scholarly journals Anaerobic Digestion of Starch Wastewater: the Effect of pH and Oxidation Reduction Potential on the Reactor Performance

2019 ◽  
Vol 3 (1) ◽  
pp. 21-23
Author(s):  
Zangta Sang ◽  
Chayanon Sawatdeenarunat ◽  
Pitchaya Suaisom
Keyword(s):  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Reduction Potential ◽  
Biogas Production ◽  
Organic Loading Rate ◽  
Continuous Stirred Tank Reactor ◽  
Reactor Performance ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Starch Wastewater

Anaerobic digestion (AD) of starch wastewater for biogas production has been widely installed in Thailand for a decade. Unfortunately, this specific waste stream contains low alkalinity (Alk) and high volatile fatty acids (VFAs) which could easily lead to system instability. The appropriate monitoring indicators could help to decrease chance of reactor failure. The aim of this study is to investigate the performance of the AD system and the effect of operating parameters i.e. oxidation-reduction potential (ORP) and pH on the system in a continuous stirred tank reactor operated in semi-continuous mode at organic loading rate (OLR) of 1.0 kg COD/m3.day.  The temperature was controlled at a mesophilic condition (35±2°C) for the whole experiment. The results showed that the average ORP and pH were -400 ±50 mV and 7.0 ± 0.2, respectively. The average biogas and methane yields were 0.901±0.128 NL/g VS added and 0.528±0.076 NL/g VS added, respectively.  The methane composition was 58.43±4.76 %. The total COD and filtrated COD removal efficiencies were   94.75±1.42% and 97.88±0.53%, respectively. It could be concluded that at the low OLR (i.e. 1.0 kg COD/m3.day), pH and ORP was stable and fell within the recommended range for AD and indicated the stability of the system.

Experimental and Artificial Neural Network Modeling of a Upflow Anaerobic Contactor (UAC) for Biogas Production from Vinasse

2016 ◽  
Vol 14 (6) ◽  
pp. 1241-1254 ◽  
Author(s):  
Ousman R. Dibaba ◽  
Sandip K. Lahiri ◽  
Stephan T’Jonck ◽  
Abhishek Dutta
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Organic Loading Rate ◽  
Neural Network Modeling ◽  
Artificial Neural

Abstract A pilot scale Upflow Anaerobic Contactor (UAC), based on upflow sludge blanket principle, was designed to treat vinasse waste obtained from beet molasses fermentation. An assessment of the anaerobic digestion of vinasse was carried out for the production of biogas as a source of energy. Average Organic loading rate (OLR) was around 7.5 gCOD/m3/day in steady state, increasing upto 8.1 gCOD/m3/day. The anaerobic digestion was conducted at mesophilic (30–37 °C) temperature and a stable operating condition was achieved after 81 days with average production of 65 % methane which corresponded to a maximum biogas production of 85 l/day. The optimal performance of UAC was obtained at 87 % COD removal, which corresponded to a hydraulic retention time of 16.67 days. The biogas production increased gradually with OLR, corresponding to a maximum 6.54 gCOD/m3/day (7.4 % increase from initial target). A coupled Artificial Neural Network-Differential Evolution (ANN-DE) methodology was formulated to predict chemical oxygen demand (COD), total suspended solids (TSS) and volatile fatty acids (VFA) of the effluent along with the biogas production. The method incorporated a DE approach for the efficient tuning of ANN meta-parameters such as number of nodes in hidden layer, input and output activation function and learning rate. The model prediction indicated that it can learn the nonlinear complex relationship between the parameters and able to predict the output of the contactor with reasonable accuracy. The utilization of the coupled ANN-DE model provided significant improvement to the study and helps to study the parametric effect of influential parameters on the reactor output.

Continuous biogas production from fodder beet silage as sole substrate

2003 ◽  
Vol 48 (4) ◽  
pp. 229-233 ◽  
Author(s):  
P.A. Scherer ◽  
S. Dobler ◽  
S. Rohardt ◽  
R. Loock ◽  
B. Büttner ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Swine Manure ◽  
Gas Production ◽  
Methane Content ◽  
Organic Loading Rate ◽  
Feeding Time ◽  
Reactor Performance ◽  
Fodder Beet ◽  
Gas Volume

Since April 2000 a two-step anaerobic plant with two subsequent 500 m3 reactors has been producing biogas from fodder beet silage (pH 4.1) as the sole substrate. The plant is located at Kirchlengern near Bielefeld, Germany. Initially the reactors were inoculated with swine manure at 37°C. After a start-up phase the process was sustained at pH 7.5-8.0 by feeding with the silage as sole substrate twice a day. Parallel to the biogas plant at Kirchlengern four one-step laboratory reactors were continuously driven at temperatures of 37°C, 45°C, 60°C and 65°C. They were fed with the same silage, but only once per day (one impulse). The organic loading rate (OLR) was adjusted to 3.9 g volatile solids (VS)/(l*d) with a concomitant hydraulic retention time (HRT) of 27 d. There was no problem with starting the reactors, but after 86 days the volumetric gas production of the 65°C reactor ceased and a high amount of approximately 130 mM propionate could be determined. By decreasing the temperature down to 60°C a stable reactor performance was recovered for a period of at least 250 further days. During impulse feeding it was observed that the quickest recovery of gas production could be observed at 37°C or at 45°C. Recovery of 75% gas volume (related to the value before or after impulse feeding) was obtained after 5.5 and 7.5 h of feeding time point whereas the 60°C reactor needed 16 h. Slight significant differences were seen in the spectrum of volatile fatty acids (VFA) reaching at 37° or 45°C its maximum with 10-30 mM total VFA at 2-3 h after feeding. After this the VFA level declined to nearly zero (except for the 60°C reactor). Therefore the 37°C reactor was favoured. A double experiment with a second 37°C reactor was started by a somewhat different inoculation procedure from the remaining 3 reactors, but revealed similar results. By increasing the temperature no significantly different specific gas production rates and methane yields could be observed, e.g. it gave 600-700 l biogas from 1 kg VS. The corresponding methane content ranged between 62-64%. With a methane content of 63 ± 1% a yield of 40.1 ± 2 m3 methane/ton fresh fodder beet silage was obtained.

Stimulation of the hydrolytic stage for biogas production from cattle manure in an electrochemical bioreactor

2016 ◽  
Vol 74 (3) ◽  
pp. 606-615 ◽  
Author(s):  
Saeed Samani ◽  
Mohammad Ali Abdoli ◽  
Abdolreza Karbassi ◽  
Mohammad Mehdi Amin
Keyword(s):  
Reduction Potential ◽  
Biogas Production ◽  
Electrical Power ◽  
Electrical Current ◽  
Cattle Manure ◽  
Biogas Yield ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Biogas Process ◽  
Electrical Source

Electrical current in the hydrolytic phase of the biogas process might affect biogas yield. In this study, four 1,150 mL single membrane-less chamber electrochemical bioreactors, containing two parallel titanium plates were connected to the electrical source with voltages of 0, −0.5, −1 and −1.5 V, respectively. Reactor 1 with 0 V was considered as a control reactor. The trend of biogas production was precisely checked against pH, oxidation reduction potential and electrical power at a temperature of 37 ± 0.5°C amid cattle manure as substrate for 120 days. Biogas production increased by voltage applied to Reactors 2 and 3 when compared with the control reactor. In addition, the electricity in Reactors 2 and 3 caused more biogas production than Reactor 4. Acetogenic phase occurred more quickly in Reactor 3 than in the other reactors. The obtained results from Reactor 4 were indicative of acidogenic domination and its continuous behavior under electrical stimulation. The results of the present investigation clearly revealed that phasic electrical current could enhance the efficiency of biogas production.

Anaerobic baffled reactor treatment of biodiesel-processing wastewater with high strength of methanol and glycerol: reactor performance and biogas production

2011 ◽  
Vol 65 (5) ◽  
Author(s):  
Darin Phukingngam ◽  
Orathai Chavalparit ◽  
Dararat Somchai ◽  
Maneerat Ongwandee
Keyword(s):  
Chemical Oxygen Demand ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Reactor Performance ◽  
Electron Microscopic ◽  
Anaerobic Baffled Reactor

AbstractBiodiesel-processing factories employing the alkali-catalyzed transesterification process generate a large amount of wastewater containing high amount of methanol, glycerol, and oil. As such, wastewater has high potential to produce biogas using anaerobic treatment. The aim of this research was to investigate the performance of an anaerobic baffled reactor for organic removal and biogas production from biodiesel wastewater. The effect of different organic loading rates, varying from 0.5 kg m−3 d−1 to 3.0 kg m−3 d−1 of chemical oxygen demand, was determined using three 22 L reactors, each comprising five separate compartments. Wastewater was pretreated with chemical coagulants to partially remove oil prior to experimentation. Results show that the anaerobic baffled reactor operated at 1.5 kg m−3 d−1 of chemical oxygen demand and ten days of hydraulic retention time provided the best removal efficiencies of 99 % of chemical oxygen demand, 100 % of methanol, and 100 % of glycerol. Increasing the organic loading rate over 1.5 kg m−3 d−1 of chemical oxygen demand led to excessive accumulation of volatile fatty acids thereby making the pH drop to a value unfavorable for methanogenesis. The biogas production rate was 12 L d−1 and the methane composition accounted for 64–74 %. Phase-separated characteristics revealed that the highest chemical oxygen demand removal percentage was achieved in the first compartment and the removal efficiency gradually decreased longitudinally. A scanning electron microscopic study indicated that the most predominant group of microorganisms residing on the external surface of the granular sludge was Methanosarcina.

scholarly journals Polyhydroxyalkanoated-Rich Microbial Cells from Bio-Based Volatile Fatty Acids as Potential Ingredient for Aquaculture Feed

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 38
Author(s):  
Alice Botturi ◽  
Federico Battista ◽  
Marco Andreolli ◽  
Filippo Faccenda ◽  
Salvatore Fusco ◽  
...  
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Microbial Biomass ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Feed Additive ◽  
Continuous Stirred Tank Reactor ◽  
Microbial Cells ◽  
High Concentrations

In this study, the production of polyhydroxyalkanoated PHA-rich microbial biomass as a novel feed additive in aquaculture was investigated at a lab-scale. Bio-based volatile fatty acids (VFAs), obtained from the acidogenic fermentation of agricultural residues in existing anaerobic digestion plants, were used as carbon and energy to cultivate the PHA-rich microbial biomass. The experimental activities were carried out using Thauera sp. Sel9 as pure strain, which was grown in a continuous stirred-tank reactor (CSTR) operated at three different hydraulic retention times (HRT). The highest productivity obtained of biomass cells was 0.69 g/L day, operating at one day HRT while the observed PHAs production yield was 0.14 gPHA/g soluble COD removed. At these conditions, the PHA concentration in the microbial cells was 41%. Although the sulfur amino acids were available at high concentrations and above the typical concentration found in fishmeal, the amino acids profile of the obtained biomass revealed a lack of histidine and threonine. A preliminary economic analysis showed that the production of a novel source of feed additive from the conversion of agro-residues could give higher benefits in terms of revenues compared to the production of biogas production through anaerobic digestion.

Effects of calcium concentration on up-flow multistage anaerobic reactor performance in treating bagasse spraying wastewater

BioResources ◽  
2019 ◽  
Vol 14 (2) ◽  
pp. 4254-4269
Author(s):  
Jinghong Zhou ◽  
Xiaona Shang ◽  
Zhiwei Wang ◽  
Cancan Zhu ◽  
Shuangfei Wang
Keyword(s):  
Anaerobic Digestion ◽  
Loading Rate ◽  
Biogas Production ◽  
Scale Up ◽  
Anaerobic Treatment ◽  
Cod Removal ◽  
Microbial Community Analysis ◽  
Organic Loading Rate ◽  
Reactor Performance ◽  
Anaerobic Reactor

Bagasse spraying wastewater (BSW) is a source of organic pollutants during bagasse processing. In this study, the feasibility of anaerobic treatment of BSW under different calcium concentrations (60 to 2400 mg/L) was studied. The experiment was performed in a lab-scale up-flow multistage anaerobic reactor (UMAR) inoculated with granular sludge, and operated for 160 days at a constant organic loading rate of 6 kg COD/(m3·d). Treatment of BSW with 60 to 800 mg Ca2+/L resulted in 80.7 to 82.7% of COD removal, 161 to 232.7 mg COD/L of volatile fatty acid (VFA) yield, 0.56 to 0.79 m3/(kgCOD·d) of biogas production rate, and 2.4 to 2.66 m3/(m3·d) of volume loading rate (VLR). The pH remained within the optimal range for anaerobic digestion (adjust to pH = 6.8 to 7.0). The VFAs were composed of 77 to 85% acetic acid, 8.4 to 13.2% butyric acid, and 6.6 to 9.6% propionic acid. At higher influent calcium concentrations (> 800 mg/L), the hydrolysis process appeared to be inhibited, affecting the anaerobic digestion performance of the reactor. In particular, the COD removal efficiency decreased to 55.5%, and the VFA content in the effluent significantly increased due to the lower pH. Microbial community analysis showed that at the end of anaerobic digestion, the Syntrophobacter disappeared, and Clostridium and Anerolineaceae were the main genus and family, respectively. Overall, the results indicated that low calcium (< 300 mg/L) had a positive effect on the UMAR performance.

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