Environmental Engineering Reference
In-Depth Information
6.4.1.6 Developing and testing molecular tracking
recombinant organisms
in situ ..................................... 175
6.4.1.7 Construction of multiple ortho-PCB
dechlorinator LB400(
ohb
) ............................................... 177
6.4.1.8 Growth on defined PCB mixtures ............................... 182
6.4.1.9 Validation of PCB remediation strategy in
soil (microcosm studies) ................................................ 182
6.4.1.10 Developing protocol for inoculum delivery .............. 184
6.4.1.11 Recommendations for inoculum delivery
during pilot test .............................................................. 187
6.4.1.12 Compatibility of anaerobic and aerobic phases in
remediation process ....................................................... 187
6.4.2 Microbial-surfactant compatibility experiments ...................... 188
6.4.3 Plasmid stability studies .............................................................. 189
6.4.4 PCB-surfactant solubilization experiments............................... 191
6.4.5 Mathematical modeling ............................................................... 192
6.4.6 PCB transformation experiments ............................................... 193
6.5 Accomplishments of the pilot evaluation.............................................. 196
6.5.1 Site consideration for field test ................................................... 196
6.5.2 Site description .............................................................................. 200
6.5.3 Pilot-scale demonstration............................................................. 201
6.5.4 Sampling schedule ........................................................................ 204
6.5.5 Analytical methods ....................................................................... 206
6.6 Conclusions ................................................................................................. 208
6.7 Recommendations for further transitional research ............................ 208
References............................................................................................................. 209
6.1 Project background and rationale
PCBs remain among the most expensive hazardous waste cleanup problems
facing the country. Through the use of existing technology, principally incin-
eration, the cleanup cost is estimated to exceed $20 billion. If PCB concen-
trations could be reduced
in situ
using bioremediation approaches, these
costs could be substantially reduced. The research on microbial degradation
of PCBs has a 20-year history (Ahmed and Focht, 1973), and many field trials
of PCB bioremediation have taken place. This research has shown that biore-
mediation requires a more sophisticated technology than the simplistic
attempts that have been tried thus far. The 20 years of PCB research, however,
defined the barriers that must be overcome to achieve successful bioreme-
diation, and the discoveries in basic biochemistry and molecular biology
have now provided feasible approaches to overcome these barriers.
The fundamental barriers to bioremediation of PCBs are:
•
The absence from nature of organisms that will grow on PCBs
