Locus is one of the nations leading firms in the application of advanced solutions to address perchlorate contamination issues. Since it was first identified as a chemical of concern in 1997, perchlorate has been detected in the subsurface in more than 30 states and affects the drinking water of millions of people. Locus had the foresight to address this emerging concern, providing leading edge forensic technologies to identify sources of perchlorate, offering unique solutions to investigate impacted soils and groundwater, providing remedy solutions, and supporting site closure.
Forensic/Fate and Transport Specialists
Locus was selected to provide a background and source evaluation of perchlorate on the Santa Clara Valley Water District (SCVWD) project. The project includes several phases carefully planned to ensure a high, defensible level of data quality to differentiate natural and anthropogenic sources. After establishing Data Quality Objectives for each phase, the groundwater study includes a determination of historical groundwater gradient directions to identify potential background areas and selected aquifer depths not affected by human activities, followed by well sampling and data interpretation. Locus' project implementation includes statistical data analysis and chemical forensic evaluation, along with Locus' robust database management system to ensure data validity and defensibility.
Innovative Perchlorate Remediation Technologies
Using an innovative remedial application, Locus treated soils from the Aerojet site in the Sacramento area using a closed-loop bioreactor (CLB) air circulation system that induces an in situ closed loop system with a continual circulation of nutrient-rich vapor through the affected media using vadose injection and vacuum extraction wells. The CLB System combines technologies to promote and maintain an engineered biodegradation environment. At the initiation of the process, the CLB technology uses a small surface bioreactor to initiate the formation of degrading bacteria at the surface operation location. The bioreactor enhances moisture, nutrients, and associated co-metabolites, to accelerate the growth of indigenous bacteria which are then capable of destroying perchlorate constituents. The process uses a system of blended humic, fulvic, and acetic organic nutrients to accelerate the growth and degradation characteristics of existing indigenous bacteria. Delivery of the nutrient train is via moist vapor in the closed vapor loop, not liquid, thus the potential for vertical leaching of perchlorate is greatly reduced. The bench scale application of this technology was highly successful as the project demonstrated a >99% removal of perchlorate from the soil.
Closure Expertise
At the Rialto Perchlorate site, Locus performed a detailed site usage history from historical records, air photos and regulatory records, followed by a field investigation to determine if the operations by the PRP had impacted the soil with perchlorate. Locus sampled 11 separate areas of concern, based on past site activities related to propellant or munition manufacturing, operations or handling, following a strict RWQCB approved work plan. The Locus investigation enabled our client to avoid future liabilities associated with past practices at their property successfully closing their involvement in the issue.