MBBRs as post-treatment to ozonation: Degradation of transformation products and ozone-resistant micropollutants

• Published in: The Science of the total environment Vol. 754; p. 142103
• Main Authors: Edefell, Ellen, Falås, Per, Kharel, Suman, Hagman, Marinette, Christensson, Magnus, Cimbritz, Michael, Bester, Kai
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-02-2021
• Subjects: Contrast media; Engineering and Technology; Environmental Biotechnology; MBBR; Miljöbioteknik; N-oxides; Organic micropollutants; Ozonation; Teknik; Transformation products; Vattenbehandling; Water Treatment; Transformation products; Ozonation; MBBR; Organic micropollutants; N-oxides; Contrast media
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2020.142103

The degradation potential of micropollutants and transformation products in biological post-treatment after ozonation is partly unknown. A pilot plant with ozonation and subsequent biological treatment in a moving bed biofilm reactor (MBBR) was thus operated over 16 months to investigate the removal of micropollutants and the formation and removal of N-oxide transformation products. Lab-scale kinetic experiments were performed in parallel. At a moderate ozone dose of 0.5 g O3 g−1 DOC, further degradation of gabapentin and 3 iodinated contrast media (iomeprol, iopamidol, and iohexol) could be induced by the biofilm at prolonged exposure times. To facilitate comparison of feeding regimens in biofilm systems a new surface-related degradation rate constant was introduced. The availability of substrates in the pilot MBBR influenced the micropollutant degradation kinetics with increasing and decreasing degradation rates. N-oxides from erythromycin, clarithromycin, tramadol, and venlafaxine were formed during ozonation and could not be degraded by the biofilm.
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•Significant micropollutant removal by ozonation and MBBR treatment of wastewater.•N-oxides formed during ozonation were not removed biologically.•Ozone-resistant micropollutants were biologically degradable.•Substrate availability affected the biological degradation of micropollutants.