Laserfiche WebLink
r <br /> Monitoring Well Sampling and Development <br /> The groundwater monitoring well will be developed by the purge and surge method <br /> to remove the drilling muck, grade the sand pack and provide a more complete <br /> hydraulic connection to the aquifer. The well volume will be calculated and a <br /> number of those volumes will be removed until the water becomes clear and the <br /> amount of sand pumped is minimal. The well will be allowed to recover (at least 24 <br /> hrs.) prior to sampling. A log of the development will be kept for the well. <br /> Groundwater Sampling <br /> The groundwater monitoring well will be sampled. The well will be purged using <br /> calculated well volumes based upon the depth to water in the casing. Depth to <br /> groundwater measurements will be made to the nearest one-one hundredth of one <br /> foot, and also checked for the presence of separate phase product. As each purge <br /> volume is removed, measurements of pH, electrical conductiviity, and temperature <br /> will be taken until these parameters stabilize, which is interpreted to be aquifer <br /> water entering the casing. The sample will be carefully collected with a clean bailer <br /> and poured into the appropriate laboratory prepared container with minimum <br /> cavitation. Each water sample will be labeled, logged onto a chain-of-custody form <br /> and placed in a chilled ice chest. Upon completion of well sampling, the well will be <br /> closed and locked. <br /> Existing Deep Vapor Well Modification <br /> The existing vapor monitoring well is in our opinion, poorly designed with <br /> excessively long screened interval. While the well appears to be positioned where <br /> some soil vapor recovery is possible, the excessive amount of screen is not <br /> appropriate for the vapor extraction of contamination known to be present in the <br /> upper 30 feet. Wright feels that modifying this well would allow for more effective <br /> cleanup of the upper soil column where the previous consultant chemical data shows <br /> the most apparent contamination. <br /> Wright will modify the well by backfilling the lower 53 feet of the existing vapor <br /> monitoring well with a thin cement grout slurry placed in the well by tremie line <br /> filling the well from the bottom to top (see Figure 3). In this way the remaining well <br /> screen and sand pack will be plugged so that some vadose extraction can be made in <br /> the interval from 10 feet to 30 feet where the elevated contaminant concentrations <br /> have been previously identified during tank removal and sampling data. <br /> Chemical Analysis <br /> Up to 12 soil samples and one groundwater sample will be analyzed at a State certified <br /> analytical laboratory. Selected samples will tested for the following; Total Petroleum <br /> hydrocarbons as Gasoline (TPHG), Benzene (13), Toluene (T), Ethyl Benzene (E) and <br /> Xylene (X) using EPA Methods 3510/8015, and 8020; Total lead using CPA Method 6000, <br /> and microbial activity. The analyses will be run on an "normal" turnaround (ten <br /> working days). <br /> Waterloo School Workplan Page 3 <br />