Final Notes from Site Visit at Tennessee Valley Authority’s Paradise Fossil Plant

on February 26, 2009

EPA conducted a site visit at Tennessee Valley Authority’s Paradise Fossil Plant (Paradise) located in Drakesboro, KY on February 26, 2009 to learn about the operations at the plant, in particular the ash and flue gas desulfurization (FGD) wastewater handling s ystems. Table 1, located at the end of these notes, identifies the site visit participants. The pres entation that the Paradise personnel gave during the site visit is provided as Attachment 1.

These notes describe the information collected during the site visit and the pre-s ite visit phone call, which was held on February 18, 2009.

Plant Overview

• Paradise is the second largest TVA plant in the United States; the plant has 425 employees.

• Paradise operates three coal-fired generating units, with a total combined capa city of 2,500 MW. The table below contains some general information for the three generating units.

Unit Installation

Date Gross

Capacity (MW) Particulate

Control NOx Control 1 SO 2 Control
1 1963 700 Wet FGD scrubber (see
SO 2 Control) Overfire air;

selective catalytic reduction (SCR) Wet FGD installed in

1982; >88% removal

2 1963 700 Wet FGD scrubber (see
SO 2 Control) Overfire air; SCR Wet FGD installed in 1982; >88% removal

3 1970 1,150 ESP (coldside) Overfire air; SCR Wet FGD installed in 2006; >97.5% removal

• Paradise burns approximately 23,000 tons of coal per day, which is received at the plant via truck, rail, and barge. The plant burns a low sulfur coal blend.

 Currently, all three units burn a blend of 95% Illinois Basin bituminous coal and 5% coal fines. However, in October the coal blend Units 1 and 2 will be changed to 80% Illinois Basin bituminous coal, 15% PRB coal, and 5% coal fines. Additionally, the coal blend for Unit 3 will be changed to 65% Illinois Basin bituminous coal, 30% PRB coal, and 5% coal fines.

1 Overfire air is a NOx reduction technology which re duces the amount of fuel NOx produced. The quantity of air injected with the fuel is reduced, thus leading to a fuel-rich co mbustion. The required air to complete the combusti on is provided through overfire air ports. The first stage of the combusti on, under fuel rich conditions, leads to a reductio n in fuel NOx emissions.Page 2

 Paradise modified Unit 3 in the 1990s to burn a blend of up to 80% PRB coal. These modifications cost approximately $23 million.

 Paradise is developing strategies to burn flexible blends of coal and is currently conducting a test burn to burn paint waste blended with coal fines. Paradise has approximately 30 tons of paint waste on site, and is burning about one ton per day during the test.

• The sulfur content of the Illinois Basin bituminous coal used at Paradise is typically <5.2 lbs SO 2 /MMBTU, or <2.5% sulfur content. The coal blends
burned in the units have a lower sulfur content because of the addition of PRB
coal.

• Coal pile runoff, which collects in one of three coal yard basins, flows by gravit y to the bottom ash pond, or may overflow to the Red Water Ditch #2 before flowing to the bottom ash pond. Prior to the site visit, Paradise personnel collected samples of the coal pile runoff and measured the pH. The table below presents the results of the measurements.

Location pH (S.U.)
Coal Yard Basin #1 – northwest 6.77
Coal Yard Basin #2 – north 5.47
Coal Yard Basin #3 - south 7.29

• The plant operates cyclone boilers on all three units, which produce an 80/20 splitof bottom ash to fly ash. This is the opposite of the ratio generated from wallfired or tangentially-fired boilers.

• Paradise operates SCRs and FGDs on all three generating units.

• Unit 3 has an ESP for particulate removals with an efficiency of 93 to 94 percent; however, Units 1 and 2 do not have ESPs. Instead, the wet FGDs on Units 1 and 2 act as the particulate removal system.

• Paradise initially had ESPs on Units 1 and 2, but they were removed to make room for the installation of the SCR systems.

• Paradise used to operate a coal wash facility on site, when they received coal f rom an on-site coal mine. The coal wash facility was idled in 2006 when the mine closed. All coal suppliers wash the coal before it arrives at the plant. Paradise stated that they have no plans to restart the coal washing operation.

• Paradise is located on approximately 4,200 acres.

• A wastewater flow schematic of the plant is included as Attachment 2.Page 3

FGD System and Wastewater Handling

• Paradise operates limestone forced oxidation FGD scrubbers on all three generating units. Attachment 3 presents diagrams of the scrubbers.

• The Units 1 and 2 FGD scrubbers were installed in 1982 at a cost of $320 million (1982 $). There are a total of six venturi scrubbers for the two units combined. Three of the scrubbers treat the flue gas from Unit 1 and the other three scrubbers treat the flue gas from Unit 2 (i.e, the Unit 1 and 2 flue gases are not mixed prior to the FGD scrubbers). Each scrubber contains 3 spray headers and has its own recycle tank. The pH of the scrubbers is controlled to 5.8 S.U., and the sulfur dioxide removal is approximately 88 percent.

• The Unit 3 FGD was installed in fall 2006 at a cost of $300 million (2006 $) andis a two-tower FGD system. There is one co-current flow tower and one countercurrent flow tower. The spray in each tower is a double contact spray fountain. There is one common reaction tank for the two towers. The pH of the scrubbers is controlled to between 5.8 and 6.0 S.U., and the sulfur dioxide removal is approximately 98 percent.

• All three FGD systems operate recirculation pumps to recycle the slurry within the system. The limestone slurry feed enters the system, reacts with the flue gas, and is transferred to the venturi/absorber recycle tanks. The slurry is periodi cally
blown down from the FGD scrubber.

• For Units 1 and 2, Paradise adds make-up water to the FGD system to control the density to a target of 12% solids. Additionally, Paradise adds limestone to control the pH to a target of 5.8 S.U. The Unit 1 and 2 FGD systems have an overflow system that is used to keep a constant level in the reaction tank, so as make-up water or limestone are added to the FGD system, some slurry is blowndown to maintain the level in the reaction tank. For Unit 3, make-up is used to control the level in the reaction tank and pumps blow down the slurry from the system to control the density in the reaction tank to a target of 23.5% solids.

• Because the Unit 1 and 2 generating units do not have a particulate control device prior to the FGD, the FGD slurry from these units contains fly ash.

• The FGD slurry blowdown from all three units is transferred to a segregated gypsum pond system, where the plant uses a rim-ditch stacking method to control the wastewater handling.

• The gypsum pond system consists of four different ponds: an east pond, a west pond, a “duck” pond, and a stilling pond. Currently the plant sends gypsum slurry from Units 1 and 2 to the east pond; gypsum slurry from Unit 3 is sent first to the “duck” pond located between the east and west ponds and can then feed to either pond.Page 4

• Paradise plans to modify the pond system so that all gypsum slurry is first sent t o the duck pond and then flow will alternate between the east and west pond approximately once a month. When the east pond is receiving the FGD slurry blowdown, the plant would use a backhoe to excavate the settled gypsum from the west ditch and west pond and place it on the pond dike to increase the pond’s elevation. After the west pond is cleaned out, the plant would switch the intake and begin cleaning the east pond.

• Paradise provided the following information about the gypsum pond:

 Pond is unlined;

 Pond has about 45 yrs of life remaining (526 months from Feb 09);

 Berms are about 30-35 feet above grade;

 Elevation is expected to increase several feet per year;

 Facility expects grade of pond to increase 200 feet over life of pond; and

 Total surface area is approximately 190 acres, including 74 acres for the east pond, 70 acres for the west pond, and 45 acres that are not yet
stacked.

• Wastewater from the east and west pond is discharged to the stilling pond and then to the Peabody ash pond.

• Paradise stated that approximately 100,000 cubic tons per year of fly ash enter the gypsum pond from the Units 1 and 2 FGD slurry blowdown.

• Paradise stated that because the gypsum contains fly ash, it is not marketable to wallboard manufacturers. Paradise also stated that they could not market the U nit 3 gypsum because the plant is in a remote location.

• Paradise is currently conducting a test of treating gypsum pond water throug h a passive water treatment system, which includes a constructed wetlands sys tem. Information regarding the passive water treatment system is included as Attachment 4. Paradise also provided the following information about the constructed wetland system:

 The wetlands beds are comprised of 1) fine limestone, 2) iron filings, and 3) wetlands plants.

 Cattails are the only plants species that are currently growing in the constructed wetlands. The other plant species did not survive because of competition and boron levels in the water. Paradise is currently attempting to supplement the plant life with bulrush.

 Of the 5 MGD of FGD wastewater generated, about one-third can be treated by the constructed wetlands.

 Personnel noted that they have a difficult time reducing the salt content.Page 5

Ash Handling and Wastewater Treatment

• Paradise operates wet bottom ash handling on all three units. The bottom ash is sluiced to the bottom ash (“slag”) pond.

 The bottom ash pond consists of three cells (alpha, bravo, and stilling cells), which are operated in series.

 The bottom ash pond system discharges two-thirds of the flow to the Green River and transfers the other one-third of the flow to the Peabody ash pond to facilitate movement of the fly ash and for pH control.

 The bottom ash pond does not have defined berms; backhoes and trucks enter alpha cell to remove bottom ash for sale.

 This pond system is unlined and located adjacent to the Green River.

 Paradise is currently cleaning out a portion of the pond to increase the holding capacity of the pond.

• A contractor collects the bottom ash that settles out in the first cell of the bo ttom ash pond (i.e., alpha cell) and markets the bottom ash. The bottom ash is sold for use in abrasives and shingles. The plant generates 350,000 cubic yards per year. Prior to marketing the bottom ash, it was stockpiled onsite. The current stockpile is approximately 85 feet above ground level.

• Paradise operates a wet fly ash handling system on Unit 3. Fly ash from units 1 and 2 is captured by the wet FGD scrubbers. The Unit 3 fly ash sluice is transferred to the Peabody fly ash pond, which began operating in the 1980s. Paradise provided the following information about the Peabody fly ash pond:

 Pond covers approximately 200-250 acres and has 28 years of life remaining (297 months from Feb 09);

 Pond discharges to Jacobs Creek (flow makes up greater than 75% of creek flow);

 Discharge is sampled two times per month for hardness, pH, TSS, O&G and one time per quarter for metals and toxicity;

 Berms are approximately 25 feet above grade;

 The pond system is unlined;

 Paradise is unsure of the pond depth, but one point in the pond is 80’ deep;

 Facility bubbles in CO 2 near discharge to control pH; and

 Algal blooms have occurred in summer.

• The Peabody fly ash pond receives the following wastewaters:

 Unit 3 fly ash sluice;

 Bottom ash pond overflow;

 Gypsum pond overflow;

 East and west dredge pond overflow (discussed below);

 Metal cleaning wastes;

 Air preheater washwater;

 Reclaimed strip mine area drainage; and

 Water from the precipitator washwater area.Page 6

• The overflow from the Peabody fly ash pond is discharged to Jacobs Creek, which
flows to the Green River.

• TVA is looking at converting all TVA plants to dry fly ash handling systems. However, since Paradise generates so little fly ash compared to other plant s, due to the use of cyclone boilers, it is a low priority to convert the Paradise system s.

• Paradise previously used the Jacobs Creek ash pond; however, this pond is currently inactive but not closed. Personnel stated that they can still move some miscellaneous wastes to this pond if needed. Berms are 10-15 feet high.

• As part of the operation of the ash ponds, Paradise created the east and west dredge ponds, which are used to store the ash that is dredged from the ash ponds. Rainfall collected in these dredge ponds is transferred to the fly ash pond. Paradise stated that the east and west dredge ponds have not received any dred ged ash in over a decade and the plant does not currently have plant to use them.

• Paradise stated that the use of cyclone boilers at the plant is advantageous bec ause the majority of the ash produced is bottom ash, which is almost 100 percent marketed; therefore, the plant stores less ash on the site.

• Paradise has two metal cleaning ponds, but now only performs boiler cleaning once every four years. Pond #1 is now inactive and Pond #2 currently receives air preheater wastes. Pond #2 is sampled prior to pumping the water to the Peabody ash pond; caustic is added to adjust pH as necessary.

• Paradise has the following pond inspection program:

 Conducted each year by fossil support personnel (internal to TVA) and a report generated; ongoing since early 1990s.

 Recently had a 3rd party inspection; currently conducting core sampling for compaction of berms.

 Inspections look for erosion, freeboard, interior slopes for interior erosion (caused by wave action), vegetation (don’t want exposed material), red waste seeps, and burrowing animals.

 Inspections are also conducted after every “significant” rainfall event (inspected for gulleys, etc).Page 7Table 1. Site Visit AttendeesNameOrganization (Representing)TelephoneE-mailPatrick Hjelm Tennessee Valley Authority (TVA) (270) 476-4395 pfhjelm@tva.govBrian LankfordTVA(270) 602-7901 Bslankford@tva.govGreg NunleyTVA(270) 476-3320 Gknunley@tva.govJared VincentTVA(270) 476-4020 javincent@tva.govSteve WestTVA(270) 476-3335 scwest@tva.govDonna HillUWAG(205) 257-5234 dbhill@southernco.comRon Jordan EPA/Office of Water (202) 566-1003 jordan.ronald@epa.govDeb Bartram ERG (Contractor to EPA) (703) 633-1669 deborah.bartram@erg.com