|
I
<br /> and deionized water)to be used in cleaning the equipment If the sample is being collected from an operating vapor
<br /> between wells. extraction system,the target vapor manifolds must be set up
<br /> with sample ports that can be isolated witgput interrupting ,
<br /> Prior to measurement,the instrument tip is lowered into the system operation. Prior to the actual collection of the vapor
<br /> well until it touches bottom. Using the previously established sample,source data is recorded:air flow,temperature,and.
<br /> top-of-casing or top-of-box(i.e.,wellhead vault)point,the pressure;or,well identification number and depth intervai of
<br /> probe cord(or halyard)is marked and a measuring tape screen.
<br /> (graduated in hundredths of a foot)is used to determine the
<br /> distance between the probe end and the marking on the Typical sampling ports consist of a 1/4—inch ball valve fitted
<br /> cord. This measurement is then recorded on the liquid-level with a 3/16-inch hose barb to form a slip stream from the
<br /> data sheet as the"Measured Total Depth"of the well. sample source.
<br /> When necessary in using the interface probe to measure The sampling procedure requires one end of the tubing be
<br /> liquid levels,the probe is first electrically grounded to either slipped over the sample port hose barb and the other end
<br /> the metal stove pipe or another metal object nearby. When over the diaphragm pump inlet hose barb to form an air-tight
<br /> no ground is available,reproducible measurements can be connection. The sampling pump is then started and the
<br /> obtained by clipping the ground lead to the handle of the pump is purged for one minute with the vapor to be sampled.
<br /> interface probe case.
<br /> Following purging,the discharge of the pump is then
<br /> The probe tip is then lowered into the well and submerged in connected to the"Tedlar"bag using a section of 3/16-inch
<br /> the groundwater. An oscillating(beeping)tone indicates the tubing.The pump is restarted and the bag is opened and
<br /> probe is in water. The probe is slowly raised until either the allowed to fill to approximately 3/4 of its capacity. Caution
<br /> oscillating tone ceases or becomes a steady tone. In either should be taken not to overfill the sampling bag. The sample
<br /> case,this is the depth-to-water(DTW)indication and the is placed in a non-refrigerated dry cooler with sufficient
<br /> DTW measurement is made accordingly. The steady tone packing to prevent damage during transport. Cooling
<br /> indicates floating liquid hydrocarbons(FLH). In this case, samples will cause condensation of moisture within the
<br /> the probe is slowly raised until the steady tone ceases. This sample,thereby distorting the laboratory analysis.
<br /> is the depth-to-product(DTP)indication and the DTP
<br /> measurement is made accordingly. For quality control purposes,a duplicate vapor sample
<br /> should be collected from each sampling port. This sample is
<br /> The process of lowering and raising the probe must be then put on hold at the laboratory pending initial analysis. To
<br /> repeated several times to ensure accurate measurements. ensure quality control and minimize the potential for cross-
<br /> The DTW and DTP measurements are recorded on the contamination prior to and during sampling,the diaphragm
<br /> liquid-level data sheet. When FLH are indicated by the pump is thoroughly purged for approximately five minutes
<br /> probe's response,a product bailer is lowered partially with nitrogen or clean air(i.e.,compressed clean air). A
<br /> through the FLH-water interface to confirm the FLH on the "blank"sample of the discharged air is captured in a"Tedlar"
<br /> water surface and as further indication of the FLH thickness, bag at the end of the purging procedure and may be
<br /> particularly in cases where the FLH layer is quite thin. This analyzed to ensure the purging was effective.
<br /> measurement is recorded on the data sheet as"FLH
<br /> thickness." To minimize the potential for cross-contamination between
<br /> air samples,the polyethylene tubing,if not sample
<br /> In order to avoid cross-contamination of wells during the dedicated,is thoroughly cleaned and rinsed.
<br /> liquid-level measurement process,wells are measured in the
<br /> order of"clean"to"dirty"(where such information is Vapor samples are subject to very limited holding times,
<br /> available). In addition,all measurement equipment is typically 48 hours. Thus,care must taken to avoid delays in
<br /> cleaned with solution and thoroughly rinsed with deionized submittal of vapor samples to the laboratory. In the event
<br /> water before use,between measurements in respective the vapor samples cannot be submitted to the analytical
<br /> wells,and at the completion of the day's use. laboratory on the same day they are collected,they are to be
<br /> temporarily stored in the dry,non-refrigerated,packed cooler
<br /> SOP-11 until the very first opportunity for submittal well within the
<br /> SOIL VAPOR SAMPLING: "TEDLAR"BAG SAMPLING required holding time,taking into account the time needed
<br /> TECHNIQUE/REMEDIATION SYSTEM SAMPLING for shipment to and receipt by the laboratory.
<br /> Prior to vapor sampling,the vacuum system must reach a SOP-12
<br /> stabilized air flow(cubic feet per minute)for approximately VAPOR SAMPLING:SUMMA CANISTER SAMPLING
<br /> 15 minutes. Prior to the actual collection of the vapor TECHNIQUE
<br /> sample,the following data is recorded:air flow,temperature,
<br /> and pressure at collection ports and gauges. Prior to vapor sampling,the vacuum system must reach a
<br /> stabilized air flow(cubic feet per minute)for approximately
<br /> The sampling.equipment consists of a TedlarTm bag 15 minutes. Prior to the actual collection of the vapor
<br /> (available in 1,3,5,and 10 liter sizes),a diaphragm pump, sample,the following data is recorded:air flow,temperature,
<br /> and 3/16-inch-diameter polyethylene tubing(approximately 1 and pressure at collection ports and gauges.
<br /> foot long).The TedlarTm bag should be fitted with an integral
<br /> valve for filling and sealing the bag after sampling.The The sampling equipment consists of a sterilized,gas-tight,
<br /> diaphragm pump inlet and outlet are fitted with 3/16-inch "Summa"stainless steel canister(available in one and six
<br /> hose barbs for attaching the sample tubing.Prior to vapor liter volumes),flow meter(if required,obtained and
<br /> sampling,the soil vapor source(vapor screen,vapor calibrated by the laboratory)and 1/4-inch-diameter
<br /> extraction well or manifold,etc.)must be isolated for polyethylene tubing approximately 2 feet in length.
<br /> sampling.A sample label with the sample number and date
<br /> and time of sample collection is prepared and placed on the The sampling ports are brass connections fitted with silicone
<br /> TedlarTm bag. septa and threaded into a tapped hole in the system piping.
<br />
|