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ethane. Biodegradation can be sustained for as long as sufficient concentrations of <br />substrate remain in the groundwater. For this reason, emulsified oil will be used as the <br />substrate because it is aslow-release compound, and therefore should release organic <br />carbon into the groundwater for three to five years. <br /> <br />1. The Basic Services of ENGINEER as described in Section 1 of said Agreement <br />are amended and supplemented as follows: <br />CDM will perform three tasks related to the in situ groundwater remediation at the <br />Cabarrus County Closed Unit 2/3 Landfill site in Cabarrus County, North Carolina. <br />CDM proposes to perform.the following tasks: <br />• Task 1-Injection and Monitoring Well Installation <br />' Task 2 -Emulsified Oil Injection <br />• Task 3 -- Performance Reporting <br /> <br /> <br />1 <br /> <br /> <br /> <br /> <br />1 <br /> <br /> <br /> <br />Each of these tasks is described in more detail below. <br />Task 1-Injection and Monitoring Well Installation <br />Under this Task, CDM will install six injection wells and four monitoring wells. The <br />injection wells (IW-1 through IW-6) will be installed with air-rotary methods to <br />anticipated total depths of 60 feet. At each injection well location, a 4-inch diameter, <br />schedule 40 PVC outer rasing will installed from land surface into the top of bedrock. <br />The remainder of the. boring will be completed as an open-hole baring to the 60-foot <br />depth. The wells will be completed with locking above-grade protective covers and 2- <br />foot by 2-foot concrete pads. Following installation, the wells will be developed and <br />surveyed to State Plane coordinates. <br />The monitoring wells will be installed as nested pairs (AMW-1/1D and AMW-2/2D) <br />down gradient of the injection wells and MW-E/E-deep. At each nested pair, a shallow <br />monitoring well will be installed in saturated overburden utilizing hollow-stem auger <br />techniques and a deeper monitoring well will be installed in the shallow fractured <br />bedrock utilizingair-rotary tecluliques. The shallow monitoring wells will be <br />constructed with 2-inch diameter schedule 40 PVC with 10 to 15 feet of 0.010-inch slotted <br />screen. The bedrock wells will be constructed with 6-inch diameter schedule 40 PVC <br />outer casing from land surface into the top of bedrock. The well will be completed with <br />2-inch diameter schedule 40 PVC with 5 to 10 feet of 0.010-inch slotted screen. All <br />monitoring wells will be constructed in accordance with the North Carolina Well <br />Construction Standards described in 15A NCAC 2C and will be completed with locking <br />above grade protective covers and 2-foot by 2-foot concrete pads. Following installation, <br />the wells will be developed and surveyed to State Plane coordinates. <br />Prior to installation of the injection and monitoring wells, CDM will obtain an <br />Underground Injection Control permit from the Aquifer Protection Section. <br />Page 2 of 4 <br />Amendment 37. <br />A a°chment number 3 <br />' F, - 9 Page 110 of 199 <br />