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.

Sludge electrooxidation as pre-treatment for anaerobic digestion

2016 ◽  
Vol 75 (4) ◽  
pp. 775-781 ◽  
Author(s):  
J. A. Barrios ◽  
U. Duran ◽  
A. Cano ◽  
M. Cisneros-Ortiz ◽  
S. Hernández
Keyword(s):  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Wastewater Sludge ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
Treatment Conditions ◽  
Volatile Solids ◽  
Pre Treatment

Anaerobic digestion of wastewater sludge is the preferred method for sludge treatment as it produces energy in the form of biogas as well as a stabilised product that may be land applied. Different pre-treatments have been proposed to solubilise organic matter and increase biogas production. Sludge electrooxidation with boron-doped diamond electrodes was used as pre-treatment for waste activated sludge (WAS) and its effect on physicochemical properties and biomethane potential (BMP) was evaluated. WAS with 2 and 3% total solids (TS) achieved 2.1 and 2.8% solubilisation, respectively, with higher solids requiring more energy. After pre-treatment, biodegradable chemical oxygen demand values were close to the maximum theoretical BMP, which makes sludge suitable for energy production. Anaerobic digestion reduced volatile solids (VS) by more than 30% in pre-treated sludge with a food to microorganism ratio of 0.15 g VSfed g−1 VSbiomass. Volatile fatty acids were lower than those for sludge without pre-treatment. Best pre-treatment conditions were 3% TS and 28.6 mA cm−2.

Anaerobic co-digestion of spent coconut copra with cow urine for enhanced biogas production

2020 ◽  
pp. 0734242X2097509
Author(s):  
Uduak U Ndubuisi-Nnaji ◽  
Utibe A Ofon ◽  
Nnanake-Abasi O Offiong
Keyword(s):  
Performance Indicators ◽  
Volatile Fatty Acids ◽  
Control Experiment ◽  
Biogas Production ◽  
Batch Mode ◽  
Mixing Ratios ◽  
Volatile Solids ◽  
Cow Urine ◽  
Thermophilic Condition ◽  
Biomethane Production

Laboratory-scale bioreactors were used to co-digest spent coconut copra (SCC) and cow urine (CU) as a co-substrate (SCC + CU) in a batch mode under thermophilic condition (45 ± 2°C) in order to enhance biogas production. The effect of CU pretreatment on the performance indicators (biogas and biomethane yields, total solids (TS), and volatile solids (VS) reduction, pH and volatile fatty acids (VFAs) concentrations) were also examined. This was compared with mono-digestion of SCC. The experiment was performed with different mixing ratios in reactors labelled as follows: A = 75 g SCC + 5 ml CU; B = 70 g SCC + 10 ml CU; C = 65 g SCC + 15 ml CU; and D (control) = 80 g SCC at a hydraulic retention time of 42 days. Co-digestion (SCC + CU) significantly improved anaerobic digestion (AD) performance resulting in a threefold and fivefold increase in biogas and biomethane production, respectively, with concomitant TS (44.9–57.7%) and VS (55.4–60.3%) removal efficiencies. But for mono-digestion (control experiment), all CU treated and co-digestion assays showed pH stability ranging between 6.6 and 7.4 and VFAs’ concentrations ranging from 15–330 mgL-1. By acting as a buffer, CU effectively enhanced the AD performance of SCC as demonstrated in this study.

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 Efektivitas Pemanfaatan Serbuk Gergaji dan Limbah Media Tanam Jamur (Baglog) sebagai Bahan Baku Pembuatan Biogas

2016 ◽  
Vol 2 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Dikdik Mulyadi ◽  
Lela Mukmilah Yuningsih ◽  
Desi Kusumawati
Keyword(s):  
Fermentation Process ◽  
Volatile Fatty Acids ◽  
Anaerobic Fermentation ◽  
Biogas Production ◽  
Volume Measurement ◽  
Raw Material ◽  
Cow Dung ◽  
Total Volatile ◽  
A Value ◽  
Volatile Solids

Biogas is  one of energy   that can be produced by anaerobic fermentation of the organic compounds. The objective of this study was to determine the effectiveness of the utilization of waste of media  mushroom growth (baglog) with sawdust as raw material for biogas with  cow dung  activators. The study was conducted through anaerobic fermentation of the samples containing waste baglog (sample 1) and sawdust (sample 2), with the addition of cow manure activator to each sample. Both of these samples do anaerobic fermentation for 32 days, then measuring the volume of biogas every 4 days for 32 days. Methane content  in  samples 1 and 2 measured by  using gas chromatography. To see the effect of the addition of activators cow dung biogas volume measurement was  carried out with  cow dung without addition baglog waste and sawdust. The process of degradation baglog and sawdust with an activator of cow dung could be observed  in  some of the parameters through  total solids (TS), total volatile solids (TVS), volatile fatty acids (VFA), the degree of acidity (pH), and C/N ratio. The results showed that effectiveness of sample 1 resulted in the everage of total volume biogas 28% higher than  sample 2. The content of methane in  sample 1  and sampel 2  was 54% %, and 0.21% respectively. The fermentation process biogas production in this experiment  was carried out  at pH 7, with a value of TS, TVS and VFA showed a decrease  trend after the fermentation process,  C/N ratiowas  lower than the baglog waste sawdust until day 32 retention time. Keywords: Sawdust, baglog waste, biogas, fermentation, methane DOI : http://dx.doi.org/10.15408/jkv.v2i1.3100

scholarly journals Biogas Production from Excess Sludge Oxidized with Peracetic Acid (PAA)

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3434
Author(s):  
Iwona Zawieja ◽  
Małgorzata Worwąg
Keyword(s):  
Peracetic Acid ◽  
Production Efficiency ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Anaerobic Conditions ◽  
Excess Sludge ◽  
Methane Fermentation ◽  
Sludge Digestion ◽  
Human Functioning ◽  
High Degree

Human functioning related to living and economic activity involves generating an increasing amount of sewage and sludge, which needs to be subjected to advanced processes of treatment, neutralization, and management. The deterioration in the susceptibility of excess sludge to biochemical decomposition observed under anaerobic conditions leads to the development and application of highly effective methods of wastewater treatment based on the removal of biogenic compounds using activated sludge, with a high degree of sludge thickening obtained in mechanical facilities. The concentration of volatile fatty acids, being an important intermediate product of anaerobic stabilization, directly determines biogas production efficiency. This study aimed to determine the effect of chemical disintegration with peracetic acid on biogas production efficiency using methane fermentation of pretreated sludge. Intensification of the hydrolysis phase is an important determinant of the efficiency of biochemical sludge decomposition under anaerobic conditions. The association of excess sludge oxidation, initiated by peracetic acid with biological hydrolysis, which is the first phase of methane fermentation, led to an increase in sludge digestion degree and biogas production efficiency. The compound of STERIDIAL W-10, which is an aqueous solution of 10% peracetic acid, 10% acetic acid, and 8% hydrogen peroxide, was used. The disintegration of excess sludge with a reactant dose of 3.0 mL of STERIDIAL W-10/L yielded a specific biogas production of 0.52 L/g VSS and a 74% degree of sludge digestion.

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 Mesophilic and Thermophilic Anaerobic Digestion of Wheat Straw in a CSTR System with ‘Synthetic Manure’: Impact of Nickel and Tungsten on Methane Yields, Cell Count, and Microbiome

2022 ◽  
Vol 9 (1) ◽  
pp. 13
Author(s):  
Richard Arthur ◽  
Sebastian Antonczyk ◽  
Sandra Off ◽  
Paul A. Scherer
Keyword(s):  
Wheat Straw ◽  
Methane Production ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Cell Counts ◽  
Volatile Solids ◽  
Thermophilic Conditions ◽  
Pure Cultures ◽  
Biogas Reactors ◽  
And Tungsten

Lignocellulosic residues, such as straw, are currently considered as candidates for biogas production. Therefore, straw fermentations were performed to quantitatively estimate methane yields and cell counts, as well as to qualitatively determine the microbiome. Six fully automated, continuously stirred biogas reactors were used: three mesophilic (41 °C) and three thermophilic (58 °C). They were fed every 8 h with milled wheat straw suspension in a defined, buffered salt solution, called ‘synthetic manure’. Total reflection X-ray fluorescence spectrometry analyses showed nickel and tungsten deficiency in the straw suspension. Supplementation of nickel and subsequently tungsten, or with an increasing combined dosage of both elements, resulted in a final concentration of approximately 0.1 mg/L active, dissolved tungsten ions, which caused an increase of the specific methane production, up to 63% under mesophilic and 31% under thermophilic conditions. That is the same optimal range for pure cultures of methanogens or bacteria found in literature. A simultaneous decrease of volatile fatty acids occurred. The Ni/W effect occurred with all three organic loading rates, being 4.5, 7.5, and 9.0 g volatile solids per litre and day, with a concomitant hydraulic retention time of 18, 10, or 8 days, respectively. A maximum specific methane production of 0.254 m3 CH4, under standard temperature and pressure per kg volatile solids (almost 90% degradation), was obtained. After the final supplementation of tungsten, the cell counts of methanogens increased by 300%, while the total microbial cell counts increased by only 3–62%. The mesophilic methanogenic microflora was shifted from the acetotrophic Methanosaeta to the hydrogenotrophic Methanoculleus (85%) by tungsten, whereas the H2-CO2-converter, Methanothermobacter, always dominated in the thermophilic fermenters.

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.

Anaerobic digestion and dewatering characteristics of mechanically disintegrated excess sludge

1997 ◽  
Vol 36 (11) ◽  
pp. 129-136 ◽  
Author(s):  
Julia Kopp ◽  
Johannes Müller ◽  
Norbert Dichtl ◽  
Jörg Schwedes
Keyword(s):  
Anaerobic Digestion ◽  
Ball Mill ◽  
Anaerobic Degradation ◽  
Excess Sludge ◽  
Particle Structure ◽  
Disintegration Rate ◽  
Digestion Time ◽  
Stirred Ball Mill ◽  
High Pressure Homogenizer ◽  
Cell Disintegration

Mechanical cell disintegration and its influence on anaerobic digestion was investigated using four different methods. Methods to describe the degree of cell-disruption were developed and the release of organic components into the sludge water was measured. The best results were optained using a stirred ball mill and a high-pressure homogenizer. The influence of disintegration rate and digestion time on the performance of the anaerobic process and the dewatering characteristics were investigated. The degradation is accelerated and the digestion time can be reduced, especially when using immobilised microorganisms. It could be shown that the mechanical disintegration results in a disruption of particle structure and an increase of polymer-demand. As a result of better anaerobic degradation the density and dewatering results of disintegrated sludges are improved in comparison to non-treated sludges.

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.

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