<p><p><strong>Reference(s):</strong></p><p><em>Casagrande (1983)</em></p><p><strong>Method Summary</strong></p><p>Water discharge monitoring at the cathodes can be an effective QC measurement if monitored over time. If the cumulative amount of water discharged with time becomes constant, it is an indication that the process can be terminated. Sometimes the process may have to be reversed to reduce non-uniformity between the electrodes. The water discharge amount can also be a QA tool, provided all the water is coming out at cathodes. However, if the subsurface layers have any pervious sand lenses that provide drainage channels for the water, then the discharged amount of water would not correspond to the anticipated values. In a case study reported by Casagrande (1983), a total quantity of 9,000 gallons of water was removed by the pumping from the well points. However, the estimated total volume of water was about 30,000 gallons (based on moisture content reduction measurements). The difference between these quantities was attributed to the presence of pervious materials in the subsurface layers.</p><p><strong>Accuracy and Precision</strong></p><p>Accuracy and precision of these test methods are hard to quantify due to the nature of the measurement.</p><p><strong>Adequacy of Coverage</strong></p><p>Results provide a measure of the amount of water discharged from a cathode. The coverage area depends on the number of cathode monitoring locations.</p><p><strong>Implementation Requirements </strong></p><p>Some experience and special equipment is necessary in assessing the results. Measurements can be obtained using simple procedures involving the use of a pump, container, and a stop watch.</p><p><strong>General Comments</strong></p><p>Monitoring water discharge is a process control (QC) technique.</p></p>