Skip to main content
Log in

Photobioreactors for utility-scale applications: effect of gas–liquid mass transfer coefficient and other critical parameters

  • Review Article
  • Published:
Environmental Science and Pollution Research Aims and scope Submit manuscript

Abstract

Cultivation of microalgae and controlling its growth and performance in closed photobioreactors (PBRs) are easier than open pond systems for wastewater treatment. The performance of PBRs is influenced by geometry, hydrodynamic behavior, and mass transfer. Horizontal and vertical configurations as common designs of PBR are reviewed based on their features, advantages, and disadvantages. However, vertically operated PBRs like bubble columns are preferably used for utility-scale applications of microalgae-based processes. Moreover, an appropriate reactor design reduces the inhibitory effect of dissolved oxygen concentration produced by microalgae and consequently increases the level of available CO2 in the medium. Medium properties, superficial gas velocity, gas holdup, bubble sizes, shear stress, mixing time, sparger design, and the ratio of inner diameter to effective height are shown to influence the overall volumetric mass transfer coefficient (KLa) and PBR’s performance. The vertical PBRs like bubble columns provide a high mass transfer, a short liquid circulation time, and a long frequency of light/dark cycle for utility application of microalgae. Different flow regimes are obtained in PBRs based on the gas flow rate, inner diameter, and medium properties. Hydraulic retention time as the main operational parameter is determined in a batch mode for continuous wastewater treatment.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3

Similar content being viewed by others

Data availability

Not applicable.

Abbreviations

HRAPs:

High-rate algae ponds

PBR:

Photobioreactor

k l :

Mass transfer coefficient (m h−1)

a :

Specific interfacial area (m−1)

k l a :

The volumetric mass transfer coefficient (h−1)

K L :

The overall mass transfer coefficient (m h−1)

K L a :

The overall volumetric mass transfer coefficient (h−1)

DO:

Dissolved oxygen

OPR:

The oxygen production rate

OTR:

The oxygen transfer rate

\({P}_{{\mathrm{O}}_{2}}\) :

The partial pressure of oxygen in equilibrium with DO (pa)

\({C}_{\mathrm{O}2}^{*}\) :

The O2 saturation concentration in the liquid (mol L−1)

C O2 :

The concentration of O2 at any time (mol L−1)

C co2 :

The concentration of CO2 at any time (mol L−1)

\({C}_{{\mathrm{CO}}_{2}}^{*}\) :

CO2 saturation concentration (mol L−1)

C CO2 :

CO2 concentration in the liquid phase (mol L−1)

H :

Henry’s constant (pa L mol−1)

ε g :

The gas holdup

U sg :

Superficial gas velocity (m s−1)

d 32 :

Sauter mean diameter (mm)

D CO2 :

The diffusivity of CO2 (cm2 s−1)

D O2 :

The diffusivity of O2 (cm2 s−1)

t c :

Liquid circulation time (s−1)

U circ :

Circulation velocity (m s−1)

HRT:

Hydraulic retention time (day)

A d/A r :

The ratio of downcomer to riser surfaces

μ L :

The liquid medium viscosity (pa s)

ρ L :

Density (kg m−3)

References

Download references

Author information

Authors and Affiliations

Authors

Contributions

Fariba Rezvani: writing original draft preparation, writing, editing, and validation.

Khosrow Rostami: reviewing, editing, and supervision.

Corresponding author

Correspondence to Fariba Rezvani.

Ethics declarations

Ethical approval

Not applicable.

Consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.

Additional information

Responsible Editor: Philippe Garrigues

Publisher's note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Highlights

• Closed PBRs are more efficient than open pond systems.

• Mass transfer rate for O2 and CO2 is high in vertical PBRs.

• Scale-up of vertical PBRs is more convenient than horizontal.

• Bubble size influences effectively on both gas holdup and mass transfer.

• Increasing height-to-diameter ratio leads to higher gas holdup.

• HRT for large-scale application is preferably determined in a batch mode.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Rezvani, F., Rostami, K. Photobioreactors for utility-scale applications: effect of gas–liquid mass transfer coefficient and other critical parameters. Environ Sci Pollut Res 30, 76263–76282 (2023). https://doi.org/10.1007/s11356-023-27644-4

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11356-023-27644-4

Keywords

Navigation