VIA ELECTRONIC MAIL: OW-docket@epa.gov

Effluent Limitations Guidelines and Standards for the Steam Electric Power Generating Point

Source Category

Attn: Docket ID No. EPA-HQ-OW-2009-0819 (Water Docket)

Environmental Protection Agency, Mailcode: 4203M

1200 Pennsylvania, Ave. NW

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 Effluent Limitations Guidelines (ELG) and Coal Combustion Residuals (CCR) 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 proposed rule. 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-OW-2009-0819 Page 2 of 15

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 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 ELG and CCR 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 15

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-OW-2009-0819 Page 4 of 15

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 Proposed Rule and Preamble

Referenced Plants

In EPA’s Final Detailed Study Report (EPA 821-R-09-008), reference is made to site visits and

sampling activities from plants in the United States, including an evaluation of waste streams and

processes associated primarily with coal ash handling operations and FGD air pollution control

systems. EPA visited the JEA Northside Power Station in Jacksonville, FL and inspected the

DSS system in use there. Information EPA collected in its evaluation of this plant is not reflected

or mentioned in the proposed ELG rule preamble. The JEA Northside Power Station is the only

plant in the U.S. where DSS is currently being employed. The presence of only one plant in the

U.S. is the likely reason for this technology being omitted in the development of the proposed

rule. The technology is, however, being utilized at multiple plants in other parts of the world

where it has demonstrated compliance with strict EU environmental regulations.

Use and Reference of Foreign Technology

In the preamble of the proposed ELG rule (III, B, 3), EPA discusses Best Available Technology

Economically Achievable (BAT). In EPA’s discussion, it is recognized that foreign plants may

be referenced in part to define BAT. DSS has been used for a long time outside of the United

States and has demonstrated favorable environmental performance. Because of this history of
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-OW-2009-0819 Page 5 of 15

favorable performance, it is appropriate for EPA to consider the technical merits of DSS for

wider deployment in the United States and to also consider it as a viable benchmark BAT

technology for the management of wastewater by using the wastewater to stabilize coal

combustion products.

Use of Wastewater to “Condition” Ash

EPA references the use of FGD water in U.S. power plants to “condition” dry fly ash to control

dust and/or to assist with compaction in its Final Detailed Study Report (Page 4-39). Clearly

wastewater is already being mixed with ash as a mechanism to reduce wastewater volume and

this referenced application is referred to as a “dry ash management technology”.

A primary intent of the proposed rule is to reduce, and in some cases eliminate, discharge of

wastewater to the surface waters of the United States. This intent makes it understandable that

the EPA emphasizes the use of “dry ash” management systems.

DSS technology clearly straddles the proposed ELG and CCR rules and is thus pertinent to

EPA’s discussion on the Intersection Between the Proposed ELG and Coal Combustion

Residuals Rules (ELG preamble III, G). The wording of the proposed ELG rule uses the term

“sluicing” with the same meaning as the specialized definition: “transport water” (423.11(p)).

At first glance, this may seem correct. But the specialized definition of “transport water” also

includes the term “wastewater”. With DSS, the water that is mixed with the ash (whether it is

FGD water, impoundment leachate, process water or other water) is consumed by hydration,

pozzolanic reactions, bound by capillary forces and/or encapsulation and some water evaporates.

Thus, with DSS, “transport water” is not wastewater pursuant to how wastewater is defined in

the proposed rule. Instead, the transport water is stabilized along with the ash in a solid end

product exhibiting favorable environmental properties. Leachate collected from dense slurry ash

impoundments and/or landfills can be returned to the plant and used to produce additional dense

slurry if appropriate.

The proposed rule requires revision to further define and distinguish terms such as “sluicing”.

While DSS resembles “sluicing” during the initial preparation of the slurry, it results in a solid

product exhibiting high compressional strength with no wastewater treatment or discharge

requirements.

BAT & BADCT Technology Reference

In the preamble of the proposed ELG rule (VIII, 1, 2), EPA identified a subset of treatment

processes and operational practices that it deemed most promising as candidate BAT/BADCT

options. It is clear that these options focus on a process termed “dry ash” management and

enhanced water treatment techniques. It is important to note that “dry ash” management

techniques discussed in the proposed rule are not truly dry. These techniques typically mix 15-

20% water with ash to control dust and to facilitate compaction and more is added later (often

with sprinklers) at the disposal facility. Thus, the intent of EPA’s use of this “dry ash”

terminology is not to imply that an ash management system uses no water. Instead, the intent of

the use of the “dry ash” terminology refers to ash management techniques that do not produce

wastewater requiring treatment or discharge.
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-OW-2009-0819 Page 6 of 15

DSS achieves zero discharge of transport water while producing a solidified ash product

exhibiting properties that are clearly superior to the “dry ash” management techniques described

in the preamble. In addition, DSS typically uses less energy than traditional “dry ash”

management particularly with respect to ash transport and disposal.

In the final rule, DSS should be considered in EPA’s technology basis in defining BAT/BADCT

technology. Such consideration is deserved because DSS: 1) is technically demonstrated and

available; 2) is economically achievable; 3) is a relatively simple process; 4) is energy efficient;

5) is capable of achieving target effluent standards; 6) can often utilize existing plant

infrastructure; and 7) has less of an impact on other non-water quality environmental standards

compared to traditional “dry ash” management systems. DSS should also be referred to as a “dry

ash” management technique in the context of, and consistent with the intent of, the described

process. This is because DSS results in a solid product and because it exhibits zero discharge of

transport water to the waters of the United States.

GEA EGI recommends that the proposed rule be modified to refine the definition of “dry ash”

management to mean any ash management system or technique that eliminates waste transport

water destined for treatment and/or off-site discharge regardless of its initial appearance or how

it is prepared (even if it uses more water than the concept of “dry ash” management as referenced

in the proposed rule). The current use and definition of “dry ash” in the proposed rule and

preamble is not clear and seems to imply that “dry ash” management techniques do not employ

the use of water even though most do.

Anti-Circumvention Provisions

EPA describes the proposed Anti-Circumvention Provisions in the ELG Preamble (page 34465).

The intent of the proposed provision is to limit mixing of wastewaters in an effort to preclude the

practice of diluting a waste stream or otherwise re-categorizing wastewater for purposes of more

easily achieving compliance. DSS is an effective treatment method for FGD and other

wastewater by virtue of stabilizing and immobilizing the water in hydration reactions, entraining

and trapping suspended solids, and by enhanced sequestration of contained metals. The very low

hydraulic conductivity and high capillary forces of the cured slurry product reduces leachate

quantities and the enhanced sequestration of metals reduces their concentration in leachate (see

Tables 5, 6, 9, &11).

The DSS practice of combining wastewaters for purposes of ash solidification and stabilization

results in an overall reduction of water consumption and reduces the generation of wastewater

destined for treatment and/or discharge. Thus, mixing wastewater for purposes of ash

solidification and stabilization does not violate the intent of the Anti-Circumvention Provisions.

In fact, this practice enhances the goals and objectives of the proposed rule. Therefore, care

should be exercised in crafting the anti-circumvention language to allow mixing of wastewater

for purposes of solidification and stabilization of ash products while preserving the intent of the

Anti-Circumvention Provisions.

Zero Discharge of Leachate

In the ELG preamble (page 34473), EPA is seeking additional information on alternatives for

reducing pollutants discharged in leachate before making a finding with respect to what
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-OW-2009-0819 Page 7 of 15

technologies represent BAT for leachate management. As mentioned in other parts of this

comment, DSS technology produces a solidified product that exhibits low hydraulic conductivity

and enhanced sequestration of metals in the solidified product. Measured hydraulic

conductivities range from 2 X 10-4 to 1 X 10-10 cm/sec (see Tables 6 & 11). Leachate chemistry

from working DSS impoundments exhibit low concentrations of metals (see Table 12), which

demonstrates enhanced metal sequestration. These two factors result in low volumes of leachate

generation (which can be comparable to a capped landfill) and leachate water that exhibits low

contamination levels. By reprocessing leachate collected from landfills and/or impoundments to

produce more dense slurry (as is being done at the Matra Power Plant), zero discharge of

leachate generated from these impoundments can be achieved without a significant cost impact

over existing operating costs for a DSS system.

EPA should reference DSS as a viable BAT option for achieving zero discharge of leachate from

impoundments and landfills containing solidified products of DSS.

Best Management Practices for Surface Impoundments

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

subject to a constant hydraulic head 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 the DSS process are solid, exhibit high compressional

strength and are not susceptible to liquefaction (see Tables 6 & 11). Upon discharge, dense

slurry spreads out into a thin layer (<5 cm) and exerts no appreciable hydraulic pressure on

containment dikes prior to solidification (in less than 72 hours). 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. For these reasons, impoundments containing the products of DSS

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

requirements as those for impoundments that 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

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

Docket ID No. EPA-HQ-OW-2009-0819 Page 8 of 15

The steepness of the impoundment slope and height of the impoundment are determined in part

by the compressional strength of the solidified product. The compressional strength, in turn, 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 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. Because

of the solid nature of DSS products, dam safety (MSHA) requirements should not apply, and less

stringent dike inspection requirements consistent with lower risks should be allowed.

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

Voluntary Incentive Program

EPA describes the Voluntary Incentive Program on pages 34467-38 of the ELG preamble. The

primary objectives of the incentive program are to:

1. Install advanced pollution prevention technologies or make process changes that reduce

the release of toxic pollutants to the environment.

2. Promote water conservation and water recycling.

3. Lead to superior effluent quality and greater environmental protection.
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-OW-2009-0819 Page 9 of 15

The “advanced technology performance requirements” described in the voluntary incentive

program do not recognize the possibility of impoundments consisting entirely of solid, stabilized

ash products from the DSS process.

Treating ash and wastewater to produce a solidified and stable ash product in a landfill or

impoundment satisfies all of the objectives of the incentive program. Plants that choose to install

and operate DSS systems should qualify for Tier 1 or Tier 2 program status.

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 reused 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

 Enhanced operational worker safety due to reduced noise and 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

“dry ash” management as described in the proposed rule. It is also safer and less expensive.

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

proposed ELG rule, as well as the CCR rule. The wording of the proposed ELG and CCR rules

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 and economical technology and is hindering its further deployment.

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

as a viable option for wastewater and ash management. Specifically, the rule should be modified

to recognize a distinction between the two fundamentally different types of slurry that are used to

transport coal combustion products to an impoundment or landfill. The two types include:
Comments by: GEA EGI Contracting/Engineering Co. Ltd

Docket ID No. EPA-HQ-OW-2009-0819 Page 10 of 15

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 excess contact water that is

currently prohibited in new impoundments and that is prohibited altogether under the

proposed ELG rule. This type of slurry does not produce a solid product but instead

produces a sludge that presents a risk of liquefaction in the event of a dike failure. In

addition, the contents of lean slurry impoundments are not consolidated or cemented. So in

the event that this material dries on the surface, it can be easily mobilized by wind to create

a dust hazard. Lastly, lean slurry impoundments exhibit relatively high hydraulic

conductivity and so tend to produce large quantities of leachate that can pose a threat 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 transport 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.

GEA EGI is suggesting that the proposed rule be modified to specifically 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, does not require treatment/discharge of transport water and

otherwise satisfies the intent of the proposed rule. Demonstrating dense slurry product

performance can be achieved by testing selected “recipes” consisting of various mixtures of

CCRs and wastewater from candidate plants in advance of deployment.

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-OW-2009-0819 Page 11 of 15

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-OW-2009-0819 Page 12 of 15

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-OW-2009-0819 Page 13 of 15

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-OW-2009-0819 Page 14 of 15

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-OW-2009-0819 Page 15 of 15

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