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MEMORANDUM • J ` a CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD - CENTRAL VALLEY REGION Phone: (916) 361-5600 3443 Routier Road, Suite A ATSS Phone: 8-495-5600 Sacramento, CA 95827-3098 TO: Wendy L. Cohen FROM: Polly Lowry Senior Engineer Associate Engineering Geologist DATE: 17 September 1992 SIGNATURE: SUBJECT: SYSTEM CHECK OF INTERIM GROUND WATER REMEDIATION, KEARNEY-KPF, STOCKTON, SAN JOAQUIN COUNTY I have reviewed the 8 September 1992 letter from Hargis and Associates regarding the completion of the system check of the interim ground water remediation system at the Kearney-KPF facility in Stockton. My only concern is that lines WP-006-CA, WP-007- CA, WP-008-CA, and WP-011-CA were not pressure tested at 150 percent of the design pressure as required in Discharge Specification C. 1(b) of WDR Order No. 91-220. Tom Ryan, Engineering Manager at Hargis and Associates has explained to me that the design pressure for the four lines was selected to account for the worst case situation of a blocked valve. The design pressure for line esWP -008- CA was for mistakenly listed as 100 pounds per square inch (psi) . The line is actually 50 psi . The test pessure of 84 psi on line WP-008-CA was 170 percent of the design pressure, thus meeting the requirements of the WDRs. In order not to exceed the maximum allowable operating pressure of 150 psi for the flanged PVC piping, the test pressures for WP-006-CA, WP-007-CA, and WP-011-CA were 120 psi or 110 percent rather than 150 percent of their design pressure. The test pressures of lines WP-006-CA and WP-007-CA were 130 percent of the operating pressures expected at the remediation system' s design flow rate of 250 gallons per minute (gpm) , while the test pressure of line WP-011 was 300 percent of its operating pressure. To prevent inadvertent closure of valve PCV-11 , the handle of the butterfly valve upstream of this valve has been removed. In addition, a blocked valve in the system would result in a high liquid level in the air stripper tower and automatic shut down of the remediation system approximately one minute after the valve becomes blocked. SUMMARY To prevent exceeding the maximum allowable operating pressure of the flanged PVC piping, lines WP-006-CA, WP-007-CA, and WP-011-CA were pressure tested at only 1110 percent of their design pressure, as opposed to the 150 percent required in the WDRs. For WP-006-CA and WP-007-CA this is 130 percent of the operating pressure expected at the remediation system's design flow rate of 250 gpm. For WP-011 this was 300 percent of its expected operating pressure. With the safeguards taken (i .e. , removal of the butterfly valve in valve PCV-11 and the automatic shut down of the remediation system if the liquid level in the air stripper gets too high) the test pressures for WP-006-CA, WP-007-CA, and WP-011-CA are acceptable. However, before the long-term remediation system begins operating, the test pressures of all the lines should be reevaluated for the design flow rate of 500 gpm.