TY - JOUR
T1 - Coupling Bioflocculation of Dehalococcoides mccartyi to High-Rate Reductive Dehalogenation of Chlorinated Ethenes
AU - Delgado, Anca
AU - Fajardo-Williams, Devyn
AU - Bondank, Emily
AU - Esquivel-Elizondo, Sofia
AU - Krajmalnik-Brown, Rosa
N1 - Funding Information:
This work was funded by the National Science Foundation (NSF) CAREER award number 1053939 to R.K.-B. The authors thank Joel Peterson from Synergy Environmental for assistance with natural groundwater sampling and analyses. We acknowledge David Lowry (Electron Microscopy Laboratory, School of Life Sciences, Arizona State University) for help with SEM sample preparation and Ceś ar I. Torres (School for Engineering of Matter, Transport and Energy, Arizona State University) for expertise and assistance in the SEM imaging.
PY - 2017/10/3
Y1 - 2017/10/3
N2 - Continuous bioreactors operated at low hydraulic retention times have rarely been explored for reductive dehalogenation of chlorinated ethenes. The inability to consistently develop such bioreactors affects the way growth approaches for Dehalococcoides mccartyi bioaugmentation cultures are envisioned. It also affects interpretation of results from in situ continuous treatment processes. We report bioreactor performance and dehalogenation kinetics of a D. mccartyi-containing consortium in an upflow bioreactor. When fed synthetic groundwater at 11-3.6 h HRT, the upflow bioreactor removed >99.7% of the influent trichloroethene (1.5-2.8 mM) and produced ethene as the main product. A trichloroethene removal rate of 98.51 ± 0.05 me- equiv L-1 d-1 was achieved at 3.6 h HRT. D. mccartyi cell densities were 1013 and 1012 16S rRNA gene copies L-1 in the bioflocs and planktonic culture, respectively. When challenged with a feed of natural groundwater containing various competing electron acceptors and 0.3-0.4 mM trichloroethene, trichloroethene removal was sustained at >99.6%. Electron micrographs revealed that D. mccartyi were abundant within the bioflocs, not only in multispecies structures, but also as self-aggregated microcolonies. This study provides fundamental evidence toward the feasibility of upflow bioreactors containing D. mccartyi as high-density culture production tools or as a high-rate, real-time remediation biotechnology.
AB - Continuous bioreactors operated at low hydraulic retention times have rarely been explored for reductive dehalogenation of chlorinated ethenes. The inability to consistently develop such bioreactors affects the way growth approaches for Dehalococcoides mccartyi bioaugmentation cultures are envisioned. It also affects interpretation of results from in situ continuous treatment processes. We report bioreactor performance and dehalogenation kinetics of a D. mccartyi-containing consortium in an upflow bioreactor. When fed synthetic groundwater at 11-3.6 h HRT, the upflow bioreactor removed >99.7% of the influent trichloroethene (1.5-2.8 mM) and produced ethene as the main product. A trichloroethene removal rate of 98.51 ± 0.05 me- equiv L-1 d-1 was achieved at 3.6 h HRT. D. mccartyi cell densities were 1013 and 1012 16S rRNA gene copies L-1 in the bioflocs and planktonic culture, respectively. When challenged with a feed of natural groundwater containing various competing electron acceptors and 0.3-0.4 mM trichloroethene, trichloroethene removal was sustained at >99.6%. Electron micrographs revealed that D. mccartyi were abundant within the bioflocs, not only in multispecies structures, but also as self-aggregated microcolonies. This study provides fundamental evidence toward the feasibility of upflow bioreactors containing D. mccartyi as high-density culture production tools or as a high-rate, real-time remediation biotechnology.
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U2 - 10.1021/acs.est.7b03097
DO - 10.1021/acs.est.7b03097
M3 - Article
C2 - 28914537
AN - SCOPUS:85030704202
SN - 0013-936X
VL - 51
SP - 11297
EP - 11307
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 19
ER -