Laserfiche WebLink
)EARTHCON <br />5.0 CONCLUSIONS AND RECOMMENDATIONS <br />The following is a summary of the findings for the Hazardous Waste Tank System: <br />• The hazardous waste tanks are compliant with the regulations identified in 22 CCR 66265. <br />Based on manufacturer specifications provided in Appendix C, permeation of the tank <br />contents into polyethylene may occur depending on the type of chemical being stored. <br />Ethylene glycol (antifreeze) does not attack or permeate high density crosslinkable <br />polyethylene (XLPE) resins up to 100° F. Petroleum hydrocarbons (such as fuel oil, diesel, <br />etc) also does not attack XLPE resins but can be absorbed into the wall of the tank over <br />time. Permeation and loss can slowly occur. Manufacturers design XLPE tanks to withstand <br />100° F and recommend that stored liquids should not exceed 100° F. Outdoor temperatures <br />in Stockton occasionally exceed 100° F during the summer months; however, temperatures <br />do not typically sustain over 100° F throughout the entire day and temperatures cool <br />overnight. The temperature of the used oil stored within the tanks are not likely to exceed <br />1000F. In addition, the tanks are located under roofing and are not directly exposed to the <br />elements. Some of the used oil storage tanks did appear to have discoloration, which may <br />be due to possible permeation of the tank contents overtime. However, the tanks appeared <br />to remain in good condition and replacement is not recommended at this time. Determining <br />the need for replacing the tanks should continue to be evaluated on a case-by-case basis. <br />This evaluation should continue to be conducted by continuing to perform daily visual <br />inspections of the hazardous waste tank system. <br />• The manufacturer states that the general life expectancy of the crosslink XLPE tanks is 10+ <br />years with 15 to 20 years being common depending on chemical, concentration, <br />temperature, installation and piping, and venting. The serial numbers on the used oil tanks <br />and the waste antifreeze tanks indicate manufacture dates of 1995 or earlier (with the <br />exception of 02 with an approximate manufacture date of 2009). According to Site <br />representatives, the Customer Drop Off tank is approximately 10-15 years old. All of the <br />tanks of the hazardous waste tank system were observed to be in good condition. During <br />the Site visit, evidence of damage and/or leaks with the tanks of the hazardous waste tank <br />system was not observed. However, based on the fact that these tanks are at the upperend <br />of their life expectancy, it is recommended that replacement of the tanks continue to be <br />evaluated on a case-by-case basis. This evaluation should continue to be conducted by <br />daily visual inspections of the hazardous waste tank system. <br />• Discussions with the manufacturer indicated that tanks are tested for tightness prior to <br />distribution to the client. As noted above, the earliest tank was installed in 1999 and <br />Hazardous Waste Tank Assessment Stockton, CA <br />Schnitzer Steel — Pick -n -Pull 8 Project No. 04.20160002 <br />