Numerical and experimental investigation of hydrodynamics and light transfer in open raceway ponds at various algal cell concentrations and medium depths

Amini, Hossein; Hashemisohi, Abolhasan; Wang, Lijun; Shahbazi, Abolghasem; Bikdash, Marwan; Kc, Dukka B.; Yuan, Wenqiao

doi:10.1016/j.ces.2016.09.003

Cited by 31 publications

(8 citation statements)

References 20 publications

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“…Primary treatment consists of removing settleable organic and inorganic solids from the raw wastewater by sedimentation. To date, there are several studies on optimising the HRAP operating conditions, such as depth, hydraulic retention time (HRT) and dynamics (Amini et al, 2016;Buchanan et al, 2018;Sutherland et al, 2014). However, there are no studies in the literature which investigate, in practice, the role and effect of the primary treatment step before the HRAPs.…”

Section: Introductionmentioning

confidence: 99%

The effect of primary treatment of wastewater in high rate algal pond systems: Biomass and bioenergy recovery

Arashiro

Ferrer

Rousseau

et al. 2019

Bioresource Technology

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The aim of this study was to assess the effect of primary treatment on the performance of two pilot-scale high rate algal ponds (HRAPs) treating urban wastewater, considering their treatment efficiency, biomass productivity, characteristics and biogas production potential. Results indicated that the primary treatment did not significantly affect the wastewater treatment efficiency (NH4 +-N removal of 93 and 91% and COD removal of 62 and 65% in HRAP with and without primary treatment, respectively). The HRAP without primary treatment had higher biodiversity and productivity (18 vs. 16 g VSS/m 2 d). Biomass from both systems presented good settling capacity. Results of biochemical methane potential test showed that co-digesting microalgae and primary sludge led to higher methane yields (238-258 mL CH4/g VS) compared with microalgae mono-digestion (189-225 mL CH4/g VS). Overall, HRAPs with and without primary treatment seem to be appropriate alternatives for combining wastewater treatment and bioenergy recovery.

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Section: Introductionmentioning

confidence: 99%

The effect of primary treatment of wastewater in high rate algal pond systems: Biomass and bioenergy recovery

Arashiro

Ferrer

Rousseau

et al. 2019

Bioresource Technology

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“…Variations of biomass productivity can be derived from the variations of ETRmax (Malapascua et al, 2014; Robati et al, 2021). The UVA radiations are not included in the existing predictive models coupling microalgae productivity and light transfer, which consider only the photosynthetically active radiations (Amini et al, 2016). Such data could be useful to predict the evolution of culture productivity submitted to natural oxidative stress such as solar UVA radiations.…”

Section: Discussionmentioning

confidence: 99%

Comparative study on photosynthetic and antioxidant activities of Haematococcus pluvialis vegetative and resting cells: UVA light-induced stimulation

Hamouda

Kacem

Achour

et al. 2022

Journal of Applied Microbiology

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Aim This study aims to determine how photosynthetic and antioxidant activities vary in vegetative and dormant cells of Haematococcus pluvialis subjected to stresses in conditions representative of industrial productions of microalgae under solar light. Methods and Results The effects of short‐term oxidative treatments were examined on photosynthetic and antioxidant activities of Haematococcus pluvialis vegetative and resting cells. The vegetative cells have 1.6 times higher levels of phenolic compounds, but 1.7 times less catalase, ascorbate peroxidase and superoxide dismutase activities than the astaxanthin‐enriched resting cells. Mainly, a UVA dose of 4 J cm−2 induced increases in photosystem II electron transport rates (ETRmax) (+15%), phenolic compounds (+15%), astaxanthin (+48%), catalase (+45%) and superoxide dismutase (+30%) activities in vegetative cells. Conclusion The UVA dose strongly stimulates the photosynthetic and antioxidant activities of vegetative cells, but only the accumulation of astaxanthin in resting cells. Significance and Impact of the Study These preliminary results show that oxidative stresses at sub‐lethal levels can stimulate the activities of microalgae. Further investigations are needed to estimate the real influence on metabolite productivities in industrial production conditions.

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“…In the case of Free flow 𝜈 𝑎𝑣 is very low, presenting a maximum of 0.1 Hz at the minimum concentration (𝐶 𝑏 = 0.4 g•L− 1 ) and at the minimum linear displacement of 1m. 𝜈 𝑎𝑣 decreases exponentially due to the increase in concentration (𝐶 𝑏 ) and also due to the linear displacement length of the particles, which results in a limitation of the operation and explains why raceways reactors are constantly treated with limited productivity (Inostroza et al, 2021) , This is explained by the fact that a large number of particles have slight changes in their vertical position, according to the literature (Amini et al, 2016;Barceló-Villalobos et al, 2019a;Leman et al, 2018). The analysis has been carried out to a velocity of 0.22 m•s −1 , despite the fact that authors such as Barceló-Villalobos et al, 2019;Brindley et al, 2016 recommend increasing the velocity of the liquid to increase the frequency.…”

Section: Light Regimementioning

confidence: 99%

Use of Airfoils for Enhancement of Photosynthesis Rate of Microalgae in Raceway

Inostroza

Dávila

Román³

et al. 2023

Preprint

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The lack of adequate vertical mixing is one of the factors limiting the productivity of open raceway microalgae reactors. The existence of large gradients of light involves the cells being mainly adapted to local irradiance instead of average irradiance, which would allow for maximizing the light utilization efficiency, thus maximizing the biomass productivity of microalgae cultures. To overpass this problem different alternatives have been proposed, one of the more suitable being the utilization of airfoils to improve vertical mixing. In this work, numerical and experimental studies were performed to analyse the effect of the aerodynamic airfoils patented by the University of Seville (WO2020120818A1). The goal is to improve the photosynthetic efficiency, but also a better understanding of the light regime to which the microalgae cells are exposed in these systems and how to improve it. Computational Fluid Dynamics (CFD) was used to optimize the flow generated by the airfoils. A dynamic photosynthesis model (Rubio Camacho et al., 2003) was used to estimate the photosynthesis rate as a function of the light regime to which the cells are exposed, including photo-adaptation and photo-inhibition phenomena. The results confirm that the use of airfoils improves the vertical mixing and the photosynthesis rate, with a negligible increase in energy consumption. The photosynthetic benefits were observed 10 m downstream of the airfoils, resulting in an increase in photosynthesis rate and productivity by up to 30%. These results confirm the benefits of an increase in mixing in microalgae cultures, especially when focusing on the movement of the cells between the different illuminated zones while maintaining low energy consumption and CAPEX.

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Numerical and experimental investigation of hydrodynamics and light transfer in open raceway ponds at various algal cell concentrations and medium depths

Cited by 31 publications

References 20 publications

The effect of primary treatment of wastewater in high rate algal pond systems: Biomass and bioenergy recovery

The effect of primary treatment of wastewater in high rate algal pond systems: Biomass and bioenergy recovery

Comparative study on photosynthetic and antioxidant activities of Haematococcus pluvialis vegetative and resting cells: UVA light-induced stimulation

Use of Airfoils for Enhancement of Photosynthesis Rate of Microalgae in Raceway

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