VIA ELECTRONIC MAIL: RCRA-docket@epa.gov

Disposal of Coal Combustion Residuals From Electric Utilities

Attn: Docket ID No. EPA-HQ-RCRA-2013-0209

Environmental Protection Agency

Mailcode: 5305T

Washington, DC 20460

Submitted by:

GEA EGI Contracting/Engineering Co. Ltd.

Science Park Building “B”, Irinyi J. u. 4-20, 1117 Budapest, Hungary

Phone: +36 1 225 6171, Fax: +36 1 225 6193

Attn: Mr. István Kovacsics

Dear Sir/Madam:

GEA EGI Contracting/Engineering Co., Ltd. (GEA EGI) is a company in partnership with

United States-based companies. Collectively, this team designs, builds and installs important

equipment for use in the electric power generation industry. One technology that has been

successfully deployed (commercially) is the Circumix Dense Slurry System (DSS) technology.

This technology is a unique mixing technology that is being successfully applied to solidify and

stabilize coal combustion residuals and wastewater in a single process.

The Coal Combustion Residuals (CCR) and Effluent Limitations Guidelines (ELG) proposed

rules contain wording that has created unanticipated and unintentional uncertainty in the industry

regarding the regulatory classification of DSS. This regulatory uncertainty has fostered

reluctance by industry to adopt the DSS technology despite the industry’s recognition of this

technology’s ability to achieve the goals and objectives of both proposed rules. This reluctance

is also despite the fact that costs for applying DSS are less than the benchmark technologies

referenced by EPA.

The regulatory uncertainty referenced above is due to a lack of information about the DSS made

available to the EPA at the time the proposed rules were written. This comment provides

appropriate technical information about the DSS technology and data that serve to justify a

revision of the proposed rules, the goal of which is to alleviate the above-referenced uncertainty

and to recognize DSS as an appropriate and relevant technology capable of meeting the goals

and objectives of the proposed rules.

This comment begins with explanatory content to familiarize EPA with DSS and its relevance to

the ELG and CCR Rules. This explanatory content includes a general description of the DSS

technology plus details regarding where it is being used and for how long. Following the

explanatory content are specific comments on the ELG and CCR proposed rules. The latter part

of this comment contains data that supports the claims and suggested revisions contained herein.

We appreciate the opportunity to provide these comments and suggestions and look forward to

addressing any questions or comments that EPA may have.
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-RCRA-2013-0209 Page 2 of 13

Technology Description

DSS is a high-intensity mixing process that mixes minimal quantities of water (including

wastewater) with CCR’s to produce dense, pumpable slurry. This process maximizes the

availability of reactive ions in ash products and results in near-stoichiometric use of the water

contained in the slurry. Additives (while not typically necessary) may be employed to enhance

end product performance depending upon the chemistry of the ash to be stabilized. Once

discharged, the slurry hardens within 24 to 72 hours. Once cured, the product exhibits low

hydraulic conductivity, high compressional strength, no wastewater discharge, little or no

fugitive emissions and enhanced sequestration of contained metals.

In a single process, the DSS technology facilitates:

1. Effective combined stabilization of ash and wastewater.

2. Reduction of water use by 80% to 90%, as compared to traditional “lean slurry” practice.

3. Zero discharge of transport water.

4. Significant reduction of plant-wide wastewater volume destined for treatment and discharge.

5. Enhanced protection of ground water by virtue of low hydraulic conductivity (measured 10-4

to 10-10 cm/sec) and enhanced metals sequestration exhibited by the end product.

6. Elimination of risk of catastrophic releases associated with dike failure and liquefaction due

to the solid nature and high compressional strength of the end product.

7. Significant reduction of leachate volumes due to low hydraulic conductivity, high capillary

retention, hydration reactions and the minimal amount of water used in the process.

8. Significant reduction of fugitive dust emissions due to the initially wet nature, enclosed

transport medium and later solid nature of the end product.

9. Enhanced land-use efficiencies for disposal sites because the high compressional strength of

the end product facilitates elevated impoundments and landfills.

10. Reduction in the cost of managing CCRs and wastewater compared to “dry ash” management

techniques and water treatment alternatives referenced by EPA in the proposed rules.

11. Reduced energy use and cost for pumping dense slurry compared to “dry ash” management

which typically requires pug mill mixing, hauling by truck and spreading/compaction by

heavy equipment. . Support services typically required for dry ash management are not

needed (e.g., lighting, manned impoundment security, fuel handling, etc.)

12. Enhanced safety of operations and reduced noise levels because the dense slurry can be

pumped rather than transported by truck and manipulated with heavy equipment.

13. The process can mix fly ash, bottom ash, gypsum and waste water together.

In summary, DSS achieves the goals and objectives of the proposed CCR and ELG rules in a

single process by converting wastewater and CCRs into an environmentally stable end product.

Historical Use

DSS is not new. It has been used for decades in Europe and since 2003 in the United States.

Table 1 lists the coal-fired power plants currently employing or that have employed DSS

technology, including pertinent data on the types and quantities of ash treated (per hour and

total), when DSS processing was initiated, etc.
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-OW-2009-0819 Page 3 of 13

Table 1. Summary of Global Dense Slurry Commercial Application

Reference

Plant Country

Plant

Capacity

(MW)

Plant

Ops.

Working

Hours /

Year

Bottom

Ash TPH

Fly

Ash

TPH

FGD

Handled

(Yes / No)

DSS Flow

Rate (m3/h)

Total Dense

Slurry (m3)

Pannon

Hőerőmű Zrt.

Hungary 200 1991-

2000 6,000 38.8 155.2 No 120 6,480,000

Tatabányai

Erőmű Kft.

Hungary 30 1993-

2000 4,000 - 20 No 30 840,000

AES Borsodi

Energetikai Kft. Hungary 200 1996-2000 6,000 24 156 No 200 2,400,000

Matra Hungary 836 1998- 8,000 80 640 Yes 480 23,040,000

SC Collterm SA Romania 50 2000- 3,500 3 20 No 30 1,050,000

Jacksonville

Northside

Generating

Station

USA 600 2003- 8,000 125 125 Yes 120 6,720,000

SC Collterm SA Romania 50 2002- 3,500 3 17 No 30 840,000

Rovinari Power

Plant Romania 1 720 2010- 8,000 120 508 Yes 230 1,140,000

Craiova II.

Power Plant Romania 300 2010- 8,000 18.4 204 Yes 95 760,000

Isalnita Power

Plant Romania 630 2010- 8,000 28 220.8 Yes 100 466,600

Spectrum Coal

and Power India 50 UnderConstruct. n/a 15.6 36.4 No 80 -

Turceni Romania 1320 Under

Commiss. n/a 120 440 Yes 235 -

Total 5,986 43,736,600*

* As of Spring 2012
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-RCRA-2013-0209 Page 4 of 13

In June 2010, representatives of EPA visited the JEA Northside Generating Station in

Jacksonville, Florida and observed the DSS system in operation there. The information collected

during this visit and any details on the DSS technology being employed there are not reflected in

the ELG or CCR proposed rules.

The JEA plant (a fluidized bed petroleum coke plant) employs two DSS mixing systems that

collectively process 120 tons per hour of fly ash and bed ash. Following mixing and discharge of

the dense slurry, JEA interrupts the hydration process by excavating and drying the dense slurry.

Following additional preparation steps, JEA markets this material for beneficial use as a road

construction material with the trade name EZ Base. The JEA ash exhibits favorable chemistry

for beneficial use and demonstrates the potential for beneficial use of other types of ash with or

without additives designed to enhance end product performance.

EZ Base was tested in Florida as a road surfacing material (not an underlayment) and monitored

to evaluate its environmental stability. Following baseline sampling and road construction using

EZ Base paving material, the soil, ground water, storm water and surface water were monitored

for two years by an independent engineering company. The results were reported in November

2011. The results of this monitoring showed that there was no statistical change in any of these

environmental media during the two-year monitoring period. This report is entitled: Year Two

Follow-up Investigation Report, Soil and Water Quality Evaluation, St. Mary’s Shoals Park

Roadway Improvements, Baker County, Florida. The report was prepared by Mechling

Engineering & Consulting, Inc., Jacksonville, FL and can be obtained from the Florida

Department of Environmental Protection.

Specific Comments on the Standards for the Receipt of Coal Combustion Residuals in

Landfills and Surface Impoundments (CCR Proposed Rule)

Definition of Surface Impoundment

In the CCR proposed rule, the definition of CCR Surface Impoundment or Impoundment

appears on Page 35240. GEA EGI reviewed this definition in the context of producing dense

slurry from coal combustion ash using wastewater to produce the slurry. That definition is:

“CCR Surface Impoundment or impoundment means a facility or part of a facility which is a

natural topographic depression, man-made excavation, or diked area formed primarily of earthen

materials (although it may be lined with man-made materials), which is designed to hold an

accumulation of CCRs containing free liquids, and which is not an injection well. Examples of

CCR surface impoundments are holding, storage, settling, and aeration pits, ponds, and lagoons.

CCR surface impoundments are used to receive CCRs that have been sluiced (flushed or mixed

with water to facilitate movement), or wastes from wet air pollution control devices, often in

addition to other solid wastes.”

Parts of this definition are problematic. Specifically, the statement “which is designed to hold

an accumulation of CCRs containing free liquids” specifies a design, but the spirit of the

definition is directed at impoundments that contain free liquids. Arguably, one could design an
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-RCRA-2013-0209 Page 5 of 13

impoundment to contain free liquids but if free liquids were not stored in the impoundment, then

it would not meet the intent of the definition.

An example provided as part of the definition includes: “CCR surface impoundments are used

to receive CCRs that have been sluiced (flushed or mixed with water to facilitate movement)”.

Clearly, DSS technology uses water to facilitate movement of the ash to an impoundment or

landfill. However, the water is also used to induce hydration and/or pozzolanic reactions to

solidify the ash into a cement-like product. And the water is consumed in these reactions nearstoichiometrically with remaining free water (if any) lost to evaporation or bound by capillary

forces where it continues to participate in hydration and pozzolanic reactions. So, most free

liquid that may be present initially is not free liquid for long, and certainly not after 24-72 hours.

“Dry ash” systems as referenced in the ELG rule also use water to facilitate ash movement,

although partially for a different reason. Dry ash systems mix as much as 15-20% water with

ash. This is done to facilitate movement with reduced risk of generating dust. More water is

added later (often with sprinklers) to assist in compaction and solidification once the ash is

placed in the impoundment.

One could argue that “dry ash management” mixes water to facilitate movement of the ash and

thus, even dry systems, from one perspective, could be construed to incorporate mixing with

water to facilitate movement. The point here is that water is mixed with ash in both processes,

and both processes result in a product that does not contain free water for which treatment or

discharge is required.

Both “dry ash” systems and dense slurry systems result in elimination of wastewater discharge

from ash impoundments. It seems clear that both “dry ash” management systems and DSS

technology satisfy the fundamental intent of the rule.

It is important to point out that the DSS process results in a product that exhibits:

 Hydraulic conductivity that is substantially lower than that resulting from traditional “dry

ash” management as described in the proposed rule

 80-90% less consumption of water compared to traditional sluicing

 Stabilization of wastewater (including FGD water) to produce the dense slurry

 Zero discharge of transport water

 Zero discharge of leachate if re-used for DSS

 Enhanced sequestration of contained metals

 Reduced risk of ground water contamination

 Reduced quantities of leachate produced

 Reduced or substantially eliminated risk of dust generation High compressive strength

 More efficient use of disposal space because disposal facilities may be tiered and

elevated
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-RCRA-2013-0209 Page 6 of 13

 Enhanced operational safety and reduced noise levels due to reduction or elimination of

trucks and heavy equipment for transport and manipulation of ash products

 Simplified and lower risk closure results

 Elimination of risk of dike failure and associated liquefaction of ash sludge and/or

catastrophic releases

So, from the perspective of environmental protection, DSS is a superior process compared to

standard/typical/traditional “dry ash” management.

Even though DSS uses water to facilitate movement, the end product satisfies the intent of the

proposed CCR rule, as well as the ELG rule. DSS is an effective FGD and other wastewater

treatment method by virtue of stabilizing and immobilizing the water in hydration reactions,

entraining and trapping suspended solids and by enhanced sequestration of contained metals.

The high capillary forces and very low hydraulic conductivity of the cured slurry product

significantly reduces leachate quantities and the sequestration of metals reduces their

concentration in the leachate.

The wording of the proposed rule unintentionally casts doubt and uncertainty in the industry

regarding how the DSS process will be viewed by regulating authorities. This uncertainty has

resulted in reluctance by industry to utilize this highly effective technology and is hindering its

further deployment.

GEA EGI suggests that the proposed rule be modified to recognize the dense slurry process as a

viable option for ash management. Specifically, the rule should be modified to recognize a

distinction between the two fundamentally different slurry types that are used to transport coal

combustion products to an impoundment or landfill. The two types include:

1. Pumped ash slurries that use roughly 10-20 parts water to 1 part ash (commonly termed

“lean slurry”). Lean slurry is the traditional ash transport method referenced in the

proposed rules. Lean slurry contains copious amounts of free water that requires discharge.

This is prohibited in new impoundments and is prohibited altogether under the proposed

ELG rules. This type of slurry does not produce a solid product but instead produces a

sludge that is susceptible to liquefaction in the event of a dike failure. In addition, lean

slurry particles are not consolidated or cemented. So, upon drying, wind can easily

mobilize the fine ash particles to create a dust hazard. Lastly, lean slurry impoundments

tend to produce voluminous quantities of leachate that pose a risk to ground water.

2. Pumped ash slurries that use roughly 1 part water to 1 part ash (commonly termed “dense

slurry”). Dense slurry is initially a thick pumpable fluid that solidifies by virtue of

hydration and pozzolanic reactions to create a solid product within 24-72 hours following

discharge. The water mixed with the ash is consumed near stoichiometrically (depending

upon ash chemistry) resulting in very small quantities of free liquids. Any small amount of

free liquid that may be present is lost to evaporation or bound by capillary forces in the

cured product. Thus, discharge or treatment of water is not required. Upon curing, the

dense slurry product is not subject to liquefaction or release of fugitive emissions.

Discharge of wastewater is not required and enhanced protection of ground water is

realized by virtue of enhanced metals sequestration, high capillary forces and low hydraulic

conductivity of the cured product.
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-RCRA-2013-0209 Page 7 of 13

GEA EGI suggests the proposed rule be modified to allow power plant operators to pump dense

slurry into landfills and/or impoundments provided the operator can demonstrate that the slurry

solidifies within a reasonable period of time to produce a product that is not susceptible to

liquefaction, contains little or no free water and generally satisfies the intent of the proposed rule.

Demonstrating product performance can be achieved by testing selected “recipes” consisting of

various mixtures of CCRs and wastewater from candidate plants in advance of deployment.

It is also suggested that the definition of “Surface Impoundment” or “Impoundment” in the CCR

rule be modified. The modified definition should not refer to the design of the impoundment, but

rather should describe a facility that contains CCR products that are susceptible to liquefaction,

exert constant hydraulic stress on containment dikes and/or are associated with excess free water

to the extent that the water must be discharged off site.

Best Management Practices

In the proposed ELG rule, EPA describes Best Management Practices (BMP) for CCR surface

Impoundments (ELG preamble pages 34466-67). The BMP is similar to and based upon the

promulgated Mine Safety and Health Administration (MSHA) BMP requirements at 30 CFR

77.216 (regulations for coal slurry impoundments). Both types of impoundments contain sludge

that exerts constant hydraulic pressure on containment dikes and that is susceptible to

liquefaction. The described BMP is closely related to the proposed CCR rules: §257.71 (Design

criteria for existing CCR surface impoundments), §257.72 (Design criteria for new CCR surface

impoundments and lateral expansions), and §257.83 (Surface impoundment inspection

requirements). The intent of these proposed rules is to assure the integrity of dikes that are

subjected to constant hydraulic pressure and to prevent catastrophic releases of ash products that

are subject to liquefaction and/or that contain copious quantities of free water.

The cured products produced from DSS are solid, exhibit high compressional strength and are

not susceptible to liquefaction (Tables 6 & 11). Upon discharge, dense slurry spreads into a thin

layer (<5 cm) and exerts no appreciable hydraulic pressure on containment dikes. During the

curing process, there is simply not enough dense slurry present to exert hydraulic stress on a dike

or result in any significant release. Once cured, the solid nature of DSS products permanently

eliminates the risk of catastrophic releases. Thus, impoundments containing these solid products

should not be subject to the same design criteria, operating criteria or inspection requirements as

those for impoundments which contain large quantities of materials that are susceptible to

liquefaction and/or that exert a constant hydraulic pressure on containment dikes.

Figure 1 shows the active impoundment at the Matra Power Plant in Hungary. The

impoundment has been in operation since 1998 and consists of 15 tiers averaging 10 ft. each.

The tiers are comprised of successive layers of solidified Type F ash that was pumped to the

impoundment as dense slurry from the power plant in the background. The impoundment covers

an area of 314 acres at its base and 122 acres at the top, and has been tiered and elevated an

average of 150 ft. above the impoundment base.

The slope and height of the impoundment are determined in part by the compressional strength

of the cured product. The compressional strength, is determined by the chemistry of the dense

slurry ingredients. This impoundment poses no risk of catastrophic failure or inundation of the

surrounding community by liquefaction of ash products because the compressional strength of
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-RCRA-2013-0209 Page 8 of 13

the solidified products comprising the impoundment ranges from ~5000 to 11,000 lb/ft3(see

Table 11). There have been no slope failures or other incidents requiring remedial action since

this impoundment was built and all leachate is returned to the plant for DSS processing. Thus,

this is a zero discharge impoundment with respect to transport water and leachate.

DSS needs to be taken into consideration when establishing BMPs for impoundments that

contain solidified ash products. Because of the solid nature of DSS products, dam safety

(MSHA) requirements should not apply, and less stringent design criteria, operation criteria and

inspection requirements consistent with lower risks should be allowed.

Figure 1. Elevated Solidified Ash Impoundment Containing ~ 25 million m3of DSS Product

Supporting Data

The following tables present data from chemical analyses performed on water and process

residuals used to produce dense slurry. In addition, data from testing of solidified and cured

dense slurry produced from these waters and process residuals is provided. The data on

solidified products includes hydraulic conductivity, compressional strength, total metals content,

and leach performance. These data originate from two testing programs involving two general

sources of water and process residuals. These include:

1. Matra Plant: An 880 MW lignite-fired plant located in Hungary. A series of tests on ash and

water were conducted as part of the Circumix system evaluation.

2. Mibrag: Black and Veatch Engineering Services conducted an independent evaluation of ash

and FGD water disposal options for four plants in Germany involving different varieties of

German coal. The Power Client was Mitteldeutsche Braunkohlengesellschaft GmBH

(shortened to Mibrag).
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-RCRA-2013-0209 Page 9 of 13

Table 2 presents the compositions of the various ash products used to produce dense slurry

products in the Mibrag testing program. Tables 3 and 4 show the respective compositions of the

FGD and process make-up water used in the Mibrag dense slurry mixtures. Table 5 shows the

leach performance from numerous solidified dense slurry samples from Mibrag. Table 6

presents the hydraulic conductivity and compressional strength from the solidified dense slurry.

Table 2. Normalized Ash Compositions for Mibrag Dense Slurry Tests

Oxide Wt % of Oxide

CaO 38.10 37.70 15.36 60.38 37.33 40.22

SiO2 29.10 29.54 58.71 13.34 29.23 30.04

MgO 4.55 4.40 2.45 2.21 5.15 4.64

Al2O3 11.85 11.60 16.73 4.41 11.57 7.26

Fe2O3 5.08 5.91 3.13 2.51 6.31 7.36

SO3 11.32 10.85 3.62 17.15 10.41 9.78

Na2O 0.00 0.00 0.00 0.00 0.00 0.50

K2O 0.00 0.00 0.00 0.00 0.00 0.20

Total* 100.00 100.00 100.00 100.00 100.00 100.00

Table 3. Mibrag FGD Water used in Dense Slurry

Parameter Units Value

pH 7.6

Conductivity mS/cm 22.6

Total Solids mg/l 57100

TSS mg/l 9620

Cl mg/l 6100

F mg/l 89.7

NO2 mg/l 0.15

NO3 mg/l 1080

PO4 mg/l 1.63

SiO2 mg/l 25.2

SO4 mg/l 15000

Arsenic mg/l <0.001

Lead mg/l <0.04

Cadmium mg/l 0.08

Calcium mg/l 715

Chromium mg/l <0.05

Cobalt mg/l 0.05

Magnesium mg/l 5855

Nickel mg/l 0.38

Mercury mg/l <0.0005

Selenium mg/l 0.166

Thallium mg/l <0.02

Zinc mg/l 1.4
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-RCRA-2013-0209 Page 10 of 13

Table 4. Make-up Process Water Properties used for Mibrag Dense Slurry

Parameter Units Value

pH 12.7

Conductivity mS/cm 8.8

Ca2+ mg/l 1200

Fe mg/l 0.1

K

+ mg/l 29.6

Mg2+ mg/l <1

Na+ mg/l 290

NH4

+ mg/l 0.4

Cl- mg/l 820

NO2

- mg/l 0.5

NO3

- mg/l 5.8

PO4

3- mg/l 0.1

SO4

2- mg/l 1250

SiO2 mg/l 0.5

Table 5. Leach Performance* of Solidified Dense Slurry from Mibrag Ash and Wastewater

Parameter Units I-2 I-3 II-1 II-2 II-3 III-1 III-2 III-3 IV-2 IV-3 V-1 V-2 V-3

pH 12,7 12,7 12,6 12,2 12,6 11,9 12 12 13,1 12,9 12,9 12,9 12,7

Conductivity mS/cm 4,27 3,91 3,66 2,18 3,83 1,01 1,25 1,71 8,84 9,67 6,65 7,33 7,35

TDS mg/l 0,9 0,3 1,6 1 0,7 1 0,9 0,9 2,5 3,4 1,7 1 1,3

Arsenic μg/l 1,6 2,1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1

Lead μg/l <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10 <10

Cadmium μg/l <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1 <1

Chrome μg/l <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20

Copper μg/l <50 <50 <50 <50 <50 <50 <50 <50 110 100 <50 <50 100

Nickel μg/l <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20

Mercury μg/l <0,5 <0,5 <0,5 <0,5 <0,5 <0,5 <0,5 <0,5 0,5 <0,5 <0,5 <0,5 <0,5

Zinc μg/l 170 170 190 110 170 90 90 110 370 370 230 170 280

Ammonium mg/l 0,11 0,12 0,06 0,04 0,07 0,04 0,01 <0,01 <0,01 <0,01 0,25 0,07 0,18

Chloride mg/l 121 342 -- 17,4 60,8 21,9 67,5 198 168 490 94,6 60,8 180

Cyanide mg/l <0,01 <0,01 <0,01 <0,01 <0,01 <0,01 <0,01 <0,01 <0,01 <0,01 <0,01 <0,01 <0,01

Fluoride mg/l 0,11 0,27 <0,1 <0,1 <0,1 <0,1 <0,1 0,28 11,5 17,6 <0,1 <0,1 0,22

Sulfate mg/l 72,8 71,1 no data 38,3 33,6 91,3 97,1 47,6 1180 1120 84,5 33,6 131

* Leach Test Procedure: DIN 38 414 S-4
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-RCRA-2013-0209 Page 11 of 13

Table 6. Mibrag Compressional Strength & Hydraulic Conductivity of Cured Dense Slurry

DSS Mix

Water *

Cure Time

(days) Sample ID Water:AshRatio

Hydraulic

Cond.**

(cm/sec)

Wet

Density

Compressional

Strength

lb/ft2

1 90 1 1.3:1 6.8E-9 1.61 25,396

2 90 15 1:1 1.0E-10 1.51 31,014

1 90 31 0.8:1 2.1E-9 1.76 166,391

3 90 40 0.8:1 1.0E-10 1.71 147,720

2 90 51 0.8:1 1.0E-10 1.76 147,970

3 90 52 0.9:1 1.3E-05 1.56 13,387

2 90 23 0.9:1 4.2E-06 1.61 27,004

2 30 42 1.3:1 6.0E-07

2 60 48 1.3:1 4.8E-07

1 90 53 1.3:1 1.2E-07 1.42 13,889

1 90 53 1.3:1 1.1E-07

3 90 73 1.3:1 3.5E-09 1.52 24,331

2 90 72 1.3:1 1.9E-08 1.50 22,639

2 60 60 1.3:1 1.2E-08

2 30 54 1.3:1 1.1E-07

* 1 = 100% industrial process water, * 2 = industrial and 80% FGD water, * 3 = 100% FGD water.

** Hydraulic Conductivity Procedure: ISO/TS 17892-11:2004 Geotechnical investigation and testing. Laboratory

testing of soil. Part 11: Determination of permeability by constant and falling head (Hungarian version of the

European Technical Specification CEN ISO/TS 17892-11:2004, including Corrigendum CEN ISO/TS 17892-

11:2004/AC:2005).

Testing was performed on wastewater, ash and samples of solidified ash from the Matra Power

Plant in Hungary. The dense slurry was comprised of the components shown in Table 7. The

ash compositions from Matra are shown in Table 8.

Table 7. Components of Dense Slurry from Matra Plant

Component Concentration

(%)

Fly Ash 35.1

Coarse Fly Ash 10.5

Economizer Ash 2.5

Bottom Ash 4.3

Industrial Water 37.1

FGD Water 2.1

Lime Pre-Treatment (ion exchange)

Water

8.4
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-RCRA-2013-0209 Page 12 of 13

Table 8. Matra Plant Average Ash Compositions

Oxide Fly Ash (wt%) Bottom Ash (wt%)

SiO2 45-49 90-92

CaO 7.5-9.5 0.2-0.8

MgO 4.5-5.2 0.1-0.2

Fe2O3 7.8-8.8 2-2.9

Al2O3 17.5-18.5 1-2

K2O 0.5-0.7 0.1-0.2

Na2O 0.2-0.3 --

SO3 5.5-6.5 0.1-0.2

The dense slurry was allowed to cure for 90 days after which it was analyzed for total metals and

leach performance using techniques similar to the Toxic Characteristic Leach Procedure (TCLP)

and the Simulated Precipitation Leach Procedure (SPLP). Table 9 shows the total metals

concentration of the solidified product and the leach performance using neutral and acidic

extraction water similar to the SPLP and TCLP tests, respectively. Table 10 presents the

chemistry of the FGD water that was used to produce the dense slurry, and Table 11 presents the

compressional strength and hydraulic conductivity of the cured Matra samples.

Table 9. Total Metals and Leach Performance of Matra Dense Slurry

As Ba Ca Cd Cr Cu Hg Mn Pb V

Total Metals mg/l

Min 34.1 52 53500 0.11 12.9 22.6 0.08 328 5.66 46

Max 39.2 93.5 57000 0.15 13.3 24.6 0.11 341 6.34 51

Av. 36.9 71.6 55770 0.14 13.17 23.63 0.093 336 6.06 48.8

Neutral Water Leach Test mg/l (SPLP)*

Min 0.092 0.06 490 0.0004 <0.05** <0.02 <0.001 <0.02 <0.005 <0.005

Max 0.2 0.06 660 0.0004 <0.05 <0.02 <0.001 <0.02 <0.005 0.008

Av. 0.14 0.06 587 0.0004 <0.05 <0.02 <0.001 <0.02 <0.005 <0.008

Acidic Leach Water mg/l (TCLP)*

Min 0.021 0.37 1920 0.0007 0.071 0.05 <0.001 8.21 <0.005 <0.005

Max 0.112 0.44 2310 0.0011 0.106 0.06 <0.001 10.2 <0.005 <0.005

Av. 0.069 0.4 2017 0.0009 0.089 0.057 <0.001 8.88 <0.005 <0.005

* Leach tests indicated are similar to the SPLP and TCLP. Procedure used was MSZ 21979/1-1989. This procedure

has been revised and is now harmonized with the European Union. The new procedure numbers are: MSZ EN

12457-2-2003 (particle size <4mm) and MSZ EN 12457-4:2003 (particle size <10mm).

** Figures exhibiting “<” indicate element not detected at quantitation limits
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-RCRA-2013-0209 Page 13 of 13

Table 10. FGD Water Analysis from the Matra Plant

Parameter Units Value

pH 6.5

Electrical Conductance (μS/cm) 56400

Evaporation Residue (mg/l) 74900

LOI of Evaporation

Residue

(%) 54.2

Chem. Oxygen Demand (mg/l) 1125

Sulfide (mg/l) 0.23

Sulfate (mg/l) 1100

Chloride (mg/l) 27100

Table 11. Matra Plant Solidified Dense Slurry Physical Properties

Sample No. Curing

Time

Hydraulic

Cond.

Comp.

Strength

Days cm/sec lb/ft2

Matra-30 30 2 X 10-4

--

Matra-60 60 7 X 10-5

5661

Matra-90 90 2.5X 10-4

7395

Matra-120 120 6 X 10-5

1065

Matra-150 150 4 X 10-5

4867

Matra-180 180 1X 10-4

11030

Table 12. Matra Impoundment Leachate Chemistry

Parameter Units Value

pH 8.2

Conductivity mS/cm 1.3

Evaporation Residue mg/l 1182

LOI of Evap. Residue Wt% 26.7

KOI mg/l <10

Sulfide mg/l <0.1

Sulfate mg/l 570

Chloride μg/l 82

Aluminum mg/l <0.25

Arsenic μg/l 1

Calcium μg/l 195

Cadmium μg/l <10

Chromium μg/l <50

Copper mg/l <0.02

Mercury μg/l <1

Manganese mg/l <0.02

Lead μg/l <100

Vanadium mg/l <0.25