Bioaugmentation costs as a component of enhanced in situ bioremediation (EISB) are small relative to the overall costs of implementing EISB. The additional costs to include bioaugmentation typically represent less than 3% of the total costs for an EISB system. Given the small relative cost and the potential benefits, bioaugmentation can be an important enhancement to EISB.
The key potential economic benefits of bioaugmentation are: (1) reduction in the time required to achieve complete dechlorination of chlorinated solvents (or complete degradation of other target compounds), thereby reducing both the monitoring costs and the overall costs for the electron donor (or capturing more of the value of the electron donor initially injected); (2) reduction in regulatory oversight by achieving treatment objectives sooner; (3) reduction in the time required to return the groundwater to beneficial use by achieving treatment goals in a shorter period of time; and (4) ability to apply EISB at sites where this approach would otherwise not be effective and where other more expensive approaches would be required. These benefits will be realized only at sites where suitable microorganisms are not present or are present at low initial concentrations. There are no drawbacks to conducting bioaugmentation even when suitable microorganisms are present, other than the additional cost.