Berth 142 Creosote Remedial Approach and Implementation
City of Los Angeles, Harbor Department (Port of Los Angeles) • Los Angeles, CA
Solution Overview
Client:
City of Los Angeles, Harbor Department (Port of Los Angeles)
Business Challenge:
- Soil and groundwater beneath the Port of Los Angeles Harbor Department were found to have been affected by creosote in vadose zone soils
- Restore the site and prevent further environmental degradation or potential risk
Solution:
- Presented a focused dense non-aqueous phase liquid (DNAPL) removal program to reduce future creosote migration into the harbor
Results:
- Ongoing DNAPL removal actions continue to restore the environment
- Focused removal actions allowed the City to avoid implementing a full-scale cleanup
Challenge
Soil and groundwater beneath the site of a wood treatment operation at the Port of Los Angeles Harbor Department were found to have been affected by creosote in vadose zone soils. To restore the site and prevent further environmental degradation or potential risk to human and environmental receptors, the Port required a an experienced remediation consultant to assist with delineation and remediation of the contaminant plume.
Solution
Apex presented a focused DNAPL removal program to the Port and then to Regional Water Quality Control Board (RWQCB); this approach involved a targeted surgical removal of deep DNAPL pockets near the harbor waters and a grout curtain to reduce future creosote migration into the harbor. DNAPL extraction included well drilling in areas identified by laser-induced cone penetration testing (CPT) soundings, and high‑vacuum mobile extraction. Using solid steel‑casings to a depth of 30 feet and 5-foot-diameter augers, deep creosote‑saturated soil zones were removed and hauled offsite; remediation was followed by installation of a grout curtain to reduce the permeability of these formations.
Results
Apex’s rapid planning, regulatory approval and swift and efficient implementation of remediation services allowed the Port to proceed with construction of the cargo handling facilities. Currently, Apex personnel conduct quarterly DNAPL removal and semi-annual groundwater sampling at the Port terminal during nightshift operations, requiring detailed schedule coordination with the Port’s tenant. Importantly, the removal of the most heavily contaminated soil and groundwater from the Site and the installation of the grout current resulted in the stabilization of the residual dissolved phase and DNAPL plumes. Ongoing DNAPL removal actions continue to restore the environment, while semi-annual groundwater monitoring and sampling demonstrates that the ecological sensitive receptors in the adjoining harbor waters are protected. The combination of focused removal actions, placement of the grout curtain, and ongoing removal actions allowed the City of Los Angeles to avoid implementing a full-scale cleanup cleanup which is estimated to cost hundreds-of-millions of dollars.