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HomeMy WebLinkAboutNC0005088_1-4 Basin Excavation Soil Sampling Plan_20170302DUKE ENERGY,. March 2, 2017 Mr. S. Jay Zimmerman. Director Divi!Jon of Wafer Resources North Car—ulina Departme, it of Ei-ivirnmental Quality o 1 1 Mail Service Center Raleigh, NC 27699-1611 Subject: James. F. Rugars EneNy Complex Units i -zF Inactive /Ash Basin Exceva;ion Soil Sampling Plan Dear Mr. Zimmerman: =u sourm MUM" street mn9u., PC 2M MWIMV— Address: FVMX I= Mai! Cade ECr3x UnalWft, IVU ,?Bzai-100 `W 3/J 3/TJ In accordance with the CCR Surface Impoanameni Ciosare Gaiaelines for Protection of Ground..atu provided by the Diviaiun of Water Rasoarcu3 on NuvGmber 4, 2016, Duke E'nurgy Garulinas, LLC (DEC) has prepared an Excavation Soil Sampling Plan for the Units 1-4 Inactive HsM basin at the Rogers Energy Complex. This plan will be utilized to confirm ash removal from the U,ita 1-41, acti-e Ash Basin and conduit soil sampling that will be incurperated into an opdsied fate and transpoR groundwater model for Rogers Energy Complex. If yuo have any questions an the enclosed infurmatian, please cuntact Ryan Ccup at ryan.czop@tla><e-energy.com or at 980-373-2779. Respectfally submitted, D. Edwin M. Sullivan, PE Director - Waste & Groundwater Programs Environmental, Health & Safety Attachment: E,,caveuiun Suii Sampling Plan Rogers Energy Complex Units 1-4 Inactive Ash Basin ecc: Steve Lamar, NCDEQ Landon Davidson, Ni✓DEu Larry Frust, NCDEQ Ed Mussler, NCDEu Mickey Willuaghby, Dake Energy Phil Mooney. Dake Energy Scott Martin, Duku Energy Ryan Cz-up, Dake Energy EXCAVATION SOIL SAMPLING PLAN ROGERS ENERGY COMPLEX UNITS 1-4 INACTIVE ASH BASIN FOR ASH BASIN EXCAVATION NORTH CAROLINA ASH BASIN CLOSURE DUKE ENERGY CAROLINAS, LLC. 526 SOUTH CHURCH STREET/ECI3K CHARLOTTE, NORTH CAROLINA 28202 � DUKE ENERGY, Waste & Groundwater Programs Revision 0 March 2017 Excavation Soil Sampling Plan March 2017 Rogers Energy Complex Units 1-4 Inactive Ash Basin Revision 0 TABLE OF CONTENTS SECTION PAGE 1.0 PURPOSE................................................................................................................................1 2.0 SOIL SAMPLING METHODOLOGY.............................................................................................1 2.1 Method Summary 1 2.1.1 Equipment 1 2.1.2 Sample Locations 2 2.1.3 Collection of Representative Samples 2 2.1.4 Sample Preservation, Containers, Handling and Storage 3 2.1.5 Decontamination 4 3.0 VISUAL CONFIRMATION OF ASH REMOVAL..............................................................................4 3.1 Pre -Excavation Documentation 4 3.2 Ash Removal Verification Protocol 4 3.2.1 Field Documentation 5 3.2.2 Fill Evaluation Criteria 5 3.3 Visual Removal Not Applicable 6 4.0 SOIL SAMPLING AND ANALYSIS...............................................................................................6 4.1 Soil Sampling 6 4.1.1 Scenario 1 7 4.1.2 Scenario 2 7 4.2 Fate and Transport Modeling 7 5.0 DOCUMENTATION SUMMARY.................................................................................................8 LIST OF TABLE Table 1- Soil Parameters and Analytical Methods LIST OF FIGURE Figure 1 - Rogers Energy Complex Units 1-4 Inactive Ash Basin Page i Excavation Soil Sampling Plan March 2017 Rogers Energy Complex Units 1-4 Inactive Ash Basin Revision 0 1.0 PURPOSE The purpose of this Excavation Soil Sampling Plan is to provide a standardized method for collecting soil samples at Duke Energy North Carolina ash basins that are to be closed via excavation. Soil samples are being collected following all visible ash removal from certain ash basins or other management units referenced in Coal Ash Excavation Plans to support closure activities. This Excavation Soil Sampling Plan is applicable to the collection of representative soil samples. Analysis of soil samples may be chemical or physical in nature and may be used to determine the following: • Extent and magnitude of constituent occurrence • Input concentrations for groundwater fate and transport model The methodologies discussed in this Excavation Soil Sampling Plan are applicable to the sampling of soil in ash basin excavation areas. For the purposes of this plan, soils are those mineral and organic materials remaining after all visible ash has been excavated. 2.0 SOIL SAMPLING METHODOLOGY 2.1 Method Summary This Excavation Soil Sampling Plan has been adapted from Environmental Protection Agency (EPA) Standard Operating Procedures (SOPS) #2012 and #2006; and North Carolina Department of Environmental Quality (DEQ) Attachment 1 Coal Combustion Residuals Surface Impoundment Closure Guidelines for Protection of Groundwater, November 4, 2016. Soil samples are collected directly using stainless steel or plastic trowel, spade, shovel, or scoops. Following collection, soil is transferred from the sampling device to a stainless steel or plastic bowl to be homogenized. Once homogenized, the soil is transferred into Duke Energy Laboratory supplied sample bottles. Soil samples will be submitted under chain of custody for the proper analyses dependent on two scenarios described in Section 4.1 below. Analytical methods for total metals and SPLP metals are described in Table 1. Ash presence is quantitatively determined by polarized light microscopy (PLM) by RJ Lee Laboratory (or other approved vendor). PLM analysis passes visible light through a pair of polarizing filters to create optical effects used in identifying unknown materials. This method is commonly used in asbestos and coal ash identification. 2.1.1 Equipment • Stainless steel or plastic trowel, scoop, spade or shovel — used for collecting soil samples from surface locations. • Sample containers —To be supplied by Duke Energy Laboratory with appropriate cooler(s). Estimated that 5-8 ounce samples bottles with Teflon -lined lids will be Page 1 Excavation Soil Sampling Plan Rogers Energy Complex Units 1-4 Inactive Ash Basin March 2017 Revision 0 required for each sample location and sample depth. For return of cooler to the lab, ice will be required. • Gloves — used for personal protection and to prevent cross -contamination of samples — nitrile, disposable, powderless. • Field clothing and Personal Protective Equipment — used as specified in the site Health and Safety Plan. • Sampling flags — used for identifying soil sampling locations. • Field notebook — a bound book used to record progress of sampling effort and record any problems and field observations during sampling. • Three-ring binder book — used to store necessary forms and record and track samples collected at the site. • Permanent marking pen — used to label sample containers, document field logbooks, data sheets and chain of custody. • Stainless steel or plastic spoon — used for homogenizing soil samples within a stainless steel or plastic bowl. • Stainless steel or plastic bowl — used for homogenizing soil samples, when applicable. • Camera — used for photo -documentation of sample locations and samples. • GPS — device used to obtain elevation, latitude and longitude of sample location. • Trash bag — used to dispose of gloves and any other non -hazardous waste generated during sampling. • Decontamination supplies and equipment. 2.1.2 Sample Locations General locations for soil sampling are determined by the soil scientist in the field at a rate of one soil sample for every 1 acre of ash basin area excavated. Actual sampling locations on-site may vary to account for site conditions and to allow collection of representative samples. Representative samples reflect areas where all ash has been visually excavated and natural soil is observed. 2.1.3 Collection of Representative Samples For the purpose of this plan, discrete surface soil samples are considered to range from 0 to 6 inches in depth while deeper subsurface soil samples will be collected at a range of 2 to 2.5 feet below ground surface (bgs), 7 to 7.5 feet bgs, 12 to 12.5 feet bgs and 17 to 17.5 feet bgs (unless bedrock, refusal, or the water table are encountered). A surface soil sample and deeper subsurface soil samples will be collected at each location for every 1 acre of ash basin excavated Page 2 Excavation Soil Sampling Plan Rogers Energy Complex Units 1-4 Inactive Ash Basin March 2017 Revision 0 when following Scenario 2. A new pair of nitrile gloves is worn at each sampling location and each depth. Each sampling location is recorded on the site map prior to collecting the sample if location is not already noted on the map. The GPS location of each sampling location (i.e. elevation, latitude and longitude), sample descriptions, and area photographs are also recorded. All sampling equipment is decontaminated prior to use irrespective of depth. The following procedure will be used to collect representative soil samples with a scoop, shovel, trowel, geoprobe or excavator: • Locate general sampling locations. • Determine suitability of sampling location for a representative sample. • If sampling location appears to reflect representative conditions that would allow collection of a representative sample, proceed with sampling procedure. If location is not indicative of conditions that would allow collection of a representative sample, notify the project manager so an alternate location can be identified. • Using a decontaminated sampling instrument, remove the desired thickness and volume of soil from the sampling area. The sampler must obtain enough soil to fill five 8 -ounce sample bottles. • Transfer the sample into an appropriate sample or homogenization bowl. Non- dedicated containers should be adequately decontaminated. Stir for approximately one minute until there appears to be a uniform color and consistency. • Transfer homogenized sample to a labeled container(s) of appropriate size and construction for the analyses requested. • Secure sample container tightly. 2.1.4 Sample Preservation, Containers, Handling and Storage Chemical preservation of soils is generally not recommended. Cooling to 4°C on wet ice is usually the best approach, supplemented by the appropriate holding time for the analyses requested. The Duke Energy Laboratory will supply the appropriate sample bottles for the collected soil samples. The sample volume is a function of the analytical requirements and the Duke Energy Laboratory will ensure the appropriate number of bottles are supplied. Ensure chain of custody is completed for sample bottle return to the Duke Energy Laboratory. Table 1 contains a list of parameters to be analyzed with corresponding reporting units and analytical methods. If a parameter or group of parameters is not included in Table 1, the laboratory performing the analysis should be contacted to determine the appropriate sample bottles, volumes, and preservatives. Page 3 Excavation Soil Sampling Plan March 2017 Rogers Energy Complex Units 1-4 Inactive Ash Basin Revision 0 All non -dedicated sampling devices should be decontaminated and wrapped in plastic. The sampling device should remain in this wrapping until it is needed. Each sampling device should be used for only one sample and then decontaminated or disposed of. Non dedicated sampling devices should be cleaned in the field using the decontamination procedure described below. 2.1.5 Decontamination Decontamination procedures can be time consuming; having a sufficient quantity of sampling tools available is recommended. All non -dedicated sampling equipment must be decontaminated prior to reuse. Equipment decontamination consists of: Detergent wash and brush cleaning Tap water rinse Deionized water rinse Air dry Wrap sampling tools with plastic 3.0 VISUAL CONFIRMATION OF ASH REMOVAL 3.1 Pre -Excavation Documentation Closure by removal is defined herein as removing the primary source (primary source of potential constituents of interest) to the point that ash is not visible to the unaided eye at the ground surface. Primary source ash is the main body of ash that was deposited in the basin. This method is intended solely to verify and document primary source ash removal and is not intended to validate environmental quality standards of the subsurface (considered the secondary source of potential constituents of interest). Pre -excavation documentation would consist of: • Review topographic mapping, aerial photography, construction drawings, and boring logs to estimate the pre -ash placement topography and/or ash/soil interface • Preparation of an ash basin figure illustrating a grid spacing of 100 feet (Figure 1). Each grid point (node) will be assigned a unique identifier. Each node of the grid spacing (grid point) will represent a visual verification location. 3.2 Ash Removal Verification Protocol Ash excavation will be considered complete based on visual confirmation that all ash has been removed. Ash removal will be based on sampling of the ash/soil interface and analysis by PLM. Soil samples will be examined utilizing methods outlined in American Society for Testing and Materials (ASTM) D2488, Standard Practice for Description and Identification of Soils (Visual -Manual Procedure). Vertical and horizontal excavation of ash can terminate when the remaining material can be documented using PLM to contain less than SO% ash. Page 4 Excavation Soil Sampling Plan Rogers Energy Complex Units 1-4 Inactive Ash Basin March 2017 Revision 0 Project will excavate ash until a visible change in color or texture confirms removal. This location shall be referred to as the ash/soil interface. If visual evaluation is inconclusive, then request additional evaluation to confirm ash removal. 3.2.1 Field Documentation Evaluate the excavated surface elevation relative to the pre -ash placement topography. Periodically check bottom elevation to evaluate if fill is present above historic bottom elevation. Visual confirmation will be performed on a 100 foot grid system (Figure 1) unless conditions prevent such confirmation, as described in Section 3.3. Soil sampling will be performed on an acre grid system and will be analyzed using PLM. • Personnel will locate each node by GPS or survey control, determine elevation and evaluate whether that point is above or below the historic bottom elevation. Personnel will then observe the surface area represented by the node to note if visible ash is present at the surface. If present, the location should be documented and excavation will need to continue. If the evaluation indicates the surface soils are residuum or bedrock, then hand auger to two feet below surface (or refusal) and perform visual -manual classification of the soils at the surface and depth according to ASTM method D2488. Submit sample from surface and depth (or shallower if refusal) for PLM analysis. The conditions shall be documented by taking photographs. The classification indicator for fly ash will be grey to black silt -sized particles with no plasticity. The classification indicator for bottom ash will be grey to black sand to gravel sized particles and porous. If the material can not be positively identified as soil, submit a sample for PLM analysis. If the node point elevation is near the historic bottom elevation and either (1) residuum is indicated by observation or (2) soil is confirmed by visual manual classification (ASTM D2488) and PLM analysis is less than 50%, then personnel can conclude the primary source is removed. 3.2.2 Fill Evaluation Criteria The following procedure provide an approach that can be used to ascertain if the fill can remain in place. The procedure specified is based on the fill material and depth. • If the elevation is less than eight feet above the historic bottom elevation and residuum is not observed, then test pits may be excavated to historic bottom elevation or until residuum or bedrock is encountered but no more than eight feet below the surface. o Personnel will evaluate existing information to determine if the test pits are necessary. If necessary personnel may recommend excavating test pits at a frequency no tighter than 100 feet by 100 feet. o If visible ash is not discovered based on information defined above, then the primary source removal may be confirmed. o If visible ash is discovered, then continue excavation. Page 5 Excavation Soil Sampling Plan Rogers Energy Complex Units 1-4 Inactive Ash Basin March 2017 Revision 0 • If the elevation is more than eight feet above historic bottom elevation and residuum is not observed, discuss with CCP Closure Personnel. o CCP Closure Personnel will confirm historic information and recommend a drilling and sampling program at a frequency no tighter than 100 feet by 100 feet to evaluate the presence of ash below the fill in accordance with the information defined above. If unusual features are revealed by the drilling, CCP Closure Engineering may request/recommend additional borings. Exploration is to be performed by continuous sampling during drilling. o If visible ash is not discovered based on information defined above, then the primary source removal may be confirmed. o If visible ash is discovered, then continue excavation. 3.3 Visual Removal Not Applicable If possible, excavation of ash should continue even if groundwater is encountered. Visual documentation cannot be completed where ash is under the water table. If Duke Energy cannot complete visual removal because of site conditions or other restricting factors, documentation shall be presented to DEQ. Duke Energy anticipates that in locations where visual documentation cannot be completed, additional ash characterization along with groundwater fate and transport modeling will be completed. Ash characterization may consist of SPLP and/or other testing with results imputed into an updated site wide groundwater fate and transport model. Details will be provided to DEQ for review and concurrence. 4.0 SOIL SAMPLING AND ANALYSIS 4.1 Soil Sampling Soil sampling of the remaining soils (less than 50% ash per PLM analysis) will be necessary to evaluate the extent of potential secondary source depending on the depth of the water table and any proposed institutional or engineering controls that may be used in the area of excavation. Soil sampling will not be required if refusal or the top of bedrock are encountered or the remaining soils are below the water table. Soil samples for laboratory analysis must be collected in a manner that will ensure a relatively uniform distribution of particles throughout the six inch sample. The systematic approach and design for soil sampling an analysis is dependent upon two scenarios: • Scenario 1: Remaining soil (containing less than 50% ash per PLM analysis) is located above the seasonal high water table and final constructed institutional and/or engineering controls will restrict infiltration from the surface reaching the water table (e.g. installation of a liner system). Scenario 2: Remaining soil (containing less than 50% ash per PLM analysis) is located above the seasonal high water table and infiltration from the surface would continue to reach the water table. Page 6 Excavation Soil Sampling Plan Rogers Energy Complex Units 1-4 Inactive Ash Basin 4.1.1 Scenario 1 March 2017 Revision 0 Confirmation sampling will include discrete surface samples collected from the first six inches of the soil. Sampling will be performed on an acre grid system. This sample collection methodology shall be sufficient to characterize the horizontal extent of any remaining potential secondary source impacts for comparison with the DEQ Preliminary Soil Remediation Goals (PSRG). The samples shall be analyzed by a North Carolina certified laboratory for total concentrations for the following parameters: antimony, aluminum, arsenic, barium, beryllium, boron, cadmium, calcium, chloride, chromium (total and hexavalent), cobalt, copper, iron, lead, magnesium, manganese, mercury, molybdenum, nickel, nitrate as nitrogen, pH, potassium, selenium, silver, sodium, strontium, sulfate, thallium, vanadium and zinc. No SPLP testing is required. 4.1.2 Scenario 2 Confirmation sampling will include collection of both discrete surface and subsurface soil samples performed on an acre grid system. Discrete surface samples will be collected from the first six inches of the soil and a subsurface soil sample will be collected at 2 to 2.5 feet below ground surface (bgs), 7 to 7.5 feet bgs, 12 to 12.5 feet bgs and 17 to 17.5 feet bgs unless refusal, bedrock or the water table are encountered. The use of a geoprobe or excavator is anticipated. This sample collection methodology shall be sufficient to characterize both the horizontal and vertical extent of any remaining potential secondary source impacts for comparison with the DEQ PSRGs and/or input into the soil leachate model. The samples shall be analyzed by a North Carolina certified laboratory for both total concentrations and SPLP for the following parameters: antimony, aluminum, arsenic, barium, beryllium, boron, cadmium, calcium, chloride, chromium (total and hexavalent), cobalt, copper, iron, lead, magnesium, manganese, mercury, molybdenum, nickel, nitrate as nitrogen, pH, potassium, selenium, silver, sodium, strontium, sulfate, thallium, vanadium and zinc. 4.2 Fate and Transport Modeling Contingency for stabilization of remaining amounts of potential secondary source impacts in a manner that will meet the intent of North Carolina Groundwater 2L Rules and closure requirements shall be considered as site conditions dictate. Provisions to develop groundwater flow and transport models to evaluate protection of groundwater criteria if some secondary source impacts are left in place shall be considered. In addition, the possibility of metals leaching from a potential change in pH and geochemical conditions related to dewatering and excavation shall be considered along with plans for groundwater models to assess resulting site conditions. Page 7 Excavation Soil Sampling Plan March 2017 Rogers Energy Complex Units 1-4 Inactive Ash Basin Revision 0 5.0 DOCUMENTATION SUMMARY 100'x 100' Grid Node (Figure 1) Visually confirm primary source removal and document with photographs Soil Sample Collection at a Grid Node (1 Per Acre) Depth/Test PLM Total Metals (Table 1) SPLP (Table 1) 0— 6 inches X X X 2' — 2.5' X X X 7' — 7.5' N/A X X 12'— 12.5' N/A X X 17'— 17.5' N/A X X Page 8 Excavation Soil Sampling Plan Rogers Energy Complex Units 1-4 Inactive Ash Basin Table March 2017 Revision 0 Excavation Soil Sampling Plan Rogers Energy Complex Units 1-4 Inactive Ash Basin TABLE 1 SOIL PARAMETERS AND ANALYTICAL METHODS TOTALS AND SPLP ANALYSIS NORTH CAROLINA ASH BASINS TO BE CLOSED VIA EXCAVATION March 2017 Revision 0 INORGANIC COMPOUNDS UNITS METHODI Aluminum mg/kg or µg/I EPA 6010D Antimony mg/kg or µg/I EPA 6020B Arsenic mg/kg or µg/I EPA 6020B Barium mg/kg or µg/I EPA 6010D Beryllium mg/kg or µg/I EPA 6020B Boron mg/kg or µg/I EPA 6010D Cadmium mg/kg or µg/I EPA 6020B Calcium mg/kg or µg/I EPA 6010D Chloride mg/kg or µg/I EPA 9056A Chromium mg/kg or µg/I EPA 6010D Cobalt mg/kg or µg/I EPA 6020B Copper mg/kg or µg/I EPA 6010D Hexavalent Chromium mg/kg or µg/I EPA Method 7199/218.7 Iron mg/kg or µg/I EPA 6010D Lead mg/kg or µg/I EPA 6020B Magnesium mg/kg or µg/I EPA 6010D Manganese mg/kg or µg/I EPA 6010D Mercury mg/kg or µg/I EPA Method 7470A/7471B Molybdenum mg/kg or µg/I EPA 6010D Nickel mg/kg or µg/I EPA 6010D Nitrate as Nitrogen mg/kg or µg/I EPA 9056A pH SU EPA 9045D Potassium mg/kg or µg/I EPA 6010D Selenium mg/kg or µg/I EPA 6020B Silver mg/kg or µg/I EPA 6020B Sodium mg/kg or µg/I EPA 6010D Strontium mg/kg or µg/I EPA 6010D Sulfate mg/kg or µg/I EPA 9056A Thallium (low level) (SPLP Extract only) mg/kg or µg/I EPA 6020B Vanadium mg/kg or µg/I EPA 6020B Zinc mg/kg or µg/I EPA 6010D Notes: 1. Soil samples to be analyzed for Total Inorganics using USEPA Methods 6010/6020 and pH using USEPA Method 9045, as noted above (or similar approved methods). Soil samples will also be analyzed for leaching potential using SPLP Extraction Method 1312 in conjunction with USEPA Methods 6010/6020 (or similar approved methods). Excavation Soil Sampling Plan Rogers Energy Complex Units 1-4 Inactive Ash Basin Figure March 2017 Revision 0 Excavation Soil Sampling Plan Rogers Energy Complex Units 1-4 Inactive Ash Basin Figure 1— Rogers Energy Complex Units 1-4 Inactive Ash Basin March 2017 Revision 0 FIGURE 1 1 aP /f i � i c M i� a ASH BASIN CLOSURE - REMOVAL OF ASH r ._ -. �•Eoster ROGERS ENERGY COMPLEX -CLEVE-047 ASH REMOVAL ASSESSMENT FT GRIO -100 E EON ��L1>, FIGURE 1