2.7.2.4. Comparison of Ground Water Treatment Option Costs
For each extraction and treatment alternative described above, several
treatment technology options passed initial screening and were subjected to a
detailed evaluation in Section 4 of the FS. For purposes of comparing the
treatment technologies in the FS, cost estimates were prepared (see Appendices
D, E, and F of the FS) using U.S. EPA's suggested 30 years operating and
maintenance period (U.S. EPA, 1989b). A supplemental analysis was conducted
for several of the treatment facilities assuming 90 years of operation would be
required for Alternative No. 2 to achieve ARARs. This detailed analysis
indicates that, in general, for the same length of operation (e.g., 30 years),
(1) GAC is about 1.8 times more expensive in present worth for a treatment
facility than air stripping and (2) UV/oxidation treatment is 1.3 times as
expensive in present worth as air stripping. Alternative No. 3 has a very low
present worth, ranging from $30,000 for air stripping to $280,000 for GAC,
largely because the long timespan prior to possible commencement of treatment
reduces the total costs of this alternative in the discounting procedure. This
also takes into account the different combinations of contaminants and
treatment options at each treatment facility.
In summary, GAC is generally the most costly treatment technology, followed by
UV/oxidation, and then by air stripping. However, the costs in the FS do not
include
the program operations costs in Appendix A of the PRAP. These costs do not
significantly affect the relative costs of the treatment options, but they are
significant in magnitude when comparing remedial alternatives with different
periods of operation.
2.7.3. Unsaturated Zone Alternatives
UCRL-AR-109105
