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Home My WebLink AboutWI0100357_Report_20140501 TRS Accelerating Value Electrical Resistance Heating Design Report Former Clifton Precision Facility Murphy, North Carolina Issued: May 2014 TRS Group,Inc. PO Box 737 n Longview,WA 98632 •• www.thermairs.com —Carbodund.«9— TABLE OF CONTENTS 1.0 INTRODUCTION......................................................................................................................3 2.0 PROJECT GOALS.....................................................................................................................3 3.0 DESIGN BASIS.........................................................................................................................4 3.1. OVERVIEW..............................................................................................................................4 3.2. ERH DESCRIPTION.................................................................................................................4 3.3. POWER CONTROL UNIT..........................................................................................................7 3.4. ERH STEAM CONDENSER SYSTEM.........................................................................................8 3.5. VAPOR RECOVERY BLOWER..................................................................................................8 3.6. VAPOR TREATMENT...............................................................................................................9 3.7. WATER TREATMENT...............................................................................................................9 3.8. ELECTRODES...........................................................................................................................9 3.9. ELECTRODE SUPPLY CABLES.................................................................................................9 3.10. VAPOR RECOVERY WELLS...............................................................................................10 3.11. PERFORMANCE MONITORING WELLS...............................................................................10 3.12. SURFACE CAP...................................................................................................................10 3.13. ELECTRODE DRIP WATER.................................................................................................11 3.14. TEMPERATURE MONITORING POINTS...............................................................................11 4.0 OPERATING GUIDANCE......................................................................................................11 4.1. SAFETY.................................................................................................................................11 5.0 SYSTEM STARTUP................................................................................................................12 5.1. START-UP.............................................................................................................................12 5.2. STEP-AND-TOUCH SURVEY..................................................................................................12 5.3. OPERATIONS SEQUENCE.......................................................................................................12 6.0 OPERATIONS.........................................................................................................................13 6.1. OPERATIONS OVERVIEW......................................................................................................13 6.2. VAPOR RECOVERY................................................................................................................13 6.3. VAPOR TREATMENT CONFIGURATION.................................................................................13 6.4. CONDENSATE TREATMENT AND DRIP..................................................................................13 6.5. TEMPERATURE MONITORING...............................................................................................14 7.0 SITE RESTORATION.............................................................................................................14 8.0 RECORD KEEPING&REPORTING....................................................................................14 8.1. TRS DATA TRACKING PROGRAM.........................................................................................14 8.2. LOCAL DATA(HAND DATA SHEETS)...................................................................................15 8.3. OPERATIONS REPORTING......................................................................................................15 8.4. FINAL REPORT......................................................................................................................15 9.0 SAMPLING PLAN..................................................................................................................15 9.1. VAPOR MONITORING............................................................................................................15 9.2. GROUNDWATER MONITORING.............................................................................................15 9.3. PERFORMANCE EVALUATION...............................................................................................16 10.0 SCHEDULE.............................................................................................................................16 11.0 REFERENCES.........................................................................................................................16 MUR55 Design Report 051914 acf 1 GTRS List of Figures Figure 1 Site Plot Plan Figure 2a Electrode Detail Figure 2b Electrode Detail Bedrock Figure 3 Performance Well Locations Figure 4 TMP Detail Figure 5 Process Flow Figure 6 Mass Balance Figure 7 One-Line Diagram List of Appendices Appendix 1 QA/QC Plan Appendix 2 ERH Design Drawings Appendix 3 Health and Safety Plan Appendix 4 Standard Operating Procedures Appendix 5 Operation and Maintenance Plan Appendix 6 Murphy ERH Project Schedule Abbreviations and Acronyms °C degrees Celsius cis1,2-DCE cis 1,2-dichloroethene COC contaminant of concern CPVC chlorinated polyvinyl chloride CVOC chlorinated volatile organic compounds DOC dissolved organic carbon ERH electrical resistance heating Freon 113 trifluorotrichloroethane ft2 square feet ft bgs feet below grade surface GAC granular activated carbon gpm gallons per minute HASP Health and Safety Plan HSA Hollow Stem Auger kW kilowatt kWh kilowatt-hours mg/kg milligrams/kilogram NAPL non-aqueous phase liquid NCDENR North Carolina Department of Environmental and Natural Resources Northrop Grumman Northrop Grumman Guidance and Electronics Company, Inc. MUR55 Design Report 051914 ad 2 TRS PCE trichloroethene PCU power control unit PM performance monitoring ppb parts per billion PVC polyvinyl chloride QA/QC quality assurance/quality control RG remediation goal RTO regenerative thermal oxidizer scfm standard cubic feet per minute SOP Standard Operating Procedure TAT turnaround time TCE trichloroethene TMP Temperature Monitoring Point TRS TRS Group, Inc. TOC total organic carbon VOC volatile organic compounds VR vapor recovery 1,1,1-TCA 1,1,1-trichloroethane 1,1-DCE 1,1-dichloroethene 1,1-DCA 1,1-dichloroethane LOINTRODUCTION The TRS Group,Inc. (TRS)has entered into a contract with Northrop Grumman Guidance and Electronics Company, Inc. (Northrop Grumman)to perform a source area environmental remediation by applying electrical resistance heating(ERH) at Waste Management Unit WMU-B of the Former Clifton Precision Facility located in Murphy,North Carolina. ERH is an in situ thermal process for the remedial treatment of chlorinated volatile organic compounds(CVOCs)in soil and groundwater. The implementation of the ERH source area groundwater remedy at WMU-B will be conducted in accordance with Quality Assurance/Quality Control(QA/QC)Plan in Appendix 1. 2.0 PROJECT GOALS The remedial goals(RG) for this project are based on the reduction of VOCs in soils and groundwater. The soil and groundwater at the Murphy site are impacted primarily by trichloroethene (TCE); with relatively minor amounts of tetrachloroethene(PCE), 1,1,1-trichloroethane (1,1,1-TCA), 1,1-dichloroethene(1,1-DCE), 1,1-dichloroethane(l,1-DCA), cis 1,2-dichloroethene (cis 1,2-DCE), trifluorotrichloroethane(Freon 113) and 1,4-dioxane. The remedial goal of the project is to remediate the soil to 2 milligrams per kilogram(mg/kg) and the groundwater to 5 milligrams per liter as a combined total of the above VOCs. MUR55 Design Report 051914 ad 3 TRS 3.0 DESIGN BASIS This section discusses the basis for the remediation and the general functions and components of the ERH system. 3.1. Overview The treatment area is approximately 23,045 square feet(ft2)and extends from approximately 25 feet below grade surface(ft bgs)to 84 ft bgs for a total volume of 37,000 cubic yards. Due to contaminant depth profile,not all ERH electrodes will be installed to the same depth. The average depth of ERH treatment ranges from approximately 25' to 68' bgs. A plot plan of the proposed treatment area is illustrated on Figure 1. A total of 112 electrodes with co-located vapor recovery(VR) screens will be installed in the treatment zone. Figures 2a and 2b present the electrode design for the ERH system. Subsurface temperature data will be collected from 14 Temperature Monitoring Points (TMPs), each with a string of approximately 10 thermocouple sensors. The thermocouples will monitor subsurface temperatures at approximately 5-foot intervals. The locations of the TMPs and performance wells are shown on Figure 3 and the construction detail for the TMPs is illustrated on Figure 4.A complete set of ERH design drawings for the project is included in Appendix 2. As the heating vaporizes CVOCs and water in the subsurface,two vacuum blowers will remove the vapors and pull them through two condenser units where the water is removed from the air. The air and CVOCs will then pass through the blowers and advance for treatment through a vapor remediation system. The vapor steam will be treated via common methods such as a thermal oxidizer or carbon. The actual method of treatment will be determined during electrode installation. The contaminant concentrations and calculated mass will determine treatment method.A regenerative thermal oxidizer(RTO)will be the preferred method of vapor treatment as well as vapor phase granular activated carbon(GAC) system if practical.Additionally,the condensate removed from the vapor stream will be treated with liquid phase GAC before being added to the process cooling water and eventually evaporated, stored onsite, or dripped back into the electrodes. The ERH system process flow is illustrated on Figure 5 and mass balance on Figure 6. The power control unit(PCU)will use an industrial electrical service rated for 4,500 kilowatt(kW)to power the electrodes and heat the subsurface. The PCU will also distribute power to the condensers, blowers and vapor treatment system. All other ancillary equipment such as data monitoring will be powered via the PCU. The one line drawing for the electrical system is illustrated on Figure 7. 3.2. ERH Description ERH passes an electrical current through the soil and groundwater that requires treatment. The electrical current warms the soil and then boils a portion of the soil moisture into steam. This in situ steam generation occurs in all soil types,regardless of permeability. Electrical energy evaporates the target contaminant and provides steam as a carrier gas to sweep the CVOCs to the VR wells.After the steam is condensed and the extracted air is cooled to ambient conditions,the CVOC vapors are treated using a either a regenerative thermal oxidizer or vapor phase GAC. The type of contaminant and the desired clean-up goal affect the energy,time, and cost to remediate a site. However,two subsurface parameters are particularly important: the amount of total organic carbon(TOC)and the presence of heavy hydrocarbons such as diesel, oil,or grease. TOC preferentially adsorbs CVOCs in comparison to water; this is why activated carbon is often used for vapor and water treatment. Historical data for the site indicate a concentration of 0.15%TOC. MUR55 Design Report 051914 ad 4 GTRS The presence of oil, grease,or other low volatility hydrocarbons can also slow the evaporation rate of CVOCs as described by Raoult's Law.No fuel or other non-chlorinated hydrocarbons have been reported at the site. Dalton's Law of Partial Pressures The boiling points of TCE and other VOCs of concern are below the boiling point of water(100 degrees Celsius ['Cl at sea level pressure conditions). It should be noted that when a CVOC is immersed in water,the combined boiling point is depressed as described by Dalton's Law of Partial Pressures. Dalton's Law even describes the boiling temperature of non-aqueous phase liquids (NAPLs) in contact with moist soil. Consequently,the CVOC/water interface will boil when the vapor pressure of the CVOC plus the vapor pressure of water are equal to the ambient pressure. The Dalton's Law effect on site CVOCs are summarized in Table 1. Table 1 -Boiling Temperatures of VOCs Maximum Boiling Temperature Boiling Temperature VOC Concentration in Soil in Contact with Air at in Contact with Water (mg/kg) Site Elevation at 35 ft bgs Pure Water N/A 980C 1060C TCE 29,000 850C 790C PCE 1,200 1190C 940C 1,1,1-TCA 1,100 720C 710C 1,1-DCE 5 300C 360C cis 1,2-DCE 4 570C 600C Freon 113 30 460C 510C HP-1 DNAPL* 30,120 850C 790C *HP-1 DNAPL is based on a soil sample from 35 ft bgs that contained 97%TCE and 3%PCE by mole fraction Once subsurface heating starts,the boiling points of various VOC/water mixtures are reached in the following order: separate phase NAPL in contact with water or soil moisture, followed by dissolved VOCs, and finally,uncontaminated groundwater. This order is advantageous for remediation because contaminated water will tend to boil off before uncontaminated water,reducing the time and energy required to complete treatment. Other in Situ Treatment Process Enhancements Resulting from ERH Although volatilization is usually the primary removal mechanism for VOCs,TRS has documented on several sites that a significant fraction of the VOCs will be degraded in place by other in situ processes. Depending on the site,these in situ processes may include biodegradation,hydrolysis, and reductive dehalogenation by zero-valent iron. MUR55 Design Report 051914 ad 5 TRS Bioremediation Heat accelerates most chemical reactions,both the breakdown of the site contaminants and the breakdown of naturally occurring materials such as soil humus or TOC. TCE is an important CVOC at the site and is degraded by anaerobic microbes through the pathway: TCE--*cis-1,2-DCE--*vinyl chloride--+ethene Thermophilic(heat-loving)bacteria are an important contributor in the first two steps of the above chain. For this reason,we may see some slight increases in 1,2-DCE during the remediation; however, any 1,2-DCE increases would be insignificant in comparison to the TCE decreases. In the months and years after ERH treatment is complete;the heat will slowly spread away from the treatment region into the surrounding soil and increase the rate of bioremediation in these surrounding regions. Humic material is measured as TOC. The concentration of TOC in the site soil impacts the remediation in three important ways: • The TOC slows the evaporation rate of VOCs, • TOC can provide a food source to encourage bioremediation, and • Some of the TOC breakdown products can be measured in standard VOC analyses. VOCs bond to TOC through van der Waals forces; this bonding is why GAC is used for water filtration. Sites with higher TOC require more energy,time, and money to break the Van der Waals bonds and remove the CVOCs from the subsurface. The presence of TOC also impacts bioremediation because TOC breakdown products have an important interaction with bioremediation.Microbes such as dehalococcoides and other CVOC- degrading microbes need a carbon source to eat. These microbes use TCE and other CVOCs for respiration;they use the CVOCs in the same way that people use oxygen. TOC is formed from natural humus materials and it consists of long chain humic acids with very low water solubility. For a microbe to process a CVOC,the CVOC must diffuse inside through the cell wall; only water-dissolved compounds can diffuse through the microbe cell wall. For this reason, TOC is biologically unavailable. When the subsurface is heated,many of the TOC long chain humic acids break apart into smaller compounds with greater water solubility. Heating speeds the conversion of TOC into dissolved organic carbon(DOC). This conversion makes the organic carbon bioavailable and improves the site bioremediation activity. The benefit of using heat to make organic molecules easier to adsorb through cell walls explains why humans cook food. An example of the effect of ERH on DOC is depicted on Figure 1 below. This data is from a site in Springfield,MO. However,the relative increase of DOC is representative of conditions typically observed at ERH sites. MUR55 Design Report 051914 ad 6 TRS 300 ❑pre-ERH 250 250 ❑post-ERH 41 times higher 200 190 190 Dissolved 160 160 Organic 150 Carbon (mg/1) 100 50 6 31 A6J* 3 5 0 MW B2 MW B5 MW C4 MW E5 average Monitoring Wells Figure 1 -Effect of ERH on DOC When TOC is broken apart into simpler molecules,most of the DOC consists of less toxic compounds. However, about 1 percent of the DOC consists of acetone and other ketones(acetone is the simplest ketone and butanone, also known as methyl ethyl ketone,is the second simplest ketone). Like the other DOC components,the ketones have low health risk and are rapidly consumed by soil microbes. Low levels of acetone and butanone are continually produced at the site. Concentrations of acetone and butanone are likely to increase as the site is heated and the TOC to DOC conversion speeds up. After ERH is complete,the DOC production rate will return to baseline levels,microbes will consume the extra DOC, and ketones will return to low or non-detectable levels. 3.3. Power Control Unit The power control unit(PCU)will deliver energy to the electrodes for soil and groundwater heating. A PCU is best described as a variable transformer system capable of providing three simultaneous power outputs at adjustable levels. This is referred to as a three-phase electrical output PCU. Power output from the PCU may be routed through an auto-transformer and/or step-down transformer, allowing for further adjustment of power at electrodes when needed. TRS will use a 4,500 kW PCU that requires 225 amps of 13,000 volt alternating current primary power for operations. If the TRS 4,500 kW PCU is not available for mobilization, (2) 2,000 kW PCUs will be used as a contingency. The PCU(s) is designed for 100%cycle duty and is sized for an average power application of approximately 2,600 kW. The PCU is housed in a weather-tight steel enclosure that provides security and electrical insulation. During ERH operation,the applied voltage is adjusted to the appropriate level for optimum subsurface heating. The primary electrical connection and grounding system will be installed to meet facility and local electrical codes. As the subsurface is heated, the conductive properties of the subsurface can change, and the PCU output voltage will be adjusted based on those changes to maintain optimum system performance. The anticipated range for this site is between 215 and 650 volts. MUR55 Design Report 051914 ad 7 GTRS The electrical service is considered temporary and will been installed by the Murphy Electrical Power Board.An electrical one-line drawing is provided on Figure 7. 3.4. ERH Steam Condenser System The ERH steam condenser system will consist of two steam condensers, four cooling towers, and ancillary pumps and controls. The condensers will be positioned in a parallel configuration. Each condenser consists of an inlet air/water separation vessel, a plate and frame heat exchanger, a condensate tank, and an outlet air/water separation system. Air and contaminant vapors are pulled from the condenser into the vapor treatment system by the vacuum created by the VR blower. The inlet separation vessel removes water from the influent vapor streams. Air and steam then enter the air side of the heat exchanger, where steam is converted to condensate as heat is removed from the mixture. The vapor outlets of the condensers contain a mist eliminator that is 99 percent efficient in removing droplets to a size of 10 microns. Automated pumping functions are monitored, controlled, and recorded by the PCU computer. It is also possible to monitor the condenser system remotely. The operation of an ERH condenser is based on Henry's Law. As the fine water droplets condense from the steam, they do so in concentration equilibrium with the gaseous phase that includes air. Henry's Law can be rearranged to calculate the percentage of contaminant of concern (COC) mass that will become dissolved in the condensed water as follows: 7.1(gpm)x 3.785 l l gal l x 100%=0.20% 7.l(gpm)x 3.785 +0.417 x 1120(scfm)x 28.32 gal T s *gpm — gallons per minute; gal — gallons; scfm — standard cubic feet per minute; and ft3 -cubic feet The dimensionless Henry's Law coefficient for TCE, the primary anticipated COC, at a typical condenser outlet temperature of 25°C is 0.417. The condensate that is produced by the condenser will pass through one 200 pound liquid GAC vessel prior to being added to the cooling loop as makeup water. The energy balance inside the condenser is such that the amount of water evaporated from the cooling tower is almost exactly equal to the amount of steam condensed. To the extent practical, the condensers are operated as closed-loop systems. The exact water balance is dependent upon the relative humidity during the operational period. Water lost to evaporation needs to be replaced to maintain proper operating levels in the cooling tower. By using the generated condensate for cooling tower water makeup, potable water usage during treatment and wastewater for disposal can be reduced significantly. There is a potable water source for the makeup water to the cooling towers presently onsite. 3.5. Vapor Recovery Blower The ERH system will use two 40-hp positive displacement blowers to apply vacuum to the subsurface. The blowers will pull steam, air,and VOC vapors from the subsurface treatment area through the associated ERH steam condenser. Recovered air and contaminant vapors will pass through the blower and continue to the vapor treatment system. Each blower is permanently installed MUR55 Design Report 051914 aef 8 GTRS in a sound reducing enclosure and is controlled by a variable frequency drive for precise vacuum control. 3.6. Vapor Treatment The vapor stream treatment method will be determined by anticipated mass. There are two possible treatment methods that will be considered at the site; RTO and conventional GAC. RTOs are thermal oxidation systems that control VOC emissions. RTOs use a bed of ceramic packing to preheat the vapor discharge stream to minimize fuel consumption.Up to 95%of the heat is recaptured in the ceramic packing with an RTO system. The RTOs have two beds of packing. The vapor discharge stream reverses flow through the beds on a 5-minute cycle time so that one bed is always absorbing heat from the exhaust gas while the other is transferring heat to the inlet vapors. Combustion in an RTO typically occurs at a temperature around 1,500 degrees Fahrenheit. The destruction efficiency for an RTO is typically in the range of 95 to 98%. The RTO is constructed of AL6XN metallurgy for treatment of chlorinated solvents and it includes a caustic scrubber to capture and neutralize hydrochloric acid generated during the combustion of the chlorinated solvents. The RTO system is a skid mounted system that allows for ease of installation. Conventional GAC are container units filled with pelletized carbon. The contaminant-laden air will pass across the carbon and the VOCs will bind to the carbon surface. The carbon vessels will consist of multiple units in a series or series parallel configuration. The size of the units will be dependent on expected mass removal and area constraints at the site. 3.7. Water Treatment All water generated as a part of ERH operations,whether condensate or entrained groundwater(or a combination of the two),will be treated with liquid GAC prior to being added as makeup water in the cooling tower,evaporated from the cooling tower, or re-injected back into the electrodes. Each condenser will use a two vessel system that contains 200 lbs of liquid GAC per vessel. 3.8. Electrodes The ERH system will use bored single element and multi-element electrodes to delivery energy into the subsurface at the site. Two methods of subsurface boring will be used,hollow-stem auger(HSA) and sonic. The site will consist of 93 HSA bored electrodes and 19 sonic bored electrodes. The HSA locations will be drilled to bedrock refusal.The sonic locations will be drilled to a depth of 10' below bedrock surface. The electrode positions are shown on Figure 2 and noted by a circle in circle symbol. Each bedrock electrode will consist of a multi-element design using carbon steel pipe and copper plates. Each element will be connected at the surface via an electrical cable. Due to various angles of borings and depths of treatment, each element length will vary depending on location. The average shallow and deep extent of ERH will be from approximately 25 to 84 ft bgs. Each ERH electrode will contain a co-located VR point at 20 ft bgs. 3.9. Electrode Supply Cables Based on the anticipated voltage and current levels for each electrode, a single cable will be required to supply power to each electrode. However, due to the depth and difficulty of the site logistics,a second cable will be added to each element. The below grade portion of the cable will have a high temperature and chemically resistant rating that will transition to an above grade design rated for outdoor use and heavy traffic. Each of the dedicated electrode cables will have fuse protection and electrical current monitoring. MUR55 Design Report 051914 ad 9 GTRS 3.10. Vapor Recovery Wells Each electrode will have a dedicated well co-located within the bore hole at approximately 20 feet bgs. The VR wells will be constructed using 3-inch-diameter, 5-foot-long, stainless steel screens. Each VR well will be trenched and connected to a manifold system. A control valve for vacuum and flow adjustments will be associated with manifold groups and accessible via well vaults. The manifold groups will be piped to the subsurface and connected to the ERH condenser. The size and material type of the below grade VR piping will depend on contaminant concentration. Chlorinated polyvinyl chloride(CPVC)or fiberglass reinforced epoxy pipe will be used for the VR piping. There will also be four additional VR wells located under the facility building. These four wells will be installed at a nearly horizontal angle. The VR wells will be under continuous vacuum during the remediation in order to provide additional flow closer to the building slab. These four wells are designed as a supplemental system and are not the primary flow apparatus for the remediation system. 3.11. Performance Monitoring Wells The temperatures achieved by the ERH system will require the monitoring wells be constructed of temperature rated components. The polyvinyl chloride(PVC)pipe used in most monitoring wells will not handle the temperature and collapse as a result.Performance monitoring(PM)wells will be located as shown on Figure 3. PM-1S and PM-11)will be installed to pass just beneath the existing sheet pile wall—this orientation is shown on Figure Y-1 of the design drawings. In the event that a performance monitoring well nears bedrock prior to reaching the planned total depth,the well will be terminated as described on Figure 1. To aid in PM well planning, TRS will install the three adjacent electrodes prior to installing each PM well.TRS will log the PM well borings. 0 is 07 i, V C1 guaranteed -------------------- 2' non-guaranteed 2' .................... marble 2• Figure 1 -Bedrock Cross Section and Guaranteed Regions A dedicated pneumatic bladder groundwater sample pump will be installed in each of the 14 PM wells that are located in the treatment region. The teflon bladder pumps will be used for sampling. Existing wells constructed with PVC and located within the treatment area will need to be abandoned due to their inability to withstand the ERH temperatures. The following wells will be converted to TMPs as they are abandoned: RW-ID, GW-513, GW-21), GW-813, GW-31). For these monitoring well to TMP conversions,thermocouples will be inserted within the wells and then grouted in place. 3.12. Surface Cap Once subsurface installation is complete. The excavated trench areas will be covered using asphalt or concrete material.The actual surface material will be dependent on the existing surrounding area. The MUR55 Design Report 051914 aef 10 GTRS use of fabric membrane is not anticipated at the site due to the depth of treatment,which starts at 25 feet below grade. 3.13. Electrode Drip Water During operations,the area immediately surrounding each electrode has the potential to dry out, which may reduce the effectiveness of the electrode. This dry out condition is addressed by periodically adding water to the electrodes. This is commonly referred to as a drip system. The source of the drip water will be from the process cooling water which is composed of treated condensate and potable water. The drip tube will consist of a%2-inch-diameter tube that is installed to 30 feet bgs and controlled by a solenoid and software program in the PCU. Each drip tube supply line will be routed to the surface via trenches. 3.14. Temperature Monitoring Points As a means of monitoring the ERH process,TRS will install 13 TMPs to provide continuous temperature data collection within the subsurface. Temperature data will be automatically recorded at least once per day from the 13 TMPs. As described above, five of the TMPs will be installed in converted monitoring wells;the other eight TMPs will be installed in new borings. Each TMP will be constructed using 1'h-inch-diameter CPVC pipe or a black iron pipe and will include a TRS-installed string of temperature sensors that monitor temperatures at 5-foot intervals from 20 ft bgs to the total depth of treatment in the TMP region.The locations of the TMPs are shown on Figure 1. The eight TMPs that are installed in new borings will also include a vacuum piezometer section near 15 ft bgs. These piezometers will be used to verify vacuum influence for steam and vapor capture. Each TMP will be installed within the ERH treatment volume in the middle of an electrode array. Each individual TMP is constructed with a Type"T"thermocouple. Data will be automatically recorded once per day using the TRS data acquisition software. 4.0 OPERATING GUIDANCE This section discusses operations guidance and describes the tasks to be performed during the startup and operations phase of the project. 4.1. Safety All TRS personnel are to read and understand the TRS site specific Health and Safety Plan(HASP) prior to working on the site. The HASP is included as Appendix 3. • Personal protective equipment, as defined in the HASP,must be worn by personnel at all times. • The majority of the system components(electrodes, electrode supply cables,VR piping, drip piping, etc.)will be installed below grade. However, once the system components daylight, this will result in cables,wiring, and piping running across the surface of the site in certain areas. Caution should be taken when working around these hazards due to the possibility of slip,trips, and falls. • All traffic rules must be monitored carefully due to limited access areas and active roadways. • Daily tailgate safety meetings will be crucial for site communication and planning. MUR55 Design Report 051914 ad 11 A TRS 5.0 SYSTEM STARTUP This section describes the project specific tasks to be performed and the special consideration for startup. 5.1. Start-Up Once all quality assurance inspections and testing have been completed,Part I of the internal TRS Start-up Safety Checklist will be completed and approved by TRS senior management to determine that the system is ready for operations while attended.ERH startup will be initiated by energizing the electrodes at 130 volts applied. With the electrode field energized, operating parameters in the ERH PCU are compared against known standards along with step-and-touch, step-and-step voltage surveys, and current surveys to be completed throughout the area. This surveyed area includes all of the overlying and surrounding zones of the four treatment areas. Once all operating conditions are within accepted standards as outlined in design documents and TRS SOPs,the voltage to the electrode field is slowly increased. With each significant increase in applied voltage, operating parameters are reviewed, current surveys are completed and step-and-touch and step-and-step voltage surveys are performed again. If operating conditions were not within accepted limits,changes are made to the system configuration until they are once again acceptable. Once power application levels have reached optimum design conditions, final safety inspections and data quality checks are completed. System interlocks will again be verified for correct operation. During this process, operations of the ERH PCU will be observed while optimum voltage is applied to the electrode field. Remote capabilities of the PCU and data acquisition system are also verified. Part 11 of the internal TRS Start-up Safety Checklist will be completed and approved by TRS senior management to determine that the system is ready for unattended operations. 5.2. Step-And-Touch Survey Within the treatment area,the electrodes are energized as shallow as 25 feet bgs. Any other locations with the potential for possible voltages in excess of TRS safety protocol will be checked during system startup and weekly throughout the duration of operations. TRS will conduct voltage surveys around the treatment area, inside the site facility, and any area within 75 feet of an electrode. Any surface or object voltage above the TRS limit will be mitigated accordingly through either isolation, bonding or other necessary means. TRS will follow the guidelines laid out in the Voltage Survey described in the SOPs in Appendix 4. 5.3. Operations Sequence All electrodes will be connected to the PCU or ancillary transformer. Initial power application will be approximately 20%of the design average input of 2,600 kW. Current surveys will be conducted to establish operational conditions and identify any electrode issues. Once all parameters indicate that the ERH system is functioning as designed,the power will be increased incrementally to the design input of 2,600 kW or greater. Each upper interval ERH electrode is expected to have a variable current draw within 25%of the average. The deep bedrock electrodes will have a current draw in excess of 25%of the upper interval average. This variation is anticipated and monitored repeatedly throughout operations. Adjustments to individual electrode performance will be performed on an as needed basis. MUR55 Design Report 051914 ad 12 TRS 6.0 OPERATIONS This section briefly describes the tasks to be performed during operations,the data to collect and analyze and the planned revisions in response to the analyzed data.Also included in this section are the planned steps for the operations sequence intended to optimize the ERH application and performance to the contract. A more detailed description of the operations task for the ERH system operation are included in the Operations and Maintenance Plan(OMP) in Appendix 5. 6.1. Operations Overview During site remediation, it is anticipated that all 112 ERH electrodes will be operated simultaneously. The ERH system will be monitored and adjusted continuously to provide the most uniform heating possible. The estimated energy application required to achieve the soil cleanup goal is 5,160,000 kilowatt-hours(kWh). Based on an average power application of 2,600 kWs including down time, heating is estimated to last between 75 to 100 days. Downtime is expected and accounted for on all ERH sites and does not typically have an impact on site performance or the completion duration. At most ERH sites there is a potential for dehydration in the unsaturated zone. However,the conductive interval at this site begins at or below the water table,which should decrease the potential for dehydration.At this site the groundwater flow rate is considered slow. It is possible to dehydrate the immediate soil/electrode interface. In order to reduce the probability of dehydrating the interface and reduce excess condensate production for disposal,the addition of drip water will be required. The amount and placement of drip water is carefully balanced and monitored to ensure optimum system performance relative to soil hydration. 6.2. Vapor Recovery The VR system will apply a vacuum to the 112 co-located VR screens in the treatment area and 4 sub-slab VR locations. Each VR screen will be connected to a manifold system with control valves to adjust flow from each area. The anticipated applied vacuum will be between 2 and 4 inches of Mercury with a cumulative air flow rate from the treatment area of 1,120 scfm. 6.3. Vapor Treatment Configuration TRS will provide two steam condensers and two VR blowers for the project.As described above,this dual system provides an installed back-up and it also allows VR to continue during maintenance on one of the systems. Each steam condenser will have two cooling towers(four towers total)and includes automated water addition and condensate pumping systems. Two 40-hp vapor blowers with noise-quieting enclosures will exert the overall vacuum on the subsurface. The blowers pull air from the condensers and deliver the air and VOC vapor to one of two treatment methods. The two possible treatment methods are;thermal oxidation and conventional GAC. Each method is described above in Section 3.6. 6.4. Condensate Treatment and Drip The design model estimates that approximately 886,000 gallons of condensate will be produced by the ERH system during the remediation. All condensate will be treated by liquid phase GAC vessel prior to being introduced to the process cooling stream. Process water in the cooling system will be evaporated and any excess process water will be used in the drip system to the electrodes for soil hydration. The evaporation of cooling water and addition of drip water will consume the majority of condensate during the remediation.The drip water will ensure that the soil immediately adjacent to the electrodes remains moist and electrically conductive, as dry soils adjacent to the electrode reduces its efficiency. The average rate of drip to the electrode field will vary for each electrode location. MUR55 Design Report 051914 ad 13 GTRS From past experience and Henry's Law calculations,the concentration of VOCs in any recycled drip water without liquid GAC treatment will be less than 30 micrograms per liter. However, drip used during operation is likely to be transformed back into steam and re-enter the process system. Drip used to moisten the electrodes will be introduced into the top of the groundwater zone (at approximately 25' ft bgs). The two cooling towers are sized adequately for the project and are powered by variable frequency drives. The speed of the cooling tower fans can be adjusted to evaporate between 1.5 and 3.0 gpm to help maintain water balance. This capacity should allow the system to operate without accumulating water for disposal;however a small volume of water will likely remain at the end of the project and total less than 1,000 gallons. The use of a thermal oxidizer will require a sewer discharge with a flow rate of approximately 4 gpm. The water discharged to the electrodes should be below laboratory reporting limits for VOCs. The liquid GAC vessels will have sample ports at the pre-and post-treatment locations to obtain water samples for laboratory analysis, if required. TRS will be responsible for collecting any water samples necessary for permit compliance. 6.5. Temperature Monitoring Temperatures in the subsurface,process equipment, and vapor stream will be automatically recorded and logged daily by the control system and reviewed by TRS personnel. The temperatures from the 14 TMPs within the treatment area will be provided in the weekly status reports. Below is a list of all automatically logged temperatures. • 14 TMPs within the treatment area • Vapor Stream temperatures, including;pre and post condenser,post blower, and treatment system temperatures • Condensate volume production, and blow down volume • PCU enclosure and transformer temperatures • Ambient temperature 7.0 SITE RESTORATION Upon completion of the work, TRS will be responsible for removing all above grade temporary structures,piping, cables, and equipment that TRS placed on the Site. The PCU will be removed from service by Murphy Electric Power Board. TRS will perform demolition and removal of all temporary utility service and meters.All TRS trash and debris will be removed from site or appropriately discarded. All equipment,tools,unused materials, supplies,trash, and debris will be removed from the project site. Procuring abandonment permits and abandoning all thermal remediation wells unless otherwise directed by Northrop Grumman. Removal or in-place abandonment of all subgrade piping and re-compaction and paving will be performed as necessary to provide a neat and finished condition. 8.0 RECORD KEEPING & REPORTING The following briefly outlines the digital and hand recorded records to be kept for this project. 8.1. TRS Data Tracking Program The ERH data tracking program will reside in the PCU and be proprietary to TRS. Data will be downloaded daily for project team analysis and updates. MUR55 Design Report 051914 ad 14 TRS 8.2. Local Data (Hand Data Sheets) The data sheets are to be completed daily when TRS personnel are on site. The hand entered data will be entered into the electronic copies on the same day the data is collected. The hard copies will reside in the PCU office for the duration of the project. The electronic copies will be maintained on the TRS project server site. 8.3. Operations Reporting TRS will submit a weekly operations report to Northrop Grumman that summarizes data from both the TRS tracking program as well as the local data sheets (hand recorded data). The report will summarize weekly changes in parameters such as; electrical power, energy applied,hours of operation, system uptime, system flow rates,temperatures,vacuums/pressures,thermocouple temperatures, applied vacuum,vacuum at monitoring points,groundwater levels,temperature of soil gas transferred to the treatment system, groundwater extraction rate,temperature of groundwater transferred to treatment system,recovered DNAPL quantities(if any),influent sampling results for the soil gas and groundwater treatment systems,VOC mass removal rates, and condensate production. The weekly report will include illustrations of some of these changes in the form of charts and/or graphs. 8.4. Final Report Upon completion of power application, and receipt of the confirmatory analytical results,TRS will prepare a final report that summarizes the ERH system installation, description of the remediation system, description of field procedures(well installation; soil, soil gas, and groundwater sampling activities), copies of as-built drawings,boring and well construction permits with logs,well abandonment permits and records,tables of all the data collected, graphs of temperature,VOC concentrations,VOC mass removal rates with time copies of all laboratory reports,power application to the subsurface over time, subsurface temperatures over time, and CVOC extraction data. 9.0 SAMPLING PLAN 9.1. Vapor Monitoring TRS will conduct compliance monitoring and sampling in accordance with the treatment system permits. At a minimum,this will include weekly influent and effluent samples of the soil gas. 9.2. Groundwater Monitoring TRS will collect monthly groundwater samples from the eight paired-cluster PM wells (16 samples) during thermal operation. The weekly treatment system samples and monthly performance well samples shall be analyzed for VOCs on a 48-hour turnaround time(TAT)by EPA Method TO-15 for soil gas and 5-day TAT by EPA Method 8260B for water. The laboratory reporting limit for the analytes shall be 0.5 parts per billion(ppb)for PCE; TCE; 1,1,1-TCA;1,1-DCE; 1,1-DCA; and cis- 1,2-DCE; 5 ppb for Freon-113; Freon-12; and 1,4-dioxane; and 50 ppb for acetone. Monthly PM well samples shall also be tested for dissolved gases including carbon dioxide,ethene, ethane, and methane by USEPA Method RSK-175. Samples shall be collected using methodology acceptable to the USEPA and NCDENR. After active heating has been completed, subsurface temperatures will remain elevated for several months. TRS estimates that it will take a minimum of 50 days for the site to cool below 80°C,which is the maximum temperature that we believe is safe to collect a grab groundwater sample. It will take MUR55 Design Report 051914 aef 15 GTRS about 150 days for the site to cool to 50°C,which is about the maximum temperature at which TRS would recommend collecting a sample without sample cooling. SOPS for both hot soil and hot groundwater sampling are included in the appendices for the HASP. 9.3. Performance Evaluation Groundwater performance evaluation will be determined by collecting groundwater samples from the eight paired-cluster PM wells at approximately 7 and 21 days after thermal remediation shut down. This period is known as the 30 day performance evaluation period. A total of 16 samples will be collected during each event. The total VOCs for each of the groundwater samples shall not exceed 5,000 ppb. Soil performance samples will be collected during the 30-day performance evaluation period at four boring locations to be determined by Northrop Grumman. Soil samples will be collected from each boring within the treatment zone at 10-foot intervals from 30 to 110 feet below grade.Additionally, one sample will be collected from each boring within 1 foot of the top of bedrock. The four soil borings will be in the vicinity of wells PM-1,PM-2,PM-3, and PM-5. The samples will be analyzed for VOCs as described in section 9.2. TRS will conduct performance evaluation testing as described above to demonstrate achievement of groundwater and soil performance criteria.Evaluation testing shall be performed under Northrop Grumman's supervision. Thermal remediation activity will be determined complete in accordance with performance criteria described in Section 2.0. TRS will wait 5 days after completion notification for Northrop Grumman to determine sample and evaluation validity.Northrop Grumman may choose to extend thermal operations in order to achieve lower cleanup levels. 10.0 SCHEDULE The TRS project schedule is attached as Appendix 6. 11.0 REFERENCES Northrop Grumman,2013. Scope of Work for ERH Remedial Services Former Clifton Precision, Murphy, NC,March. TRS Group, Inc., 2014.PI084 PT Northrop Grumman Murphy, NC 013114acf. MUR55 Design Report 051914 ad 16 TRS Figures MUR55 Design Report 051914 acf 17 TRS PRELIMINARY- DO NOT L—T-k gUSEFOR � NE SHOP Li CONSTRUCTION rvi �" PAEAN-so Fr eos[•aaonry 0 Rue ® m cu mr a 8' v Pcn.a" H' 7r n` v g'' WIPN+Y 9 Gri PAEAN sa0 �inL W,PW 15)'• Apo I s® BUILDING ry' 1 MAIN BUILDING 0 0 G,nAnx I+ ®�®FOIXELECIFCCE NORTHROP GhNUMMAN x TRS ELECTRODE LAYOIJT o 5CV-E IN FEET Y-2 Figure 1. Plot Plan MUR55 Design Report 051914 acf 18 TRS VERTICAL BED ROCK ELECTRODE PRELIMINARY - Rfl NOT ELECTRODE CABLE U SE FOR CROUND SURFACE —— NEAT CEMENT GROUT —— (5 G4L/90 LB) PEX PIPE ——— - 3"CP,C PIPE -_—_ h"SHARKECE COUPLER 3'CPVC FEMALE ADAPTER 3'STAINLESS STEEL SCREEN ]¢"COPPER DRIP TUBE —_—_ 3"CAP .. ..:.:UTE —- -— 2 r 2"X 10.5' STEEL PIPE ——— 2'S=COUPLER ———— :z 2 #3 SAND ——— 2`X 21' STEEL PIPE --- 3 -- 3 ' 4DL 2"SfEE1 CCl1PLER q ' 2'1 21' STEEL PIPE —_— 5 DL q 551 CONDUCTIVE BACEFLL -- 8 (I ' 2"5TEEL CAP -- a ' —— #3 SAND CONDUCTIVE BACKFILL —— METAL PLATE 7 MARBLE BEDROCK S2 GRDUND WATER 9 PORING Wllifl-I EXAGGERATED FOR DETAIL EsTEti)ELECTRODE 10'INTO BEDROCK ALL MATERIAL INSTALLED By TREMMIE 1 OA. BELOW THE WATER TABLE T. TRS VERTICAL BEDROCK Arrekrv!ing�hlue �� ELECTRODE DETAIL rvmu °A4"� u�ras . � M-1 Figure 2a. Electrode Detail Bedrock MUR55 Design Repoli 051914 acf 19 TRS PRELIMINARY- ❑O NOT USE FOR CONSTRUCTION VERTICAL ELECTRODE ELECTRODE CMLE GRD'JND SURFACE NEAT CEMENT GROAT —— i5 GAL/90 A PEx PIPE CWC PIPE Vy- -_—_ h'SH6R1®rTE COUPLER —— Y CM FEMALE A{AFU ——— 3'STAINLESS STEEL SCREEN 'COPPER DRIP TUBE ——_ 3'CAP Scl-'"UTE20,—— 2'X 10.5'STEEL PIPE ——— 2'STEEL COUPLER #3 SAND ——— 2'Y 21'STEIl PIPE -- z 2'STEEL COUPLER 4. 2'K 21'S=PIPE —— 5 CONDUCTNE KKFTLL BY- 2'STEEL CAP 10 O.C. RERrAL S2 GROUND WATER BARING WTDTN DfAGCOWED FOR DETWL WRBLE ALL MATERIAL INSTALLED BY TREMMIE BEDROCK BELOW THE WATER TABLE veerMx .w�esa.iuir�re im •ueMr,xpaix�IXxu TRS `" VERTICAL ELECTRODE DETAIL AUelemiirg lmi:. M-2 Figure 2b. Electrode Detail MUR55 Design Report 051914 acf 20 TRS PRELIMINARY-DO NOT wt.T.nk MACHINE s GB USE FOR Li CONSTRUCTI o o 0 Mft 11-80FTSGS I9,MMW) O O O O Rood O 0 O O O 5 Cutoff G O P.-Pole .�rw�eo � Poo er Pole �. o O�so 0 o LOUPONY GM µ.5g 300 PPM gyp' $P8 FA III (f PMso O 55 FT 9G5)12,325N') ➢ ]GO PPM m �® IPGEHo O O O aw 0 1 m BRLDING S BU ILDING o a o Q 11 iris t o a i°J o Engineering Lab � �no�crs� MAIN BUILDING �,s,a��ad.wooE pa NORTHROP GRUMMAN T � TRS VE ICAL ELEGFRODE LAYOUT A0.YbXRkp lbHnP m f41��. scuE iu Fir a„m Y-3 Figure 3.Performance Well Locations MUR55 Design Report 051914 ad 21 TRS PRELIMINARY- DO NOT VERTICALTUP USE FOR (TYPICAL OF 9) CONSTRUCTION —— 1-,REPK hPE —— I.e�10E0 eY ifs -- i5Wu0iA i»Wr ;!:LITE _—— .f0' I'RVACfO�iRBi —— � Irmnoeomrwm so' —— F —— 65 za' T THBMOCOUPLE F:LE RE�F:..:r•K. 12 GRDUND WATER n,ew IN ADDITION TO INSTALUNC NEW TAPS, THERMXDDPLES HILL BE PLACED IN WELLS BORING MDTH UAGGERATEI' °O RW—TD,GW-58,GW-25,GW-85,AND GW-35 FOR DETAIL AND THEN GRCUIE➢IN PLACE fele�l d1RON IIYGW W FAGutt TRSVERTICAL GPOITEMPERATURE TDETAI A[['�lafofkrp 5k♦u� �� MONITORING POINT DETAIL ocmu °A"' uirrs M_7 Figure 4.TMP Detail MUR55 Design Repoli 051914 acf 22 TRS PRELIMINARY-DO NOT USE FOR CONSTRUCTION REFERTO ORAWINO SHEET L.T _____------ ___ __________________ I i7� � 6 4CRl99Hi ]1 RISLH4R6E TO O10 AL--- ----- — — — -----REFER TODIAWING SHEETP- REFHT TD DRAWING SH REF ER TO ORAWI NG SHEFT PB-- — -- — ---1 r-------------------------� I I I I I I I I I 3 D I I COOLING I mPIL W4) I I _ 15 13 IB BLgM190WN WATER I I I LIRLVIATNG ORIPSW.:IBI I I I I NRIN T I �Inro'R�' a'r'wEus �°�L'R0°E"E'TING I I I I I --------JL-----------------J L------------------------J TRSVPPO PROCOVERY ESS FLOWN AND CONDENSING Ar.�MmlLigt�e, PROCESS FLOW DIAGRAM m P2 Figure 5.Process Flow MUR55 Design Report 051914 acf 23 TRS PRELIMINARY- DO NOT USE FOR CONSTRUCTION Pro[ess SUem 1aaGon tir MAre+Y s LYater LYE Chlorine Afars Tcipaaore Aes�re o�puar a pwrda) L 1 @VAri j W-I nvmm] tff mi iILA—] Lpprr} Pwmial [vwrt] oc ar µrmm baaara�ne] fair aM st=_am from}epor recovery rynem �fm "rig vac oiWurgearfrom contlemer afrer scem removal �fm e"rig vac [aralmw[e tliuharge from cadercvm rcdc 10 psig mrdeoffie tlietlarge af@r 1P.dC 10 peig 9etl airfo raaryloxe hlowm0.1 0 0 Nfd �rargearfmm raary lobe hNas ]}21r Ipcg �argearfromlbemvl vapatreahratsptan0 Nfd moling air inm coaling tower0 m Nfd dir e.baucf trommoiirg lower romp0 0 17 Nfd rtula[ion waterfrom MYea'tlrargertn rod ing'—'_- 1�95 ]fl pag aboling xefxfo or�rrr<r t�ea[entlrariga artl smBNer >.ypp to pag Make�p»a[er for coolingtowa fran pol-�'e murte 15 psig Water fix tlriP s:sfem antl blowtlown ]9 pag Water to tlrip reciralat�s/stem ]!1 p9g Moving'.�afer in tlrip recinvla[im Wstan ]0 pag my water to eiemo�a �ws xPwc7,vnwm. �ws —bba- up water 10 prig wacba aawmwlr waer io paig mnwaoarvmtllanlal rapatrea4nent srotem02 4 0 0 a U 0 D M W Nfd Gstlargexfmmswhher[o amugfree cr xfd t. wc�TnsinacaTmxTafsTwwoTOTrewrwnoN rvualeas PnoPom oNagrrvi. TRS PROCESS FLOW MASS BALANCE nttelemNngwNr ��,e��v P-3 Figure 6. Mass Balance MUR55 Design Report 051914 acf 24 TRS �wrcEcw«snu-m�o�rxuncw.�+w------—as. ?Ul' .wrl r- ————————————————— �� a " ,aa. sru e,u ru r-- L----_______________—Nwmi__J na Fu ,.ru u a a L_________J L__________________ �."e,�2__J L_______J L_______________J a�Eom„xn.",w uxecxexae�nce�,awn.e�rn,emw PRELIMINARY-DO NOT TRS x �w M USE FOR Y kwriny ONE{INE DIAGRAM CONSTRUCTION M-17 Figure 7. One-Line Diagram MUR55 Design Report 051914 acf 25 TRS