scholarly journals Effects of Ultrasonic and Microwave Pretreatment on Lipid Extraction of Microalgae and Methane Production from the Residual Extracted Biomass

2020 ◽  
Author(s):  
Magdalena Rokicka ◽  
Marcin Zieliński ◽  
Magda Dudek ◽  
Marcin Dębowski
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Energy Recovery ◽  
Extraction Efficiency ◽  
Lipid Extraction ◽  
Botryococcus Braunii ◽  
Methane Yield ◽  
Economic Viability ◽  
Ultrasonic Pretreatment ◽  
Microwave Pretreatment

Abstract The extraction of lipids from microalgae cells of Botryococcus braunii and Chlorella vulgaris after ultrasonic and microwave pretreatment was evaluated. Cell disruption increased the lipid extraction efficiency, and microwave pretreatment was more effective compared with ultrasonic pretreatment. The maximum lipid yield from B. braunii was 56.42% using microwave radiation and 39.61% for ultrasonication, while from C. vulgaris, it was respectively 41.31% and 35.28%. The fatty acid composition in the lipid extracts was also analyzed. The methane yield from the residual extracted biomass pretreated by microwaves ranged from 148 to 185 NmL CH4/g VS for C. vulgaris and from 128 to 142 NmL CH4/g VS for B. braunii. In the case of ultrasonic pretreatment, the methane production was between 168 and 208 NmL CH4/g VS for C. vulgaris, while for B. braunii ranging from 150 to 174 NmL CH4/g VS. Anaerobic digestion showed that lipid-extracted biomass presented lower methane yield than non-lipid-extracted feedstock, and higher amount of lipid obtained in the extraction contributed less methane production. Anyway, anaerobic digestion of the residual extracted biomass can be a suitable method to increase economic viability of energy recovery from microalgae.

scholarly journals Enhancing methane production from the invasive macroalga Rugulopteryx okamurae through anaerobic co-digestion with olive mill solid waste: process performance and kinetic analysis

2021 ◽  
Author(s):  
D. de la Lama-Calvente ◽  
M. J. Fernández-Rodríguez ◽  
J. Llanos ◽  
J. M. Mancilla-Leytón ◽  
R. Borja
Keyword(s):  
Anaerobic Digestion ◽  
Solid Waste ◽  
Methane Production ◽  
Methane Yield ◽  
Specific Rate ◽  
Order Kinetic ◽  
Two Phase ◽  
First Order ◽  
Olive Mill Solid Waste ◽  
Olive Mill

AbstractThe biomass valorisation of the invasive brown alga Rugulopteryx okamurae (Dictyotales, Phaeophyceae) is key to curbing the expansion of this invasive macroalga which is generating tonnes of biomass on southern Spain beaches. As a feasible alternative for the biomass management, anaerobic co-digestion is proposed in this study. Although the anaerobic digestion of macroalgae barely produced 177 mL of CH4 g−1 VS, the co-digestion with a C-rich substrate, such as the olive mill solid waste (OMSW, the main waste derived from the two-phase olive oil manufacturing process), improved the anaerobic digestion process. The mixture improved not only the methane yield, but also its biodegradability. The highest biodegradability was found in the mixture 1 R. okamurae—1 OMSW, which improved the biodegradability of the macroalgae by 12.9% and 38.1% for the OMSW. The highest methane yield was observed for the mixture 1 R. okamurae—3 OMSW, improving the methane production of macroalgae alone by 157% and the OMSW methane production by 8.6%. Two mathematical models were used to fit the experimental data of methane production time with the aim of assessing the processes and obtaining the kinetic constants of the anaerobic co-digestion of different combination of R. okamurae and OMSW and both substrates independently. First-order kinetic and the transference function models allowed for appropriately fitting the experimental results of methane production with digestion time. The specific rate constant, k (first-order model) for the mixture 1 R. okamurae- 1.5 OMSW, was 5.1 and 1.3 times higher than that obtained for the mono-digestion of single OMSW and the macroalga, respectively. In the same way, the transference function model revealed that the maximum methane production rate (Rmax) was also found for the mixture 1 R. okamurae—1.5 OMSW (30.4 mL CH4 g−1 VS day−1), which was 1.6 and 2.2 times higher than the corresponding to the mono-digestions of the single OMSW and sole R. okamurae (18.9 and 13.6 mL CH4 g−1 VS day−1), respectively.

scholarly journals Efficiency of integrated electrooxidation and anaerobic digestion of waste activated sludge

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
J. A. Barrios ◽  
A. Cano ◽  
F. F. Rivera ◽  
M. E. Cisneros ◽  
U. Durán
Keyword(s):  
Anaerobic Digestion ◽  
Current Density ◽  
Methane Production ◽  
Energy Recovery ◽  
Energy Analysis ◽  
Mathematical Optimization ◽  
Waste Activated Sludge ◽  
Bdd Electrode ◽  
Vs Removal ◽  
Pre Treatment

Abstract Background Most of the organic content of waste activated sludge (WAS) comprises microbial cells hard to degrade, which must be pre-treated for energy recovery by anaerobic digestion (AD). Electrooxidation pre-treatment (EOP) with boron-doped diamond (BDD) electrode have been considered a promising novel technology that increase hydrolysis rate, by the disintegrating cell walls from WAS. Although electrochemical oxidation could efficiently solubilize organic substances of macromolecules, limited reports are available on EOP of WAS for improving AD. In this endeavour, the mathematical optimization study and the energy analysis of the effects of initial total solids concentrations [TS] of WAS and current density (CD) during EOP on the methane production and removal of chemical oxygen demand (COD) and volatile solids (VS) were investigated. Because limited reports are available on EOP of WAS for improving biogas production, it is not well understood; however, it has started to attract interest of scientists and engineers. Results In the present work, the energy recovery as biogas and WAS conversion were comprehensively affected by CD and [TS], in an integrated EOP and AD system. When working with WAS at 3% of [TS] pre-treated at current density of 24.1 mA/cm2, the highest COD and VS removal were achieved, making it possible to obtain the maximum methane (CH4) production of 305 N-L/kg VS and a positive energy balance of 1.67 kWh/kg VS. Therefore, the current densities used in BDD electrode are adequate to produce the strong oxidant (hydroxyl radical, ·OH) on the electrode surface, allow the oxidation of organic compounds that favours the solubilization of particulate matter and VS from WAS. Conclusions The improvement of VS removal and COD solubilization were due to the effects of pre-treatments, which help to break down the microbial cells for faster subsequent degradation; this allows a decomposition reaction that leads to biodegrade more compounds during AD. The balance was positive, suggesting that even without any optimization the energy used as electricity could be recovered from the increased methane production. It is worth noting that this kind of analysis have not been sufficiently studied so far. It is therefore important to understand how operational parameters can influence the pre-treatment and AD performances. The current study highlights that the mathematical optimization and energy analysis can make the whole process more convenient and feasible.

scholarly journals Thermophilic Alkaline Fermentation Followed by Mesophilic Anaerobic Digestion for Efficient Hydrogen and Methane Production from Waste-Activated Sludge: Dynamics of Bacterial Pathogens as Revealed by the Combination of Metagenomic and Quantitative PCR Analyses

2018 ◽  
Vol 84 (6) ◽  
Author(s):  
Jingjing Wan ◽  
Yuhang Jing ◽  
Yue Rao ◽  
Shicheng Zhang ◽  
Gang Luo
Keyword(s):  
Microbial Community ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Quantitative Pcr ◽  
Methane Production ◽  
Bacterial Pathogens ◽  
Methane Yield ◽  
Metagenomic Analysis ◽  
Waste Activated Sludge ◽  
Hydrogen Yield

ABSTRACT Thermophilic alkaline fermentation followed by mesophilic anaerobic digestion (TM) for hydrogen and methane production from waste-activated sludge (WAS) was investigated. The TM process was also compared to a process with mesophilic alkaline fermentation followed by a mesophilic anaerobic digestion (MM) and one-stage mesophilic anaerobic digestion (M) process. The results showed that both hydrogen yield (74.5 ml H 2 /g volatile solids [VS]) and methane yield (150.7 ml CH 4 /g VS) in the TM process were higher than those (6.7 ml H 2 /g VS and 127.8 ml CH 4 /g VS, respectively) in the MM process. The lowest methane yield (101.2 ml CH 4 /g VS) was obtained with the M process. Taxonomic results obtained from metagenomic analysis showed that different microbial community compositions were established in the hydrogen reactors of the TM and MM processes, which also significantly changed the microbial community compositions in the following methane reactors compared to that with the M process. The dynamics of bacterial pathogens were also evaluated. For the TM process, the reduced diversity and total abundance of bacterial pathogens in WAS were observed in the hydrogen reactor and were further reduced in the methane reactor, as revealed by metagenomic analysis. The results also showed not all bacterial pathogens were reduced in the reactors. For example, Collinsella aerofaciens was enriched in the hydrogen reactor, which was also confirmed by quantitative PCR (qPCR) analysis. The study further showed that qPCR was more sensitive for detecting bacterial pathogens than metagenomic analysis. Although there were some differences in the relative abundances of bacterial pathogens calculated by metagenomic and qPCR approaches, both approaches demonstrated that the TM process was more efficient for the removal of bacterial pathogens than the MM and M processes. IMPORTANCE This study developed an efficient process for bioenergy (H 2 and CH 4 ) production from WAS and elucidates the dynamics of bacterial pathogens in the process, which is important for the utilization and safe application of WAS. The study also made an attempt to combine metagenomic and qPCR analyses to reveal the dynamics of bacterial pathogens in anaerobic processes, which could overcome the limitations of each method and provide new insights regarding bacterial pathogens in environmental samples.

scholarly journals Biogas Potential from the Anaerobic Digestion of Potato Peels: Process Performance and Kinetics Evaluation

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2311 ◽  
Author(s):  
Spyridon Achinas ◽  
Yu Li ◽  
Vasileios Achinas ◽  
Gerrit Jan Willem Euverink
Keyword(s):  
Anaerobic Digestion ◽  
Energy Recovery ◽  
Biogas Production ◽  
Combined Treatment ◽  
Methane Yield ◽  
Cow Manure ◽  
Potato Peel ◽  
Potato Peels ◽  
The Impact ◽  
Kinetics Of

This article intends to promote the usage of potato peels as efficient substrate for the anaerobic digestion process for energy recovery and waste abatement. This study examined the performance of anaerobic digestion of potato peels in different inoculum-to-substrate ratios. In addition, the impact of combined treatment with cow manure and pretreatment of potato peels was examined. It was found that co-digestion of potato peel waste and cow manure yielded up to 237.4 mL CH4/g VSadded, whereas the maximum methane yield from the mono-digestion of potato peels was 217.8 mL CH4/g VSadded. Comparing the co-digestion to mono-digestion of potato peels, co-digestion in PPW/CM ratio of 60:40 increased the methane yield by 10%. In addition, grinding and acid hydrolysis applied to potato peels were positively effective in increasing the methane amount reaching 260.3 and 283.4 mL CH4/g VSadded respectively. Likewise, compared to untreated potato peels, pretreatment led to an elevation of the methane amount by 9% and 17% respectively and alleviated the kinetics of biogas production.

scholarly journals Pretreatment of Animal Manure Biomass to Improve Biogas Production: A Review

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3573 ◽  
Author(s):  
Meneses-Quelal Orlando ◽  
Velázquez-Martí Borja
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Biogas Production ◽  
Poultry Manure ◽  
Animal Manure ◽  
Methane Yield ◽  
Operational Parameters ◽  
Advantages And Disadvantages ◽  
Physical Chemical ◽  
Chemical Pretreatments

The objective of this research is to present a review of the current technologies and pretreatments used in the fermentation of cow, pig and poultry manure. Pretreatment techniques were classified into physical, chemical, physicochemical, and biological groups. Various aspects of these different pretreatment approaches are discussed in this review. The advantages and disadvantages of its applicability are highlighted since the effects of pretreatments are complex and generally depend on the characteristics of the animal manure and the operational parameters. Biological pretreatments were shown to improve methane production from animal manure by 74%, chemical pretreatments by 45%, heat pretreatments by 41% and physical pretreatments by 30%. In general, pretreatments improve anaerobic digestion of the lignocellulosic content of animal manure and, therefore, increase methane yield.

scholarly journals Evaluation on the Methane Production Potential of Wood Waste Pretreated with NaOH and Co-Digested with Pig Manure

Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 539 ◽  
Author(s):  
Renfei Li ◽  
Wenbing Tan ◽  
Xinyu Zhao ◽  
Qiuling Dang ◽  
Qidao Song ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Lignocellulosic Biomass ◽  
Methane Production ◽  
Biogas Production ◽  
Untreated Wood ◽  
Wood Waste ◽  
Methane Yield ◽  
Pig Manure ◽  
Naoh Pretreatment ◽  
Digestion Technique

Wood waste generated during the tree felling and processing is a rich, green, and renewable lignocellulosic biomass. However, an effective method to apply wood waste in anaerobic digestion is lacking. The high carbon to nitrogen (C/N) ratio and rich lignin content of wood waste are the major limiting factors for high biogas production. NaOH pre-treatment for lignocellulosic biomass is a promising approach to weaken the adverse effect of complex crystalline cellulosic structure on biogas production in anaerobic digestion, and the synergistic integration of lignocellulosic biomass with low C/N ratio biomass in anaerobic digestion is a logical option to balance the excessive C/N ratio. Here, we assessed the improvement of methane production of wood waste in anaerobic digestion by NaOH pretreatment, co-digestion technique, and their combination. The results showed that the methane yield of the single digestion of wood waste was increased by 38.5% after NaOH pretreatment compared with the untreated wood waste. The methane production of the co-digestion of wood waste and pig manure was higher than that of the single digestion of wood waste and had nonsignificant difference with the single-digestion of pig manure. The methane yield of the co-digestion of wood waste pretreated with NaOH and pig manure was increased by 75.8% than that of the untreated wood waste. The findings indicated that wood waste as a sustainable biomass source has considerable potential to achieve high biogas production in anaerobic digestion.

Anaerobic degradation of palm oil mill effluent with aluminum bauxite residue for methane production

2020 ◽  
pp. 0958305X2092312
Author(s):  
Anwar Ahmad ◽  
Salam S AlDawey ◽  
SS Reddy
Keyword(s):  
Anaerobic Digestion ◽  
Palm Oil ◽  
Methane Production ◽  
Bauxite Residue ◽  
Oxygen Demand ◽  
Palm Oil Mill Effluent ◽  
Methane Yield ◽  
Yield Coefficient ◽  
Methanogenic Activity ◽  
Palm Oil Mill

Experimental study of the anaerobic digestion of palm oil mill effluent (POME) was carried out in an anaerobic upflow sludge blanket reactor (UASBR) with bauxite residue. The production rate of methane 114 L/gCOD/d and CH4 concentration was 205 L gCOD/d at 8.5 g/L of bauxite residue in UASBR. The results showed that the highest methane yield was 37.5 L gCODadded/h; CO2 reduction 1.5 L gCODadded and chemical oxygen demand (COD) removal reached 98.3% at 8.5 g/L of bauxite residue, respectively. The results the best by the modified kinetic model and Umax was 100 mg/L. The kinetic of methane production was also studied. The methane yield coefficient, YM, was 0.69 L CH4/gCODremoved. Anaerobic digestion of acetate was the dominant soluble metabolites in development and specific methanogenic activity results showed that high observed between stoichiometric and experimental higher methane production.

Effect of sodium salt on anaerobic digestion of kitchen waste

2016 ◽  
Vol 73 (8) ◽  
pp. 1865-1871 ◽  
Author(s):  
Naveed Anwar ◽  
Wen Wang ◽  
Jie Zhang ◽  
Yeqing Li ◽  
Chang Chen ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Sodium Salt ◽  
Salt Concentration ◽  
Methane Production ◽  
Volatile Fatty Acids ◽  
Production Performance ◽  
Methane Yield ◽  
Production Model ◽  
Lag Phase ◽  
Kitchen Waste

The effect of different sodium salt concentration on anaerobic digestion of kitchen waste was investigated. The methane production performance, the corresponding methane production model and sodium salt inhibition model were studied, and the degradation efficiency was analyzed. With the increase of sodium salt concentration, the methane yield and the maximal methane production rate decreased along with the increase of lag phase time. The highest methane yield of 594 mL/g-VSadded (VS: volatile solids) was found with no sodium salt addition while the lowest was obtained with addition of 16 g/L NaCl. The declines of the methane yield were negligible when the sodium salt concentration was below 8 g/L, which corresponded to <10% inhibiting efficiency. In contrast, a sharp decrease of methane yield was observed with addition of >8 g/L NaCl (causing 17–80% inhibition). Five kinds of regression models were developed to describe the sodium salt inhibition efficiency, and the cubic regression model of y = 0.508 + 2.401x − 0.369x2 + 0.033x3 showed the best fitting. The volatile fatty acids/ethanol gradually accumulated along with the increase of the sodium salt concentration, and the volatile solid removal efficiency represented a gradual decline accordingly. It is recommended that the sodium salt concentration in the anaerobic digesters should be controlled below 8 g/L in order to avoid intense methane inhibition.

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