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-6- <br /> 1. 3 PURGING PROCEDURES <br /> 1 . 3 . 1 Before entry into the field: <br /> a. Assemble all essential equipment (decontaminated <br /> as required) in the purge truck . <br /> b. Prepare (as much as possible) the field logs in <br /> advance. <br /> c. Review the day' s planned activity with the imme- <br /> diate supervisor . <br /> d. Calibrate the pump rates of the bladder and <br /> centrifugal pumps as needed. <br /> e. Calibrate conductivity, pH, and temperature <br /> monitors at the beginning of each day. <br /> 1 . 3 . 2 Set up for purging: <br /> a. Note observations of the well area, well condi- <br /> tion, and well security. <br /> b. Measure the distance from the top of the well <br /> pipe to the surface of the water (S) . <br /> 1 . 3 . 3 "A"-zone Wells <br /> a. Purge the well from the surface to the bottom. <br /> Use a surface centrifuge pump for shallow wells ( to <br /> roughly 25 ft) and a submersible bladder pump for <br /> deeper wells. <br /> b. Plan to pump three well volumes of water from the <br /> well into holding tanks in the back of the purge <br /> truck . <br /> C. Measure well water conductivity, pH, and tempera- <br /> ture during purging. Plan the monitorings at equal <br /> intervals (when possible) during the purging. <br /> d. Continue purging until: <br /> three well volumes of water are removed, and two <br /> consecutive measurements of conductivity, pH, and <br /> temperature indicate formation stability, or <br />