SITE INFORMATION AND CORRESPONDENCE_1988-1991

Home Browse Search

David Wang, P.E. , Chief August 12, 1991 Page 8 contaminant presented in Table 4 . 1-1, with the exception of TCE, are present in the groundwater at concentrations less than 5 ug/L. . . " 6. Section 4 .2 - Ground Water Recovery - At numerous locations within that section, the statements are made that although a given well is outside the 5 ug/L contour, the well is within the capture zone. However, no information is provided to support those statements. It may be appropriate to provide supporting graphics or applicable references which detail the capture zones for the various ground water extraction systems. 7. Table 4. 3-3 - Are the costs for surface water discharge to the SSJIDC or to the San Joaquin River? 8. Section 6.8 - State Acceptance - With the exception of the no action alternative, all the various ground water remedial alternatives considered could be acceptable to the Department. Specifically: AIR STRIPPING - As was stated in our March 15, 1991 letter Air Stripping with emissions control is acceptable. GAC TREATMENT - GAC could be approved. However, concerns regarding the permanent destruction of the contaminant and not just a contaminant media transfer would need to be resolved. Carbon regeneration issues would need to be clearly addressed. OZONATION/UV LIGHT - This is an acceptable technology and offers the benefit of permanent destruction of the VOCs. BIOLOGICAL TOWERS - This option could be approved. NO ACTION ALTERNATIVE - An unacceptable alternative since it would not treat the contamination and does not protect the beneficial uses of the ground water. ACTIVATED ALUMINA OR COPRECIPITATION WITH FERRIC CHLORIDE (FOR ARSENIC REMOVAL) - Either treatment method could be approved, pending additional treatability studies, as