Injection

The injection portion of the treatment program begins with the mobilization of our equipment and personnel. Our equipment consists of a treatment vehicle (about 28 ft to 40 ft). Typically GCI utilizes one treatment specialist and sampling technician per treatment vehicle on-site. All sites need to be equipped with power and water, which can be supplied by GCI, if necessary. Mobilization and set-up typically take about 1-day.

Prior to commencement of injection, GCI obtains a round of groundwater samples from all of the injectors and monitoring wells on-site to establish site wide baseline conditions. These samples are analyzed for pH, alkalinity, iron, chloride, peroxide concentrations, PID headspace, and temperature.

GCI will typically begin the injection with a catalyst pre-treatment, followed by a radius of influence study. GCI will then begin to simultaneously inject oxidant and catalyst into the subsurface. Each treatment vehicle is equipped to inject into 4 injection locations simultaneously.



GCI typically injects peroxide at concentrations between 3% and 12%, starting at lower concentrations and increasing throughout the treatment program.

GCI will proportion the reagents throughout the injectors on-site using three main determinants: ROI, baseline contaminant mass, and PID headspace response. Initially, GCI determines a volume of oxidant that needs to be added to each injector in order to establish connectivity between locations, then calculates a mass of contaminant and a corresponding volume of oxidant needed to oxidize this mass at each injector location. These two quantities are compared and the higher of the two volumes is then assigned to each injector location.



During the injection, injectors are sampled daily to monitor the progression of the treatment program. GCI evaluates the peroxide distribution on a daily basis using the PID headspace response ensuring that reagents are delivered to areas on-site where treatment is not yet complete. GCI employs a continuous injection methodology in order to create and maintain optimal subsurface oxidizing conditions.