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APPENDIX C <br /> Diamond Pet Food Processors of Ripon,LLC June 30,2011 <br /> Report of Waste Discharge—Groundwater Sampling Plan Page 2 of 7 <br /> During well purging and sample collection, water quality measurements will be taken using field <br /> meters as described above. Measurements will be recorded to the following standards: pH to <br /> ±0.1 units, conductivity to±1 microsiemens per centimeter(µS/cm), and temperature to±PC. The <br /> field meters will be operated consistent with the manufacturers' recommendations. The <br /> manufacturers' instrument manuals will be available for reference during sampling. <br /> Instruments will be calibrated daily to a known standard before they are used, and they will be <br /> checked again at the end of the day. Calibration standards will be prepared according to the <br /> instrument manufacturer's specifications. Calibration procedures, dates, and times will be recorded <br /> in the field. <br /> GROUNDWATER SAMPLING METHODS AND PROCEDURES <br /> Low-flow purging techniques are used at the site. The low-flow sampling technique is premised on <br /> minimizing drawdown of the aquifer and achieving stabilization of field parameters before and <br /> during sample collection. This groundwater sampling method, as described in the April 1996 US <br /> EPA document Groundwater Issue Paper entitled"Low-Flow (Minimal Drawdown) Groundwater <br /> Sampling Procedures" (EPA/540/S-95/504),has received wide-spread acceptance in the industry. <br /> The low-flow sampling method has been shown in published, third party,peer-reviewed studies to <br /> improve on traditional sampling methods. <br /> Pump flow rates for low-flow sampling are typically selected to approximate the yield of the well, so <br /> that the water level is not significantly lowered during purging and sampling. Minimal drawdown <br /> procedures consist of evacuating the total volume of groundwater in the sampling system to clear the <br /> well pump and tubing of any stagnant water left from the previous sampling of the well. The <br /> maximum flow rate is determined by pumping at a rate that causes minimal drawdown of the water <br /> level inside the well. Field measurements are taken at the start of purging and continued at evenly- <br /> spaced intervals until the measurements stabilize. Once stabilization is achieved, samples are <br /> collected directly from the pump discharge tubing while maintaining the same pumping rate. <br /> Low-flow purging and sampling will be conducted using dedicated pumps, peristaltic pumps, 12-volt <br /> purge pumps, or bailers. The wells will be purged at low-flow purge rate (generally less than 2 liters <br /> per minute [1/min]). Field measurements will be initiated at the start of purging and continued at <br /> evenly spaced intervals until stabilization. Measurements of the indicator parameters will be taken at <br /> a frequency based on the time it takes to purge one (1) volume of the pump and associated tubing. <br /> For example, if the volume of the pump and associated tubing is 3.0 L and the well is being purged at <br /> 1.0 L/minute, the pump, associated tubing, and flow cell will be purged in three (3) minutes. In this <br /> 010070.00, Task I Lawrence&Associates <br /> w:Iclientsldiamond pet foods1010107.00-ripon rowdldiamondpet_rowd_june2011 draft.docx <br />