TY - JOUR
T1 - Aerobic biodegradation of emerging azole contaminants by return activated sludge and enrichment cultures
AU - Jog, Kalyani V.
AU - Hess, Kendra Z.
AU - Field, Jim A.
AU - Krzmarzick, Mark J.
AU - Sierra-Alvarez, Reyes
N1 - Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/9/5
Y1 - 2021/9/5
N2 - Azoles are an emerging class of contaminants with a growing ubiquitous presence in the environment. This study investigates the aerobic microbial degradation of four azoles, pyrazole (PA), 1,2,4-triazole (TA), benzotriazole (BTA) and 5-methylbenzotriazole (5-MBTA), with return activated sludge and microbial enrichment cultures. Slow degradation of PA was observed in the presence of glucose and NH4+ with a peak degradation rate of 0.5 mg d-1 gVSS-1. TA was found to be highly persistent, with no significant degradation observed in 6–8 months under any incubation condition. In contrast, the benzotriazoles were readily degraded at faster rates in all incubation conditions. The degradation rates observed for BTA and 5-MBTA, when provided as the sole substrates, were 8.1 and 16.5 mg d-1 gVSS-1, respectively. Two enrichment cultures, one degrading BTA and the other degrading 5-MBTA, were developed from the activated sludge. Mass balance studies revealed complete mineralization of 5-MBTA and partial breakdown of BTA by the enrichment cultures. Nocardioides sp. and Pandoraea pnomenusa were the most abundant bacteria in the BTA and 5-MBTA degrading enrichment cultures, respectively. The research shows large differences in the biodegradability of various azoles, ranging from complete mineralization of 5-MBTA to complete persistence for TA.
AB - Azoles are an emerging class of contaminants with a growing ubiquitous presence in the environment. This study investigates the aerobic microbial degradation of four azoles, pyrazole (PA), 1,2,4-triazole (TA), benzotriazole (BTA) and 5-methylbenzotriazole (5-MBTA), with return activated sludge and microbial enrichment cultures. Slow degradation of PA was observed in the presence of glucose and NH4+ with a peak degradation rate of 0.5 mg d-1 gVSS-1. TA was found to be highly persistent, with no significant degradation observed in 6–8 months under any incubation condition. In contrast, the benzotriazoles were readily degraded at faster rates in all incubation conditions. The degradation rates observed for BTA and 5-MBTA, when provided as the sole substrates, were 8.1 and 16.5 mg d-1 gVSS-1, respectively. Two enrichment cultures, one degrading BTA and the other degrading 5-MBTA, were developed from the activated sludge. Mass balance studies revealed complete mineralization of 5-MBTA and partial breakdown of BTA by the enrichment cultures. Nocardioides sp. and Pandoraea pnomenusa were the most abundant bacteria in the BTA and 5-MBTA degrading enrichment cultures, respectively. The research shows large differences in the biodegradability of various azoles, ranging from complete mineralization of 5-MBTA to complete persistence for TA.
KW - 1,2,4-triazole
KW - 5-methylbenzotriazole
KW - Aerobic biodegradation
KW - Benzotriazole
KW - Pyrazole
UR - http://www.scopus.com/inward/record.url?scp=85106954638&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85106954638&partnerID=8YFLogxK
U2 - 10.1016/j.jhazmat.2021.126151
DO - 10.1016/j.jhazmat.2021.126151
M3 - Article
C2 - 34229401
AN - SCOPUS:85106954638
SN - 0304-3894
VL - 417
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
M1 - 126151
ER -