FIELD DOCUMENTS AND WORK PLANS 2004-2014

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Mr. David Lieb • - 2 - 22 July 2004 Marley Cooling Tower Facility, Stockton with an automatic safety system shutdown mechanism,will be utilized to ensure that the treated water meets the NPDES Permit requirements prior to discharge to the Stockton Diverting Canal. Phase 1: The current IX system will be shut down during the course of this one-week Phase 1 study. Phase 1 will treat groundwater flow from the most impacted wells,which presently goes to the ECS system. Approximately 150-200 gallons per minute (gpm) of this flow will be routed through the Demo System. The treated water will be sent back to the ECS influent tank and will flow through the ECS system to ensure compliance with the NPDES permit. The discharge from the ECS system will be monitored via the online pH and chromium analyzers with an automatic safety shutdown mechanism, to ensure discharge parameters are being met. In addition, the system influent and effluent samples will be collected daily and analyzed to collect performance (including NPDES permit compliance) and cost data. Regeneration of the IX columns will be done using salt brine (6 percent sodium chloride). The brine is washed out of the treatment system and will be stored on-site for proper off-site disposal later. Upon completion of Phase 1 study, data and results will be provided to the Department of Toxic Substances Control (DTSC) and the Regional Board. Upon concurrence from DTSC and the Regional Board that the Demonstration system has performed to expectations on the high hexavalent influent concentrations,Phase 2 will start. Phase 2: Phase 2 is intended to collect additional performance and cost data at higher flow rates. The existing IX system will be bypassed during this three-week study period. Combined water from wells feeding the existing IX and ECS systems, will be routed to the Demonstration system for treatment prior to discharge to the Stockton Discharge Canal. The flow will be increased in 100 gpm increments every three days, until a full flow rate between 450 and 550 gpm is reached, to allow for confirmation from laboratory analyses that the system is meeting discharge requirements. Periodic influent and effluent sampling(on Day 1, 4, 7, 10, 13, 16, 19, and 21) will be conducted to collect performance (including NPDES permit compliance) and cost data to evaluate the effectiveness of the Demonstration system. As done in the Phase 1 study, brine generated during the regeneration process will be stored on-site for proper off-site disposal later. Upon completion of the Phase 2 study, a report including the findings, operational parameters, laboratory and field data, evaluation of the Demonstration system and other supporting information will be submitted for DTSC and Regional Board review. Our comments on this report are provided below: 1. We appreciate SPX-Marley efforts to consider and implement new technologies and wish you success in realizing the potential benefits as presented in your work plan. As you are aware, Provision G.3 of the NPDES Permit includes an Effluent Limitation Time Schedule for TDS to comply with a new monthly average effluent limitation of 500 milligrams/liter by 1 February 2008 and requires study and implementations necessary for compliance. We believe the proposed demonstration study should help in evaluating potential alternatives to meet this requirement. In addition, removal of the current acid addition/pH control system, if implemented, should greatly reduce the potential for discharge of high pH water to the Stockton Diverting Canal. 2. Please provide additional time for RWQCB and DTSC review of the data collected from Phase 1 study than what is shown in Table 2.