TY - JOUR
T1 - Continuous-mode acclimation and operation of lignocellulosic sulfate-reducing bioreactors for enhanced metal immobilization from acidic mining-influenced water
AU - Miranda, Evelyn M.
AU - Severson, Carli
AU - Reep, Jeffrey K.
AU - Hood, Daniel
AU - Hansen, Shane
AU - Santisteban, Leonard
AU - Hamdan, Nasser
AU - Delgado, Anca G.
N1 - Publisher Copyright:
© 2021 The Authors
PY - 2022/3/5
Y1 - 2022/3/5
N2 - Lignocellulosic sulfate-reducing bioreactors are an inexpensive passive approach for treatment of mining-influenced water (MIW). Typically, microbial community acclimation to MIW involves bioreactor batch-mode operation to initiate lignocellulose hydrolysis and fermentation and provide electron donors for sulfate-reducing bacteria. However, batch-mode operation could significantly prolong bioreactor start-up times (up to several months) and select for slow-growing microorganisms. In this study we assessed the feasibility of bioreactor continuous-mode acclimation to MIW (pH 2.5, 6.5 mM SO42−, 18 metal(loid)s) as an alternate start-up method. Results showed that bioreactors with spent brewing grains and sugarcane bagasse achieved acclimation in continuous mode at hydraulic retention times (HRTs) of 7–12-d within 16–22 days. During continuous-mode acclimation, extensive SO42− reduction (80 ± 20% –91 ± 3%) and > 98% metal(loid) removal was observed. Operation at a 3-d HRT further yielded a metal(loid) removal of 97.5 ± 1.3 –98.8 ± 0.9% until the end of operation. Sulfate-reducing microorganisms were detected closer to the influent in the spent brewing grains bioreactors, and closer to the effluent in the sugarcane bagasse bioreactors, giving insight as to where SO42− reduction was occurring. Results strongly support that a careful selection of lignocellulose and bioreactor operating parameters can bypass typical batch-mode acclimation, shortening bioreactor start-up times and promoting effective MIW metal(loid) immobilization and treatment.
AB - Lignocellulosic sulfate-reducing bioreactors are an inexpensive passive approach for treatment of mining-influenced water (MIW). Typically, microbial community acclimation to MIW involves bioreactor batch-mode operation to initiate lignocellulose hydrolysis and fermentation and provide electron donors for sulfate-reducing bacteria. However, batch-mode operation could significantly prolong bioreactor start-up times (up to several months) and select for slow-growing microorganisms. In this study we assessed the feasibility of bioreactor continuous-mode acclimation to MIW (pH 2.5, 6.5 mM SO42−, 18 metal(loid)s) as an alternate start-up method. Results showed that bioreactors with spent brewing grains and sugarcane bagasse achieved acclimation in continuous mode at hydraulic retention times (HRTs) of 7–12-d within 16–22 days. During continuous-mode acclimation, extensive SO42− reduction (80 ± 20% –91 ± 3%) and > 98% metal(loid) removal was observed. Operation at a 3-d HRT further yielded a metal(loid) removal of 97.5 ± 1.3 –98.8 ± 0.9% until the end of operation. Sulfate-reducing microorganisms were detected closer to the influent in the spent brewing grains bioreactors, and closer to the effluent in the sugarcane bagasse bioreactors, giving insight as to where SO42− reduction was occurring. Results strongly support that a careful selection of lignocellulose and bioreactor operating parameters can bypass typical batch-mode acclimation, shortening bioreactor start-up times and promoting effective MIW metal(loid) immobilization and treatment.
KW - Acid mine drainage
KW - Bioremediation
KW - Lignocellulose
KW - Spent brewing grains
KW - Sugarcane bagasse
KW - Sulfate-reducing bacteria
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U2 - 10.1016/j.jhazmat.2021.128054
DO - 10.1016/j.jhazmat.2021.128054
M3 - Article
C2 - 34986575
AN - SCOPUS:85121131116
SN - 0304-3894
VL - 425
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
M1 - 128054
ER -