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 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.

Sludge accumulation and methanogenic activity in an anaerobic lagoon

2000 ◽  
Vol 42 (10-11) ◽  
pp. 247-255 ◽  
Author(s):  
J. Paing ◽  
B. Picot ◽  
J. P. Sambuco ◽  
A. Rambaud
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Anaerobic Degradation ◽  
Volatile Fatty Acids ◽  
Anaerobic Fermentation ◽  
Methanogenic Activity ◽  
Start Up ◽  
Anaerobic Lagoon ◽  
Methane Production Rate ◽  
Sludge Accumulation

Sludge accumulation and the characteristics of anaerobic digestion in sludge had been investigated in a primary anaerobic lagoon. Methanogenic potential of sludge was evaluated by an anaerobic digestion test which measured the methane production rate. Sludge was sampled at several points in the lagoon to determine spatial variations and with a monthly frequency from the start-up of the lagoon to observe the development of anaerobic degradation. Maximum amounts of sludge accumulated near the inlet. The mean methane production of sludge was 2.9 ml gVS–1 d–1. Sludge near the outlet presented a greater methanogenic activity and a lesser concentration of volatile fatty acids than near the inlet. The different stages of anaerobic degradation were spatially separated, acidogenesis near the inlet and methanogenesis near the outlet. This staged distribution seemed to increase efficiency of anaerobic fermentation compared with septic tanks. Methane release at the surface of the lagoon was estimated to be very heterogeneous with a mean of 25 l m–2 d–1. The development of performance and sludge characteristics showed the rapid beginning of methanogenesis, three months after the start-up of the anaerobic lagoon. Considering the volume of accumulated sludge, it could however be expected that methanogenic activity would further increase.

Start-Up Operation and Hydraulic Retention Time Selectivity for Palm Oil Mill Wastewater at Mesophilic Temperature in Anaerobic Suspended Growth Closed Bioreactor

2014 ◽  
Vol 955-959 ◽  
pp. 1330-1334
Author(s):  
Yee Shian Wong ◽  
Tjoon Tow Teng ◽  
Soon An Ong ◽  
Morad Norhashimah ◽  
Mohd Rafatullah
Keyword(s):  
Palm Oil ◽  
Retention Time ◽  
Anaerobic Degradation ◽  
Hydraulic Retention Time ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Anaerobic Bioreactor ◽  
Start Up ◽  
Palm Oil Mill ◽  
Pome Wastewater

The start-up operation and hydraulic retention time (HRT) selectivity of anaerobic degradation for palm oil mill effluent (POME) wastewater was carried out in an anaerobic bioreactor. HRT between 35 and 5 days were investigated. The start-up process for the anaerobic degradation of POME wastewater was found to be completed after 40 days of operation. This study also recommended that the anaerobic degradation of POME wastewater should be operated at the HRT between 35 and 10 days without acid risk. The performance of anaerobic bioreactor could reach 90.55% - 87.55% chemical oxygen demand (COD) reduction, 0.06 - 0.40 ratio between volatile fatty acid (VFA) and alkalinity (Alk), -368.2 mV to-445.80 mV of oxygen reduction potential (ORP) and 9.08 - 37.2 liters of biogas production, respectively.

Comparison of start-up of an upflow anaerobic sludge blanket reactor and a polyurethane carrier reactor

1996 ◽  
Vol 34 (5-6) ◽  
pp. 509-515 ◽  
Author(s):  
Huub J. Gijzen ◽  
Frank Kansiime
Keyword(s):  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Operational Conditions ◽  
Start Up ◽  
And Performance ◽  
Anaerobic Sludge Blanket

The start-up and performance of an Upflow Anaerobic Sludge Blanket (UASB) reactor and a Polyurethane Carrier Reactor (PCR) was investigated under similar operational conditions. The presence of polyurethane cubes as a carrier material in the PCR resulted in fast reactor start-up due to quick immobilization of methanogenic associations. Start-up of the UASB was slower compared to the PCR, which was mainly reflected in a lower biogas production and acetate degradation efficiency. However, when enough biomass had accumulated in the UASB reactor after 15 weeks of operation, the performance of the two reactors was almost the same in terms of biogas production and volatile fatty acids degradation. Efficient VFA degradation (about 90%) and biogas production (5.2 l/l.d) were achieved at an organic loading rate of 13.2 g/l.d) and HRT of 6 h. When hydraulic retention time was subsequently reduced from 6 to 2 h, the performance of the UASB reactor was better than that of the PCR. The inferior performance of the PCR may have been attributed to channelling of the influent in the reactor at high liquid flow rate.

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.

Impact of volatile fatty acids to alkalinity ratio and volatile solids on biogas production under thermophilic conditions

2020 ◽  
pp. 0734242X2095739
Author(s):  
Abdul-Aziz Issah ◽  
Telesphore Kabera
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Total Alkalinity ◽  
Stable Range ◽  
Start Up ◽  
Volatile Solids ◽  
Significant Difference ◽  
Thermophilic Conditions ◽  
The Impact

The study assessed the impact of volatile fatty acids (VFA) to total alkalinity (TA) ratio (VFA/TA), and percentage volatile solids (VS) reduction of batch and semi-continuous anaerobic co-digestion of palm nut paste waste (PNPW) and anaerobic-digested rumen waste (ADRW) on digester stability and biogas production under the environmental condition of 50 ± 1°C and hydraulic retention time of 21 days for the batch studies and 14 days for semi-continuous co-digestion. The co-digestion ratios were based on percentage digester volume corresponding to 90%:10%, 75%:25% and 50%:50%. During batch and semi-continuous anaerobic co-digestion, VFA/TA of 0.32–1.0 and VS reduction of 53–67% were observed as the stable range at which biogas production was maximum. In terms of semi-continuous anaerobic digestion (AD), except for the 50%:50% ratio where biogas production progressed steadily from the first to fourteenth days, biogas production initially dropped from 180.1 to 171.3 mL between the first and third days of the 90%:10% reaching a maximum of 184 mL on the fourteenth day. Biogas production declined from 198.8 to 187.5 mL on the second day and then increased to 198.8 ± 0.5 mL in the case of the 75%:25% with a significant difference between the treatment ratios at p < 0.05. Therefore, the study can confirm that the 50%:50% ratio (PNPW:ADRW) is a suitable option for managing crude fat-based waste under thermophilic AD due to its potential for rapid start-up and complete biodegradation of active biomass within a 21-day period. This presupposes that residual methane as greenhouse gas will be void in the effluent if disposed of.

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>

The effect of extreme temperatures (70–80°C) on the effluent quality and sludge characteristics of UASB reactors

1997 ◽  
Vol 36 (6-7) ◽  
pp. 325-332 ◽  
Author(s):  
Raghida Lepistö ◽  
Jukka Rintala
Keyword(s):  
Volatile Fatty Acids ◽  
Granular Sludge ◽  
Anaerobic Sludge ◽  
Methanogenic Activity ◽  
Sludge Characteristics ◽  
Effluent Quality ◽  
Start Up ◽  
Thermomechanical Pulping ◽  
Increasing Temperature ◽  
Uasb Reactors

The study focused on the effluent quality and sludge characteristics during the start-up and operation of extreme thermophilic (70 to 80°C) upflow anaerobic sludge bed (UASB) reactors, inoculated with mesophilic and thermophilic granular sludge and fed with acetate, volatile fatty acids (VFA), and thermomechanical pulping (TMP) whitewater. Low effluent quality and long start-up periods were observed during the start-up of the 70 to 76°C, VFA-fed UASB reactors inoculated with mesophilic granulae, while better effluent quality and considerably shorter start-up periods were observed when thermophilic (55/70°C) inocula were used. With VFA feed, a significant amount of acetate was removed at 70°C and even at 80°C, while propionate removal was negligible. With TMP whitewater feed, low VFA effluent concentration was obtained at 70°C. The volatile solids (VS) and the VS/total solids (TS) content of the sludge decreased significantly during the first 2–3 months of operation when mesophilic inocula were used. The initial specific methanogenic activity (ISMA) of the extreme thermophilic sludge decreased with increasing temperature and was slightly higher on glucose than on acetate. At 70 to 80°C, various rod-like bacteria were dispersed through the granulae in either individual or in low density micro colonies surrounded with a varying degree of precipitates.

scholarly journals Structure of Microbial Communities When Complementary Effluents Are Anaerobically Digested

2021 ◽  
Vol 11 (3) ◽  
pp. 1293
Author(s):  
Ana Eusébio ◽  
André Neves ◽  
Isabel Paula Marques
Keyword(s):  
Anaerobic Digestion ◽  
Microbial Communities ◽  
Volatile Fatty Acids ◽  
Olive Mill Wastewater ◽  
Organic Load ◽  
Rrna Gene ◽  
Bacterial Populations ◽  
Next Generation Sequencing Ngs ◽  
Generation Sequencing ◽  
Olive Mill

Olive oil and pig productions are important industries in Portugal that generate large volumes of wastewater with high organic load and toxicity, raising environmental concerns. The principal objective of this study is to energetically valorize these organic effluents—piggery effluent and olive mill wastewater—through the anaerobic digestion to the biogas/methane production, by means of the effluent complementarity concept. Several mixtures of piggery effluent were tested, with an increasing percentage of olive mill wastewater. The best performance was obtained for samples of piggery effluent alone and in admixture with 30% of OMW, which provided the same volume of biogas (0.8 L, 70% CH4), 63/75% COD removal, and 434/489 L CH4/kg SVin, respectively. The validation of the process was assessed by molecular evaluation through Next Generation Sequencing (NGS) of the 16S rRNA gene. The structure of the microbial communities for both samples, throughout the anaerobic process, was characterized by the predominance of bacterial populations belonging to the phylum Firmicutes, mainly Clostridiales, with Bacteroidetes being the subdominant populations. Archaea populations belonging to the genus Methanosarcina became predominant throughout anaerobic digestion, confirming the formation of methane mainly from acetate, in line with the greatest removal of volatile fatty acids (VFAs) in these samples.

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