Final Site Information Package for National Remedy Review Board ...

SITE INFORMATION PACKAGE FOR NATIONAL REMEDY REVIEW BOARD
PART B, SECTION 9: COMPARATIVE ANALYSIS OF ALTERNATIVES
estimated effectiveness at completion of remedial actions is also slightly higher for
Alternative 4+ than for Alternative 3+. The differences in ranking among the OU 2
alternatives under this criterion do not outweigh the differences between Alternatives 3+
and 4+. The ranking of the OU 2 alternatives under this criterion, from highest to lowest, is
as follows: e, d, c, a, and b. This ranking is based on the relative differences in post-remedial
dissolved zinc loads in the SFCDR, immediately following the implementation of remedial
actions.
9.1.4 Reduction of Toxicity, Mobility, or Volume through Treatment
All the remedial alternatives are considered to satisfy the statutory preference for treatment,
and the treated water flow rates are relatively similar for all the alternatives. OU 2
Alternatives (a) and (b) do not include treatment and, therefore, rank lower under this
criterion. Alternative 4+ ranks higher than Alternative 3+ because, although the estimated
flow rate for treatment at the CTP is very similar, a significantly higher number of adit
discharges would be treated under Alternative 4+. The statutory preference for treatment is
satisfied through reduction of total volume of contaminated media—in this case, surface
water. The water treatment technologies to be employed would separate the metals from the
water. These metals would then require disposal in repositories. For each of the remedial
alternatives except for No Action, Tables B9-1a and B-91b present an estimate of the total
dissolved zinc load removed from the water through treatment (and therefore a reduction in
the zinc loading to the surface water). The estimates in Table B9-1a range from 700 pounds
per day (lb/day) for Alternative 3+(a) to 1,880 lb/day for Alternative 3+(d); the estimates in
Table B9-1b range from 600 lb/day for Alternative 4+(a) to 1,760 lb/day for
Alternative 4+(d).
9.1.5 Short-Term Effectiveness
All of the alternatives based on Alternative 3+ rank higher under the criterion of short-term
effectiveness than those based on Alternative 4+ because Alternative 4+ would pose much
greater short-term negative impacts during construction than Alternative 3+, regardless of
which OU 2 alternative it is coupled with. This is primarily due to the extensive nature of
the remedial actions that would be conducted under Alternative 4+, which would require a
much longer time period to complete (decades longer); the similar water quality expected to
be achieved after the implementation of remedial actions; and the similar time frame needed
for natural source depletion to further improve water quality and achieve ARARs. The
ranking of the OU 2 alternatives from highest to lowest short-term effectiveness is as
follows: d, c, b, a, and e. This ranking is based on a balance of implementation time,
effectiveness, and short-term risks.
9.1.6 Implementability
All of the alternatives based on Alternative 3+ rank higher under the criterion of
implementability than those based on Alternative 4+, because Alternative 4+ would have
substantially increased technical and administrative feasibility considerations compared to
Alternative 3+. Alternative 4+ has generally the same types of implementability
considerations as Alternative 3+, but with much larger quantities and larger repository
requirements. The ranking of the OU 2 alternatives from most to least desirable on the basis
of implementability is as follows: c, d, b, a, and e.
B9-4