### ENGINEERINGAND ENVIRONMENTAL GUIDANCE ONTHEBENEFICIALUSE OF COALCOMBUSTIONPRODUCTS INENGINEERED STRUCTURALFILL PROJECTS
Purpose Statement: This document is intendedto provide Coal Combustion Product (CCP) Managers with information to ensure that CCP engineered structural fills are planned and implemented in a mannerthatprotects the environment and meets regulatory requirements. 

### Scope: This information is intended to be used in planning and implementing engineered structural fill projects associated with the beneficial use of"coalcombustion products" including fly ash, bottom ash, boiler slag, or flue gas desulfurization (FGD) material produced primarily from the combustion ofcoal. 1 Engineered structural fill projects consist ofeither an engineered fill or an engineered embankment with a beneficial end use. 2 Engineered structural fills are typically constructed in layers ofuniform thickness and, where appropriate, compactedto a desired unit of density in a mannerto control the compressibility, strength, and/or hydraulic conductivity ofthe placed material. The generic issues and examples in this Guidance are designed solely to be an educational resource for CCP Managers by illustrating the requirements and considerations thatmay applyto engineered structural fill projects and should be taken into consideration depending onthe quantities ofash used atthe site. The Standard Guide for Design and Construction ofCoal Ash Structural Fills designated ASTM E2277-03 is incorporated herein byreference. Each CCP project shouldbe evaluated for site-specific requirements including all permitting requirements and the project should be appropriately described. 

### Characterization/Testing: CCPs should be adequately characterizedto ensure thatthe proposed use ofthe material does not cause environmental orpublic health problems and has physical properties that are compatible with the end use. The characterization, atminimum, should demonstrate the physical characteristics, including geotechnical properties, and identifY the primary chemical constituents ofthe CCPs and leaching potential. CCPs should also be sampled and analyzed to verifY thatthe materials meet the applicable regulatory standards for beneficial use. CCP leach testing procedures should be selected based on the material used, hydrogeologic setting, and structural fill application. See Appendix 1 for a reference to guidelines for potentially applicable leaching tests. For assessing engineering properties ofthe CCP, referto ASTME-2777.

1 Fly ash andbottom ash includes both materials produced by "conventional units" as well as fluidized bedboilers. 2 Examples ofengineered structural fill projects include use as fill for building sites and foundations, subbase fill for recreational facilities, and as embankments for highways, railroads, dikes and levees.Samples should be representative ofthe CCPs supplied for the engineered structural fill. See Appendix 2 for a reference to guidelines for collecting a representative sample. The frequency at which the CCPs should be tested is dependent on the variability ofthe composition ofthe CCPs.3
Moisture content ofthe CCPs shouldbe evaluated in orderto determine whether additional moisture is neededto condition the ash to help control fugitive dust and to enhance compaction. Project Suitability/Qualification: In addition to meeting all applicable state standards and guidelines, identifying a suitable site for an engineered structural fill using CCPs should include an evaluation ofthe site commensurate with the leaching potential ofthe CCPs, considering such factors as local zoning and land use plans, environmental characteristics ofthe proposed site, engineering aspects, and proximity to and relationship with landowners and neighbors. The historic use ofthe potential site and adjacent properties should be evaluated to assess whether there is potential for existing contamination atthe site. In addition, consideration should be given to the reasonable future uses orplanned development ofthe site and surrounding properties, including the distance betweenthe potential site and adjacentproperties. The soil, geology and groundwater ofthe proposed site should be evaluated. The site geology shouldbe assessed for the presence ofany conditions such as sinkholes, karst, orbedrock outcrops. Groundwater quality and quantity, the location ofgroundwater users, groundwater flow direction, and depth to the groundwaterwill be important considerations in the process. The evaluation should be done in a manner consistentwith ASTME 2277-03. 

### See Section 7.2 Site Characterization. Groundwater modeling is not typically necessary for hydrogeologic characterization in support ofa structural fill plan. However, in some cases, particularly larger fills, modeling may be useful in evaluatingthe potential for groundwater impacts. Screening models such as EPA's IWEM and EPRI'sMYGRT are typically sufficient given the nature ofthe sites and limited availability ofhydrogeologic data. Numerical models such as MODFLOW/MT3D are generally not warranted for these applications, except for very large sites in complexhydrogeologic environments. Briefdescriptions ofthese models are provided in Appendix 3. The site should also be evaluated in relationship to its distance from surface waters, including wetlands, and the location offloodplains and other environmental regulatory constraints that couldpotentially impactthe project. While site specific factors including size, rainfall, climate and terrain should always be considered, other considerations involving the location ofthe proposed engineered structural fill project include whether the site is:

• Within floodplain, floodways and ·drainage areas, • In ornear a wetland area, • Near an active fault,

3 Additional testing should be conducted when conditions changethat could significantly impact constituent concentrations in the CPP such as, for example, through the use boiler additives and/or changes in coal source or type. -2- DC2DOCS1-#1007872• In an unstable area 

### (e.g., in a karst area or areas prone to sinkholes), • Within a wellhead protection area, • Near a drinking water well, ornear a public water supply, such as a community well, reservoir, orwatertreatment facility, • Near a surface-waterbody, such as a lake, stream, river, or pond, or • An impact on a critical habitat for an endangered orthreatened species or an historic or archaeological site. The landowner(s) should provide written permission for using CCPs onthe site. As appropriate, the presence ofCCPs should be acknowledged on the deedto provide notice to subsequent purchasers ofthe site. Current site conditions and engineering and economic considerations, as well as the intended future use ofthe property, should be analyzed to ensure the material can beplaced in a manner that will achieve needed structural stability. The ability ofequipmentto move on and around the site should be evaluated especially ifa project will extend over months in which inClement weather is expected. Onand offsite traffic limitations should be considered. Agency Communications: The state or local government agency responsible for administering the program for beneficial use ofCCPswill vary depending onthe nature ofthebeneficial use. Site requirements for structural fill projects will also vary by locality. Where appropriate, details ofthe proposed structural fill should be discussed with the appropriate agency for their input. These steps maybe useful during and after any project. 1. Draft a plan for the proposed engineered structural fill and identify the agency responsible for approving the structural fill ifapproval is required. 2. Contactthe appropriate agency staffto discuss the proposed engineered structural fill project when the detailed plan is complete and approval is required. 3. Provide the lead agency and otherregulatory bodies with information they require to understand the project. 4. Follow-up to ensure the project is meeting State and local government and community requirements. Maintain an active dialog with all parties and document all material discussions. Community Outreach: As appropriate, CCPManagers should contact local community officials and offerto meetwith them to provide information and answer questions thatthey may have aboutthe proposed project. After the operations commence, the CCP Manager should remain in contactwith the local officials and offer to meet with them periodically to provide a project update and to answer questions that may be raised. Local officials should beprovided with a contact name, address and telephone number thatthey may use to inquire aboutthe ongoing project. 

### -3- DC2DOC51-#1007872ContractorPerformance Standards: CCP Managers should considerthe reliability, performance history, compliance and safety records ofany potential contractor. The contractor selected should have proven technical capabilities and experience with CCP placement. The potential contractor's financial resources and financial stability shouldbe assessed priorto signing a contract, to ensure thatthe contractor has the ability to fulfill the obligations ofthe contract. The contract should include conditions requiringthe contractor to comply with all local, state and federal highway regulations during hauling ofthe CCP, and all local, state and federal environmental and occupational safety and healthregulations during all ofits operations. It should also address how the contractor's performance will be assessed. Oversight ofcontractor performance should be ongoing. Transportation on Public Roadways: Possible community concerns associated with transportation routes should be identified, reviewed and properly addressed prior to project implementation. Access routes to the project site should consider:

• Impact onlocal communities. • Road conditions. • Timing oftransportation. • Volume oftraffic. • Noise. • Vehicle operational condition and cleanliness (free ofdust and dirt). Drivers or other personnel should ensure thatvehicles are loaded and unloaded in a mannerthat minimizesthe generation ofdust and should ensure that all trucks are covered while in transit. Vehicles mustbe operated and maintained in a safe working order and in compliance with all applicable federal, state, and local requirements. They should not negatively impact road conditions or safety, especially at project ingress and egress locations. For examples, see Appendix 3. Project Operation Controls and Security: Site Access Controls- To the extentpossible, access controls should be utilized atthe placement site to discourage unauthorized entrance to the site. Controls should be implementedto ensure appropriate pickup and delivery ofCCPs. The construction ofengineered structural fills should follow the procedures described in Sections 7.7.6 & 8 "Construction" ofthe ASTM E 2277-03 Standard Guide for Design and Construction ofCoal Ash Structural Fills. The ASTM standard includes operating procedures for weather restrictions, dust control, erosion control, source and delivery, on-site storage, site preparation, placement and compaction, cover and quality control. These standards are incorporated herein byreference.

-4- DC2DOCS1-#1007872Spill/Off-Site Release Response: Trucks hauling CCPs onpublic roadways should have a Material Safety Data Sheet and should be responsible for responding to spills. All CCPs spilled during transit shouldbe cleaned up and eithertaken to the placement site orreturned to the plant oforigin. A plan should be developed for potential off-site releases. The plan should identify the individual who is responsible for implementingresponse actions and notifying appropriate regulatory officials, contact information for response assistance, procedures to follow in the event ofan offsite release, and an inventory ofresponse equipment/services. Inthe event ofan off-site release, all discharges ofCCPs shouldbe cleanedup and returned to the placement site.

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### APPENDIXl Characterization/Testing: Examples ofleaching procedures: • EPA SW846Method 1313- 1316, Methods 1313 through 1316 are a recently developed set ofprocedures designedto fully evaluate leaching potential under a wide range ofpotential environmental conditions, sometimes collectivelyreferred to as the Leaching Framework. The framework includes batch leaching as a function ofpH (1313), column leaching (1314), mass transfer leaching for monolithic materials (1315), and batch leaching as a function ofsolid-liquid ratio (1316). Selection oftests depends on the CCP material and the expected range ofenvironmental conditions associated with the structural fill application. • EPA SW846Method 1312, Synthetic PrecipitationLeachingProcedure (SPLP) The SPLP is a single pointbatch leachingtest similar to the TCLP butuses a nitric and sulfuric acid leachantto simulate acid rain. SPLP is commonly used to assess infiltration and leaching at CCP sites. • ASTMD3987, Shake Extraction of Solid Waste with Water ASTMD3987 is a single pointbatch leaching test similarto the SPLPbutuses a deionized water leachant. ASTM D3987 is commonly used to assess infiltration andleaching at CCP sites. 

### APPENDIX2 CollectingRepresentative Samples: Examples ofreference guidelines for collecting a representative sample. • EPA SW846 TestMethods for Evaluating SolidWaste, Physical/Chemical Methods http://wvvw.epa.gov/epaoswer/hazwaste/test/sw846.htrn • ASTM D75 Practice for Sampling Aggregates • ASTM C311 TestMethods for Sampling and Testing Fly Ash orNatural Pozzolans for Use as a Mineral Admixture in Portland-Cement Concrete. 

### APPENDIX3 Site Modeling Tools • IndustrialWasteManagementEvaluation Tool ("IWEM") IWEM (USEPA, 2002) was developed by EPA as a screening tool to evaluate industrial waste disposal and use applications. IWEM is easyto use and can be run with very little sitespecific hydrogeologic data. The core model in IWEM is the EPACMTP (USEPA, 2003) analytical model, which simulates the migration ofdissolved constituents through soil and groundwater. The model accepts input values describing geology and infiltration atthe site, and then performs a Monte Carlo analysis using a range ofvalues for attenuation parameters and hydrogeologic parameters, producing over 10,000 realizations. For each ofthe Monte Carlo realization, IWEM allows up to 10,000 years to reach a maximum concentration. Outputfor individual realizations are not provided. A facility design is deemed "protective" if90 percent ofthe IWEM realizations predict maximum concentrations atthe compliance pointthat are lowerthan the appropriate health-based number orwater quality standard. 

### • MYGRT MYGRTVersion 3.1 (EPRI, 2005) is a collection of22 analytical models that calculate the transport oforganic or inorganic constituents in the unsaturated and saturated zone, accounting for the processes ofadvection, dispersion, retardation, and decay. All ofthese models are based on analytical solutions to the 1D, 2D, and 3D mass transport equations. Inputs are specified by the user, and output is provided for each set ofinputparameters -6- DC2DOCS1-#1007872provided. The model will accepttime-varying leachate concentrations, and can be run for any length time period. MYGRT is easyto use andrequires minimal or estimated sitespecific data; it is most appropriate for screening level applications and relatively simple hydrogeologic settings. • MODFLOW/MT3D MODFLOW is a numerical groundwater flow code developed by the United States Geological Survey (McDonald and Harbaugh, 1988) that uses a finite difference approximation to solve a three-dimensional head distribution in a multi-layered aquifer. The program also calculates waterbalance at wells, rivers, and drains. MT3DMS (Zheng and Wang, 1998) is a transport code that uses a finite difference solutionto calculate concentration distribution for a single dissolved solute as a function oftime and space. MT3DMS accounts for advection, dispersion, diffusion, first-order decay, and sorption. Sorption can be calculated using linear, Freundlich, orLangmuir isotherms. MODFLOW/MT3D are relatively time consuming codes to setup and calibrate, and are most applicable for large sites with complex and well characterized hydrogeology. 

### APPENDIX4 Transportation on Public Roadways: Examples to consider: 1. Ensure vehicles, company and contractor, are in safe working order and associated inspections are up-to-date. 2. Ensure contractors are adequately insured. 3. Investigate compliance history ofcontractors. 4. Ensure proper vehicle washing at loading and unloading areas. 5. Proper vehicle covering: • The cover mustbe made ofa solid or close weave mesh material. • The covermustbe large enough to enclose the top ofthe entire load. • The cover mustbe sufficiently secured. • The cover mustbe kept in good repair 6. Ensure proper construction and maintenance ofaccess and egress points to public roadways. This could include construction oftemporary roadways and use offlagmen or othertraffic flow devices. 7. Evaluate whether water mustbe addedto conditionthe ash to help control fugitive dust.

-7- DC2DOCS1-#1007872References

USEPA, 2002. Industrial Waste ManagementEvaluationModel (IWEM) TechnicalBackground Document. Office ofSolid Waste and Emergency Response, EPA530-R-02-012.

USEPA, 2003. EPACMTP TechnicalBackgroundDocument. Office ofSolid Waste and Emergency Response, EPA530-R-03-006.

McDonald, M.G. and A.W. Harbaugh, 1988,A Modular Three-DimensionalFinite-Difference Ground-WaterFlow Model: Techniques of Water-Resources Investigations, Techniques of Water-Resources ofthe United States Geological Survey, Book6, ChapterAI.

Zheng, C., and P.P. Wang, 1998,MT3DMS, A Modular Three-DimensionalMultispecies TransportModel, Model documentation and user's guide prepared by the University ofAlabama Hydrogeology Group for the U.S. Army Corps ofEngineers.

EPRI, 2005. MYGRT Version 3.1. EPRI, Palo Alto, CA: 2005. 1010066

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