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cPu 6Cic Works 

and 

Infrastructure AUG 2 3 2010 

1600 West 56 Highway " 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 of Coal Combustion Residuals from Electric 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 EPA regarding the 

beneficial use of coal 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 from the disposal of these materials. This regulation would increase costs of construction of county 

transportation projects. 

Johnson County Kansas Department of Public Works endorses the attached summary of the benefits 

prepared for the City of Overland 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 of Overland Park. 

Coal ash is a valuable construction material used in both the production of concrete and soil stabilization. 

Should the EPA determine 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, which will 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 of these products will greatly discourage their 

continued use, given the very large demolition and disposal costs associated with hazardous wastes . 

Should the EPA have 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 Kansas 
August 3, 2010 

Mr. Michael S. Ross, P .E . 

Manager, Technical and Administrative Services 

City of 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 that would be difficult and 

expensive to replace. Two forms of ash are used in this region; self-cementing Class C fly ash 

and non self-cementing Class F. Class C ash 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 C fly 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% by weight2 . Specifications for 

Overland Park, Kansas typically require eight inches of treatment with 15% ash by weight. Class 

C fly 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 from the Kansas Department of Transportation4. 

Strength gains from incorporation of Class C ash are significant. Research published by 

Parsons and Milburn showed increases in strength of 190-480% percent for a range of soil types 

when mixed with a particular Class C fly 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 from mixing Class C ash with soil occur very 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 be 
done s . 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 of fly 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 from the ash . Due 

to its self-cementing properties, use of Class C fly 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 low permeability (paved) surface above the stabilized soil limits the volume of 

leach water that will pass through the stabilized soil . 

While the metal content of many fly 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 C fly 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 of fly 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 from beneficial use of fly ash materials, 

the weight of available evidence argues for continuing the use of fly 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 of fine 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 mix 2 . 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 form a solid mass. 

Flowable fill may be designed to be a high strength or low strength 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 150 to 200 psi2, and has a maximum strength specification of 100 psi for Kansas 

Department of Transportation (KDOT) projects s . It is especially useful as fill around objects 
such 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 of all 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 from the material . As with soil stabilization, there are no specific cases 

presented by the EPA where fly ash in flowable fill has led to negative environmental impacts, 

and available studies of metal leaching from this material indicate that what 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 of virgin materials, and reducing generation of 

greenhouse gases during the conversion of those virgin materials to cement. We believe the 

risks to the public from the 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 of Additional 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 C fly ash in particular, our view is that it should be considered a product of the coal 

combustion process in the same way the EPA views 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 vary widely 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 from future 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. If you 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) . Standard Specification for Coal Fly Ash and Raw or Calcined Natural 

Pozzolan for 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 of fly ash stabilized subgrades". 

Ground Improvement. Thomas Telford . London. v9 n1 . 33-38. 

4. Kansas Department of Transportation . (2007) . "Cement or Fly Ash Treated Subgrade". 

2007 Standard Specifications 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 of Transportation . (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 from high pH, low pH 

and high ammonia fly ash" Fuel 86 :1623-1630 

8. Kansas Department of Transportation . (2007). "Flowable Fill" . 2007 Standard 

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