Impact of osmotic shock pre-treatment on microalgae lipid extraction and subsequent methane production

2019 ◽  
Vol 7 ◽  
pp. 100214 ◽  
Author(s):  
Lina María González-González ◽  
Sergi Astals ◽  
Steven Pratt ◽  
Paul D. Jensen ◽  
Peer M. Schenk
Keyword(s):  
Methane Production ◽  
Osmotic Shock ◽  
Lipid Extraction ◽  
Pre Treatment

Osmotic shock pre-treatment of Chaetoceros muelleri wet biomass enhanced solvent-free lipid extraction and biogas production

2021 ◽  
Vol 54 ◽  
pp. 102177
Author(s):  
Lina María González-González ◽  
Sergi Astals ◽  
Steven Pratt ◽  
Paul D. Jensen ◽  
Peer M. Schenk
Keyword(s):  
Biogas Production ◽  
Osmotic Shock ◽  
Lipid Extraction ◽  
Solvent Free ◽  
Chaetoceros Muelleri ◽  
Free Lipid ◽  
Wet Biomass ◽  
Pre Treatment

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.

Analyzing and optimizing the carbon utilization and lipid yield at different light intensities for Scenedesmus arcuatus

2021 ◽  
Vol 25 (11) ◽  
pp. 1-10
Author(s):  
K. Vasumathi ◽  
Raja Vadivu G. Nadana ◽  
E.M. Nithiya ◽  
K. Sundar ◽  
M. Premalatha
Keyword(s):  
Light Intensity ◽  
Large Scale ◽  
Biomass Yield ◽  
Osmotic Shock ◽  
High Light Intensity ◽  
Carbon Utilization ◽  
Lipid Yield ◽  
The Face ◽  
Photosynthetic Microorganism ◽  
Pre Treatment

Microalgae, the photosynthetic microorganism growing abundantly in marine and aquatic ecosystems, are potential source for biological sequestration of CO2. The carbon uptake differs in the presence of other nutrients, light intensity etc. The biomass yield of Scenedesmus arcuatus var capitatus was studied based on the Face Centred Central Composite design (FCCD) of Response Surface Methodology (RSM) for nitrate, phosphate and carbonate under different conditions (laboratory, room and sunlight conditions). Various pre-treatments (osmotic shock, autoclaving, microwave and ultrasonication) were employed to find the best method for maximum lipid yield. The biomass yield reached a maximum of 1 g/L under sunlight conditions of nitrate concentration 500 ppm and carbonate 2000 ppm. The laboratory conditions resulted in a biomass yield of 0.59 g/L at 500 ppm nitrate, 1000 ppm carbonate and 250 ppm phosphate. Under room conditions, the yield was very low (0.11 g/L). Osmotic shock resulted in higher lipid yield than the other pre-treatment methods. The ability of Scenedesmus arcuatus to uptake high carbon under sunlight conditions and to adapt to high light intensity and fluctuations in light intensity concludes that this species is suitable for large-scale open pond cultivation for CO2 sequestration and production of metabolites.

scholarly journals Optimisation of Protein Recovery from Arthrospira platensis by Ultrasound-Assisted Isoelectric Solubilisation/Precipitation

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1586
Author(s):  
Ana Sánchez-Zurano ◽  
Ainoa Morillas-España ◽  
Cynthia Victoria González-López ◽  
Tomás Lafarga
Keyword(s):  
Food Industry ◽  
Functional Foods ◽  
Osmotic Shock ◽  
Arthrospira Platensis ◽  
Extraction Time ◽  
Protein Recovery ◽  
Solvent Ratio ◽  
Total Proteins ◽  
Cell Wall Disruption ◽  
Pre Treatment

A response surface methodology was used to optimise the solubilisation and precipitation of proteins from the cyanobacterium Arthrospira platensis. Two separate experiments were designed and conducted in a sequential manner. Protein solubilisation was affected by pH, extraction time, and biomass to solvent ratio (p < 0.001). Although spray-drying and the osmotic shock suffered when resuspending the dried biomass into distilled water led to a certain degree of cell wall disruption, the amount of protein that could be solubilised without an additional disruption step was in the range 30–60%. Sequential extractions improved protein solubilisation by less than 5%. For this reason, a pre-treatment based on sonication (400 W, 24 kHz, 2 min) had to be used, allowing the solubilisation of 96.2% of total proteins. Protein precipitation was affected by both pH and extraction time (p < 0.001). The optimised precipitation conditions, which were pH 3.89 over 45 min, led to a protein recovery of 75.2%. The protein content of the extract was close to 80%, which could be further increased by using different purification steps. The proteins extracted could be used in the food industry as technofunctional ingredients or as a source of bioactive hydrolysates and peptides for functional foods and nutraceuticals.

Anaerobic digestion of macroalgae: methane potentials, pre-treatment, inhibition and co-digestion

2011 ◽  
Vol 64 (8) ◽  
pp. 1723-1729 ◽  
Author(s):  
H. B. Nielsen ◽  
S. Heiske
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Organic Content ◽  
Saccharina Latissima ◽  
Green Tides ◽  
Volatile Solids ◽  
Continuously Stirred Tank Reactor ◽  
Pre Treatment ◽  
Centralized Biogas Plant ◽  
Chaetomorpha Linum

In the present study we tested four macroalgae species – harvested in Denmark – for their suitability of bioconversion to methane. In batch experiments (53 °C) methane yields varied from 132 ml g volatile solids−1 (VS) for Gracillaria vermiculophylla, 152 ml g VS−1 for Ulva lactuca, 166 ml g VS−1 for Chaetomorpha linum and 340 ml g VS−1 for Saccharina latissima following 34 days of incubation. With an organic content of 21.1% (1.5–2.8 times higher than the other algae) S. latissima seems very suitable for anaerobic digestion. However, the methane yields of U. lactuca, G. vermiculophylla and C. linum could be increased with 68%, 11% and 17%, respectively, by pretreatment with maceration. U. lactuca is often observed during ‘green tides’ in Europe and has a high cultivation potential at Nordic conditions. Therefore, U. lactuca was selected for further investigation and co-digested with cattle manure in a lab-scale continuously stirred tank reactor. A 48% increase in methane production rate of the reactor was observed when the concentration of U. lactuca in the feedstock was 40% (VS basis). Increasing the concentration to 50% had no further effect on the methane production, which limits the application of this algae at Danish centralized biogas plant.

Free ammonia pre-treatment of secondary sludge significantly increases anaerobic methane production

2017 ◽  
Vol 118 ◽  
pp. 12-19 ◽  
Author(s):  
Wei Wei ◽  
Xu Zhou ◽  
Dongbo Wang ◽  
Jing Sun ◽  
Qilin Wang
Keyword(s):  
Methane Production ◽  
Free Ammonia ◽  
Secondary Sludge ◽  
Pre Treatment

scholarly journals Effects of Thickened Excess Sludge Pre-Treatment Using Hydrodynamic Cavitation for Anaerobic Digestion

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2483 ◽  
Author(s):  
Agnieszka Garlicka ◽  
Monika Zubrowska-Sudol ◽  
Katarzyna Umiejewska ◽  
Otton Roubinek ◽  
Jacek Palige ◽  
...  
Keyword(s):  
Methane Production ◽  
Pilot Scale ◽  
Hydrodynamic Cavitation ◽  
Excess Sludge ◽  
Maximum Increase ◽  
Primary Sludge ◽  
Sludge Flocs ◽  
Pre Treatment ◽  
Flocculation Process ◽  
Different Levels

The main purpose of this study was the assessment of the possibility of increasing the production of biogas through the pre-treatment of thickened excess sludge (TES) by means of the hydrodynamic cavitation (HC) conducted at different levels of energy density (EL) i.e., 70, 140 and 210 kJ/L. The experiments were performed on a pilot scale, and a mixture of thickened primary sludge (TPS) and TES was used as digester feed. The results documented that an important parameter determining the possibility of obtaining an enhanced methane production is the value of energy input in the HC process. This parameter determines the changes occurring in sludge as a result of disintegration (i.e., sludge floc deagglomeration, lysis of cells, re-flocculation process and the related release of compounds susceptible to biodegradation from sludge flocs). The maximum increase in methane yield (MY) of 152% was obtained for EL = 140 kJ/L. In this case, HC mainly caused sludge floc deagglomeration. An increase in MY was also recorded when TES was subject to the disintegration process at EL = 210 kJ/L. However, it was 4.3 times lower than that observed for EL = 140 kJ/L. Pre-treatment of TES at EL = 70 kJ/L did not contribute to an increase in methane production.

scholarly journals Innovative Hydrodynamic Disintegrator Adjusted to Agricultural Substrates Pre-treatment Aimed at Methane Production Intensification—CFD Modelling and Batch Tests

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4256 ◽  
Author(s):  
Monika Zubrowska-Sudol ◽  
Aleksandra Dzido ◽  
Agnieszka Garlicka ◽  
Piotr Krawczyk ◽  
Michał Stępień ◽  
...  
Keyword(s):  
Methane Production ◽  
Damage Zone ◽  
Positive Energy ◽  
Net Energy ◽  
Maize Silage ◽  
Cfd Modelling ◽  
Study Objective ◽  
Testing Procedures ◽  
Methane Potential ◽  
Pre Treatment

The study objective was to adjust the hydrodynamic disintegrator dedicated to sewage sludge pre-treatment (HDS) to work with agricultural substrate. This involved the development and implementation of a mathematical model of flow via the device’s domain. An innovative disintegrator (HAD—hydrodynamic disintegrator for agriculture) was designed, built, and tested based on the obtained results. The main improvements to the HDS include the implementation of shredding knives in order to overcome clogging by crushed substrate, and the application of ribs in the recirculation zone, contributing to the development of an additional structure damage zone. The challenge of this study was also to determine the operating parameters of the HDA that would provide for an increase in methane production with positive energy balance. The testing procedures, for which maize silage was selected, involved batch disintegration tests and biochemical methane potential tests. No clogging of rotor or spontaneous shutting off of the device, in other words, problems that had occurred in the HDS, were observed. The applied pre-treatment method permitted an increase in the methane potential of maize silage by 34.4%, 27.0%, and 21.6%, respectively for samples disintegrated at energy densities of 10 kJ/L, 20 kJ/L, and 35 kJ/L with net energy profit.

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