Algae optical density sensor for pond monitoring and production process control

Yao Yao, Yufeng Ge, J. Alex Thomasson, Ruixiu Sui

Abstract


Open raceways are one of the principal commercial-scale systems for cultivating algae to produce biofuels and bioproducts. A critical process parameter in such a system is algae cell concentration in the aqueous culture, commonly measured in terms of optical density (OD). A prototype OD sensor exclusively for real-time measurement of algae cell concentration in open ponds was designed, constructed, and tested in a laboratory scale raceway and an open-pond raceway. In the lab test, the sensor OD measurements were highly correlated with spectrometer OD measurements. The OD curve recorded by the sensor clearly showed the diurnal pattern of algae growth associated with the on-off cycle of the lighting system in the lab facility. The test data also clearly highlighted unique cultivation activities such as growth media addition and harvesting. In the open pond raceway test, sensor OD data were also highly correlated with spectrometer-measured OD even though the range of OD variation was significantly less during this test. The OD curve clearly indicated a higher biomass accumulation rate in the pond from late morning to late afternoon than during the rest of the day. These tests of the OD sensor demonstrated its potential to provide accurate real-time algae concentration data in an open pond cultivation system, the type of data that would be necessary for timely management decision-making. This sensor would also eliminate the cost associated with frequently collecting and analyzing samples, making commercial-scale algae production more economically practical.
Keywords: microalgae, optical density (OD), open pond raceway, sensor, pond monitoring, circuit design, optoelectronics
DOI: 10.25165/j.ijabe.20181101.2839

Citation: Yao Y, Ge Y F, Thomasson J A, Sui R X. Algae optical density sensor for pond monitoring and production process control. Int J Agric & Biol Eng, 2018; 11(1): 212–217.

Keywords


microalgae, optical density (OD), open pond raceway, sensor, pond monitoring, circuit design, optoelectronics

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References


Chisti Y. Biodiesel from microalgae. Biotechnology Advances, 2007; 25: 294–306.

Schenk P M, Thomas-Hall S R, Stephens E, Marx U C, Mussgnug J H, Posten C, et al. Second generation biofuels: High-efficiency microalgae for biodiesel production. Bioenergy Research, 2008; 1: 20–43.

Sonnleitner B, Locher G, Fiechter A. Biomass determination. Journal of Biotechnology, 1992; 25: 5–22.

Cogne G, Cornet J F, Gros J B. Design, operation, and modeling of a membrane photobioreactor to study the growth of the cyanobacterium arthrospira platensis in space conditions. Biotechnology Progress, 2005; 21: 741–750.

Davis K B, Mewes M O, Andrews M R, van Druten N J, Durfee D S, Kurn D M, et al. Bose-einstein condensation in a gas of sodium atoms. Physical Review Letters, 1995; 75(22): 3969–3973.

Meireles L A, Azevedo J L, Cunha J P, Malcata F X. On-line determination of biomass in a microalgae bioreactor using a novel computerized flow injection analysis system. Biotechnology Progress, 2002; 18: 1387–1391.

Sandnes J M, Ringstad T, Wenner D, Heyerdahl P H, Källqvist T, Gislerød H R. Real-time monitoring and automatic density control of large-scale microalgal cultures using near infrared (NIR) optical density sensors. Journal of biotechnology, 2006; 122: 209–215.

Nedbal L, Trtílek M, Červený J, Komárek O, Pakrasi H B. A photobioreactor for precision cultivation of photoautotrophic microorganisms and for high-content analysis of suspension dynamics. Biotechnology and Bioengineering, 2008; 100: 902–910.

Thomasson J A, Sui R, Yao Y, Ge Y. Toward on-line measurement of algal properties. ASABE Paper No. 1009395. St. Joseph, Mich.: ASABE. 2010.

Yao Y. Development of an algal optical density sensor. Master Thesis. Texas A&M University, College Station, Texas, USA. 2013.

Wagenen J V, Miller T W, Hobbs S, Hook P, Crowe B, Huesemann M. Effect of light and temperature of fatty acid production in Nannochloropsis salina. Energies, 2012; 5:731–740.

Solovchenko A, Khozin-Goldberg I, Recht L, Boussiba S. Stress-induced changes in optical properties, pigment and fatty acid content of Nannochloropsis sp.: Impactions for non-destructive assay of total fatty acids. Marine Biotechnology, 2011; 13: 527–535.

Reichardt T A, Collins A M, Garcia O F, Ruffing A M, Jones H D T, Timlin J A. Spectroradiometric monitoring of Nannochloropsis salina growth. Algal Research, 2012; 1: 22–31.

Gitelson, A A, Laorawat S, Keydan G P, Vonshak A. Optical properties of dense algal cultures outdoors and their application to remote estimation of biomass and pigment concentration in Spirulina patensis (cyanobacteria). Journal of Phycology, 1995; 31: 828–834.




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