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Corrective Action Plan Page 27 Air-Quality Concerns } Under SJVUAPCD Rule 2220 an Authority to Construct or Permit to Operate is not required for any process unit if the uncontrolled emissions of air contaminants does not exceed 2 pounds in any 24 hour period (Ref 4 ) If it is conservatively assumed that all of the components of fuel hydrocarbons in the affected groundwater are volatile and the air stripper will be 100% effective in removing these compounds, the concentration of total petroleum hydrocarbons in the stream of water passing through the treatment system, when it is operating at its rated hydraulic capacity of 30 gpm, would have to be 5 55 mg/liter (ppm) before emissions from the air stripper would be equal to the regulatory hnut of 2 lb per day For the reasons discussed below, it is extremely unlikely that this limit will be approached However, as is also described later, provision has been made to manage any unexpected increase in contaminant loading that might occur As has been previously discussed, a very conservative estimate of the maximum total concentration of dissolved petroleum hydrocarbons in the influent stream to the groundwater treatment has been made for the purpose of sizing the process equipment That estimate is conservative because it was derived from the results of analyses of groundwater samples recovered from monitoring wells in the most contaminated zones beneath the site and considered historical data that includes unique, single-sample occurrences where the apparent concentration of hydrocarbons in the groundwater was an order of magnitude greater than those that have been consistently detected since a regular program of water-quality monitoring has been established Despite that conservatism, the estimated maximum contaminant concentration of 5 3 ppm in the treatment system 4 influent is less than the concentration that would cause uncontrolled emissions from the system to exceed the regulatory linvt even when it is assumed that the treatment system runs continuously at it rated hydraulic capacity of 30 gpm and, regardless of their volatility, the au stripper could extract 100% of the hydrocarbons compounds from the water Although the extreme estimate cited above is useful as a check to see that the treatment system can be safely operated without generating excessive emissions to the air, a more functional result can be obtained by considering the results from analyses of groundwater samples recovered from morutonng wells NAV-3, NAV-4 and ULT-9 (all of which are in the near field of the proposed recovery wells), in the period July 1993 through February 1994 (See Table 3 for the relevant water-quality data) Because they represent current groundwater-quality conditions in the subsurface beneath the site, these data more closely approxnriate the situation the that are likely to prevail when the proposed remediation i system begins operation When the water-quality data obtained from samples recovered from wells NAV-3, NAV-4 and ULT-9 in the period July 1993 through February 1994 are used, an estimated maximum total contaminant concentration of 2 1 ppm in the influent to the treatment