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EGIS ENVIRONMENTAL, INC. <br /> STANDARD OPERATING PROCEDURE <br />! RE: MEASURING LIQUID LEVELS USING WATER LEVEL OR INTERFACE PROBE <br /> SOP-12 <br /> Field equipment used for liquid-level gauging typically includes the measuring probe (water-level or <br /> interface), light filter(s), and product bailer(s) The field kit also includes cleaning supplies (buckets, <br /> TSP, spray bottles, and deionized water) to be used in cleaning the equipment between wells. <br />' r into the well until �t touches bottom Using the <br /> Prior to measurement, the probe tip �s lowered g <br /> previously established top-of-casing or top-of-box (i e , wellhead vault) point, the probe cord (or <br /> halyard) is marked and a measuring tape (graduated in hundredths of a foot) is used to determine <br /> the distance between the probe end and the marking on the cord This measurement is then <br /> Irecorded on the liquid-level data sheet as the "depth to water" (DTW) <br /> When necessary in using the interface probe to measure liquid levels, the probe is first electrically <br />' grounded to ether the metal stove pipe or another metal object nearby When no ground is <br /> available, reproducible measurements can be obtained by cupping the ground lead to the handle of <br /> the interface probe case After grounding the probe, the top of the well casing is fitted with a light <br /> Ifilter to insure that sunlight does not interfere with the operation of the probe's optical mechanism <br /> The probe tip is then lowered into the well and submerged in the groundwater An oscillating <br /> 10(beeping) tone indicates the probe is in water The probe is slowly rased until either the oscillating <br /> tone ceases or becomes a steady tone In ether case, this is the depth-to-water indicator and the <br /> DTW measurement is made accordingly The steady tone indicates floating hydrocarbons. In this <br />' case, the probe is slowly raised until the steady tone ceases This is the depth-to-product (DTP) <br /> indicator and the DTP measurement is made accordingly <br />' The process of lowering and raising the probe must be repeated several times to ensure accurate <br /> measurements The DTW and DTP measurements are recorded on the liquid-level data sheet <br /> When floating product is indicated by the probe's response, a product baler is lowered partially <br />' through the product-water interface to confirm the product on the water surface, and as further <br /> indication of product thickness, particularly in cases where the product layer is quite thin This <br /> measurement is recorded on the data sheet as "product thickness " <br />' cross-contamination of wells during the liquid-level measurement process, wells <br /> In order to avoid cross co g q <br /> are measured in the order of "clean" to "dirty" (where such information is available) In addition, all <br />' measurement equipment is cleaned with TSP solution and thoroughly rinsed with deionized water <br /> before use, between measurements in respective wells, and at the completion of the day's use <br /> 1 <br /> ATTACHMENTISOP 12/SEPTEMBER 1992 <br />