was carried out at laboratory-scale and mesophilic temperature (35 °C). The experimental results obtained demonstrated that the optimum value of HRT for the Acidogenic Fermentation process was 12 days, for which a maximum production of total volatile fatty acids (TVFA) and, specifically, of acetic and butyric acids were obtained. It was found that a multicomponent substrate removal kinetics model adjusted very well to the experimental data obtained. A second-order kinetic model was used for the degradation of non-soluble COD whilst a first-order model was appropriate for studying both the total and soluble COD reduction. The values of the kinetic constants obtained were: 0.29, 0.29 and 0.12 g COD/g VSS per day for non-soluble, total and soluble COD degradation, respectively. A similar model was used to determine the kinetic constants for product formation, obtaining values of: 0.0007, 0.0024, 0.0022, 0.0031 and 0.0022 g COD per litre per day for acetic, propionic, butyric, valeric+caproic and TVFA, respectively. The order of the reaction of volatile fatty acids production was determined in each case, the values being in the range of 1.7–2.4, values very close to second-order. The value of the apparent kinetic constant was minimum for acetic acid formation (0.0009 g COD per litre per day) and maximum for valeric+caproic acids (0.0031 g COD per litre per day) because in the hydrolysis process of complex organic matter, long chain fatty acids appear first and faster than acetic acid. The kinetic model used was validated by comparing the theoretical and experimental values of the product formation rate (RP). The small deviations obtained (in the range between 1.0 and 20.8%) suggest that the proposed model predicts the kinetics of volatile acids production accurately.
Venkata S Mohan - One of the best experts on this subject based on the ideXlab platform.
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salinity induced Acidogenic Fermentation of food waste regulates biohydrogen production and volatile fatty acids profile
Fuel, 2020Co-Authors: Omprakash Sarkar, John Kiran Katari, Sulogna Chatterjee, Venkata S MohanAbstract:Abstract Influence of salinity on Acidogenic Fermentation (AF) specific to the production of biohydrogen (H2), volatile fatty acids (VFA) and biohythane from food waste (FW) was studied by varying salinity concentration [1 g L−1 (S1), 5 g L−1 (S5), 10 g L−1 (S10), 20 g L−1 (S20), 30 g L−1 (S30), 40 g L−1 (S40) and 50 g L−1 (S50)]. Maximum H2 production rate (HPR) of 0.044 L h−1 and cumulative H2 production (CHP) of 1.05 L was achieved at 40 g NaCl L−1 salinity. Hypersaline conditions (>10 g NaCl L−1) suppressed methanogenic activity and resulted in zero methane evolution. Benefits of salinity were also seen on VFA production with accumulation of more butyric acid (C4: 3.04 g L−1) and acetic acid (C2:1.17 g L−1) along with traces of valeric acid (C5:11 mg L−1) with good acidification potential (AP) of 65.38% at 40 g NaCl L−1. Dehydrogenase (DH) enzyme activity was well correlated with H2 production, wherein S40 showed the highest DH activity of 6.77 μg mL−1. Elevated NaCl concentration (50 g L−1) not only suppressed methanogenic activity but also reduced the Acidogenic activity. Increased salinity conditions (30–40 g L−1) depicted good in situ buffering capacity during Acidogenic Fermentation and also aided in higher H2/VFA production. Study illustrated the significance of salinity as a regulator parameter in aiding the bio-conversion of waste to bioenergy and platform chemicals.
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steering acidogenesis towards selective propionic acid production using co factors and evaluating environmental sustainability
Chemical Engineering Journal, 2020Co-Authors: Venkata S Mohan, Shikha Dahiya, Sushmitha LakshminarayananAbstract:Abstract The major challenge faced during Acidogenic Fermentation is the specificity in production of an individual biochemical in the Fermentation broth. The production of biochemicals with special focus on propionic acid (HPr) during Acidogenic Fermentation experiment was studied using cobalt (Co) and zinc (Zn) divalent ions as co-factors individually and synergistically in eleven different systems (RC1, RC2, R1-R7, RCo and RZn). Further, to check the feasibility of HPr production at higher scale, the two scale up systems (RSU1 and RSU2) were operated with the best observed condition. Life cycle assessment (LCA) was also performed using the results pertaining to the best scale up bioreactor (RSU2). Supplementation of Co2+ and Zn2+ synergistically enhanced the HPr fraction among other acids in the Acidogenic Fermentation at their respective optimum concentrations. Biosystem R2 and its respective scale up reactor (RSU2) with Co2+/Zn2+ concentration of 0.10/0.16 mM depicted highest HPr concentration of 1.03 ± 0.05 g/L and 1.22 ± 0.06 g/L, respectively. Although control operated without Co2+/Zn2+ supplementation showed higher total volatile fatty acid (VFA) (3.02 ± 0.15 g/L) production, HPr fraction was observed to be lower in the system. The presence of peaks identified on voltammetric signature corresponding to redox mediator fumarate reductase (+0.030 V) and hydrogenase (2H+/H2) (+0.421 V) supported higher titres of HPr in R1 (Co2+/Zn2+: 0.01/0.06 mM) and R2. Life cycle assessment (LCA) carried out on the performance of HPr production (RSU2) depicted process sustainability with lesser environmental impacts. The results further supported that Co2+/Zn2+ synergistically can drive selective Acidogenic Fermentation towards HPr production.
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acidogenesis of waste activated sludge biohydrogen production with simultaneous short chain carboxylic acids
Journal of environmental chemical engineering, 2018Co-Authors: Venkata S Mohan, Naresh A KumarAbstract:Abstract The potential of waste activated sludge (WAS) as Acidogenic Fermentation feedstock for biohydrogen (H2) and short chain carboxylic acids (SCA) production was studied. Primarily, WAS was subjected to pretreatment using physical, chemical and physicochemical methods to accelerate the SCOD solubilization. Alkaline-catalyzed physiochemical pretreatment of WAS resulted in higher degree of solubilization (DOS) (1% NaOH (v/v): DOS: 40.9%, SCOD: 14.6 g/l) followed by acid (1% H2SO4 (v/v): DOS: 36.4%, SCOD: 8.84 g/l). The organic-rich hydrolysate (alkaline-catalyzed) was Acidogenically fermented for the production of H2 and SCA at varying initial pH conditions (6, 7 and 10) against the untreated WAS as a control. Acidogenic Fermentation of pretreated WAS at pH-10 resulted in higher H2 (29%) and SCA production (4.9 g/l) followed by pH-6 (23%; 3.6 g/l), pH-7 (10%; 1.2 g/l) and control (5%; 0.3 g/l), respectively. SCA distribution profiles were also varied as a function of pH and retention time. Maximum SCA concentration in pH-10 system owed the highest acidification (37.9%) followed by pH-6 (25.5%), pH-7 (8.0%) and control (1.91%). The outcome of the study infers the potential of WAS as a resource for various biobased products synthesis in the framework of biorefinery. Hydrogen is a green fuel and SCA are considered as building blocks for various high-value products synthesis, production of which using WAS addresses the sustainability to current wastewater treatment units.
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Acidogenic Fermentation of vegetable based market waste to harness biohydrogen with simultaneous stabilization
Bioresource Technology, 2009Co-Authors: Venkata S Mohan, G Mohanakrishna, Kannaiah R Goud, P N SarmaAbstract:Vegetable based market waste was evaluated as a fermentable substrate for hydrogen (H(2)) production with simultaneous stabilization by dark-Fermentation process using selectively enriched Acidogenic mixed consortia under acidophilic microenvironment. Experiments were performed at different substrate/organic loading conditions in concurrence with two types of feed compositions (with and without pulp). Study depicted the feasibility of H(2) production from vegetable waste stabilization process. H(2) production was found to be dependent on the concentration of the substrate and composition. Higher H(2) production and substrate degradation were observed in experiments performed without pulp (23.96 mmol/day (30.0 kg COD/m(3)); 13.96 mol/kg COD(R) (4.8 kg COD/m(3))) than with pulp (22.46 mmol/day (32.0 kg COD/m(3)); 12.24 mol/kg COD(R) (4.4 kg COD/m(3))). Generation of higher concentrations of acetic acid and butyric acid was observed in experiments performed without pulp. Data enveloping analysis (DEA) was employed to study the combined process efficiency of system by integrating H(2) production and substrate degradation.
B Rincon - One of the best experts on this subject based on the ideXlab platform.
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effect of the organic loading rate on the performance of anaerobic Acidogenic Fermentation of two phase olive mill solid residue
Waste Management, 2008Co-Authors: B Rincon, L Travieso, Francisco Raposo, M A Martin, Enrique Garcia Sanchez, Rafael Borja, A. MartinAbstract:A study of the effect of the organic loading rate (OLR) on the anaerobic Acidogenic Fermentation of two-phase olive mill solid residue (OMSR) derived from fruits with a low ripening index was carried out in a laboratory-scale completely stirred tank reactor at mesophilic temperature (35 degrees C). Eight experimental runs were carried out at OLRs of 3.2, 5.6, 7.4, 9.6, 11.0, 12.9, 14.0 and 15.1g T-COD/ld, which were equivalent to hydraulic retention times of 50.0, 28.8, 21.8, 16.9, 14.7, 12.4, 11.5 and 10.7d, respectively. The experimental results obtained demonstrated that the optimum value of OLR for the Acidogenic Fermentation process was 12.9 g T-COD/ld, for which a maximum production of acetic acid was achieved. It was found that inhibition of the process occurred at OLRs higher than 12.9 g T-COD/ld. This was characterized by a significant decrease in the acetic acid concentration in the effluent and an increase in the concentration of other volatile acids that may affect the methanogenic step. The process inhibition was also characterized by the plateau in the curves of the effluent substrate concentration versus the OLR applied. It was found that a first-order kinetics satisfactorily described the influence of non-acetic acid soluble organic matter concentration (S-COD( *)) on the rate of soluble organic matter conversion to acetic acid (R(S-COD)( *)), and the influence of acetic acid concentration (AcH) on the rate of acetic acid production (R(AcH)), while a potential equation type adequately described the influence of acetic acid concentration on the volumetric hydrogen production (R(ACH) ). The kinetic constant for soluble organic matter removal was 0.145 d(-1), while the constant for acetic acid formation was found to be 0.075 d(-1).
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effect of the organic loading rate on the performance of anaerobic Acidogenic Fermentation of two phase olive mill solid residue
Waste Management, 2008Co-Authors: B Rincon, L Travieso, Francisco Raposo, M A Martin, Rafael Borja, E Sanchez, A. MartinAbstract:A study of the effect of the organic loading rate (OLR) on the anaerobic Acidogenic Fermentation of two-phase olive mill solid residue (OMSR) derived from fruits with a low ripening index was carried out in a laboratory-scale completely stirred tank reactor at mesophilic temperature (35 degrees C). Eight experimental runs were carried out at OLRs of 3.2, 5.6, 7.4, 9.6, 11.0, 12.9, 14.0 and 15.1g T-COD/ld, which were equivalent to hydraulic retention times of 50.0, 28.8, 21.8, 16.9, 14.7, 12.4, 11.5 and 10.7d, respectively. The experimental results obtained demonstrated that the optimum value of OLR for the Acidogenic Fermentation process was 12.9 g T-COD/ld, for which a maximum production of acetic acid was achieved. It was found that inhibition of the process occurred at OLRs higher than 12.9 g T-COD/ld. This was characterized by a significant decrease in the acetic acid concentration in the effluent and an increase in the concentration of other volatile acids that may affect the methanogenic step. The process inhibition was also characterized by the plateau in the curves of the effluent substrate concentration versus the OLR applied. It was found that a first-order kinetics satisfactorily described the influence of non-acetic acid soluble organic matter concentration (S-COD( *)) on the rate of soluble organic matter conversion to acetic acid (R(S-COD)( *)), and the influence of acetic acid concentration (AcH) on the rate of acetic acid production (R(AcH)), while a potential equation type adequately described the influence of acetic acid concentration on the volumetric hydrogen production (R(ACH) ). The kinetic constant for soluble organic matter removal was 0.145 d(-1), while the constant for acetic acid formation was found to be 0.075 d(-1).
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study and optimisation of the anaerobic Acidogenic Fermentation of two phase olive pomace
Process Biochemistry, 2005Co-Authors: Rafael Borja, B Rincon, Francisco Raposo, M A Martin, E Sanchez, A. MartinAbstract:A study of the effect of hydraulic retention time (HRT) on the anaerobic Acidogenic Fermentation of two-phase olive pomace (TPOP) was carried out at laboratory-scale and mesophilic temperature (35 °C). The experimental results obtained demonstrated that the optimum value of HRT for the Acidogenic Fermentation process was 12 days, for which a maximum production of total volatile fatty acids (TVFA) and, specifically, of acetic and butyric acids were obtained. It was found that a multicomponent substrate removal kinetics model adjusted very well to the experimental data obtained. A second-order kinetic model was used for the degradation of non-soluble COD whilst a first-order model was appropriate for studying both the total and soluble COD reduction. The values of the kinetic constants obtained were: 0.29, 0.29 and 0.12 g COD/g VSS per day for non-soluble, total and soluble COD degradation, respectively. A similar model was used to determine the kinetic constants for product formation, obtaining values of: 0.0007, 0.0024, 0.0022, 0.0031 and 0.0022 g COD per litre per day for acetic, propionic, butyric, valeric+caproic and TVFA, respectively. The order of the reaction of volatile fatty acids production was determined in each case, the values being in the range of 1.7–2.4, values very close to second-order. The value of the apparent kinetic constant was minimum for acetic acid formation (0.0009 g COD per litre per day) and maximum for valeric+caproic acids (0.0031 g COD per litre per day) because in the hydrolysis process of complex organic matter, long chain fatty acids appear first and faster than acetic acid. The kinetic model used was validated by comparing the theoretical and experimental values of the product formation rate (RP). The small deviations obtained (in the range between 1.0 and 20.8%) suggest that the proposed model predicts the kinetics of volatile acids production accurately.
Dongsheng Shen - One of the best experts on this subject based on the ideXlab platform.
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Influence of melanoidins on Acidogenic Fermentation of food waste to produce volatility fatty acids
Bioresource Technology, 2019Co-Authors: Ting Chen, Yuyang Long, Dongsheng ShenAbstract:Abstract Few studies on hydrothermal treatment (HT) of food waste (FW) considered the impact of melanoidins formation due to Maillard reaction on Acidogenic Fermentation. Here, the effects of different melanoidins doses on volatile fatty acid (VFA) production were investigated. Results showed that the solubilization and degradation of proteins can be inhibited by the presence of melanoidins. At the high-dose melanoidins, VFA production from FW was reduced by 12%. Besides, the bovine serum albumin degradation rate declined 22% with the high-dose melanoidins effectively identified their inhibition effect. However, the unaffected carbohydrates utilization led to insignificant VFA disparity at lower doses of melanoidins, because carbohydrates contributed the major VFA yield. The consumption of substrates due to melanoidins formation mainly caused VFA reduction, which contributed to 82% of substantial VFA loss. Therefore, controlling the formation of melanoidins may help the application of HT and enhance the resource recovery from FW.
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characteristics of Acidogenic Fermentation for volatile fatty acid production from food waste at high concentrations of nacl
Bioresource Technology, 2019Co-Authors: Jun Yin, Ting Chen, Jiaze Liu, Dongsheng ShenAbstract:Abstract This study explored the effects of NaCl on volatile fatty acid (VFA) production from food waste by Acidogenic Fermentation. The production and composition of VFAs, and the microbial community in Acidogenic Fermentation were investigated at four different NaCl concentrations: 10, 30, 50, and 70 g/L, and at 0 g/L (control). The highest VFA production was 0.542 g/g dry weight of food waste at 10 g/L NaCl, and about 23% lower but still high at 70 g/L NaCl. Interestingly, as NaCl concentration increased, the residence time of lactic acid in the reactor increased, and the maximum production also increased. The type of Acidogenic Fermentation also changed from butyric acid to propionic acid as the NaCl concentration increased. Microbial community analysis showed that a large number of propionibacteria were present at the end of Fermentation, indicating their high tolerance to NaCl.
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Acidogenic Fermentation characteristics of different types of protein rich substrates in food waste to produce volatile fatty acids
Bioresource Technology, 2017Co-Authors: Dongsheng Shen, Yuyang Long, Xiaoqin Yu, Meizhen Wang, Jiali Shentu, Ting ChenAbstract:Abstract In this study, tofu and egg white, representing typical protein-rich substrates in food waste based on vegetable and animal protein, respectively, were investigated for producing volatile fatty acids (VFAs) by Acidogenic Fermentation. VFA production, composition, conversion pathways and microbial communities in acidogenesis from tofu and egg white with and without hydrothermal (HT) pretreatment were compared. The results showed HT pretreatment could improve the VFA production of tofu but not for egg white. The optimum VFA yields were 0.46 g/g VS (tofu with HT) and 0.26 g/g VS (egg white without HT), respectively. Tofu could directly produce VFAs through the Stickland reaction, while egg white was converted to lactate and VFAs simultaneously. About 30–40% of total protein remained in all groups after Fermentation. Up to 50% of the unconverted soluble protein in the HT groups was protease. More lactate-producing bacteria, mainly Leuconostoc and Lactobacillus, were present during egg white Fermentation.
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Acidogenic Fermentation of the main substrates of food waste to produce volatile fatty acids
International Journal of Hydrogen Energy, 2016Co-Authors: Jun Yin, Kun Wang, Dongsheng ShenAbstract:Abstract Food waste is ideal for producing energy and value-added chemicals (e.g., biohydrogen and volatile fatty acids (VFAs)) in biorefineries. The main food waste components are carbohydrates, proteins, and lipids. Three substrates (glucose, peptone, and glycerol, representing carbohydrates, proteins, and lipids, respectively) were Acidogenically fermented in this study. For each substrate, we investigated Fermentation type and VFAs produced. We used a stoichiometric approach to identify the metabolic pathways through which the substrates were converted. The maximum VFA concentrations for glucose, peptone, glycerol, and a mixture were 38.2, 32.2, 31.1, and 38.5 gCOD/L, respectively. Mixing the substrates increased VFA production, indicating that synergistic effects between microorganisms improved Acidogenic Fermentation. Different Fermentation types occurred for different substrates. Butyric, acetic, and propionic acids were the main products for glucose, peptone, and glycerol, respectively. Glucose was metabolized through three pathways. The metabolism of glycerol was similar to glucose through the “glycerol-pyruvate-VFA” pathway.
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enhancement of Acidogenic Fermentation for volatile fatty acid production from food waste effect of redox potential and inoculum
Bioresource Technology, 2016Co-Authors: Jun Yin, Yuyang Long, Dongsheng Shen, Meizhen Wang, Yeer Zhang, Ting ChenAbstract:The aim of this study was to explore the effects of redox potential (ORP) and inoculum on volatile fatty acids (VFAs) production from food waste by Acidogenic Fermentation. Four experimental conditions with two ORP levels were tested: limited aeration conditions with ORP level of -100 to -200mV inoculating anaerobic sludge (LA+AnS) or aerobic sludge (LA+AeS), and anaerobic conditions with ORP level of -200 to -300mV inoculating anaerobic sludge with 2-bromoethanosulfophate (AN+BES) and without BES (AN). The maximal VFA yield (0.79g COD/g VS) was attained in LA+AnS reactor due to enhanced hydrolysis of substrates, especially proteins (degradation efficiency 78.3%). A higher frequency of phylum Firmicutes under limited aeration conditions (42.2-48.2%) was observed than that under anaerobic conditions (21.1%). The microbial community was more diverse in LA+AnS reactors than LA+AeS. We conclude that appropriate ORP level (from -100 to -200mV) and inoculum play essential roles in VFA production.
Rafael Borja - One of the best experts on this subject based on the ideXlab platform.
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effect of the organic loading rate on the performance of anaerobic Acidogenic Fermentation of two phase olive mill solid residue
Waste Management, 2008Co-Authors: B Rincon, L Travieso, Francisco Raposo, M A Martin, Enrique Garcia Sanchez, Rafael Borja, A. MartinAbstract:A study of the effect of the organic loading rate (OLR) on the anaerobic Acidogenic Fermentation of two-phase olive mill solid residue (OMSR) derived from fruits with a low ripening index was carried out in a laboratory-scale completely stirred tank reactor at mesophilic temperature (35 degrees C). Eight experimental runs were carried out at OLRs of 3.2, 5.6, 7.4, 9.6, 11.0, 12.9, 14.0 and 15.1g T-COD/ld, which were equivalent to hydraulic retention times of 50.0, 28.8, 21.8, 16.9, 14.7, 12.4, 11.5 and 10.7d, respectively. The experimental results obtained demonstrated that the optimum value of OLR for the Acidogenic Fermentation process was 12.9 g T-COD/ld, for which a maximum production of acetic acid was achieved. It was found that inhibition of the process occurred at OLRs higher than 12.9 g T-COD/ld. This was characterized by a significant decrease in the acetic acid concentration in the effluent and an increase in the concentration of other volatile acids that may affect the methanogenic step. The process inhibition was also characterized by the plateau in the curves of the effluent substrate concentration versus the OLR applied. It was found that a first-order kinetics satisfactorily described the influence of non-acetic acid soluble organic matter concentration (S-COD( *)) on the rate of soluble organic matter conversion to acetic acid (R(S-COD)( *)), and the influence of acetic acid concentration (AcH) on the rate of acetic acid production (R(AcH)), while a potential equation type adequately described the influence of acetic acid concentration on the volumetric hydrogen production (R(ACH) ). The kinetic constant for soluble organic matter removal was 0.145 d(-1), while the constant for acetic acid formation was found to be 0.075 d(-1).
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effect of the organic loading rate on the performance of anaerobic Acidogenic Fermentation of two phase olive mill solid residue
Waste Management, 2008Co-Authors: B Rincon, L Travieso, Francisco Raposo, M A Martin, Rafael Borja, E Sanchez, A. MartinAbstract:A study of the effect of the organic loading rate (OLR) on the anaerobic Acidogenic Fermentation of two-phase olive mill solid residue (OMSR) derived from fruits with a low ripening index was carried out in a laboratory-scale completely stirred tank reactor at mesophilic temperature (35 degrees C). Eight experimental runs were carried out at OLRs of 3.2, 5.6, 7.4, 9.6, 11.0, 12.9, 14.0 and 15.1g T-COD/ld, which were equivalent to hydraulic retention times of 50.0, 28.8, 21.8, 16.9, 14.7, 12.4, 11.5 and 10.7d, respectively. The experimental results obtained demonstrated that the optimum value of OLR for the Acidogenic Fermentation process was 12.9 g T-COD/ld, for which a maximum production of acetic acid was achieved. It was found that inhibition of the process occurred at OLRs higher than 12.9 g T-COD/ld. This was characterized by a significant decrease in the acetic acid concentration in the effluent and an increase in the concentration of other volatile acids that may affect the methanogenic step. The process inhibition was also characterized by the plateau in the curves of the effluent substrate concentration versus the OLR applied. It was found that a first-order kinetics satisfactorily described the influence of non-acetic acid soluble organic matter concentration (S-COD( *)) on the rate of soluble organic matter conversion to acetic acid (R(S-COD)( *)), and the influence of acetic acid concentration (AcH) on the rate of acetic acid production (R(AcH)), while a potential equation type adequately described the influence of acetic acid concentration on the volumetric hydrogen production (R(ACH) ). The kinetic constant for soluble organic matter removal was 0.145 d(-1), while the constant for acetic acid formation was found to be 0.075 d(-1).
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study and optimisation of the anaerobic Acidogenic Fermentation of two phase olive pomace
Process Biochemistry, 2005Co-Authors: Rafael Borja, B Rincon, Francisco Raposo, M A Martin, E Sanchez, A. MartinAbstract:A study of the effect of hydraulic retention time (HRT) on the anaerobic Acidogenic Fermentation of two-phase olive pomace (TPOP) was carried out at laboratory-scale and mesophilic temperature (35 °C). The experimental results obtained demonstrated that the optimum value of HRT for the Acidogenic Fermentation process was 12 days, for which a maximum production of total volatile fatty acids (TVFA) and, specifically, of acetic and butyric acids were obtained. It was found that a multicomponent substrate removal kinetics model adjusted very well to the experimental data obtained. A second-order kinetic model was used for the degradation of non-soluble COD whilst a first-order model was appropriate for studying both the total and soluble COD reduction. The values of the kinetic constants obtained were: 0.29, 0.29 and 0.12 g COD/g VSS per day for non-soluble, total and soluble COD degradation, respectively. A similar model was used to determine the kinetic constants for product formation, obtaining values of: 0.0007, 0.0024, 0.0022, 0.0031 and 0.0022 g COD per litre per day for acetic, propionic, butyric, valeric+caproic and TVFA, respectively. The order of the reaction of volatile fatty acids production was determined in each case, the values being in the range of 1.7–2.4, values very close to second-order. The value of the apparent kinetic constant was minimum for acetic acid formation (0.0009 g COD per litre per day) and maximum for valeric+caproic acids (0.0031 g COD per litre per day) because in the hydrolysis process of complex organic matter, long chain fatty acids appear first and faster than acetic acid. The kinetic model used was validated by comparing the theoretical and experimental values of the product formation rate (RP). The small deviations obtained (in the range between 1.0 and 20.8%) suggest that the proposed model predicts the kinetics of volatile acids production accurately.
