Annual dynamics of antimicrobials and resistance determinants in flocculent and aerobic granular sludge treatment systems

Annual dynamics of antimicrobials and resistance determinants in flocculent and aerobic granular sludge treatment systems

Pallares Vega, R. (TU Delft BT/Environmental Biotechnology; Wetsus, Centre for Sustainable Water Technology)
Hernandez Leal, Lucia (Wetsus, Centre for Sustainable Water Technology)
Fletcher, Benjamin N. (Wetsus, Centre for Sustainable Water Technology; Bournemouth University)
Vias-Torres, Eduardo (Wetsus, Centre for Sustainable Water Technology)
van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology)
Weissbrodt, D.G. (TU Delft BT/Environmental Biotechnology)
Schmitt, Heike (Wetsus, Centre for Sustainable Water Technology; Rijksinstituut voor Volksgezondheid en Milieu (RIVM); Universiteit Utrecht)

2021

The occurrence and removal patterns of 24 antimicrobial agents and antimicrobial resistant determinants namely 6 antibiotic resistance genes (ARGs) and 2 mobile genetic elements (MGEs), and the fecal indicator E. coli were investigated in three full-scale wastewater treatment plants. Their waterlines and biosolids lines (including secondary treatment based on both granular and activated sludge) were sampled monthly throughout one year. Samples were analyzed by means of LC-MS/MS, qPCR and cell enumeration, respectively. The influence of rainfall, temperature, and turbidity on the occurrence and removal of the aforementioned agents was assessed through statistical linear mixed models. Ten of the antimicrobial agents (macrolides, fluoroquinolones, tetracyclines, and sulfonamides) were commonly found in influent in concentrations of 0.1-2 µg L⁻¹, and the predominant ARGs were ermB and sul1 (6.4 and 5.9 log₁₀ mL⁻¹ respectively). Warmer temperatures slightly reduced gene concentrations in influent whilst increasing that of E. coli and produced an uneven effect on the antimicrobial concentrations across plants. Rainfall diluted both E. coli (-0.25 logs, p < 0.001) and antimicrobials but not genes. The wastewater treatment reduced the absolute abundance of both genes (1.86 logs on average) and E. coli (2.31 logs on average). The antimicrobials agents were also partly removed, but 8 of them were still detectable after treatment, and 6 accumulated in the biosolids. ARGs were also found in biosolids with patterns resembling those of influent. No significant differences in the removal of antimicrobials, genes and E. coli were observed when comparing conventional activated sludge with aerobic granular sludge. Irrespective of the type of sludge treatment, the removal of genes was significantly reduced with increasing hydraulic loads caused by rainfall (-0.35 logs per ∆ average daily flow p < 0.01), and slightly decreased with increasing turbidity (-0.02 logs per ∆1 nephelometric turbidy unit p < 0.05).

Antibiotics
ARGs
Granular sludge
Rainfall
Temperature
WWTP

http://resolver.tudelft.nl/uuid:0d1e4bf0-7b44-4162-a7ec-4bff3834bedc

https://doi.org/10.1016/j.watres.2020.116752

0043-1354

Water Research, 190

Institutional Repository

journal article

© 2021 R. Pallares Vega, Lucia Hernandez Leal, Benjamin N. Fletcher, Eduardo Vias-Torres, Mark C.M. van Loosdrecht, D.G. Weissbrodt, Heike Schmitt