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Attachment K <br /> Injection Procedures <br /> Application Requirements <br /> Describe the proposed injection procedures including pump, surge,tank,etc. <br /> Approach <br /> Injection procedures are well established for the STIG-1 well. These are described below. <br /> General descriptions of the injection procedures for the LEC-1 well and the possible backup <br /> well,LEC-2,are being developed. Both are discussed below. <br /> Operational Overview <br /> NCPA currently operates the STIG plant when electricity is needed during high demand <br /> periods. The STIG-1 well,therefore, only injects waste when the STIG plant is operational <br /> and when the required 20 percent injection occurs. <br /> The LEC is planned to meet routine power demands. The LEC-1 well will dispose of <br /> nonhazardous process wastewater from the LEC facility. It will be constructed, operated, <br /> maintained,and monitored in a manner consistent with STIG-1. The LEC-1 well is planned <br /> to be installed and tested prior to plant construction. <br /> The third well,LEC-2,may be installed at a future date to serve as a back-up well to both <br /> the LEC-1 and STIG-1 wells. This is discussed more fully in Attachment O,Plan for Well <br /> Failures. <br /> STIG-1 <br /> When operating,the STIG-1 well injects approximately 100 gpm,based on the 2008 first <br /> quarter monitoring report submitted to USEPA,which is well-below the permitted rate of <br /> 200 gpm. Historic injection pressures range from 261 to 506 pounds per square inch (psi), <br /> which is also well-below the maximum permitted wellhead injection pressure of 975 psi. <br /> The historic injection pressures and monthly injection rates are summarized in Figure K-1. <br /> Under current conditions, at least 20 percent of plant wastewater is collected in a <br /> 60,000-gallon wastewater storage tank,where its contents are tested to ensure compliance <br /> with the operating permit before being discharged to the injection well via two 100-gpm <br /> wastewater injection pumps. Current injection limitations include the following: <br /> • Maximum flow rate 200 gpm <br /> • pH between 6.5 and 8.5 <br /> • Silica <120 ppm <br /> • Injection water temperature <100°F <br /> SAC/371322/082390003(ATTACHMENT-K.DOC) K-1 <br />