scholarly journals A Preliminary Study of the Effect of Bioavailable Fe and Co on the Anaerobic Digestion of Rice Straw

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 577 ◽  
Author(s):  
Gabriele Mancini ◽  
Stefano Papirio ◽  
Piet Lens ◽  
Giovanni Esposito

Rice straw is an abundant and sustainable substrate for anaerobic digestion (AD), but it is often deficient in essential trace elements (TEs) for proper microbial growth and metabolism. A lack of TEs leads to AD imbalances and suboptimal biogas yields. However, the total TE concentration is not a sufficient indicator of the amount of TEs available to the microorganisms. Therefore, this study investigated the degree of bioavailability of iron (Fe) and cobalt (Co) during the AD of rice straw, and correlated it to the biomethane yields and volatile fatty acids (VFAs) produced. When the two TEs were dosed at 205 µg Fe/g TS and 18 µg Co/g TS of rice straw, the biomethane production was approximately 260 mL CH4/g VS, i.e., similar to that obtained when Fe and Co were not added. Despite an increased bioavailable fraction of 23 and 48% for Fe and Co, respectively, after TEs addition, the AD performance was not enhanced. Moreover, VFAs did not exceed 250 mg HAc/L both in the presence and absence of added TEs, confirming no enhancement of the methanogenesis step. Therefore, the bioavailability of Fe and Co was not a limiting factor for the biomethane production at low total VFAs concentration.

2015 ◽  
Vol 38 (8) ◽  
pp. 1623-1627 ◽  
Author(s):  
Gwon Woo Park ◽  
Ilgook Kim ◽  
Kwonsu Jung ◽  
Charles Seo ◽  
Jong-In Han ◽  
...  

2021 ◽  
Vol 9 (2) ◽  
pp. 105055
Author(s):  
Yasmim Arantes da Fonseca ◽  
Nayara Clarisse Soares Silva ◽  
Adonai Bruneli de Camargos ◽  
Silvana de Queiroz Silva ◽  
Hector Javier Luna Wandurraga ◽  
...  

2021 ◽  
Vol 129 ◽  
pp. 20-25
Author(s):  
Gamal K. Hassan ◽  
Rhys Jon Jones ◽  
Jaime Massanet-Nicolau ◽  
Richard Dinsdale ◽  
M.M. Abo-Aly ◽  
...  

2018 ◽  
Vol 78 (10) ◽  
pp. 2027-2035 ◽  
Author(s):  
M. Sbarciog ◽  
G. Giovannini ◽  
R. Chamy ◽  
A. Vande Wouwer

Abstract The anaerobic digestion (AD) technology is widely used in the treatment of waste and wastewater. To ensure the treatment efficiency and to increase the production of biogas, which can be reused as a renewable energy source, a good understanding of the process and tight control are needed. This paper presents an estimation and control scheme, which can be successfully used in the operation of the AD process. The process is simulated by the ADM1 model, the most complex and detailed model developed so far to characterize AD. The controller and the observer, which provides estimates of the unmeasurable variables needed in the computation of the control law, are designed based on a simplified model developed in a previous work. Since it has been shown that hydrogen concentration is an accurate and fast indicator of process stability, it was chosen as controlled variable. Aside from the hydrogen concentration, the only measurement employed by the proposed control structure is the volatile fatty acids concentration. Simulation results prove the effectiveness of the proposed control structure.


2004 ◽  
Vol 50 (6) ◽  
pp. 109-114 ◽  
Author(s):  
D.V. Savant ◽  
D.R. Ranade

To operate anaerobic digesters successfully under acidic conditions, hydrogen utilizing methanogens which can grow efficiently at low pH and tolerate high volatile fatty acids (VFA) are desirable. An acid tolerant hydrogenotrophic methanogen viz. Methanobrevibacter acididurans isolated from slurry of an anaerobic digester running on alcohol distillery wastewater has been described earlier by this lab. This organism could grow optimally at pH 6.0. In the experiments reported herein, M. acididurans showed better methanogenesis under acidic conditions with high VFA, particularly acetate, than Methanobacterium bryantii, a common hydrogenotrophic inhabitant of anaerobic digesters. Addition of M. acididurans culture to digesting slurry of acidogenic as well as methanogenic digesters running on distillery wastewater showed increase in methane production and decrease in accumulation of volatile fatty acids. The results proved the feasibility of application of M. acididurans in anaerobic digesters.


Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1580
Author(s):  
Farokh laqa Kakar ◽  
Ahmed El Sayed ◽  
Neha Purohit ◽  
Elsayed Elbeshbishy

The main objective of this study was to evaluate the hydrothermal pretreatment’s retention time influence on the volatile fatty acids and biomethane production from thickened waste activated sludge under mesophilic conditions. Six different retention times of 10, 20, 30, 40, 50, and 60 min were investigated while the hydrothermal pretreatment temperature was kept at 170 °C. The results showed that the chemical oxygen demand (COD) solubilization increased by increasing the hydrothermal pretreatment retention time up to 30 min and stabilized afterwards. The highest COD solubilization of 48% was observed for the sample pretreated at 170 °C for 30 min. Similarly, the sample pretreated at 170 °C for 30 min demonstrated the highest volatile fatty acids yield of 14.5 g COD/Lsubstrate added and a methane yield of 225 mL CH4/g TCODadded compared to 4.3 g COD/Lsubstrate added and 163 mL CH4/g TCODadded for the raw sample, respectively. The outcome of this study revealed that the optimum conditions for solubilization are not necessarily associated with the best fermentation and/or digestion performance.


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