Published: 12 January 2022 at Water 2022, 14(2), 221

Assessment of Nutrients Recovery Capacity and Biomass Growth of Four Microalgae Species in Anaerobic Digestion Effluent

Contributors

Paraskevi Psachoulia (author)
Sofia-Natalia Schortsianiti (author)
Urania Lortou (author)
Spyros Gkelis (author)
Christos Chatzidoukas (author)
Petros Samaras (author)

Abstract

Four microalgae species were evaluated for their bioremediation capacity of anaerobic digestion effluent (ADE) rich in ammonium nitrogen, derived from a biogas plant. Chlorella vulgaris, Chlorella sorokiniana, Desmodesmus communis and Stichococcus sp. were examined for their nutrient assimilation efficiency, biomass production and composition through their cultivation in 3.7% v/v ADE; their performance was compared with standard cultivation media which consisted in different nitrogen sources, i.e., BG-11NO3 and BG-11ΝH4 where N-NO3 was replaced by N-NH4. The results justified ammonium as the most preferable source of nitrogen for microalgae growth. Although Stichococcus sp. outperformed the other 3 species in N-NH4 removal efficiency both in BG-11NH4 and in 3.7% ADE (reaching up to 90.79% and 69.69% respectively), it exhibited a moderate biomass production when it was cultivated in diluted ADE corresponding to 0.59 g/L, compared to 0.89 g/L recorded by C. vulgaris and 0.7 g/L by C. sorokiniana and D. communis. Phosphorus contained in the effluent and in the control media was successfully consumed by all of the species, although its removal rate was found to be affected by the type of nitrogen source used and the particular microalgae species. The use of ADE as cultivation medium resulted in a significant increase in carbohydrates content in all investigated species.

Acknowledgment

Funding: This research has been co-financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH—CREATE—INNOVATE (project code: T1EDK-00406 -title «Innovative technologies for the elimination of NH3 toxicity in anaerobic fermentation to increase methane production»).