ARCHIVED REPORTS_SITE CONCEPTUAL MODEL 2009

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amec— Other industries have operated and continue to operate in the vicinity of the former plant. These include Regal Almond (now the Site of a building materials company), Ripon Milling, Guntert Steel, Nulaid Foods, Ripon Manufacturing and Ripon Canning. 3.1.1 Chemical Use The decaffeination process included the use of chemicals. The decaffeination occurred at the "Old Decaf" (Decaffeination Building) and "Decaf Penthouse" locations shown in Figure 2 (personal communication with John Meling, former Nestle factory engineer). Decaffeination was performed in a closed, batch process as follows: 1. Green coffee beans (unroasted) were placed in a rotating vessel filled with water to hydrate the beans, causing them to swell (swelling allowed the chlorinated solvent to penetrate the beans more easily). 2. After the beans had swelled, the water was drained and the vessel was partially filled with chlorinated solvent and rotated for several hours to extract the caffeine. 3. The solvent was then drained to a solution tank while the beans were retained in the vessel with a screen. 4. Steam was used to extract residual solvent from the beans, and the steam and solvent vapor was condensed and returned to the solution tank. 5. The solution tank drained to a gravity separator for recovery of non-aqueous-phase chlorinated solvent; water from the gravity separator was drained to an onsite sewer lateral located north of the Decaffeination Building and south of the warehouse that connected to the industrial sewer along Industrial Avenue. Between approximately 1957 and 1970, TCE was used as the chlorinated solvent for decaffeination in the Decaffeination Building area. Annual TCE use was estimated to be approximately 8,000 gallons (RUST, 1994a); TCE was transported to the Site by truck and was stored in aboveground tanks south of the Decaffeination Building (Figure 2). Between 1970 and 1986, methylene chloride (dichloromethane) was used for the decaffeination process, and an additional step was added, in which water from the gravity separator was sent to a stripping column to remove the chlorinated solvent before it was sent to the industrial sewer. Chloroform was also used as a solvent for laboratory-scale decaffeination processes (the location of the laboratory is shown in Figure 2). Other chemicals used at the Site include caustics and water softening agents (calcium and magnesium oxides) and perhaps small quantities of cleaning solvents such as 1,1,1-trichloroethane (1,1,1-TCA) for equipment maintenance. Hazardous chemicals (caustics and perhaps solvents) were stored in small quantities (drums and bottles) in the chemical storage building (Building 38; Figure 2); paint thinners and paints were stored in Building 36 (Figure 2) (personal communication with John Meling). AMEC Geomatrix, Inc. hDoc_Safe\9000s\9837.005\4000 REGULATORY\SCM_01.30.09\1_text\SCM Report Final.doc 8