### 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

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### 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 (m 3 

### /h) Total Dense Slurry (m 3 

### )

Pannon H ő e r ő m ű Z r t

. Hungary 200 1991- 2000 6,000 38.8 155.2 No 120 6,480,000 Tatabányai E r ő m ű K f

t

. 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 Under Construct. 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 2012Comments by: GEA EGI Contracting/Engineering Co. Ltd

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### 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 anComments by: GEA EGI Contracting/Engineering Co. Ltd

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### 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 tosolidify 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 elevatedComments by: GEA EGI Contracting/Engineering Co. Ltd

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###  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

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### 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 ofComments by: GEA EGI Contracting/Engineering Co. Ltd

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### the solidified products comprising the impoundment ranges from ~5000 to 11,000 lb/ft 3 

### (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 m 3 

### of 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

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### 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 SiO 2 

### 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 Al2O 3 

### 11.85 11.60 16.73 4.41 11.57 7.26 Fe2O 3 

### 5.08 5.91 3.13 2.51 6.31 7.36 SO 3 

### 11.32 10.85 3.62 17.15 10.41 9.78 Na 2 

### O 0.00 0.00 0.00 0.00 0.00 0.50 K 2 

### O 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 NO 2 

### mg/l 0.15 NO 3 

### mg/l 1080 PO 4 

### mg/l 1.63 SiO 2 

### mg/l 25.2 SO 4 

### 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 1.4Comments by: GEA EGI Contracting/Engineering Co. Ltd

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

Parameter Units Value pH 12.7 Conductivity mS/cm 8.8 Ca 2+ 

### mg/l 1200 Fe mg/l 0.1 K + 

### mg/l 29.6 Mg 2+ 

### mg/l <1 Na + 

### mg/l 290 NH 4 + 

### mg/l 0.4 Cl - 

### mg/l 820 NO 2 - 

### mg/l 0.5 NO 3 - 

### mg/l 5.8 PO 4 3

- 

### mg/l 0.1 SO 4 2

- 

### mg/l 1250 SiO 2 

### 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 μ g / l 1

, 6 2

, 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1
Lead μ g / l < 1 0 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0 < 1 0
Cadmium μ g / l < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1 < 1
Chrome μ g / l < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 Copper μ g / l < 5 0 < 5 0 < 5 0 < 5 0 < 5 0 < 5 0 < 5 0 < 5 0 1 1 0 1 0 0 < 5 0 < 5 0 1 0 0
Nickel μ g / l < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 < 2 0 Mercury μ g / 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 μ g / l 1 7 0 1 7 0 1 9 0 1 1 0 1 7 0 9 0 9 0 1 1 0 3 7 0 3 7 0 2 3 0 1 7 0 2 8 0
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-4Comments by: GEA EGI Contracting/Engineering Co. Ltd

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

DSS Mix Water * Cure Time

(days) Sample ID Water:Ash Ratio Hydraulic

Cond.** (cm/sec) Wet

Density Compressional

Strength lb/ft 2



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

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### 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 limitsComments by: GEA EGI Contracting/Engineering Co. Ltd

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### Table 10. FGD Water Analysis from the Matra Plant

Parameter Units Value pH 6.5 Electrical Conductance ( μ S / c m ) 5 6 4 0 0 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/ft 2 

### 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 μ g / l 8 2 Aluminum mg/l <0.25 Arsenic μ g / l 1 Calcium μ g / l 195 Cadmium μ g / l < 1 0 Chromium μ g / l <50 Copper mg/l <0.02 Mercury μ g / l <1 Manganese mg/l <0.02 Lead μ g / l <100 Vanadium mg/l <0.25