Importance of ecological interactions during wastewater treatment using High Rate Algal Ponds under different temperate climates

Amandine Galès (1, 2) , Anaïs Bonnafous (2) , Claire Carré (1) , Vincent Jauzein (3) , Elodie Lanouguère (1) , Emilie Le Floc'H (1) , Joanna Pinoit (4) , Clothilde Poullain (4) , Cécile Roques (1) , Bruno Sialve (2) , Monique Simier (1) , Jean-Philippe Steyer (2) , Eric Fouilland (1)

1 UMR MARBEC - MARine Biodiversity Exploitation and Conservation
2 LBE - Laboratoire de Biotechnologie de l'Environnement [Narbonne]
3 SAUR - Direction de la Recherche et Développement
4 SAUR

Several studies focused on wastewater treatment in High Rate Algal Ponds (HRAP) suggest that highly variable climatic conditions cause large variations of microalgal biomass productivity. In the present study, we show that similar carbon, nitrogen and phosphorus removal efficiencies were reached in different HRAPs treating urban wastewaters located in two different temperate (Mediterranean and oceanic) climates. Furthermore, similar ecological successions were observed in these HRAPs. During the start-up phase, the consumption of organic matter by detritivores, already present in the wastewater, appears to be necessary for the microalgae to grow within two weeks in spring. The growth of the rapid-growing species, Chlorella sp., followed by the grazing-resilient species, Scenedesmus sp., combined with nitrifying and denitrifying bacterial activity, removed most the ammonia. The resulting exhaustion of ammonia would limit the complete removal of dissolved COD by bacteria and phosphate by microalgae in the HRAPs. This study shows that similar biological and environmental constraints were applied on the HRAPs, making the process efficiency highly reproducible under different temperate latitudes.

Mots clés: Microalgae; predators; bacteria; urban effluents; ammonia and phosphate removal

Domaines: Ingénierie de l'environnement

Amandine Galès, Anaïs Bonnafous, Claire Carré, Vincent Jauzein, Elodie Lanouguère, et al.. Importance of ecological interactions during wastewater treatment using High Rate Algal Ponds under different temperate climates. Algal Research - Biomass, Biofuels and Bioproducts, 2019, 40, pp.101508. ⟨10.1016/j.algal.2019.101508⟩. ⟨hal-03034534⟩