BIOAUGMENTATION CONSIDERATIONS - Bioaugmentation for Groundwater Remediation - page 142

dechlorination by 190 m g/L (1.6 m M) chloroform (Maym´ -Gatell et al., 2001 ), and of PCE
dechlorination by 1,000 m g/L (8,400 m M) chloroform (Maym´ -Gatell et al., 2001 ). To overcome
inhibition, bioaugmentation cultures such as SDC-9 TM or KB-1 ® Plus, which both contain
Dehalobactor species that are capable of dechlorination of 1,1,1-TCA and CF, can be used.
5.2.6 Hydrogeology
The hydrogeology of a site also can influence the success of bioaugmentation. If the
hydraulic conductivity is very low, it will be more difficult and time-consuming to deliver both
electron donor and bacteria to the targeted treatment zone. Likewise, if the subsurface is
heterogeneous, it will be more challenging to achieve a uniform distribution of electron donor
and inoculum. Consequently in low permeability formations, injection wells will need to be
spaced closer together than in more permeable aquifers.
5.3 FIELD METHODS
5.3.1 Injection Infrastructure Considerations
Dhc culture is typically delivered to the subsurface via injection wells, which permit the
subsequent addition of electron donor, buffer or inoculum should these be required (Figure 5.1 ).
Another commonly used method to deliver culture is via direct push injection (Figure 5.2 ),
whereby culture is injected into the subsurface directly without the use of wells. The choice of
culture delivery method will hinge on both technical and economic considerations, which will be
a function of the depth of the target contaminant zone and the number of anticipated electron
donor injections. If the contamination is deep ( > ~100 feet (ft) [30 meters (m)]) and/or multiple
injections of electron donor are likely to be required, then the installation of wells will probably
Figure 5.1. Photo of injection of bioaugmentation culture in injection well.