TY - JOUR
T1 - Concomitant Cr(VI) reduction and Cr(III) precipitation with nitrate in a methane/oxygen-based membrane biofilm reactor
AU - Long, Min
AU - Zhou, Chen
AU - Xia, Siqing
AU - Guadiea, Awoke
N1 - Funding Information:
This work is supported by National Natural Science Foundation of China (No. 51378368 and No. 51678422).
Publisher Copyright:
© 2017 Elsevier B.V.
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2017
Y1 - 2017
N2 - A continuously stirred methane (CH4) and oxygen (O2)-based membrane biofilm reactor (MBfR) was investigated for removing chromium (Cr) from nitrate (NO3 −)-contaminated drinking water. Cr(VI) at an initial concentration of 100 μg/L was rapidly reduced to Cr(III) with a removal rate of 89% and a hydraulic retention time of 48 h under normal denitrifying conditions in a methane/oxygen-based MBfR. A microbial community analysis indicated that Comamonadaceae, Cytophagaceae, Hyphomicrobiaceae and Alcaligenaceae were effective denitrifiers, Methylophilaceae and Methylococcaceae were functional methanotrophic bacteria, and Comamonadaceae was a kind of Cr(VI) reducers in the reactor. Cr(VI) was reduced to Cr(III), which precipitated and adsorbed onto the biofilm as Cr(OH)3, due to the alkaline produced during denitrification. When the CH4pressure increased from 0.02 to 0.03 MPa, the Cr(VI) reduction increased by 40.3%, and the NO3 −reduction increased by 30.2%. Although the effluent Cr(VI) concentration increased with increasing influent loading, the removal efficiency of Cr(VI) reached the highest level of 99.8% under a high daily loading of 5.76 mg/d. Unlike a H2-based MBfR, it is possible to remove Cr from water without post-processing, such as precipitation, in a CH4/O2-based MBfR.
AB - A continuously stirred methane (CH4) and oxygen (O2)-based membrane biofilm reactor (MBfR) was investigated for removing chromium (Cr) from nitrate (NO3 −)-contaminated drinking water. Cr(VI) at an initial concentration of 100 μg/L was rapidly reduced to Cr(III) with a removal rate of 89% and a hydraulic retention time of 48 h under normal denitrifying conditions in a methane/oxygen-based MBfR. A microbial community analysis indicated that Comamonadaceae, Cytophagaceae, Hyphomicrobiaceae and Alcaligenaceae were effective denitrifiers, Methylophilaceae and Methylococcaceae were functional methanotrophic bacteria, and Comamonadaceae was a kind of Cr(VI) reducers in the reactor. Cr(VI) was reduced to Cr(III), which precipitated and adsorbed onto the biofilm as Cr(OH)3, due to the alkaline produced during denitrification. When the CH4pressure increased from 0.02 to 0.03 MPa, the Cr(VI) reduction increased by 40.3%, and the NO3 −reduction increased by 30.2%. Although the effluent Cr(VI) concentration increased with increasing influent loading, the removal efficiency of Cr(VI) reached the highest level of 99.8% under a high daily loading of 5.76 mg/d. Unlike a H2-based MBfR, it is possible to remove Cr from water without post-processing, such as precipitation, in a CH4/O2-based MBfR.
KW - Biofilm
KW - Chromium (Cr)
KW - Membrane biofilm reactor (MBfR)
KW - Methane
KW - Nitrate (NO )
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U2 - 10.1016/j.cej.2017.01.018
DO - 10.1016/j.cej.2017.01.018
M3 - Article
AN - SCOPUS:85009770758
SN - 1385-8947
VL - 315
SP - 58
EP - 66
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
ER -