the Cleanup or Abatement Order (CAO) No. 98-38 issued by the Central
Coast Regional Water Quality Control Board on April 3, 1998 and
revised on November 6, 1998, Phase I remediation activities were
required to be completed by the end of 2002. The Regional Water
Quality Control Board approved a revision to the schedule on October
26, 1999, extending the deadline to complete excavations until such
time that soil disposition issues are resolved.
I CAO remediation activities include characterization, excavation,
product recovery, pilot tests and treatment of affected soil (see Phase I activities). Decommissioning
activities (i.e., the removal of abandoned pipelines and unused
surface facilities) is largely complete. Completed activities and
the schedule for completing all remaining Phase I CAO remediation
activities are described below.
biosparging systems were installed
that inject air into the saturated zone to enhance biological
pilot Land Treatment Unit (LTU) was
constructed and operated. In the LTU, nutrient amendments and
oxygen are tilled into the affected soil so naturally occurring
bacteria within the soil can break down the hydrocarbon contamination.
of the first group of the Beach Sites (5X West, LeRoy 3 Sump,
and 8X Sump) were completed by the end of 1999. For these excavations,
sheet pile was driven into the ground around the perimeter of
excavation sites so hydrocarbon-affected soil could be removed
and replaced with clean soil.
The C8 Excavation was completed during the summer of 2000. Restoration
activities and installation of an ecoremediation
system at the C8 site was completed in the winter of 2000.
Excavations of the second part of the Beach Sites (5X East, A2A,
5X Road, LeRoy 6, and A1/2X) were initiated in September 2000
and were completed in February.
- In 2002-2004, Unocal tested in situ hot water and steam flooding
as a potential remediation alternative to excavating to remove
petroleum hydrocarbons from impacted soil. The Pilot Test was in operation for 5 months, and was followed by a scale-up study to assess the possibility of using the technology on a site-wide basis.
- Phase I Activities - The Supplemental EIR was certified by the San Luis Obispo Planning Commission in July 2005, but excavation
of the remaining Phase I CAO sites cannot begin until all agency permits and approvals have
been obtained. Remaining sites include:
B12/C12, B2-3, L11/M12 Sump, TB1, A5A/A5 Sump, TB4 Sump, M4, D14
Sump, B11 Sump, M2, C7 South, B6, and, if required, C2 and N12. (See Site Map)
- Wetland Restoration - Of the remaining Phase I excavation sites, none would disturb wetland habitats (B2-3, B11, B12/C12, D14, L11, M2, M4, M12 and TB1). Three other sites (B3A, B6 and N12) do not involve disturbance to wetlands, but wetland creation/restoration activities are proposed for these sites. (See Site Map, linked above.) Impacts to wetlands by excavation activities must be mitigated by creation of new wetlands or restoration of existing wetlands at a created-to-disturbed ratio of 4:1. Details may be found in the Wetland Restoration and Mitigation Plan.
- Phase II Activities - Phase II activities are under development in partnership with the RWQCB and other agencies. Emphasis of these activities will be on net environmental benefit.