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# AUG 23 2010 1600West 56Highway " Oiathe, Kansas 66061 " (913) 715-5300 " Fax- (913) 715-2453 

### Environmental Protection Agency Mailcode: 5305T 1200 Pennsylvania Ave., NW . Washington, DC 20460 Hazardous Waste Management System Identification and Listing of Special Wastes; Disposal ofCoal Combustion Residuals fromElectric Utilities Docket, Attention Docket ID No., EPA-HQ- RCRA-2009-0640 August 17, 2010 To Whom

It May Concern: Johnson County Kansas Department of Public Works wishes to submit comment to the EPAregarding the beneficial use ofcoal ash as a construction material . The EPA is proposing to regulate for the first: time, coal combustion residuals (CCRs) under the Resource Conservation and Recovery Act (RCRA) to address the risks fromthe disposal of these materials. This regulation would increase costs ofconstruction ofcounty transportation projects. Johnson County Kansas Department of Public Works endorses the attached summary ofthe benefits prepared for the City ofOverland Park by Bob Parsons, PhD, P .E. and Ed Peltier, PhD, both with the University of Kansas. The City of Overland Park is within Johnson County Kansas and benefits seen by Johnson County Kansas are similar to those documented in the report for the City ofOverland Park. Coal ash is a valuable construction material used in both the production ofconcrete and soil stabilization. Should the EPAdetermine that some or all CCRs to be hazardous waste, we support the continuation of the Bevill exemption for beneficial uses. If the CCRs are considered hazardous wastes, this will increase costs to municipalities, whichwill reduce the competitiveness of CCRs for use in construction. More importantly, it must be clear in the regulations that products made using CCRs are new products and not considered hazardous wastes, and may be treated in the same manner as similar products made without CCRs. Any uncertainty with regard to the ultimate regulatory status ofthese products will greatly discourage their continued use, given the very large demolition and disposal costs associated with hazardous wastes. Should the EPAhave any further questions or comments, please contact me by phone at (913)-715-8300 or by email at Mac.Andrewgjoco og v.org. Sincerely, 

# Lvt~ AUG 18 2010 Mac Andrew, P

.E. Director of Public Works and Infrastructure Johnson County KansasAugust 3, 2010

Mr . Michael S. Ross, P.E. Manager, Technical and Administrative Services Cityof Overland Park Overland Park, Kansas RE: Summary of the Benefits of Coal Ash for Construction of Urban Projects Dear Mr . Ross: Per your request, we have prepared this letter describing the uses of coal ash for urban construction and the difficulties additional regulation could pose to their continued use. Coal ash is an important construction material with unique properties thatwould be difficult and expensive to replace. Two forms of ash are used in this region; self-cementing Class Cfly ash and non self-cementing Class F. Class Cash is used for soil stabilization, flowable fill and concrete while Class F is used as an additive in flowable fill and concrete in our region. Benefits for each use are as follows : Soil Stabilization Benefits Self-cementing Class Cfly ash' is widely used as a soil stabilization agent for subgrades beneath pavements, parking lots, and building pads in the Kansas City area and throughout the Midwest . The major alternative stabilization materials are lime and cement . Fly ash is typically blended with existing soil to a depth of 6-18 inches at a rate of 8-16%byweight2 . Specifications for Overland Park, Kansas typically require eight inches of treatment with 15%ash by weight . Class Cfly ash consumes excess water as it hydrates, reduces the shrink/swell potential, and increases the strength of the soil3. An example of specifications for the use of Class Cash is available fromthe Kansas Department ofTransportation4. Strength gains fromincorporation of Class Cash are significant. Research published by Parsons and Milburn showed increases in strength of 190-480%percent for a range ofsoil types when mixed with a particular Class Cfly ashs and compacted. Additional research on subgrades beneath urban streets in service for up to nine years showed that stabilized soil layers were 40- 250%stronger than the natural soils below3. Strength gains frommixing Class Cash with soil occurvery quickly and the resulting stabilized soil may be paved on within a day, while lime stabilized soil requires multiple additional construction steps and may require a week of curing time before paving can bedones. For many urban projects the additional construction time associated with the use of

lime will impose substantial user costs (traffic delays and detours) on the public and leave cement as the only realistic alternative. Risks We believe the risks associated with the use offly ash in subgrades are low . The potential risks associated with the use of coal combustion products (CCPs) identified by the EPA are structural failure through the CCPs or CCP retention structures, and leaching of metals fromthe ash. Due to its self-cementing properties, use of Class Cfly ash increases soil strength and reduces the potential for a structural failure when compared with natural soil . The relatively small amount (15%of a 6-18 inch layer) limits the volume of source material available for leaching; and the construction of a lowpermeability (paved) surface above the stabilized soil limits the volume of leach water that will pass through the stabilized soil . While the metal content of manyfly ash materials is a potential cause for concern, most available studies have shown that there is minimal leaching from fly ash amended into soil' . In particular, Class Cfly ashes, because of their self-cementing properties, are likely to see minimal availability of metals for subsurface transport . It should also be noted that none of the documented cases of environmental damage cited by the EPA in the proposed regulation are related to the use offly ash for soil stabilization as described here. Additionally, the risk assessment prepared for this proposed regulation did not address beneficial use scenarios. At this point, there is no direct evidence that fly ash use for soil stabilization for subgrade material has had a negative impact on the surrounding environment . When contrasted with the significant environmental benefits that can be obtained frombeneficial use offly ash materials, the weight of available evidence argues for continuing the use offly ash materials for soil stabilization. 

### Flowable Fill Benefits Flowable fill is a product with special properties that would be difficult to duplicate without fly ash. Flowable fill is self cementing product composed offine aggregate (usually sand), cement, fly ash, and water in various proportions. Fly ash is included in flowable fill because its spherical shape enhances flowability during product placement . Fly ash can also be used to replace some of the cement if it is self-cementing. Ash or other CCPs can also be used replace aggregate as filler in the mix2. Flowable fill is mixed at a ready-mix plant and delivered to the site like regular concrete. During placement it pours as a liquid and is self leveling. After placement it solidifies quickly to forma solid mass. Flowable fill may be designed to be a high strength or lowstrength product, where the low strength product (Controlled Low Strength Material, or CLSM) is designed to be removable with commonly available equipment such as a backhoe. It is typically designed to have a 28-day strength of 150to 200psi2, and has a maximum strength specification of 100psi for Kansas Department ofTransportation (KDOT) projectss. It is especially useful as fill around objectssuch as pipes beneath roadways where compaction of soil is slow and difficult. The flowable fill fills even the small, difficult to reach voids as it is poured around these structures and cures very quickly. It can essentially eliminate the potential for settlement around these structures which makes it a superior option to conventional compaction of soil . Use of flowable fill also reduces user costs (traffic delays and detours) because its use makes it possible to reopen streets closed for construction more quickly than would be possible if the fill around pipes and other structures beneath streets were to consist of soil compacted manually, which is the primary alternative to flowable fill . The low strength of CLSM

makes it possible to easily remove the fill if access to the structure is required at a later date, which makes it superior to the use of conventional concrete for this purpose. The advantages of using flowable fill have led cities such as Overland Park to require its use for the backfilling ofall utility trenches within the public right-of-way. Risks We believe the risks associated with the use of flowable fill are low . The product is much stronger than soil and the fill is essentially self-encapsulating, thus limiting the potential for metals to be leached fromthe material . As with soil stabilization, there are no specific cases presented by the EPAwhere fly ash in flowable fill has led to negative environmental impacts, and available studies of metal leaching fromthis material indicate thatwhat leaching does occur is at sub-toxic levels9. Most soils found in northeastern Kansas are also relatively clayey and slightly alkaline pH, which will also limit the transport of those metals that do leach from the fill material over time. In addition, flowable fill will normally have some type of cover, usually pavement, reducing the infiltration of leach water. Concrete The EPA recognized the benefits of using CCPs as a substitute for cement in the proposed rule. We agree that use of CCPs in concrete is beneficial in reducing owner construction costs, improving concrete durability, reducing the use ofvirgin materials, and reducing generation of greenhouse gases during the conversion of those virgin materials to cement . We believe the risks to the publicfromthe use of fly ash as an additive in concrete is very low for the reasons identified by the EPA

. Class F ash is particularly beneficial when used in concrete in our region because it mitigates alkali-silica reaction problems and lengthens the life of the concrete. Impact ofAdditional Regulation The EPA is considering several courses of action regarding the additional regulation of CCP products. Several of these actions will make it more difficult to impossible to continue to use CCPs for the purposes described above. Given the beneficial characteristics of self-cementing Class Cfly ash in particular, our viewis that it should be considered a product of the coal combustion process in the same way the EPAviews synthetic gypsum used for wallboard and not viewed as a waste.The EPA has documented that some CCPs pose a hazard, however in the EPA's proposed

rule it is clear that leaching rates varywidely among CCPs. Our view is that CCPs should only be classified as a hazardous waste based on specific waste characteristics so that CCPs with low leaching potential may be demonstrated to be nonhazardous by testing. This approach would also address issues that could arise fromfuture changes in fly ash composition (such as higher ammonia content) caused by implementation of NO, removal strategies. If the EPA determines that some or all CCPs are to be considered hazardous wastes, we support continuation of the Bevill exemption for beneficial uses. Our view is that active use of CCPs for beneficial uses such as those discussed in this letter will continue, but only if the CCP's are not considered to be hazardous wastes at any point in the product stream . This includes the activities of transportation, storage, placement, and later demolition. If the CCP's are considered hazardous wastes during storage and transportation, then this will limit the number of marketers and transporters and increase costs to the municipalities and other end users, which will reduce the competitiveness of CCPs for use in construction. More importantly, it must be clear in the regulations that products made using CCPs (stabilized soil, flowable fill, concrete) are new

products and not considered hazardous wastes, and may be treated in the same manner as similar products made without CCPs. Any uncertainty with regard to the ultimate regulatory status of these products will greatly discourage their continued use, given the very large demolition and disposal costs associated with hazardous wastes. Thank you for your interest in our views on this matter. Ifyou have any questions we may be reached at (785) 864-2946. Sincerely,

Robert L. Parsons, PhD, P.E.

1 ,? Edward Peltier, PhD

### References 1 . ASTM

. (2008)

. StandardSpecificationfor Coal FlyAsh and Raw or Calcined Natural Pozzolanfor Use in Concrete. Standard C618-08a. ASTM International . West Conshohocken, Pennsylvania . 4p. 2. American Coal Ash Association. (2003) . Fly Ash Facts for Engineers. Federal Highway Administration. Report No. FHWA-IF-03-019. 76p. 3. Parsons and Kneebone. (2005) . "Field performance offly ash stabilized subgrades" . Ground Improvement . Thomas Telford. London. v9 n1 . 33-38. 4. Kansas Department ofTransportation. (2007) . "Cement or Fly Ash Treated Subgrade" . 2007StandardSpecifications for State Road and Bridge Construction. Kansas Department of Transportation. Section 303. http ://www

.ksdot .org/burconsmain/specprov/2007SSDefault .asp. 5. Parsons, R.L, Mifburn, J .P. "Engineering Performance of Stabilized Soils ." Transportation Research Record:Journal of the Transportation Research Board. No. 1837. National Research Council . Washington D.C. 20-29. 6 . Kansas Department ofTransportation. (2007) . "Lime Treated Subgrade" . 2007 Standard Specifications for State Road and Bridge Construction. Kansas Department of Transportation. Section 302. http ://www

.ksdot .org/burconsmain/specprov/2007SSDefault .asp. 7. Palumbo, A. V., Tarver, J . R., Fagan, L. A., McNeilly, M .S., Ruther, R. , Fisher, L. S. and Amonette, J. E. (2007) "Comparing metal leaching and toxicity fromhigh pH, lowpH and high ammonia fly ash" Fuel 86:1623-1630 8. Kansas Department ofTransportation. (2007) . "Flowable Fill" . 2007Standard Specifications for State Road and Bridge Construction. Kansas Department of Transportation . Section 843. http://www

.ksdot .org/burconsmain/specprov/2007SSDefault .asp. 9. Deng, A. and Tikalsky, P. J . (2008) "Geochemical and leaching properties of flowable fill incorporating waste foundry sand" Waste Management 28:2161-2170