Influence of light intensity on bacterial nitrifying activity in algal-bacterial photobioreactors and its implications for microalgae-based wastewater treatment

C. Vergara, R. Muñoz, J. L. Campos, M. Seeger, D. Jeison

Research output: Contribution to journalArticlepeer-review

50 Scopus citations

Abstract

The influence of irradiance on the nitrifying activity in photobioreactors of a bacterial consortium enriched from a wastewater treatment bioreactor was assessed using independent ammonium oxidation kinetic batch tests and respirometric assays. Culture irradiance below 250 μmol m-2 s-1 did not show a significant effect on nitrification activity, while irradiance at 500 and 1250 μmol m-2 s-1 caused a decrease of 20 and 60% in the specific total ammonium nitrogen removal rates and a reduction of 26 and 71% in the specific NO3- production rates, respectively. However, no significant influence of irradiance on the affinity constant of NH4+ oxidation was observed. The increasing nitrite accumulation at higher light intensities suggested a higher light sensitivity of nitrite oxidizers. Additionally, NH4+ oxidation respirometric assays showed a decrease in the oxygen uptake of 14 and 50% at 500 and 1250 μmol m-2 s-1, respectively. The experimental determination of the light extinction coefficient (λ) of the nitrifying bacterial consortium (λ = 0.0003 m2 g-1) and of Chlorella sorokiniana (λ = 0.1045 m2 g-1) allowed the estimation of light penetration in algal-bacterial high rate algal ponds, which showed that photoinhibition of nitrifying bacteria can be significantly mitigated in the presence of high density microalgal cultures.

Original languageEnglish
Pages (from-to)116-121
Number of pages6
JournalInternational Biodeterioration and Biodegradation
Volume114
DOIs
StatePublished - 1 Oct 2016
Externally publishedYes

Keywords

  • Ammonium oxidizer
  • Microalgal-bacterial consortium
  • Nitrification
  • Nitrite oxidizer
  • Photobioreactor
  • Photoinhibition
  • Wastewater treatment

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