scholarly journals Correction to: Effect of feed slurry dilution and total solids on specific biogas production by anaerobic digestion in batch and semi-batch reactors

Author(s):  
Gautham P. Jeppu ◽  
Jayalal Janardhan ◽  
Shivakumara Kaup ◽  
Anish Janardhanan ◽  
Shakeib Mohammed ◽  
...  
Author(s):  
Gautham P. Jeppu ◽  
Jayalal Janardhan ◽  
Shivakumara Kaup ◽  
Anish Janardhanan ◽  
Shakeib Mohammed ◽  
...  

AbstractBiomass from various sources such as cow dung is a significant source of renewable energy (as biogas) in many regions globally, especially in India, Africa, Brazil, and China. However, biogas production from biomass such as cattle dung is a slow, inefficient biochemical process, and the specific biogas produced per kg of biomass is relatively small. The improvement of specific biogas production efficiency using various dilution ratios (and, hence, total solids [TS]) is investigated in this work. A wide range of feed dilution (FD) ratios of cow dung: water (CD: W) was tested in batch biogas digesters with total solids ranging from 1% to 12.5% and FD ratio ranging from 2:1 to 1:20. To further verify the results from the above batch experiments, semi-batch experiments representative of field-scale biodigesters were conducted. Semi-batch reactors have a steady-state process, unlike batch reactors, which have an unsteady state process. Our results suggested that specific biogas production (mL/g VS) increased continuously when the total solids decreased from 12.5% to 1% (or when dilution increased). Our experiments also indicate that the commonly used 1:1 feed dilution ratio (TS ~ 10% for cow dung) does not produce the maximum specific biogas production. The possible reason for this could be that anaerobic digestion at higher total solids is rate limited due to substrate inhibition, mass transfer limitations, and viscous mixing problems that arise at higher total solids concentration. Hence, a higher feed dilution ratio between 1:2 and 1:4 (TS between 4 and 6.7%) is recommended for a more efficient biomass utilization of cowdung. Empirical relationships were also developed for variation of specific biogas yield with the total solids content of the cow dung slurry. Graphic abstract


2019 ◽  
Vol 37 (12) ◽  
pp. 1240-1249 ◽  
Author(s):  
Spyridon Achinas ◽  
Gerrit Jan Willem Euverink

The biodegradable portion of solid waste generated in farmhouses can be treated for energy recovery with small portable biogas plants. This action can be done across the Netherlands and all around the planet. This study aims to appraise the performance of anaerobic digestion of different wastes (cow manure, food waste and garden waste) obtained from a regional farmhouse. Batch reactors were established under mesophilic conditions in order to investigate the impact of ternary mixtures on the anaerobic digestion process performance. Different mixing ratios were set in the batch tests. The upshots from the experiments connoted that ternary digestion with cow manure:food waste:garden waste mixing ratio of 40:50:10 yielded higher biogas amount. The kinetics’ results showed quite good congruence with the experimental study. The results from the kinetic analysis appeared to be in line with the experimental one.


2009 ◽  
Vol 60 (6) ◽  
pp. 1525-1532 ◽  
Author(s):  
S. Pérez-Elvira ◽  
M. Fdz-Polanco ◽  
F. I. Plaza ◽  
G. Garralón ◽  
F. Fdz-Polanco

Prior research indicates that ultrasounds can be used in batch reactors as pre-treatment before anaerobic digestion, but the specific energy required at laboratory-scale is too high. This work evaluates both the continuous ultrasound device performance (efficiency and solubilisation) and the operation of anaerobic digesters continuously fed with sonicated sludge, and presents energy balance considerations. The results of sludge solubilisation after the sonication treatment indicate that, applying identical specific energy, it is better to increase the power than the residence time. Working with secondary sludge, batch biodegradability tests show that by applying 30 kWh/m3 of sludge, it is possible to increase biogas production by 42%. Data from continuous pilot-scale anaerobic reactors (V=100 L) indicate that operating with a conventional HRT = 20 d, a reactor fed with pre-treated sludge increases the volatile solids removal and the biogas production by 25 and 37% respectively. Operating with HRT = 15 d, the removal efficiency is similar to the obtained with a reactor fed with non-hydrolysed sludge at HTR = 20 d, although the specific biogas productivity per volume of reactor is higher for the pretreated sludge. Regarding the energy balance, although for laboratory-scale devices it is negative, full-scale suppliers state a net generation of 3–10 kW per kW of energy used.


2017 ◽  
Vol 63 ◽  
pp. 63-68 ◽  
Author(s):  
G. Paramaguru ◽  
M. Kannan ◽  
P. Lawrence ◽  
D. Thamilselvan

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 4972-4981
Author(s):  
Julios César de Souza Matos ◽  
Ladislav Rozenský ◽  
Zdeněk Vrba ◽  
Justin Michael Hansen ◽  
Miroslav Hájek ◽  
...  

Anaerobic digestion processes with biogas production are widely used for organic waste treatment with an emphasis on energy recovery. Some recent studies have demonstrated the influence of magnetism on microbiological activity. These indicate a possible influence on the efficiency of anaerobic digestion. Thus, technologies that act in anaerobic digestion enhancement can contribute to the improvement of treatment of organic compounds. The present study aimed to verify the influence of a constant electromagnetic field on the anaerobic digestion in anaerobic reactors fed with glucose (2 g/L) at 37 ± 2 °C. In each experiment, reactors were operated with a constant electromagnetic field of 5, 7.5, and 10 mT. The inoculum was granular sludge from an anaerobic treatment plant in a non-selective media culture. Biogas production, chemical oxygen demand (COD), and solids removal were measured during the experiment. Results showed differences in methane production of 21.5% and in COD removal of 15% in the tests with an electromagnetic field of 7.5 mT. These results signs for the viability of the application of a constant magnetic field as a biostimulation agent.


Biogas in the form of methane can be produced from wastewater treatment sludge mixed with a variety of biodegradable organic feedstocks through anaerobic digestion. In this study, biogas was produced from date palm seeds, which are locally available, and wastewater treatment sludge mixtures. The objective of the study was to assess the effect of date palm seed additives with different sizes on biogas production from the mixtures. In the study, two locally available types of date seeds, Khalas and Khudari, were anaerobically co-digested with wastewater treatment sludge in 50 mL serum bottles under mesophilic conditions. Date seeds with three different sizes; 1.18– 3.75 mm, 0.6 –1.18 mm; and 0.425 – 0.6 mm, were added to the sludge at date seeds to sludge total solids (TS) weight ratios of 0%, 2.5%, 5%, 7.5%, and 10%. The experimental results confirmed that the addition of date seeds significantly enhanced biogas production up to 20% to 30%. The results indicated that the date seed size slightly affected biogas production, with the order of cumulative biogas production and biogas production rates, expressed in terms of date seed sizes, being as follows: 0.425 – 0.6 mm > 0.6 – 1.18 mm > 1.18 – 3.75 mm. However, the results showed no major difference in biogas production between the two different date seed types.


2021 ◽  
Author(s):  
Venkateshkumar R ◽  
Shanmugam S ◽  
Veerappan AR

Abstract Cow dung is generally used as the feedstock material for the anaerobic digestion to produce biogas. A selection of alternate biomass material is needed to reduce the consumption or to eliminate the use of cow dung. Recently, cottonseed hull has been considered as the primary substrate to produce biogas. In this paper, the effect of biogas production on anaerobic co-digestion of cow dung with pre-treated cottonseed hull using different concentrations of sulfuric acid, hydrochloric acid, hydrogen peroxide, and acetic acid is investigated. Sodium hydroxide and calcium hydroxide are used at different concentrations for pre-treatment of cottonseed hull. The enhancement of biogas production from the batch reactors at mesophilic temperature (35 ± 2 ℃) is observed for mono- and co-digestion of cow dung with treated cottonseed hull. Maximum biogas yield is achieved for the treated cottonseed hull at 6% sodium hydroxide during mono digestion and at 6% calcium hydroxide during co-digestion.


2019 ◽  
Vol 7 (12) ◽  
pp. 682 ◽  
Author(s):  
Jung ◽  
Kim ◽  
Lee

Methanogenesis and sulfidogenesis, the major microbial reduction reactions occurring in the anaerobic digestion (AD) process, compete for common substrates. Therefore, the balance between methanogenic and sulfidogenic activities is important for efficient biogas production. In this study, changes in methanogenic and sulfidogenic performances in response to changes in organic loading rate (OLR) were examined in two digesters treating sulfur-rich macroalgal waste under mesophilic and thermophilic conditions, respectively. Both methanogenesis and sulfidogenesis were largely suppressed under thermophilic relative to mesophilic conditions, regardless of OLR. However, the suppressive effect was even more significant for sulfidogenesis, which may suggest an option for H2S control. The reactor microbial communities developed totally differently according to reactor temperature, with the abundance of both methanogens and sulfate-reducing bacteria being significantly higher under mesophilic conditions. In both reactors, sulfidogenic activity increased with increasing OLR. The findings of this study help to understand how temperature affects sulfidogenesis and methanogenesis during AD.


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