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Notes from Site Visit at Northern Indiana Public Service Company’s Bailly Generating Station on April 19, 2007

EPA conducted a site visit at Northern Indian a Public Service Company’s (NIPSCO’s) Bailly Generating Station on Thursday, April 19, 2007 to learn about the operations at the plant and determine where and how samples would be collect ed if the plant was selected for sampling. Table 1, at the end of this memorandum, identifies the site visit participants.

This memorandum summarizes the information colle cted during the site vi sit and the pre-site visit phone call, which was held on April 16, 2007.
Ownership/Operation

• NIPSCO is a subsidiary of NiSource, Inc.

• Pure Air owns and operates the FGD syst em and the FGD wastewater treatment (WWT) system used at the Bailly plant. NIPSCO and Pure Air entered into a 20-year contract agreement when the FGD system was brought on line in 1992. Under this contract, NIPSCO transfers flue gas to Pure Air’s FGD system and Pure Air transfers treated wastewater from the FGD WWT system to NIPSCO’s outfall.

Introduction of Plant

• The plant operates two coal-fired steam electric units, Units 7 and 8.

• The plant operates one gas turbine, Unit 10.

• Units 7 and 8 have cyclone boilers, a nd have capacities of 160 and 320 MW, respectively. Unit 7’s boiler includes four cyclones and Unit 8’s boiler includes eight cyclones. Both units were brought on lin e in the 1960s: Unit 7 in 1962 and Unit 8 in 1968.

• The plant burns approximately 35,000 lbs per hour of coal in each of the 12 cyclones. The plant burns approximately 5,000 t ons of coal per day in total.

• 75% of coal burned in Units 7 and 8 is Il linois Basin (Bituminous); 25% is Northern Appalachian (Eastern Bituminous).

• The coal used at the plant is pulverized prio r to use in the cyclone boilers, but it is not pulverized as finely as coal burne d in other types of boilers.

• 20 – 30% of ash produced in the cyclone boilers is fly ash. The rest is bottom ash. Donna Hill mentioned that more common bo iler types produce the opposite ratio of fly/bottom ash.

• Fly ash from Units 7 and 8 is handled in a pneumatic dry system. The plant sells most of the fly ash produced.

• Bottom ash from Units 7 and 8 is handled in a wet system.

• Units 7 and 8 each have an ESP.

• Unit 8 has an SCR and the plant is currently constructing an SCR for Unit 7.

• The plant will be in an outage from Oc tober through November 2007 for construction of the Unit 7 SCR. The Unit 7 SCR will be in service in 2008.

• The plant currently operate s the Unit 8 SCR during “ozone season” (May through September).Page 3
FGD System

• Units 7 and 8 exhaust to one FGD scrubber, which came on line in 1992.

• The FGD scrubber is a spray tower, in wh ich limestone is used as the sorbent.

• A Pure Air representative stated that the plant uses approximately 400 tons of limestone per day.

• The plant injects dry limestone into the F GD absorber, in which the dry limestone is slurried with water.

• The plant stores hydrated lime in a silo for use in upset/emergency situations.

• In the FGD absorber, which holds approximate ly one million gallons of slurry, forced oxidation is used to convert calcium sulfite to calcium sulfate (gypsum).

• The pH in the FGD absorber is typica lly maintained between 5.8 and 6.2. The maximum allowable chlorides concentrati on in the absorber is 20,000 ppm, but the plant typically maintains the chlori des concentration between 10,000 and 15,000 ppm.

• There is a continuous bleed from the abso rber to maintain 20-22 wt% gypsum in the FGD absorber. The bleed stream is transf erred to the Centrifuge Feed Tank.

• The Centrifuge Feed Tank, which is used as a surge tank, is about 25,000 to 35,000 gallons. A plant representative stated that the wastewater residence time is relatively short in the Centrifuge Feed Tank.

• Wastewater from the Centrifuge Feed Ta nk is transferred to nine centrifuges, operated in parallel, in which gypsum is separated from the filtrate.

• Gypsum separation occurs in the centrifuges in the following batch process:

- Wastewater is transferre d to the centrifuges;

- Spin cycle;

- Wash water (filtered intake water) is added to remove chlorides;

- Spin cycle;

- The separated gypsum solids are transfe rred to a storage building and sold for wall board manufacturing;

- Remaining gypsum cake is scraped out of centrifuges; and

- Centrifuges are washed out.

• All wastewater from the centrifuges is transferred to the Filtrate Sump.

• From the Filtrate Sump, wastewater is transf erred to the Filtrate Thickener tank. The main purpose of the Filtrate Thickener is to remove fly ash from the wastewater (fly ash is not removed very well in the ce ntrifuges). Underflow from the Filtrate Thickener is recycled to the Centrifuge Feed Tank, mainly to cause the fly ash to be removed from the system as part of th e gypsum. Rarely, under upset/emergency conditions, the underflow may be tran sferred to the FGD WWT system.

• Note that the plant no longe r adds hydrated lime to th e Filtrate Sump or the Centrifuge Feed Tank, as is shown on the plant’s FGD system flow diagram.

• The overflow from the Filtrate Thickener is transferred to the Thickener Overflow Tank. A portion of the thickener overflow is recycled back to the scrubber, a portion is recycled back to the Filtrate Sump for le vel control, and a portion is transferred to the FGD WWT system (as a con tinuous stream at a flow ra te of approximately 200 to 250 gpm) to maintain an acceptable chlori des concentration in the scrubber.Page 4

• The Pure Air representatives stated that the pH and chlorides concentration of the wastewater stream to the FGD WWT system is typically higher than that in the absorber, but they did not know the pH/concentration.

• Note that the plant’s FGD system diagra m shows a wastewater stream from the Thickener Overflow Tank to the Unit 8 flue gas stream, between the air preheater and the ESP. This transfer line no longer exists and is an artifact of a DOE pilot study in which the plant was involved during startup of the FGD system. During this pilot study, the plant tested an evaporation F GD WWT system. The plant injected the FGD wastewater into the Unit 8 flue gas ductwork, the wastewater was flashed to steam, and the solids were removed in the pr ecipitator. The plant ceased operation of this evaporation WWT system because the system did not have enough capacity and it had operational issues. The flue gas duc twork system was not hot enough and fly ash collected inside of the ducts.

FGD WWT

• The FGD WWT system is a segregated WWT system for FGD wastewaters.

• The first tank in the FGD WWT system is the Equalization Tank, which receives overflow from the Thickener Overflow Tank, as well as water that drains from the gypsum storage building (almost entirely gypsum truck tire wash water).

• Wastewater is transferred from the Equa lization Tank to the Neutralization Tank. Note that the plant does not add sodium hydroxide to th e Neutralization Tank, as is shown in the plant’s FGD WWT system flow diagram.

• Wastewater from the Neutralization Tank is transferred to the Coagulation Tank, in which polymer is added (using a dosing pump) based on wastewater flow rate. Pure Air representatives stated that the plant used to add ferric chloride to the Coagulation Tank, but switched to a polymer addition, whic h is less hazardous. The plant did not notice any negative effects on internal monitoring (turbi dity) with polymer use and thus, has continued to use the polymer in place of ferric chloride.

• Wastewater from the Coagulation Tank is tr ansferred to the Reactor Tank, in which a flocculent polymer is added.

• Wastewater from the Reactor Tank is transfer red to the “Densadeg” tank, which is an upflow, plate-settling clarifier/thickene r, designed by Infilco Degremont. The overflow from the Densadeg tank is transferred to the Clear Well. Note that the plant does not add sulfuric acid to the Clear We ll, as is shown in the plant’s FGD WWT system flow diagram.

• From the Clear Well, wastewater is di scharged through NIPSCO internal outfall 401A. This is the mechanism for the plant to remove chlorides from the FGD system. Internal outfall 401A, which is exclusively FGD waste, ha s a typical flow rate of approximately 200 gpm.

• The wastewater from the Clear Well is measured for turbidity.

• The wastewater from the Clear Well may be recycled back to the Equalization Tank under upset/emergency conditions.

• The majority of the underflow from the De nsadeg tank is transferred to the Sludge Tank. A portion of the underflow is recycl ed back to the Neutralization Tank to provide additional surface area for solids removal.Page 5

• The sludge from the Sludge Tank is dewatere d in the Filter Press and landfilled. The filtrate from the Filter Press is recycled to the Equalization Tank.

• No pH adjustment occurs anywhere in the FGD WWT system.

• Pure Air does not know the residence time of wastewater in the FGD WWT system.

• The FGD WWT system was designed to remove ash buildup and chlorides.

• The plant has not conducted any treatability studies for investigation of the pollutant removal performance of the FGD WWT system.

• Pure Air representatives stated that the plan t does not sample at any point in the FGD WWT system for metals concentration. The only metals sampling occurred during DOE’s test program when the FGD system came on line.

• The entire FGD system was partially funde d by DOE as a “Clean Coal” pilot program in 1992.

Plant Outfalls

• The plant has the following internal outfalls:

- 100: Bypass from Misc. Drains Collection to 001 (around ash pond).

- 101: Discharge from ash ponds.

- 111: Air heater wash water. To segregated pond and then ash ponds.

- 201: Sanitary water. Feeds into ash ponds.

- 301: Unit 7 boiler blowdown.

- 401A: FGD wastewater.

• Internal outfalls 101, 301, 401A, once-through condenser cooling water commingle into final outfall 001.

• Final outfall 001’s typical flow rate is approximately 300 MGD (note that the NDPES water balance diagram provided by NIPSCO presents maximum design flows), the majority of which is once-th rough condenser cooling water.
Plant Monitoring

• The plant’s NPDES permit is currently “in flux” while the limits for outfall 401A are decided upon. Specifically, th ere is an issue regarding a limit for low-level mercury.

• Currently the plant is monito ring at internal outfall 401A for TSS, oil and grease, pH, and mercury (total recoverable and low-le vel mercury). The plant monitors twice weekly.

• The plant’s NPDES permit requires “inter im” limits at outfall 001 for copper and mercury.

• The plant has experienced some issues rela ted to mercury sampling and analysis at internal outfall 401A. The lab has encountered interference with the field/trip blanks because the detection limit is so low. The contamination is in the parts per trillion range. Additionally, the lab has measured varying concentrations in duplicate samples (e.g., one sample is measured as non-detect for mercury, while a significant detectable concentration is measured in the duplicate sample).

• NIPSCO and UWAG agreed that chlorides and sulfates contained in FGD wastewater can interfere with low-level metals analysis.

• NIPSCO has encountered similar issues (a s with FGD wastewat er) with mercury sampling and analysis for outfall 001.Page 6

• Donna Hill suggested that NI PSCO should find out whether their lab is diluting the samples properly for low-level metals analysis.
Sampling Information

• EPA/ERG evaluated the followi ng potential sampling points:

- To Equalization Tank: A pipe is lifte d to access the wastewater flow.

- To Neutralization Tank: Th is point is where the wa stewater flow from the Equalization Tank enters the top of th e Neutralization Tank, just prior to the recycle addition from the Densadeg tank. The sample well looks as if it has not been used in a long time a nd contains a significant layer of solids that could potentially contamin ate a sample. Figure 1 presents a photo of this potential sampling point.

- Effluent from Clear Well (just prio r to outfall 401A): The sample well at this point is completely filled with water. EPA/ERG/UWAG discussed the possibility of submerging a samp le bottle or pumping out of the sample well, but determined that th e solids in the well could potentially contaminate a sample. Figure 2 presen ts a photo of the sample well. A better option appears to be an unused por t that could be flushed for several minutes prior to sample taking. Figure 3 presents a photo of the potential sample port.

- Intake Water: A sample could be taken in the pumphouse on the lakeshore. The pumphouse contains uncovered pools of intake water (on left) and plant efflue nt water (on right).

• In general, clean hands/dirty hands procedur es would be difficult at the plant because of dusty conditions.

• There are flow meters for all sample points.

• The plant representatives cautioned EPA, in case Bailly is chosen as a sampling site, that the plant power producti on fluctuates. In particular , the plant sometimes reduces Unit 7 (the smaller of the two units) to half load.

• Samplers would need to go through a 30 minute contractor orientation, including safety video, and obtain a safety work permit.

• There should be space at the production service center for a staging area.

• A plant representative thought that EPA/ERG would be able to use a small area of counter in the laboratory, but would need to check with his manager.

• The nearest hospital is the Porter Memorial Hospital.

• For an on-site emergency, dial 311 an d plant personnel will call emergency responders.

• The plant suggested shippi ng sampling materials from the nearest FedEx location.

Coal Pile Runoff

• The majority of runoff from the coal pile is absorbed in the ground under the coal pile. The remaining coal pile runoff is transferred to an “absorption field”.

• There is no discharge of coal pile runoff from the plant.Page 7

Bottom Ash Handling

• Bottom ash is sluiced to a pond system.

• The ash pond receives the following streams:

- Bottom ash sluice;

- Sanitary water;

- Water from the air heater wash water pond; and

- Water from miscellaneous drains, whic h includes water from intake water filters and demineralizer wastes.

• The majority of water from the ash pond system is recycled as bottom ash sluice.

• A bleed stream from the ash pond system (inter nal outfall 101) is used to control the level in the ash pond system.

Other Plant Water

• Intake water from Lake Michigan is filtered to remove relatively large solids from the water. This filtered intake water is used in the FGD system.

• Cooling water is a once-through system. No biofouling is required for this cooling water.

Other Notes

• NIPSCO has provided EPA with the plant’s NPDES permit and Form 2C.

• NIPSCO representatives mentioned that the RM Schahfer plant, also operated by NIPSCO, does not operate an FGD WWT system.Page 8

Figure 1. Sampling Location for Infl uent to Neutralization Tank (from Equalization Tank in FGD WWT System)

Figure 2. Sample Well at Effluent from Clear Well (just pr ior to Outfall 401A)Page 9

Figure 3. Sample Port for Effluent from Clear WellPage 10Table 1. Site Visit AttendeesNameOrganization (Representing)TelephoneE-mailDean McDevitt NiSource, Inc. (219) 647-5268 damcdevitt@nisource.comJeff Neumeier NiSource, Inc. (219) 787-7298 jneumeier@nisource.comGreg Costakis NiSource, Inc. (219) 956-5125 gcostakis@nisource.comJim Snoeyink NIPSCO (219) 787-7310 jssnoeyink@nisource.comLarry Dora NIPSCO (219) 787-7304 lldora@nisource.comBert Valenkamph NIPSCO (219) 477-6265 bcvalenkamph@nisource.comTim Wright NIPSCO (219) 787-7379 tewright@nisource.comEd Gastenveld Pure Air (219)787-9551 gastenet@apci.comGeorge Nyers Pure Air (219)787-9551 nyersgs@apci.comDonna Hill Southern Company (205) 257-5234 dbhill@southernco.comLindy Johnson Tennessee Valley Authority(423) 751-3361 lpjohnson@tva.govJosh Hall EPA/Office of Water (202) 566-1002 hall.josh@epa.govRon Jordan EPA/Office of Water(202) 566-1003 jordan.ronald@epa.govT.J. Finseth ERG (Contractor to EPA) (703) 633-1698 thomas.finseth@erg.comSarah Holman ERG (Contractor to EPA) (703) 633-1661 sarah.holman@erg.com