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Updated Low Threat Discharge Information 2 1 October2009 Lawrence Livermore National Laboratory Site 300 San Joaquin County below. To meet the schedule to deliver Hetch-Hetchy system water to LLNL Site 300, LLNL proposes to start the actions described in steps 1 and 2 during September 2009. 1. Validate the integrity of the pipeline using up to 30,000 gallons of water of either Site 300 groundwater or Hetch-Hetchy system water. The discharge water would be collected in a series of storage tanks prior to use as evaporation make-up water in the sewage evaporation pond, reducing the use of potable water used for this purpose during warm months. 2. Rinse the pipeline with at a minimum of two flushes using Hetch-Hetchy system water, approximately 30,000 gallons each flush. The discharge water would be collected in a series of storage tanks prior to use as evaporation make-up water in the sewage evaporation pond or as dust control on site or at the Carnegie SVRA. 3. Line disinfection with super-chlorination water containing up to 200 parts per million (ppm) chlorine using potable water from the Hetch-Hetchy system. The discharge water would be collected in a series storage tanks and de-chlorinated to less than 2 ppm chlorine residual. The de-chlorinated water would be discharged as evaporation make-up water in the sewage evaporation pond. 4. Line rinsing after disinfection with two to three line flushes using approximately 60,000 to 90,000 gallons of potable water from the Hetch-Hetchy system. The rinse water would be used as evaporation make-up water in the sewage evaporation pond or as dust control on site or at the Carnegie SVRA. 5. After rinsing, the line will be filled with potable water from the Hetch-Hetchy system and tested to determine if adequate disinfection was achieved. As required by State drinking water standards, two sets of coliform samples will be collected 24 hours apart. If test results indicate acceptable coliform levels, the line will be connected to the Site 300 drinking water system. If coliform levels do not conform to drinking water standards, the line will be flushed several times (approximately 30,000 gallons each flush), filled, and again disinfected and rinsed as described in actions 3 and 4 above. This process will continue until coliform test results indicate the line has been adequately treated and the water in the pipeline meets State drinking water standards. In addition to the requirements contained within the Order and the Waiver, LLNL must comply with the following: • No discharge of the wastewater to surface water will occur. • Discharge water quality used for dust control will be the same as or very similar to the water currently used for these activities. • Super-chlorinated water will be de-chlorinated to less than 2 ppm chlorine residual and will be used only as evaporation make-up water in the sewage evaporation pond. • Operations described above will only occur during months where the evaporation rate within the sewage evaporation pond requires the addition of make-up water (typically April