scholarly journals Nannochloropsis oceanica Cultivation in Pilot-Scale Raceway Ponds—From Design to Cultivation

2020 ◽  
Vol 10 (5) ◽  
pp. 1725 ◽  
Author(s):  
Pedro Cunha ◽  
Hugo Pereira ◽  
Margarida Costa ◽  
João Pereira ◽  
Joana T. Silva ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Water Depth ◽  
Production Systems ◽  
Biomass Productivity ◽  
Pilot Scale ◽  
Channel Width ◽  
Nannochloropsis Oceanica ◽  
Efficient System ◽  
Standard Configuration ◽  
Raceway Ponds

Raceways ponds are the microalgal production systems most commonly used at industrial scale. In this work, two different raceway configurations were tested under the same processing conditions to compare their performance on the production of Nannochloropsis oceanica. Biomass productivity, biochemical composition of the produced biomass, and power requirements to operate those reactors were evaluated. Water depths of 0.20 and 0.13 m, and culture circulation velocities of 0.30 and 0.15 m s−1 were tested. A standard configuration, which had a full channel width paddlewheel, proved to be the most energy efficient, consuming less than half of the energy required by a modified configuration (had a half channel width paddlewheel). The later showed to have slightly higher productivity, not enough to offset the large difference in energetic consumption. Higher flow velocity (0.30 m s−1) led to a 1.7 g m−2 d−1 improvement of biomass productivity of the system, but it increased the energy consumption twice as compared to the 0.15 m s−1 flow velocity. The latter velocity showed to be the most productive in lipids. A water depth of 0.20 m was the most suitable option tested to cultivate microalgae, since it allowed a 54% energy saving. Therefore, a standard raceway pond using a flow velocity of 0.3 m s−1 with a 0.20 m water depth was the most efficient system for microalgal cultivation. Conversely, a flow velocity of 0.15 m s−1 was the most suitable to produce lipids.

scholarly journals Growth of Haematococcus pluvialis on a Small-Scale Angled Porous Substrate Photobioreactor for Green Stage Biomass

2021 ◽  
Vol 11 (4) ◽  
pp. 1788
Author(s):  
Thanh-Tri Do ◽  
Binh-Nguyen Ong ◽  
Tuan-Loc Le ◽  
Thanh-Cong Nguyen ◽  
Bich-Huy Tran-Thi ◽  
...  
Keyword(s):  
Light Intensity ◽  
Algal Biomass ◽  
Haematococcus Pluvialis ◽  
Biomass Productivity ◽  
Pilot Scale ◽  
Small Scale ◽  
Porous Substrate ◽  
Low Light ◽  
Green Algal ◽  
Green Stage

In the production of astaxanthin from Haematococcus pluvialis, the process of growing algal biomass in the vegetative green stage is an indispensable step in both suspended and immobilized cultivations. The green algal biomass is usually cultured in a suspension under a low light intensity. However, for astaxanthin accumulation, the microalgae need to be centrifuged and transferred to a new medium or culture system, a significant difficulty when upscaling astaxanthin production. In this research, a small-scale angled twin-layer porous substrate photobioreactor (TL-PSBR) was used to cultivate green stage biomass of H. pluvialis. Under low light intensities of 20–80 µmol photons m−2·s−1, algae in the biofilm consisted exclusively of non-motile vegetative cells (green palmella cells) after ten days of culturing. The optimal initial biomass density was 6.5 g·m−2, and the dry biomass productivity at a light intensity of 80 µmol photons m−2·s−1 was 6.5 g·m−2·d−1. The green stage biomass of H. pluvialis created in this small-scale angled TL-PSBR can be easily harvested and directly used as the source of material for the inoculation of a pilot-scale TL-PSBR for the production of astaxanthin.

scholarly journals Influence of Light Intensity and Temperature on Cultivation of Microalgae Desmodesmus Communis in Flasks and Laboratory-Scale Stirred Tank Photobioreactor

2015 ◽  
Vol 52 (2) ◽  
pp. 59-70 ◽  
Author(s):  
J. Vanags ◽  
L. Kunga ◽  
K. Dubencovs ◽  
V. Galvanauskas ◽  
O. Grīgs
Keyword(s):  
Light Intensity ◽  
Shake Flask ◽  
Scale Up ◽  
Biomass Concentration ◽  
Biomass Productivity ◽  
Pilot Scale ◽  
Laboratory Scale ◽  
Stirred Tank ◽  
Light Limitation ◽  
Maximum Biomass

Abstract Optimization of the microalgae cultivation process and of the bioprocess in general traditionally starts with cultivation experiments in flasks. Then the scale-up follows, when the process from flasks is transferred into a laboratory-scale bioreactor, in which further experiments are performed before developing the process in a pilot-scale reactor. This research was done in order to scale-up the process from a 0.4 1 shake flask to a 4.0 1 laboratory-scale stirred-tank photobioreactor for the cultivation of Desmodesmus (D.) communis microalgae. First, the effect of variation in temperature (21-29 ºC) and in light intensity (200-600 μmol m-2s-1) was studied in the shake-flask experiments. It was shown that the best results (the maximum biomass concentration of 2.72 g 1-1 with a specific growth rate of 0.65 g g-1d-1) can be achieved at the cultivation temperature and light intensity being 25 °C and 300 μmol m2s-1, respectively. At the same time, D. communis cultivation under the same conditions in stirred-tank photobioreactor resulted in average volumetric productivities of biomass due to the light limitation even when the light intensity was increased during the experiment (the maximum biomass productivity 0.25 g 1-1d-1; the maximum biomass concentration 1.78 g 1-1).

scholarly journals A hydro-sedimentary modeling system for flash flood propagation and hazard estimation under different agricultural practices

2014 ◽  
Vol 14 (3) ◽  
pp. 625-634 ◽  
Author(s):  
N. N. Kourgialas ◽  
G. P. Karatzas
Keyword(s):  
Sediment Transport ◽  
Flow Velocity ◽  
Water Depth ◽  
Riparian Vegetation ◽  
Flash Flood ◽  
Flood Hazard ◽  
Hydraulic Modeling ◽  
Modeling Framework ◽  
Mike 11 ◽  
Discharge Velocity

Abstract. A modeling system for the estimation of flash flood flow velocity and sediment transport is developed in this study. The system comprises three components: (a) a modeling framework based on the hydrological model HSPF, (b) the hydrodynamic module of the hydraulic model MIKE 11 (quasi-2-D), and (c) the advection–dispersion module of MIKE 11 as a sediment transport model. An important parameter in hydraulic modeling is the Manning's coefficient, an indicator of the channel resistance which is directly dependent on riparian vegetation changes. Riparian vegetation's effect on flood propagation parameters such as water depth (inundation), discharge, flow velocity, and sediment transport load is investigated in this study. Based on the obtained results, when the weed-cutting percentage is increased, the flood wave depth decreases while flow discharge, velocity and sediment transport load increase. The proposed modeling system is used to evaluate and illustrate the flood hazard for different riparian vegetation cutting scenarios. For the estimation of flood hazard, a combination of the flood propagation characteristics of water depth, flow velocity and sediment load was used. Next, a well-balanced selection of the most appropriate agricultural cutting practices of riparian vegetation was performed. Ultimately, the model results obtained for different agricultural cutting practice scenarios can be employed to create flood protection measures for flood-prone areas. The proposed methodology was applied to the downstream part of a small Mediterranean river basin in Crete, Greece.

scholarly journals Biofertigation of Forage With Effluents From a Cattle Slaughterhouse Green Line: Impacts on Physical-Chemical Indicators of Soil Quality and on Production Biomass

2018 ◽  
Vol 10 (7) ◽  
pp. 359
Author(s):  
Joaquim Jose de Carvalho Carvalho ◽  
José Maria Rodrigues da Luz ◽  
Jaqueline Henrique ◽  
José Geraldo Delvaux Silva ◽  
Raphael Bragança Alves Fernandes ◽  
...  
Keyword(s):  
Production Systems ◽  
Biomass Productivity ◽  
Animal Husbandry ◽  
Leaf Biomass ◽  
Green Line ◽  
Meat Processing ◽  
Fine Soil ◽  
Chemical Indicators ◽  
Physical Chemical ◽  
Soil Preparation

Cattle slaughterhouses are potential causes the environmental impacts, as it require a large volume of water in meat processing, generate large effluents amount, and promote the Cerrado deforestation for animal husbandry. Therefore, we aim was carried out to assess the effects of the soil application of a green line wastewater from a cattle slaughterhouse in the Brachiaria brizantha growth. The M1 and M2 managements did not contain wastewater of slaughterhouse. The wastewater from the 3rd stabilization pond (M3 to M5), from reception box (M6 to M8), and manure (M9 and M10) were used in the biofertigation managements. The physical-chemical indicators levels did not show significant differences (p < 0.05) before soil preparation and after managements. However, biofertigation in the Cerrado soil can provide a mitigation of the leaching of fine soil particles and cations. In addition, maximum nitrogen dose of wastewater provided a higher leaf biomass productivity than commercial nitrogen. Thus, the fertigation with wastewater can reduce the use of water bodies to crops irrigation and the incorporation of new areas with native vegetation to the agricultural production systems.

Effects of operation parameters on nutrient removal from wastewater and high-protein biomass production in a duckweed-based (Lemma aequinoctialis) pilot-scale system

2014 ◽  
Vol 70 (7) ◽  
pp. 1195-1204 ◽  
Author(s):  
Yonggui Zhao ◽  
Yang Fang ◽  
Yanling Jin ◽  
Jun Huang ◽  
Shu Bao ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Biomass Production ◽  
Water Depth ◽  
Nutrient Removal ◽  
Removal Rate ◽  
Pilot Scale ◽  
Coverage Rate ◽  
High Protein ◽  
Dianchi Lake ◽  
Operation Conditions

The effects of water depth, coverage rate and harvest regime on nutrient removal from wastewater and high-protein biomass production were assessed in a duckweed-based (Lemna aequinoctialis) pilot-scale wastewater treatment system (10 basins × 12 m2) that is located near Dianchi Lake in China. The results indicated that a water depth of 50 cm, a coverage rate of 150% and a harvest regime of 4 days were preferable conditions, under which excellent records of high-protein duckweed (dry matter production of 6.65 g/m2/d with crude protein content of 36.16% and phosphorus content of 1.46%) were obtained at a temperature of 12–21 °C. At the same time, the system achieved a removal efficiency of 66.16, 23.1, 48.3 and 76.52% for NH4+-N, TN, TP and turbidity, respectively, with the considerable removal rate of 0.465 g/m2/d for TN and 0.134 g/m2/d for TP at a hydraulic retention time of 6 days. In additionally, it was found that a lower duckweed density could lead to higher dissolved oxygen in the water and then a higher removal percentage of NH4+-N by nitrobacteria. This study obtains the preferable operation conditions for wastewater treatment and high-protein biomass production in a duckweed-based pilot-scale system, supplying an important reference for further large-scale applications of duckweed.

Dynamics of capillary-driven liquid–liquid displacement in open microchannels

2014 ◽  
Vol 16 (44) ◽  
pp. 24473-24478 ◽  
Author(s):  
D. Yang ◽  
M. Krasowska ◽  
C. Priest ◽  
J. Ralston
Keyword(s):  
Flow Velocity ◽  
Channel Width ◽  
Liquid Front ◽  
Liquid Displacement

For capillary-driven liquid–liquid displacement in rectangular open microchannels, the square of the position of the liquid–liquid front increases linearly with time, whereas the flow velocity decreases with increasing channel width.

Theoretical Analysis of Flame Propagation in Meso and Microscale Channels

2003 ◽  
Author(s):  
Yiguang Ju
Keyword(s):  
Flow Velocity ◽  
Heat Loss ◽  
Flame Propagation ◽  
Critical Value ◽  
Flow Speed ◽  
External Heat ◽  
Channel Width ◽  
Recent Experimental Data ◽  
Quenching Distance ◽  
Large Flow

Extinction and flame propagation in a meso and microscale channels are investigated analytically. Emphasis was paid to the coupling of wall heat loss, wall preheating, external heat loss and chemical reaction. The results showed that, wall thermal properties, channel width and flow velocity have dramatic effects on the flame propagation and lead to multiple flame regimes and extinction limits. With the decrease of channel width, flame reaches its first quenching limit, the so called critical quenching distance. However, with a further decrease of channel width, the results show that there exists a slow burning flame. With the increase of wall heat loss the speed of the slow burning flame slightly decreases and eventually reaches its second burning limit. With the change of the flow velocity, the results show that sub-limit flame can only exist at flow velocity larger than a critical value. At moderate flow velocity, flame speed increases with the increase of flow speed. At very large flow velocity, flame will be blown off. The above results are confirmed from the recent experimental data.

scholarly journals Implementing a hydrodynamic model to complement water depth and flow velocity data for physical scale experiments of rivers and estuaries

2020 ◽  
Author(s):  
Steven A. H. Weisscher ◽  
Marcio Boechat-Albernaz ◽  
Jasper R. F. W. Leuven ◽  
Wout M. Van Dijk ◽  
Yasuyuki Shimizu ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Water Depth ◽  
Hydrodynamic Model ◽  
Tidal Flow ◽  
Measured Data ◽  
Post Processing ◽  
Model Flow ◽  
Digital Elevation ◽  
Physical Scale ◽  
Spatio Temporal

Abstract. Physical scale experiments enhance our understanding of fluvial, tidal and coastal processes. However, it has proven challenging to acquire accurate and continuous data on water depth and flow velocity due to limitations of the measuring equipment and necessary simplifications during post-processing. A novel means to augment measurements is to numerically model flow over the experimental digital elevation models. We investigated to what extent the numerical hydrodynamic model Nays2D can reproduce unsteady, nonuniform shallow flow in scale experiments and under which conditions a model is preferred to measurements. To this end, we tested Nays2D for one tidal and two fluvial scale experiments and extended Nays2D to allow for flume tilting which is necessary to steer tidal flow. The modelled water depth and flow velocity closely resembled the measured data for locations where the quality of the measured data was most reliable, and model results may be improved by applying a spatially variable roughness. The implication of the experimental data-model integration is that conducting experiments requires fewer measurements and less post-processing in a simple, affordable and labour-inexpensive manner that results in continuous spatio-temporal data of better overall quality. Also, this integration will aid experimental design.

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