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In situ bioremediation of trichloroethylene-contaminated water by a resting-cell methanotrophic microbial filter
- TAYLOR, R. T., HANNA, M. L., SHAH, N. N., SHONNARD, D. R., DUBA, A. G., DURHAM, W. B., JACKSON, K. J., KNAPP, R. B., WIJESINGHE, A. M., KNEZOVICH, J. P., JOVANOVICH, M. C.
- Hydrological sciences journal 1993 v.38 no.4 pp. 323-342
- Methylosinus trichosporium, bacteria, bioreactors, bioremediation, biotransformation, longevity, methane, methane monooxygenases, methanotrophs, sand, trichloroethylene
- An in situ microbial filter technology is being tested and developed for remediating migrating subsurface plumes contaminated with low concentrations of trichloroethylene (TCE). The current focus is the establishment of a replenishable bioactive zone (catalytic filter) along expanding plume boundaries by the injection of a representative methanotrophic bacterium, Methylosinus trichosporium OB3b. This microbial filter strategy has been successfully demonstrated using emplaced, attached resting cells (no methane additions) in a 1.1 m flow-through test bed loaded with water-saturated sand. Two separate 24 h pulses of TCE (109 ppb and 85 ppb), one week apart, were pumped through the system at a flow velocity of 15 mm h−1; no TCE (< 0.5 ppb) was detected on the downstream side of the microbial filter. Subsequent excavation of the wet sand confirmed the existence of a TCE-bioactive zone 21 days after it had been created. An enhanced longevity of the cellular, soluble-form methane monooxygenase produced by this methanotroph is a result of the laboratory bioreactor culturing conditions. Additional experiments with cells in sealed vials and emplaced in the 1.1 m test bed yielded a high resting-cell finite TCE biotransformation capacity of about 0.25 mg per mg of bacteria; this is suitable for a planned sand-filled trench field demonstration at a Lawrence Livermore National Laboratory site.