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Effluent recirculation to improve perchlorate reduction in a fixed biofilm reactor
Author(s) -
Choi Hyeoksun,
Silverstein JoAnn
Publication year - 2007
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.21425
Subject(s) - effluent , biofilm , perchlorate , bioreactor , pulp and paper industry , chemistry , reduction (mathematics) , environmental science , environmental chemistry , environmental engineering , biology , mathematics , organic chemistry , bacteria , engineering , ion , genetics , geometry
The effect of effluent recirculation on perchlorate reduction in a nominally plug‐flow fixed biofilm reactor was studied in two cases: influent concentrations of 10 and 400 µg/L at low hydraulic loading rates (1.9 and 37.5 m 3 /m 2 /day without and with recirculation, respectively) and after a step increase in perchlorate concentration to 1,000 µg/L at the higher hydraulic loading rate (5 and 100 m 3 /m 2 /day without and with recirculation, respectively). Complete perchlorate reduction was sustained for influent concentrations of 400 and 10 µg/L in both flow regimes at the lower hydraulic loading rates. Reactor tracer profiles showed that biofilm diffusion had a more significant effect on mass transfer in the plug flow reactor compared with recirculation. The recirculation bioreactor acclimated more rapidly to increased hydraulic and perchlorate mass loading rates with significantly lower effluent perchlorate compared to the plug flow reactor: 16 µg/L versus 46 µg/L, respectively, although complete perchlorate removal was not achieved in either flow regime after 21 days acclimation to the higher loading. Total biofilm mass was more uniformly distributed in the recirculation reactor which may have contributed to better performance under increased perchlorate loading. Biotechnol. Bioeng. 2007; 98: 132–140. © 2007 Wiley Periodicals, Inc.