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BLAINE TEC HSER IC SV E ,IN J SE SACRAMENTO LOS ANGELES SAN DIEGO <br /> C SANO <br /> 1 For larger purges in 2" and 3" diameter wells, BLAINE stainless steel positive air-displacement <br /> pumps may be employed This system consists of the pump, air and water lines, control box <br />' and air source The 1 75"diameter pump is stainless steel, easily broken down and contains a <br /> Teflon check valve at its base The air and water lines are made up of small diameter thick <br /> walled PE tubing with stainless steel fittings The control box permits the user to separately <br />' adjust the charge and recharge cycles of the pump The air source is an electric oiless air <br /> compressor fixed on the Sampling Vehicle Maximum purge rate is approximately 1 25 gpm <br />' For larger purges in 4" or greater diameter wells, fixed-speed 3" Grundfos electric submersible <br /> pumps may be employed Each pump has a large diameter internal stainless steel check valve <br /> The pump is attached to large diameter PE tubing also containing the electrical conduit The <br /> electrical source is a gasoline powered electric generator fixed on the Sampling Vehicle <br />' Maximum purge rate ranges from 2 to 4 gpm <br /> For 1" diameter wells or larger diameter wells with constricted casings, a WaTerra HydroLift II <br />' pump may be employed This system consists of an electrically powered variable-speed <br /> actuating arm assembly, small diameter disposable PE tubing and foot valve The arm <br /> assembly is set the top of the well casing, the tubing is lowered into the well and the speed of <br />' the actuating arm is adjusted to obtain the desired purge rate Maximum purge rate with 5/8" <br /> OD tubing is approximately 1 gpm <br />' PUMP PLACEMENT <br /> In all cases where pumping systems are employed, the pump intake is gently lowered into the <br /> well and suspended near (but not touching) the bottom <br />'w PURGE RATE VERIFICATION <br /> Purgewater is pumped into graduated 5-gallon buckets at least until a purge rate can be <br /> accurately calculated, at which time the purgewater may be pumped directly into the onboard <br />' effluent tanks fixed on the Sampling Vehicle <br /> PARAMETER MEASUREMENT AND STABILIZATION <br />' In wells with sufficient recharge, purging is considered complete when 1) the minimum purge <br /> volume has been removed and 2) groundwater parameter measurements for electrical <br /> conductivity, pH, and temperature have stabilized <br />' Parameter measurements are collected at regular intervals during the evacuation process (no <br /> less than once per case volume) using a Myron-L Ultrameter 6P Parameter stabilization is <br />' considered achieved when the difference between successive measurements is less than 10% <br /> The meter is calibrated daily or as needed according to manufacturers specifications <br />' PUMP RETRIEVAL <br /> Pumps are their associated air and water lines and/or electrical leads are gently retrieved <br /> following completion of purging in preparation of well sampling <br />' DEWATERED WELLS <br /> Normal purging activities remove no less than three case volumes of water from the well <br /> However, less water may be removed in cases where the well dewaters and does not <br />' STANDARD OPERATING PROCEDURES—BP/ARCO NORTHERN CALIFORNIA Page 4 <br />