06-096DEPARTMENT OF ENVIRONMENTAL PROTECTION
(d)At existing facilities, or where ground water contamination is suspected, the Department may require the use of geophysical techniques to aid in establishing appropriate well locations and screen elevations for additional ground water monitoring points.
(e)The downgradient monitoring wells must be located as close as practical to the solid waste boundary(s) of landfills, or the waste handling area of solid waste facilities that are not landfills, but in no case greater than 100 feet away, unless placing some of the wells at greater distances enhances the ability to detect a release from the facility. In such a case, placement of wells more than 100 feet distant may be proposed for approval by the Department
(f)All upgradient and background monitoring wells must be placed so as to avoid any facility-derived impacts both during the operating life of the facility and after closure.
(2)Sampling, Handling and Analysis of Ground Water. The ground water monitoring program must include consistent sampling procedures that are designed to ensure monitoring results that provide an accurate representation of ground water quality at all monitoring wells installed at a solid waste facility. The approved sampling protocol must be followed throughout the monitoring period of the facility so that data acquired can be compared over time and accurately represent changes in ground water quality. The following procedures must be followed during purging and sampling of monitoring wells, and the handling and analysis of the collected samples:
(a)Prior to purging. Prior to purging the well, static water level must be measured to the nearest 100th of a foot using standard techniques. If a protocol other than low flow sampling is used, well depth must be measured at least annually, or more often if suspended solids in the sample suggest that the well integrity has been impaired. Also, the ground water quality monitoring plan must include the following provisions for detecting immiscible fluids, and explosive or organic vapors, when applicable.
(i)in areas where the presence of explosive or organic vapors is suspected, appropriate instruments must be used to test and identify any constituents in the air in the well prior to purging. Results must be recorded on the field sheet.
(ii)for wells at which ground water contamination has been documented, or where contamination by non aqueous phase liquids is suspected, standing water in the well must be checked for immiscible layers or other contaminants that are lighter or heavier than water, prior to purging the well. If present, these liquids must be sampled and analyzed separately by a method described in the facility ground water monitoring plan.
(b)Purging and Sampling. Wherever possible, purging and sampling must be accomplished at low flow rates using a pump. The pump intake must be within the screened interval of the well, and the purging and sampling procedure must minimize drawdown in the well in order to minimize both the creation of artificial gradients in the vicinity of the well and the introduction of stagnant water into the well screen.
(i)purge methods, including type of pump, pumping rate, and depth of pump intake must be included in the ground water monitoring plan;
(ii)dissolved oxygen, pH and Eh must be measured inline at the discharge of the pump, in a closed flow cell; and
Chapter 405: Water Quality Monitoring, Leachate Monitoring, and Waste Characterization
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