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The following procedure is supplemental to the instruction found in the instrument-specific operating manual and relates to continuous low-flow sampling: • Connect the gas line to the regulator or pump controller. • Connect the pump outlet to an in-line flow cell (for low-flow applications); see Section 13.12, "Standard Practice for the Use of a Flow Cell for Field Measurements." • Place calibrated pH, conductivity, and temperature electrodes in the flow cell or the open container. • Initiate pumping and routinely monitor and record the volume purged and the pH, conductivity, and temperature measurements. Note: low flow sampling protocols indicate that flow rates should be maintained between 0.1 and 0.5 L/min. The minimum purge volume should be the sum of the volumes of the discharge line, pump and intake line (note the volume of the gas supply line is not factored into this calculation). • This volume is given by the following formula: 1(t 2 x 7r x h, x 12)+(p2 x 7r x hp)+(t2 x 7L x h2 x 12)lx 0.00429= purge volume in gallons • Where: ■ tl is the radius of the discharge tubing ID (in.) ■ h1 is the length of the discharge tubing (ft.) ■ p2 is the pump radius ID (in.) ■ hp is the pump length (in.) ■ t2 is the radius of the intake tubing ID (in.) ■ h2 is the length of the intake tubing (ft.) NOTE: High TDS purge water must be contained and properly disposed of in the waste pond or other appropriate receptacle. • When these readings have stabilized to ±10 percent for two successive well volumes, sampling can begin. • Clean and decontaminate the equipment, as required. B.8.4.1. Well Bore Fluid Purging Procedure Well bore fluid purging typically involves the use of some sort of bailer and is more typically suited for shallow wells with relatively small diameter casing. Those conditions result in smaller volumes of purge water being generated. Well bore purging, in general, is not appropriate for NS groundwater monitoring applications due in part to the larger volumes of purge water (up to approximately 1,200 gallons of water for a single purge of a deeper well) and potentially slower recharge rates. B.8.4.2. Calculation of Volume of Standing Water in a Well Calculations are performed for the amount of water in the well with the following formula: r2 x;r x(h, -h2)x 7.48= casing volume in gallons Daub &Associates, Inc. Page B-21 Natural Soda LLC 2022 SAP