Excessive Ozonation Stress Triggers Severe Membrane Biofilm Accumulation and Fouling.
Environ Sci Technol
; 58(13): 5899-5910, 2024 Apr 02.
Article
em En
| MEDLINE
| ID: mdl-38502922
ABSTRACT
The established benefits of ozone on microbial pathogen inactivation, natural organic matter degradation, and inorganic/organic contaminant oxidation have favored its application in drinking water treatment. However, viable bacteria are still present after the ozonation of raw water, bringing a potential risk to membrane filtration systems in terms of biofilm accumulation and fouling. In this study, we shed light on the role of the specific ozone dose (0.5 mg-O3/mg-C) in biofilm accumulation during long-term membrane ultrafiltration. Results demonstrated that ozonation transformed the molecular structure of influent dissolved organic matter (DOM), producing fractions that were highly bioavailable at a specific ozone dose of 0.5, which was inferred to be a turning point. With the increase of the specific ozone dose, the biofilm microbial consortium was substantially shifted, demonstrating a decrease in richness and diversity. Unexpectedly, the opportunistic pathogen Legionella was stimulated and occurred in approximately 40% relative abundance at the higher specific ozone dose of 1. Accordingly, the membrane filtration system with a specific ozone dose of 0.5 presented a lower biofilm thickness, a weaker fluorescence intensity, smaller concentrations of polysaccharides and proteins, and a lower Raman activity, leading to a lower hydraulic resistance, compared to that with a specific ozone dose of 1. Our findings highlight the interaction mechanism between molecular-level DOM composition, biofilm microbial consortium, and membrane filtration performance, which provides an in-depth understanding of the impact of ozonation on biofilm accumulation.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ozônio
/
Purificação da Água
Idioma:
En
Revista:
Environ Sci Technol
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
China