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Advantages Disadvantages <br /> Easy to decontaminate. Labor intensive. <br /> Inexpensive. Difficult to sample from a set depth. <br /> Portable Creates turbidity. <br /> Table 7.Inertia Pump Advantages and Disadvantages <br /> B.6.8. Positive-Displacement Mechanisms <br /> Positive-displacement mechanisms consist of gas-driven devices and gas-operated bladder <br /> pumps. NS currently uses nitrogen gas. These devices are generally used to sample <br /> groundwater when the liquid must be pumped to the surface. Positive-displacement devices <br /> can be constructed of a variety of materials to fit most sampling situations. Table 8 and Table 9 <br /> present the advantages and disadvantages of positive-displacement mechanisms. <br /> Advantages Disadvantages <br /> Device can be used in wells with Oxidation and gas-stripping of volatiles may <br /> inside diameter as small as 2.0 inches. occur if air or oxygen is used as the driving gas. <br /> Device is inexpensive and highly Requires compressor or large compressed-gas <br /> portable for most sampling tanks. Application of excessive pressure can <br /> applications. rupture the gas entry or discharge tubing. <br /> Permanent installation is possible in Difficult to retrieve for repair, cleaning, and <br /> boreholes without casing. maintenance when installed permanently in <br /> boreholes without casing. <br /> Inert materials can be used for <br /> construction of device. Sample <br /> delivery rate can be controlled. <br /> Burst strength of the materials used <br /> to make device and tubing is only <br /> limiting factor in determining <br /> sampling depth. <br /> Table 8.Gas-Driven Device Advantages and Disadvantages <br /> Daub&Associates, Inc. Page B-16 Natural Soda LLC 2022 SAP <br />