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• Successful redevelopment requires that water be forced from the casing into the formation, <br /> and from the formation into the casing. This is best accomplished through the use of a <br /> surge block. Compressed-nitrogen jetting can also accomplish this flow reversal to some <br /> extent. <br /> • Before placing any redevelopment equipment in a monitoring well, the equipment shall be <br /> cleaned by washing with soapy water (Alconox or equivalent) and deionized water, and <br /> wiping dry with a lint-free tissue. After removing redevelopment equipment from a well, <br /> the equipment shall be cleaned again. <br /> B.15.6.1. Nitrogen-Jetting Redevelopment Procedure <br /> If this procedure is to be used, Health and Safety department must be notified and the work <br /> steps must be added to the IWP. <br /> • If site conditions require that purge water from the well be contained, a discharge-control <br /> apparatus should be installed on the well riser. This apparatus typically consists of a <br /> compression-sleeve coupling with a discharge port that is connected to the well riser. A <br /> compression-type seal for the jetting pipe is rigged at the top of the discharge-control <br /> apparatus. Even if site regulations do not require discharge water to be collected and <br /> stored, a discharge-control apparatus should be used at sites that may have contaminated <br /> groundwater. Use of the discharge-control apparatus will prevent the splashing of <br /> discharge water on well-maintenance technicians. <br /> • A jetting-T is connected to a series of PVC pipes (the jetting pipe) and lowered to the top of <br /> the screened interval. The top of the jetting pipe is connected to a compressed nitrogen <br /> source via a flexible compressed gas transmission hose. The flexible hose is connected to a <br /> two-stage regulator on the nitrogen source. The first stage of the regulator displays the <br /> pressure in the nitrogen tank. The second stage displays the pressure at the flexible hose <br /> when the regulator is opened. To prevent injury caused by the nitrogen tank falling over, <br /> the tank must be either secured in an upright position with a chain or placed on its side and <br /> secured by wheel chocks. <br /> • Set the line pressure on the regulator at a maximum of 60 pounds per square inch. Jet the <br /> well screen by quickly opening the line valve, allowing the water to rise in the well, and then <br /> closing the line valve. As air (or nitrogen) escapes from the water column, the water in the <br /> well will fall back to near static levels and give rise to a flow reversal from the well into the <br /> formation. This pulsed jetting should be repeated for the entire length of screened interval <br /> by lowering the jetting pipe in small increments. The pulsed jetting will loosen sediment <br /> from the screen, the filter pack, and the well bottom. <br /> • As material is loosened during the pulsed jetting, the well should be air-lift pumped to <br /> remove the dislodged sediment. Air-lift pumping is accomplished by slowly but steadily <br /> opening the line valve. This action will discharge nitrogen into the water column within the <br /> well. The water will rise in the well as the nitrogen is introduced and expands. If the water <br /> level reaches the top of the well before the injected nitrogen reaches the top of the water <br /> Daub &Associates, Inc. Page B-38 Natural Soda LLC 2022 SAP <br />