scholarly journals A Review on Anaerobic Digestion of Lignocellulosic Wastes: Pretreatments and Operational Conditions

2019 ◽  
Vol 9 (21) ◽  
pp. 4655 ◽  
Author(s):  
Tahseen Sayara ◽  
Antoni Sánchez

Anaerobic digestion (AD) has become extremely popular in the last years to treat and valorize organic wastes both at laboratory and industrial scales, for a wide range of highly produced organic wastes: municipal wastes, wastewater sludge, manure, agrowastes, food industry residuals, etc. Although the principles of AD are well known, it is very important to highlight that knowing the biochemical composition of waste is crucial in order to know its anaerobic biodegradability, which makes an AD process economically feasible. In this paper, we review the main principles of AD, moving to the specific features of lignocellulosic wastes, especially regarding the pretreatments that can enhance the biogas production of such wastes. The main point to consider is that lignocellulosic wastes are present in any organic wastes, and sometimes are the major fraction. Therefore, improving their AD could cause a boost in the development in this technology. The conclusions are that there is no unique strategy to improve the anaerobic biodegradability of lignocellulosic wastes, but pretreatments and codigestion both have an important role on this issue.

2018 ◽  
Vol 65 ◽  
pp. 05025 ◽  
Author(s):  
Sagor Kumar Pramanik ◽  
Fatihah Binti Suja ◽  
Biplob Kumar Pramanik ◽  
Shahrom Bindi Md Zain

Solid organic wastes create potential risks to environmental pollution and human health due to the uncontrolled discharge of huge quantities of hazardous wastes from numerous sources. Now-a-days, anaerobic digestion (AD) is considered as a verified and effective alternative compared to other techniques for treating solid organic waste. The paper reviewed the biological process and parameters involved in the AD along with the factors could enhance the AD process. Hydrolysis is considered as a rate-limiting phase in the complex AD process. The performance and stability of AD process is highly influenced by various operating parameters like temperature, pH, carbon and nitrogen ratio, retention time, and organic loading rate. Different pre-treatment (e.g. mechanical, chemical and biological) could enhance the AD process and the biogas yield. Co-digestion can also be used to provide suitable nutrient balance inside the digester. Challenges of the anaerobic digestion for biogas production are also discussed.


2016 ◽  
Vol 75 (4) ◽  
pp. 775-781 ◽  
Author(s):  
J. A. Barrios ◽  
U. Duran ◽  
A. Cano ◽  
M. Cisneros-Ortiz ◽  
S. Hernández

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.


2014 ◽  
Vol 955-959 ◽  
pp. 2692-2696 ◽  
Author(s):  
Li Fan Liu ◽  
Yong Wei Liao ◽  
Jie Liang ◽  
Shu Ting Lai

The characteristics such as pH, dry matter, carbon concentration, the total solid and volatile solid of kitchen wastes produced by a canteen in Guangzhou were measured. The anaerobic digestion process performances were evaluated through the examination of operational conditions like activated sludge inoculation, temperature on SS, biogas production, COD concentration and pH in the reactor. When the proportion between kitchen wastes to seed sludge inoculation was 1:1, the biogas production reached the peak at 45 °C. The kitchen waste pH decreased at the first four days then increased adversely after 4 days digestion, but COD concentration showed the opposite variation.


2014 ◽  
Vol 675-677 ◽  
pp. 680-684
Author(s):  
Zhao Mei Du ◽  
Qin Wu ◽  
Xiao Qin Zhang

The feasibility of pulp and paper mill wastewater sludge as substrates for biogas production was evaluated in labrotory scale. Also the influence of pre-acidification, feeding modes and sludge concentration on anaerobic digestion system were studied.


2006 ◽  
Vol 53 (8) ◽  
pp. 23-32 ◽  
Author(s):  
D. Bolzonella ◽  
P. Pavan ◽  
S. Mace ◽  
F. Cecchi

This paper presents a comparison of dry anaerobic digestion reactors fed with differently sorted municipal organic solid wastes. One reactor was fed with source sorted organic wastes and a second reactor was fed with mixed organic wastes consisting of grey wastes, mechanically selected municipal solid wastes and sludge. The two reactors utilised the same process (Valorga) and operational conditions at full scale. The results of the study emphasise the influence of the kind of treated material on the process performances, especially in terms of biogas and methane production, thus, energy reclamation. The reactor treating the source sorted organic waste and the reactor treating the mixed organic wastes generated some 200 m3 and 60 m3 of biogas per ton of waste treated, respectively, while the specific methane production was some 0.40 and 0.13 m3CH4/kgTVS, respectively. The mass balance and the final fate of the digested material from the two reactors were also clearly different. As for the costs, these were some 29 € per ton of treated waste (50% for personnel) and 53 €/ton for disposing of the rejected materials. Incomes were some 100 €/ton (on average) and an other 15 €/ton came from green certificates. The initial investment was 16 million Euros.


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


Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1094
Author(s):  
Marco Chiappero ◽  
Francesca Cillerai ◽  
Franco Berruti ◽  
Ondřej Mašek ◽  
Silvia Fiore

Biochar (BC) recently gained attention as an additive for anaerobic digestion (AD). This work aims at a critical analysis of the effect of six BCs, with different physical and chemical properties, on the AD of mixed wastewater sludge at 37 °C, comparing their influence on methane production and AD kinetics. AD batch tests were performed at the laboratory scale operating 48 reactors (0.25 L working volume) for 28 days with the addition of 10 g L−1 of BC. Most reactors supplemented with BCs exhibited higher (up to 22%) methane yields than the control reactors (0.15 Nm3 kgVS−1). The modified Gompertz model provided maximum methane production rate values, and in all reactors the lag-phase was equal to zero days, indicating a good adaptation of the inoculum to the substrate. The potential correlations between BCs’ properties and AD performance were assessed using principal component analysis (PCA). The PCA results showed a reasonable correlation between methane production and the BCs’ O–C and H–C molar ratios, and volatile matter, and between biogas production and BCs’ pore volume, specific surface area, and fixed and total carbon. In conclusion, the physic-chemical properties of BC (specifically, hydrophobicity and morphology) showed a key role in improving the AD of mixed wastewater sludge.


2019 ◽  
Vol 38 (6) ◽  
Author(s):  
Fang‐Chen Lo ◽  
Kae‐Long Lin ◽  
Tzu‐Yi Pai ◽  
Wen‐Goang Yang ◽  
Yew‐Min Tzeng ◽  
...  

2002 ◽  
Vol 46 (4-5) ◽  
pp. 447-453 ◽  
Author(s):  
J. Zábranská ◽  
M. Dohányos ◽  
P. Jeníček ◽  
P. Zaplatílková ◽  
J. Kutil

Thermophilic anaerobic digestion of sewage sludge has been successfully operated in full-scale tanks almost three years. The higher loading capacity and specific biogas production rate in comparison with mesophilic digestion was proved. Thermophilic anaerobic sludge is also more resistant against foaming problems. Biogas from thermophilic tanks contains less hydrogen sulphide and other malodorous substances. Pathogens removal rate is apparently more efficient in the thermophilic process.


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