scholarly journals Diauxie Studies in Biogas Production from Gelatin and Adaptation of the Modified Gompertz Model: Two-Phase Gompertz Model

2021 ◽  
Vol 11 (3) ◽  
pp. 1067
Author(s):  
Carolina Scaraffuni Gomes ◽  
Martin Strangfeld ◽  
Michael Meyer
Keyword(s):  
Anaerobic Degradation ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Gompertz Model ◽  
Direct Consequence ◽  
High Accuracy ◽  
Batch Reactors ◽  
Two Phase ◽  
Accurate Representation ◽  
Modified Gompertz Model

The anaerobic degradation of gelatin results in a two-phase cumulative biogas production curve, i.e., diauxie behaviour. The modified Gompertz model is normally used to fit these curves but due to the diauxie it would result in a less accurate representation. Furthermore, this inhibition slows down the production of biogas in batch reactors. This study adapted the modified Gompertz model to fit cumulative biogas production curves with diauxie behaviour and to investigate the inhibition that leads to this diauxie. Results show that the two-phase Gompertz model can fit diauxie curves with high accuracy and that diauxie curves are not a direct consequence of the accumulation of volatile fatty acids produced in the process of anaerobic digestion.

scholarly journals Microbial and Phenyl Acid Dynamics during the Start-up Phase of Anaerobic Straw Degradation in Meso- and Thermophilic Batch Reactors

2019 ◽  
Vol 7 (12) ◽  
pp. 657 ◽  
Author(s):  
Eva Maria Prem ◽  
Rudolf Markt ◽  
Nina Lackner ◽  
Paul Illmer ◽  
Andreas Otto Wagner
Keyword(s):  
Anaerobic Degradation ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Lignocellulose Degradation ◽  
Batch Reactors ◽  
Highly Active ◽  
Start Up ◽  
Negative Effect ◽  
Complex Organic ◽  
Generation Sequencing

Aromatic compounds like phenyl acids derived from lignocellulose degradation have been suspected to negatively influence biogas production processes. However, results on this topic are still inconclusive. To study phenyl acid formation in batch reactors during the start-up phase of anaerobic degradation, different amounts of straw from grain were mixed with mesophilic and thermophilic sludge, respectively. Molecular biological parameters were assessed using next-generation sequencing and qPCR analyses. Metagenomic predictions were done via the program, piphillin. Methane production, concentrations of phenylacetate, phenylpropionate, phenylbutyrate, and volatile fatty acids were monitored chromatographically. Methanosarcina spp. was the dominant methanogen when high straw loads were effectively degraded, and thus confirmed its robustness towards overload conditions. Several microorganisms correlated negatively with phenyl acids; however, a negative effect, specifically on methanogens, could not be proven. A cascade-like increase/decrease from phenylacetate to phenylpropionate, and then to phenylbutyrate could be observed when methanogenesis was highly active. Due to these results, phenylacetate was shown to be an early sign for overload conditions, whereas an increase in phenylbutyrate possibly indicated a switch from degradation of easily available to more complex substrates. These dynamics during the start-up phase might be relevant for biogas plant operators using complex organic wastes for energy exploitation.

scholarly journals Effect of Mechanical Pre-Treatment of the Agricultural Substrates on Yield of Biogas and Kinetics of Anaerobic Digestion

2018 ◽  
Vol 10 (10) ◽  
pp. 3669 ◽  
Author(s):  
Józef Szlachta ◽  
Hubert Prask ◽  
Małgorzata Fugol ◽  
Adam Luberański
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Gompertz Model ◽  
Model Parameters ◽  
Production Potential ◽  
Pre Treatment ◽  
Sorghum Silage ◽  
Kinetics Of ◽  
Degree Of Fragmentation ◽  
Modified Gompertz Model

The effect of mechanical pre-treatment of nine different agricultural substrates minced to particle sizes of 1.5 mm, 5 mm and 10 mm on biogas and methane yields and fermentation kinetics was investigated. The results showed, that for five of the nine tested substrates (grass, Progas rye, Palazzo rye, tall wheatgrass, beet), a higher biogas production was obtained for the degree of fragmentation of 10 mm compared to fragmentation of 5 mm and 1.5 mm. For fragmentation of 5 mm, the highest biogas production was achieved for sorghum silage, Atletico maize and Cannavaro maize—649.80, 735.59 and 671.83 Nm3/Mg VS, respectively. However, for the degree of fragmentation of 1.5 mm, the highest biogas production (510.43 Nm3/Mg volatile solid (VS)) was obtained with Topinambur silage. The modified Gompertz model fitted well the kinetics of anaerobic digestion of substrates and show a significant dependence of the model parameters Hmax (biogas production potential) and Rmax (maximum rate of biogas production) on the degree of substrate fragmentation.

scholarly journals Thermophilic Anaerobic Co-Digestion of Exhausted Sugar Beet Pulp with Cow Manure to Boost the Performance of the Process: The Effect of Manure Proportion

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 67
Author(s):  
Xiomara Gómez-Quiroga ◽  
Kaoutar Aboudi ◽  
Luis Alberto Fernández-Güelfo ◽  
Carlos José Álvarez-Gallego ◽  
Luis Isidoro Romero-García
Keyword(s):  
Sugar Beet ◽  
Rural Areas ◽  
Volatile Fatty Acids ◽  
Gompertz Model ◽  
Sugar Beet Pulp ◽  
Cow Manure ◽  
Methane Generation ◽  
Beet Pulp ◽  
By Products ◽  
Modified Gompertz Model

Sugar beet by-products are a lignocellulosic waste generated from sugar beet industry during the sugar production process and stand out for their high carbon content. Moreover, cow manure (CM) is hugely produced in rural areas and livestock industry, which requires proper disposal. Anaerobic digestion of such organic wastes has shown to be a suitable technology for these wastes valorization and bioenergy production. In this context, the biomethane production from the anaerobic co-digestion of exhausted sugar beet pulp (ESBP) and CM was investigated in this study. Four mixtures (0:100, 50:50, 75:25, and 90:10) of cow manure and sugar beet by-products were evaluated for methane generation by thermophilic batch anaerobic co-digestion assays. The results showed the highest methane production was observed in mixtures with 75% of CM (159.5 mL CH4/g VolatileSolids added). Nevertheless, the hydrolysis was inhibited by volatile fatty acids accumulation in the 0:100 mixture, which refers to the assay without CM addition. The modified Gompertz model was used to fit the experimental results of methane productions and the results of the modeling show a good fit between the estimated and the observed data.

Effects of disintegration on anaerobic degradation of sewage excess sludge in downflow stationary fixed film digesters

2000 ◽  
Vol 41 (3) ◽  
pp. 171-179 ◽  
Author(s):  
M. Engelhart ◽  
M. Krüger ◽  
J. Kopp ◽  
N. Dichtl
Keyword(s):  
Anaerobic Degradation ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Soluble Proteins ◽  
Excess Sludge ◽  
Mechanical Pretreatment ◽  
Volatile Solids ◽  
Fixed Film ◽  
High Pressure Homogenizer ◽  
Anaerobic Digestibility

The effects of mechanical disintegration on anaerobic digestibility of sewage excess sludge in downflow stationary fixed film (DSFF) digesters were investigated on laboratory scale. Mechanical pretreatment using a high pressure homogenizer led to significantly enhanced concentrations of soluble proteins and carbohydrates in the feed sludge. Using DSFF digesters with two different tubular plastic media as support material it was shown that a stable digestion process could be achieved at hydraulic retention times (HRT) down to 5 days. Compared to conventional digesters at 10 d and 15 d HRT respectively, the degradation of volatile solids was enhanced up to 25%, also resulting in a higher specific biogas production. Further investigations on degradation of soluble proteins and carbohydrates showed that a slowly degradable fraction of carbohydrates was released via disintegration. Using the distribution of chain length and the concentrations of volatile fatty acids as process parameters, the dependability on the HRT and the degree of disintegration (the release of soluble COD) predominated the effects of specific surface area of the support media.

scholarly journals Application of Modified Gompertz Model to Study on Biogas production from middle temperature co-digestion of pig manure and dead pigs

2019 ◽  
Vol 118 ◽  
pp. 03022
Author(s):  
Hongguang Zhu ◽  
Jing Yang ◽  
Cheng Xiaowei
Keyword(s):  
Anaerobic Digestion ◽  
Degradation Rate ◽  
Biogas Production ◽  
Raw Materials ◽  
Gompertz Model ◽  
Gas Production ◽  
Raw Material ◽  
Pig Manure ◽  
Middle Temperature ◽  
Modified Gompertz Model

The dead pig is an organic waste rich in oil and protein, and is an ideal anaerobic digestion raw material. This study based on single factor ANOVA and Modified Gompertz model. It investigated the effects of the ratio of dead pigs on biogas production by middle temperature co-digestion of pig manure and dead pigs. And the biogas production potential was determined. The results showed that there was no significant correlation between the ratio of dead pigs and the biogas production. The ratio would significantly affect the average methane content and degradation rate. When the addition ratio was in the range of 3 to 15%, the biogas production was between 191.39 and 202.44 (L/kg VS). The average contents of methane were 50.67%, 50.35%, 41.83%, 45.53% and 44.57%, respectively. The time required to reach 80% of the biogas production was 28, 34, 36, 65 and 63 days, respectively. The degradation rate of the raw materials was generally decreased with the increase of the addition ratio. The results of Modified Gompertz model fitting showed that the mixed raw materials had a fully anaerobic digestion with high utilization rate and short hysteresis in the range of 0 ~ 9%. Therefore, a hydraulic retention time (HRT) of 30 days and the addition ratio was in the range of 0 to 6% could be recommended for a continuous digester. It could get a better gas production and higher raw material utilization.

scholarly journals Performance and Kinetic Model of a Single-Stage Anaerobic Digestion System Operated at Different Successive Operating Stages for the Treatment of Food Waste

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 600 ◽  
Author(s):  
Sagor Kumar Pramanik ◽  
Fatihah Binti Suja ◽  
Mojtaba Porhemmat ◽  
Biplob Kumar Pramanik
Keyword(s):  
Experimental Data ◽  
Anaerobic Digestion ◽  
Kinetic Model ◽  
Removal Efficiency ◽  
Food Waste ◽  
Biogas Production ◽  
Gompertz Model ◽  
Methane Yield ◽  
Biogas Yield ◽  
Modified Gompertz Model

A large quantity of food waste (FW) is generated annually across the world and results in environmental pollution and degradation. This study investigated the performance of a 160 L anaerobic biofilm single-stage reactor in treating FW. The reactor was operated at different hydraulic retention times (HRTs) of 124, 62, and 35 days under mesophilic conditions. The maximum biogas and methane yield achieved was 0.934 L/g VSadded and 0.607 L CH4/g VSadded, respectively, at an HRT of 124 days. When HRT decreased to 62 days, the volatile fatty acid (VFA) and ammonia accumulation increased rapidly whereas pH, methane yield, and biogas yield decreased continuously. The decline in biogas production was likely due to shock loading, which resulted in scum accumulation in the reactor. A negative correlation between biogas yield and volatile solid (VS) removal efficiency was also observed, owing to the floating scum carrying and urging the sludge toward the upper portion of the reactor. The highest VS (79%) and chemical oxygen demand (COD) removal efficiency (80%) were achieved at an HRT of 35 days. Three kinetic models—the first-order kinetic model, the modified Gompertz model, and the logistic function model—were used to fit the cumulative biogas production experimental data. The kinetic study showed that the modified Gompertz model had the best fit with the experimental data out of the three models. This study demonstrates that the stability and performance of the anaerobic digestion (AD) process, namely biogas production rate, methane yield, intermediate metabolism, and removal efficiency, were significantly affected by HRTs.

scholarly journals Effects of Salt on Anaerobic Digestion of Food Waste with Different Component Characteristics and Fermentation Concentrations

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3571 ◽  
Author(s):  
Li ◽  
Huang ◽  
Liu ◽  
Huang ◽  
Maurer ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Food Processing ◽  
Biogas Production ◽  
Gompertz Model ◽  
Salt Addition ◽  
Vs Removal ◽  
Processing Effects ◽  
Kinetics Of ◽  
Modified Gompertz Model

Effects of salt on anaerobic digestion are dosage-dependent. As salt is a widely used condiment in food processing, effects of salt are bound to be considered when food waste is digested. In this study, salt addition effects (0, 2, 4, 6, 9, 12 g∙L−1) on biogas and methane yields and kinetics of biogas production were researched. Meanwhile, component characteristics (food waste featured in carbohydrate, protein and fat, respectively) and fermentation concentrations (5 and 8 gVS∙L−1) were also taken into consideration. Results showed that 2–4 g∙L−1 salt addition was the optimal addition dosage for AD systems as they not only have the maximum biogas and methane yields, but also the maximum vs. removal in most cases. Also, according to the results of a modified Gompertz model, which is used to predict biogas and methane production rates, suitable salt addition can accelerate biogas production, improving the maximum biogas production rate (Rmax). Factorial design (2 × 2) proved that interaction of salt and fermentation concentrations was significant for food waste featured with carbohydrate and with protein (p <0.05). High salt addition and fermentation concentration can break the AD system when the feeding material was food waste featured with carbohydrate, but for food waste featured with protein, interaction of fermentation concentrations and salt addition can alleviate inhibition degrees.

scholarly journals The Use of Lignin as a Microbial Carrier in the Co-Digestion of Cheese and Wafer Waste

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2073 ◽  
Author(s):  
Agnieszka A. Pilarska ◽  
Agnieszka Wolna-Maruwka ◽  
Krzysztof Pilarski ◽  
Damian Janczak ◽  
Krzysztof Przybył ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Cell Immobilization ◽  
Total Alkalinity ◽  
Batch Reactors ◽  
Adhesive Properties ◽  
Volatile Solids ◽  
Wide Ph Range ◽  
Ph Range ◽  
Microbiological Analyses

The aim of the article was to present the effects of lignin grafted with polyvinylpyrrolidone (PVP) as a microbial carrier in anaerobic co-digestion (AcoD) of cheese (CE) and wafer waste (WF). Individual samples of waste cheese and wafers were also tested. The PVP modifier was used to improve the adhesive properties of the carrier surface. Lignin is a natural biopolymer which exhibits all the properties of a good carrier, including nontoxicity, biocompatibility, porosity, and thermal stability. Moreover, the analysis of the zeta potential of lignin and lignin combined with PVP showed their high electrokinetic stability within a wide pH range, that is, 4–11. The AcoD process was conducted under mesophilic conditions in a laboratory by means of anaerobic batch reactors. Monitoring with two standard parameters: pH and the VFA/TA ratio (volatile fatty acids-to-total alkalinity ratio) proved that the process was stable in all the samples tested. The high share of N–NH4+ in TKN (total Kjeldahl nitrogen), which exceeded 90% for WF+CE and CE at the last phases of the process, proved the effective conversion of nitrogen forms. The microbiological analyses showed that eubacteria proliferated intensively and the dehydrogenase activity increased in the samples containing the carrier, especially in the system with two co-substrates (WF+CE/lignin) and in the waste cheese sample (CE/lignin). The biogas production increased from 1102.00 m3 Mg−1 VS (volatile solids) to 1257.38 m3 Mg−1 VS in the WF+CE/lignin sample, and from 881.26 m3 Mg−1 VS to 989.65 m3 Mg−1 VS in the CE/lignin sample. The research results showed that the cell immobilization on lignin had very positive effect on the anaerobic digestion process.

scholarly journals Evaluation of the aerobic and anaerobic degradation of an industrial effluent from vegetable tannery processing of leather on batch reactors

2020 ◽  
Keyword(s):  
Chemical Oxygen Demand ◽  
Industrial Wastewater ◽  
Anaerobic Degradation ◽  
Volatile Fatty Acids ◽  
Industrial Effluent ◽  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Tannery Effluent ◽  
Batch Reactors ◽  
Aerobic And Anaerobic

<p>In this study, the aerobic and anaerobic biodegradability of the industrial wastewater from the vegetable tanning process were evaluated. Water from a food wastewater treatment system was used as seed inoculum for the aerobic process and mature granular methanogenic sludge from a brewery industrial wastewater plant was used for the anaerobic process. The water from the tanning industry had a biological to chemical oxygen demand ratio of 33% with values of total chemical oxygen demand (COD) in the range of 342000 mg O2/L and total dissolved solids of 506595 mg/L. The assay of the tannery effluent under aerobic conditions resulted in a decrease of COD of 39.2% and a degradation of tannins lower than 12% after 26 days, while the anaerobic degradation showed a COD reduction of 65% with a 39% of degradation of tannins. The production of methane and Volatile Fatty Acids, during the anaerobic treatment, suggests a potential adaptation of biological organisms present in the mature anaerobic granular methanogenic sludge.</p>

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