TY - JOUR
T1 - Two-dimensional distribution of microbial activity and flow patterns within naturally fractured chalk
AU - Arnon, Shai
AU - Ronen, Zeev
AU - Adar, Eilon
AU - Yakirevich, Alexander
AU - Nativ, Ronit
N1 - Funding Information:
We would like to thank Zoë Grabinar and Camille Vainstein for editorial assistance. We also thank two anonymous reviewers for their constructive comments. This research was supported in part by a grant from the Israel Science Foundation (251/98).
PY - 2005/10/1
Y1 - 2005/10/1
N2 - The two-dimensional distribution of flow patterns and their dynamic change due to microbial activity were investigated in naturally fractured chalk cores. Long-term biodegradation experiments were conducted in two cores (∼20 cm diameter, 31 and 44 cm long), intersected by a natural fracture. 2,4,6-tribromophenol (TBP) was used as a model contaminant and as the sole carbon source for aerobic microbial activity. The transmissivity of the fractures was continuously reduced due to biomass accumulation in the fracture concurrent with TBP biodegradation. From multi-tracer experiments conducted prior to and following the microbial activity, it was found that biomass accumulation causes redistribution of the preferential flow channels. Zones of slow flow near the fracture inlet were clogged, thus further diverting the flow through zones of fast flow, which were also partially clogged. Quantitative evaluation of biodegradation and bacterial counts supported the results of the multi-tracer tests, indicating that most of the bacterial activity occurs close to the inlet. The changing flow patterns, which control the nutrient supply, resulted in variations in the concentrations of the chemical constituents (TBP, bromide and oxygen), used as indicators of biodegradation.
AB - The two-dimensional distribution of flow patterns and their dynamic change due to microbial activity were investigated in naturally fractured chalk cores. Long-term biodegradation experiments were conducted in two cores (∼20 cm diameter, 31 and 44 cm long), intersected by a natural fracture. 2,4,6-tribromophenol (TBP) was used as a model contaminant and as the sole carbon source for aerobic microbial activity. The transmissivity of the fractures was continuously reduced due to biomass accumulation in the fracture concurrent with TBP biodegradation. From multi-tracer experiments conducted prior to and following the microbial activity, it was found that biomass accumulation causes redistribution of the preferential flow channels. Zones of slow flow near the fracture inlet were clogged, thus further diverting the flow through zones of fast flow, which were also partially clogged. Quantitative evaluation of biodegradation and bacterial counts supported the results of the multi-tracer tests, indicating that most of the bacterial activity occurs close to the inlet. The changing flow patterns, which control the nutrient supply, resulted in variations in the concentrations of the chemical constituents (TBP, bromide and oxygen), used as indicators of biodegradation.
KW - 2,4,6-tribromophenol
KW - Bioclogging
KW - Biodegradation
KW - Channeling
KW - Flow distribution
KW - Fracture flow
KW - Fractured chalk
KW - Multi-tracer experiment
KW - Preferential flow path
UR - http://www.scopus.com/inward/record.url?scp=26044443036&partnerID=8YFLogxK
U2 - 10.1016/j.jconhyd.2005.06.007
DO - 10.1016/j.jconhyd.2005.06.007
M3 - Article
AN - SCOPUS:26044443036
SN - 0169-7722
VL - 79
SP - 165
EP - 186
JO - Journal of Contaminant Hydrology
JF - Journal of Contaminant Hydrology
IS - 3-4
ER -