Roadblocks to the implementation of biotreatment strategies - Bioremediation of Recalcitrant Compounds - page 49

use of activated carbon. Frequently, this technology is not cost effective or
publicly acceptable. Biotreatment offers a possible alternative. Biotreatment
can cost effectively eliminate contaminants and avoid the use of harsh chem-
icals and physical treatments. However, special care must be employed to
ensure that the proper remediation system is designed and engineered to
optimize cleanup and minimize costs.
Unfortunately, not all bioremediation efforts have been successful. In an
attempt to develop bioremediation technology from the flask (bench scale)
to the field (full-scale design), many scientists and engineers have failed to
understand the phenomena that influence bioremediation. Issues such as
additional mass transport mechanisms/limitations, the presence of multiple
phases, spatial heterogeneities, and unfavorable factors for bacterial growth
represent only a few of the phenomena that can limit or complicate biodeg-
radation. Successful bioremediation requires a complete examination of the
phenomena that can be observed as the scientist and engineer progress
together from the bench to the field.
An excellent way to examine these phenomena is to use the conceptual
scales of observation: microscale, mesoscale, and macroscale (Sturman et al.,
1995). The microscale represents the level at which chemical and microbial
species and reactions can be characterized independently of any transport
phenomena. These activities are those occurring at the microbial cell level
and generally are the focus of bench-level work. The mesoscale is the level
at which transport phenomena and system geometry are first apparent, with
the exclusion of advective or mixing processes. This scale represents those
activities that occur at the pore channel, soil particle, or microbial aggregate
level. The macroscale is the scale at which one has the ability to discern
advective or mixing phenomena. These activities are generally associated on
a site level and are the focus of the design engineer. The critical path as
bioremediation technology is developed from flask to field is to observe and
understand the phenomena that exert influence at each scale of observation
so that its effects can be incorporated into the final remediation design.
References
Atlas, R.M. 1984. Microbiology Fundamentals and Applications . Macmillan Publishing
Company, New York.
Benemann, J.R. 1991. Literature Review on the Use of Bioaccumulation for Heavy Metal
Removal and Recovery , WSRC-TR-175-Vol. 2 (February). Westinghouse Savan-
nah River Co., Aiken, SC.
Blackburn, J.W. and Hafter, W.R. 1993. The input of biochemistry, bioavailability, and
bioactivity on the selection of bioremediation techniques. TIBTECH 11 (Au-
gust): 329.
Brock, T.D., Smith, D.W., and Madioan, M.T. 1984. Biology of Microorganisms , 4th ed.
Prentice Hall, Englewood Cliffs, NJ.