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Perchlorate reduction from a highly contaminated groundwater in the presence of sulfate‐reducing bacteria in a hydrogen‐fed biofilm
Author(s) -
OntiverosValencia Aura,
Tang Youneng,
KrajmalnikBrown Rosa,
Rittmann Bruce E.
Publication year - 2013
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.24987
Subject(s) - biofilm , sulfate , denitrifying bacteria , perchlorate , chemistry , bacteria , electron acceptor , sulfate reducing bacteria , effluent , environmental chemistry , nuclear chemistry , inorganic chemistry , denitrification , environmental engineering , biology , biochemistry , organic chemistry , nitrogen , engineering , ion , genetics
We used a hydrogen (H 2 )‐based biofilm to treat a groundwater contaminated with perchlorate (ClO 4 − ) at ∼10 mg/L, an unusually high concentration. To enhance ClO 4 − removal, we either increased the H 2 pressure or decreased the electron‐acceptor surface loading. The ClO 4 − removal increased from 94% to 98% when the H 2 pressure was increased from 1.3 to 1.7 atm when the total acceptor surface loading was 0.49 g H 2 /m 2 day. We then decreased the acceptor surface loading stepwise from 0.49 to 0.07 g H 2 /m 2 day, and the ClO 4 − removal improved to 99.6%, giving an effluent ClO 4 − concentration of 41 µg/L. However, the tradeoff was that sulfate (SO 4 2− ) reduction occurred, reaching 85% conversion at the lowest acceptor surface loading (0.07 g H 2 /m 2 day). In two steady states with the highest ClO 4 − reduction, we assayed for the presence of perchlorate‐reducing bacteria (PRB), denitrifying bacteria (DB), and sulfate‐reducing bacteria (SRB) by quantitative polymerase chain reaction (qPCR) targeting characteristic reductases. The qPCR results documented competition between PRB and SRB for space within the biofilm. A simple model analysis for a steady‐state biofilm suggests that competition from SRB pushed the PRB to locations having a higher detachment rate, which prevented them from driving the ClO 4 − concentration below 41 µg/L. Biotechnol. Bioeng. 2013;110: 3139–3147. © 2013 Wiley Periodicals, Inc.