SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

CLEANUP AND ABATEMENT ORDER NO.R5-2006-0720 NESTLE USA,INC. RIPON, SAN JOAQUIN COUNTY 15. In October 1993, the Regional Board issued Cleanup&Abatement Order(CAO)Number 93-712 that provided a list/schedule of interim and final remedial actions, groundwater cleanup standards, and reporting requirements. The Feasibility Study,Record of Decision, and Remedial Design documents required under the 1993 CAO have not been completed. A Feasibility Study was submitted in October 1994, but was not approved by the Regional Board. In response to comments raised by Regional Board staff, the Discharger also submitted addendums to the Feasibility Study in February 1998 and October 1998, and completed an evaluation of in situ oxidation using KMn04 in September 2000. The in situ oxidation pilot study demonstrated that KMn04 can quickly oxidize TCE and its degradation products, but delivery of this reagent to the affected areas is problematic. 16. In October 1999, the Discharger began extracting and treating groundwater at a second location approximately 1,400 feet southwest of the former Facility. Extraction well E-2, installed in August/September 1999, near the corner of Stockton Avenue and 4h Street(Stockton Avenue property), is screened in the Upper aquifer zone and extracts groundwater at a rate ranging from approximately 40 to 120 gpm; pumped water is treated at a nearby plant on Stockton Avenue and discharged to the City of Ripon's industrial sewer. 17. On 27 June 2000, the Discharger submitted the Draft Groundwater Flow Model Evaluation for Groundwater Treatment System Design Report(Draft Flow Model Report) for review by the Regional Board. This Draft Flow Model Report evaluates various pumping scenarios and the relative hydraulic capture provided by each one. The model demonstrated that limiting pumping at municipal wells MW4 and MW-7 should minimize the TCE plume migration northward beneath the City of Ripon. With the exception of flow to MW-10, the Draft Flow Model Report states VOC concentrations higher than 3.0µg/ would be contained horizontally and vertically within all aquifers by expanding the groundwater treatment system and the continuous pumping of municipal well MW-9. Regional Board approved installation of a new Intermediate zone extraction well (E-6) as an interim remedial action. The Discharger has submitted several refinements to the Draft Flow Model Report since June 2000, but the Report has not been finalized due to issues related to calibration of the model and the discovery of the TCE plume on the south side of the Stanislaus River. 18. In November 2000 the Discharger installed extraction well E-6 at the Stockton Avenue property to extract and treat groundwater in the Intermediate Aquifer Zone. Recent pumping data indicates this extraction well can sustain flows up to 425 gpm with an average flow of 390 gpm. The City of Ripon constructed a non-potable water distribution system to supply water to local industrial facilities and irrigate parks. In July/August 2004, extraction well E-6 became operational and started discharging to the non-potable water distribution system. The Discharger installed an air stripper with a GAC polisher to treat groundwater pumped from both E-2 and E-6. 19. In the 1990s,the Discharger completed several soil vapor investigations and installed 12 soil vapor extraction (SVE) wells to remediate the vadose zone on- and off-site. A total of 170 pounds of VOCs have been removed from the vadose zone by these extraction wells. The SVE systems operated until VOCs were below detection or achieved asymptotic levels, but concurrence on no further action (NFA) was not issued by Regional Board staff. The Discharger is currently assessing 5