Final Notes from Site Visit at 

Duke Energy’s Wabash River Generating Station 

on February 25, 2009 

EPA conducted a site visit at Duke Energy’s Wabash River Generating Station (Wabash River) 

located in Terre Haute, IN on Wednesday, February 25, 2009 to learn about the operations at the 

plant, specifically the ash handling systems. EPA also gathered information to better understand 

the integration between this plant and the gasification operations at Unit 1 related to the 

treatment and discharge of wastewater from these operations. To accomplish this, EPA also met 

with the Wabash Valley Power Association (WVPA) separately to discuss the gasification 

operations at Unit 1. Table 1, located at the end of these notes, identifies the site visit 

participants. The presentation that the Wabash River personnel gave during the site visit is 

provided as Attachment 1. 

These notes describe the information collected during the site visit and the pre-site visit phone 

call, which was held on February 19, 2009. 

Plant Overview 

 Wabash River stated that there are five coal-fired generating units at the plant, in 

addition to the integrated gasification combined cycle (IGCC) unit (Unit #1, 

operated by WVPA). The boiler unit 1 was retired in the 1990’s and the steam 

turbine and generator were repowered using steam from a new coal (currently 

petroleum coke) gasification plant adjacent to the plant. The table below contains 

some general information for Units 2 through 6. 

Unit 

Installation 

Date 

Net Capacity 

(MW) Particulate Control NOx Control SO2 Control 

2 1953 85 ESP (cold-side) Low NOx burner None 

3 1954 85 ESP (cold-side) Low NOx burner None 

4 1955 85 ESP (cold-side) Low NOx burner None 

5 1956 95 ESP (cold-side) Low NOx burner None 

6 1968 318 ESP (cold-side) Low NOx burner None 

 The flue gas from each of the units is combined in one stack. 

 Wabash River does not operate any FGD systems. Wabash River stated that they 

evaluate whether to install FGDs at Wabash River on an ongoing basis, but it has 

been Duke Energy’s strategy to install FGDs on the largest units in the company 

first. 

 Wabash River burns Illinois Basin coal, which they receive via rail from a 

supplier about 20 miles from the plant. Coal may also be received via truck. The 

coal is typically stored on site for 35 days. However, due to the status of a New 

Source Review (NSR) lawsuit which resulted in limiting the operation of 

generating Units 2, 3, and 5, the number of days the coal is stored on site has 

increased to 48. Current economic conditions and coal contracts have also 

affected the amount of time coal is stored on site. 

 The sulfur content of the coal is approximately 3%. 
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 Units 2 through 5 burn pulverized coal; coal is pulverized in a ball and tube mill. 

 Duke operates their units as needed based on the economics. During the site visit, 

Units 4 and 6 were in operation. Units 2, 3, and 5 were off line because of the 

NSR lawsuit. 

 Prior to the site visit, Wabash River personnel collected samples from the coal 

pile runoff pond and measured the pH. The table below presents the results of the 

measurements. 

Location Date pH (S.U.) 

North side 2/23/2009 6.96 

Northeast side 2/23/2009 7.07 

Southeast side 2/23/2009 7.02 

Ash Handling and Wastewater Treatment 

 Wabash River operates wet bottom ash handling on all five of the generating 

units. 

 Wabash River operates wet fly ash handling on all five of the generating units; 

however, the plant is in the process of converting Unit 6 to a dry fly ash handling 

system. The ash handling silo for this system was in service on April 22, 2009. 

The plant is still in the process of transitioning between the ash pond and the ash 

silo, but the plant plans to handle all Unit 6 fly ash in a dry fashion. However, the 

plant will still have the option to sluice Unit 6 fly ash to the ash pond, if the need 

arises. 

 Wabash River installed the ash silo for the environmental and economic benefits 

of marketing the ash. 

 Wabash River stated that the conversion to the dry fly ash handling system on 

Unit 6 does not require a shut down of the unit as they have been able to do the 

work during normal plant outages. 

 The plant will still use the existing hydroveyor to pull the vacuum on the 

ash, but the ash will be directed to a 1,000-ton capacity silo 

(approximately 3 to 4 days of ash production) instead of being pulled into 

the water stream. See Slide 8 in Attachment 1 for a diagram of the silo 

system. 

 The water used in the hydroveyor system is plant service water which will 

be transferred to the plant’s ash pond. About 1-3 percent of the fly ash 

enters the hydroveyor water system and is transferred to the ash pond. 

Plant personnel noted that if the plant if the plant is unable to send the fly 

ash to the silo during abnormal conditions, then 100 percent of the fly ash 

will enter the hydroveyor water system. The plant uses service water in 

the hydroveyor water system. 
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 Fly ash from Unit 6 is used for housing material. 

 [CBI information has been removed from this document.] 

 The wet bottom ash and wet fly ash are sluiced to the plant’s ash pond system. Fly 

ash from Units 2 through 5 is not considered marketable by the plant because it is 

a high loss-on-ignition (LOI) ash. Overflow from the ash pond is not reused by 

the plant due to the expense of pumping the water uphill to the plant. 

 Wabash River’s ash pond system comprises three ponds covering 155 acres at the 

site. See Slide 5 of Attachment 1 for an aerial photo of the ash pond system. 

 The “primary” pond and “secondary settling cell” were built in 1985. Plant 

personnel believe that both pond units have a compacted clay liner. The 

primary pond has a surface area of approximately 85 acres and the 

secondary settling cell is 10-15 acres. The primary pond and secondary 

settling cell are part of the same pond structure but have been segregated 

in terms of wastewater flow. The depth of the secondary settling pond is 

approximately 13.65 feet. The water level in the primary pond varies 

between 16.5 feet up to 26.5 feet depending on the location within the 

pond. 

 The “new” pond, built in 2005, is lined with 60mL HDPE + clay and 

covers about 70 acres. The berms are made of encapsulated ash, capped 

with clay. The berms are about 20’ high on the north end of the pond and 

30-40’ high on the south end of the pond. This pond has a depth ranging 

from 18.5 to 23.5 feet. 

 Wabash River sluices fly and bottom ash to the primary pond, then 

hydraulically dredges the ash from the initial settlement area of the 

primary pond approximately 5,000 feet to the new pond, and the water 

than overflows back to the primary pond and discharges after flowing 

through the secondary settling cell. 

 Wabash River conducts pond integrity inspections quarterly for effects 

from rodents and vegetation; no third party inspections are conducted. 

 The original ash pond for the plant is located on the north side of the site 

and is closed. 

 The new ash pond cost more than $10 million to build. It was designed for a 10-

year life, but converting Unit 6 dry fly ash is expected to extend the pond life to 

20 years. Plant personnel noted that the conversion to dry fly ash handling was 

made because of the environmental and economic benefits of marketing the ash, 

not to increase the life of the new ash pond. 

 Wabash River stated that there is not much capacity left in the primary ash pond, 

which contributed to the decision to convert the Unit 6 fly ash handling system. 

 The primary ash pond receives the bottom ash and fly ash sluice, and coal pile 

runoff waste streams, as well as the wastewaters associated with the gasification 

process (internal Outfall 102). 
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 The primary ash pond overflows to the finishing cell, which overflows to the 

Wabash River via Outfall 002. 

 Wabash River has limits on the following parameters for Outfall 002: TSS, oil 

and grease, pH, copper, and iron, although the copper and iron limits are only 

when chemical metal cleaning wastes are sent to the ash pond. The plant also 

monitors the discharge for arsenic, cyanide, hexavalent chromium, and mercury. 

Plant personnel noted that metal cleaning wastes have not been sent to the pond in 

the past. Wabash River has completed a chemical metal cleaning in the last nine 

year, but the waste was evaporated in the units after appropriate testing. 

 Wabash River has limits on the following parameters for internal Outfall 102 

(gasification wastewater): ammonia, arsenic, cadmium, chromium, hexavalent 

chromium, copper, cyanide, lead, mercury, nickel, selenium, and zinc. The plant 

also monitors for pH. 

 Wabash River stated that the WVPA gasification operation currently has a 

NPDES permit to discharge the internal Outfall 102 wastewaters directly from 

their plant. Wabash River stated that WVPA is still designing/constructing a 

treatment system and discharge weir for the outfall, but once that is completed, 

Duke Energy will no longer receive wastewater from internal Outfall 102. 

 Wabash River stated that after they stop receiving the internal Outfall 102 

wastewater, they will continue to monitor the Outfall 002 discharge for the same 

parameters, but will consider asking to have some of the parameters removed 

when the permit expires. 

 Duke Energy staff discussed the ash handling practices at other Duke energy 

plants, noting the following: 

 Beckjord has dry fly ash. 

 Miami Fort handles fly ash dry (similar to the Unit 6 system). 

 The Gallagher plant operates four units. The plant installed baghouses and 

converted to dry fly ash handling. 

 Zimmer has dry fly ash. 

 Cayuga has wet fly ash. 

 Edwardsport has wet fly ash, but plant is shutting down. 
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Table 1. Site Visit Attendees 

Name Organization (Representing) Telephone E-mail 

Sherry Fisher Duke Energy Corporation (812) 535-2209 sheryl.fisher@duke-enTena Hopkins Duke Energy Corporation (317) 459-2375 tena.hopkins@duke-enFrank Klopfstein Duke Energy Corporation (812) 535-2221 frank.klopfstein@dukeHoward Lewis Duke Energy Corporation (371) 838-1661 howard.lewis@duke-enDebbie Nispel Duke Energy Corporation (317) 838-1957 debbie.nispel@duke-enDonna Hill UWAG (205) 257-5234 dbhill@southernco.com Sean Ramach US EPA – Region 5 (312) 886-5284 ramach.sean@epa.gov Ron Jordan EPA/Office of Water (202) 566-1003 jordan.ronald@epa.gov Deb Bartram ERG (Contractor to EPA) (703) 633-1669 deborah.bartram@erg.c