Author(s): Ji Wu; Xiaoyu Wang; Chen Xie; Ziwu Fan

Linked Author(s): Ziwu Fan

Keywords: Lgal organic matter; Algae filtrate; Ozone oxidation; Two-dimensional correlation spectroscopy; Phosphate recovery

Abstract: Various algae separation methods have been used to suppress cyanobacterial biomass, and this has resulted in the generation of a large amount of algae residues and highly concentrated algae filtrate due to the rupture of algal cells. In this study, the efficacy of combined ozonation and ion-exchange processes for algae filtrate treatment and selective nitrate and phosphate recovery was evaluated. Diverse approaches were used to characterize variation in the functional groups and conformations of algal organic matter (AOM) in algae filtrate during the ozonation process at the molecular scale. The final concentration (< 0.1 μg/L) of the microcystin-LR was far lower than the standard for drinking water. The chromophores and fluorophores were destroyed via ozone oxidation within 5 min. The organic nitrogen in algae filtrate were effectively oxidized to NO3--N, resulting in a continuous increase in inorganic nitrogen. In the post-oxidation treatment, the nano-scale La (OH) 3-loaded resin could achieve near 100% phosphate removal, and this was maintained during five successive adsorption-desorption cycles; the NO3--N removal performance was enhanced with resin containing a triethylamine group. Overall, combined ozonation and ion-exchange processes could be used to effectively treat algae filtrate and promote selective nitrate and phosphate recovery; our findings also demonstrate the high potential for this approach to treat algae-laden water.

DOI: https://doi.org/10.3850/iahr-hic2483430201-441

Year: 2024