ARCHIVED REPORTS_XR0011977 - Laserfiche WebLink

Home Browse Search

. Frequency of Groundwater Monitoring: Quarterly Sampling Date: February 26, 2003 Is Free Product(FP) Present on Site: No FP Recovered This Quarter: NIA Cumulative FP Recovered to Date: NIA Approximate Depth to Groundwater: 41.98 to 43.11 feet below ground surface (bgs) Groundwater Flow Direction: Northeast Groundwater Gradient: 0.003 ft/ft DISCUSSION: Groundwater elevations have increased approximately 0.19 to 0.70 feet since the previous sampling event (December 11, 2003). The groundwater flow direction on February 26, 2003, was calculated to be towards the northeast at a gradient of approximately 0.003 ft/ft. Groundwater flow directions have predominantly been toward the northeast and east during previous monitoring events. Depth-to-water measurements were corrected to mean sea level (MSL) and used to construct a groundwater elevation contour map(Figure 3). In addition to quarterly groundwater sampling, additional groundwater samples were collected on a monthly basis during the first quarter 2003 to evaluate and optimize the performance of ozone injection system. Tabulated results of groundwater elevation and analytical summary of groundwater samples ® collected under ozone injection monitoring plan and quarterly monitoring program are presented in Tables 1 and 2. A discussion on the results of petroleum hydrocarbon concentrations is presented later in remediation system status section of this report. REMEDIATION SYSTEM STATUS The following presents the results of the first quarter 2003 operation of the ozone injection (C-SpargeTM) system and the current status. As per the Interim Remedial Action Plan, following 180 days of operation, the system's performance and effectiveness will be evaluated to determine if C-SpargeTM is an appropriate technology for final remediation. System Description The C-SpargeT"' system, manufactured by KVA®, consists of a control panel (ozone generator, air compressor, and tubing manifold), and strategically located injection points (IW-1 through IW-5, see Figure 2) used to inject low concentrations of ozone into groundwater. In addition, the control panel also has a programmable timer that limits the amount of ozone injected into each injection point. The system injects a timed pulse of ozone at low flows and low pressures (10-30 psi) to each of the five injection points in a sequence. The ozone dissolved in groundwater is anticipated to oxidize petroleum hydrocarbons into carbon dioxide and water, and any un-reacted ozone will degrade to dissolved oxygen, which is likely to enhance natural biodegradation of residual petroleum hydrocarbons. System Operation Details The C-SpargeT"' system was started on December 26, 2002. The C-SpargeT" control panel was programmed and scheduled to inject ozone cyclically in each injection point for 14 minutes. Based on this programming, each injection point will have ozone injection in 18 cycles for 4.2 hours every day. p:\Bp-Arco for URS\54691Quarterly\2003\Arca_5469_1Q03.doc 5TKA ru.s