Treatment of secondary urban wastewater with a low ammonium-tolerant marine microalga using zeolite-based adsorption

• Published in: Bioresource technology 2022-09, Vol.359, p.127490-127490, Article 127490
• Main Authors: López-Rosales, L., López-García, P., Benyachou, M.A., Molina-Miras, A., Gallardo-Rodríguez, J.J., Cerón-García, M.C., Sánchez Mirón, A., García-Camacho, F.
• Format: Article
• Language: English
• Subjects: Adsorption; Ammonium; Microalga; Photobioreactor; Wastewater treatment; Zeolite
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2022.127490

[Display omitted] •Zeolites provide ammonium-rich wastewater streams tolerable to marine microalgae.•The ammonium adsorption of the natural zeolite used is among the highest reported.•Amphidinium carterae grows in culture media containing zeolite-treated UWW.•To adjust the culture medium salinity improves the growth of A. caterae.•Zeolite-treated UWW allow to produce microalga’s specialty metabolites sustainability. The low tolerance of marine microalgae to ammonium and hyposalinity limits their use in urban wastewater (UWW) treatments. In this study, using the marine microalga Amphidinium carterae, it is demonstrated for the first time that this obstacle can be overcome by introducing a zeolite-based adsorption step to obtain a tolerable UWW stream. The maximum ammonium adsorption capacities measured in the natural zeolite used are among the highest reported. The microalga grows satisfactorily in mixtures of zeolite-treated UWW and seawater at a wide range of proportions, both with and without adjusting the salinity, as long as the ammonium concentration is below the threshold tolerated by the microalgae (6.3 mg L−1). A proof of concept performed in 10-L bubble column photobioreactors with different culture strategies, including medium recycling, showed an enhanced biomass yield relative to a control with no UWW. No noticeable effect was observed on the production of specialty metabolites.