# Engineering Site Visit Report for First Energy Generation Corp. Bruce Mansfield Power Plant Shippingport, PA

Prepared by:



## U.S. Environmental Protection Agency Engineering and Analysis Division Office of Water 1200 Pennsylvania Avenue Washington, DC 20004

August 21, 2008i TABLE OF CONTENTS

Page

1.0 Site Visited and Date...................................................................................................... ... 1

2.0 Attendees .................................................................................................................. ......... 1

3.0 Background and Objectives............................................................................................... 1

4.0 Plant Description .......................................................................................................... ..... 2 4.1 Overview of Plant Operations.................................................................................. 2 4.2 Flue Gas Desulfurization (FGD) System................................................................. 3 4.3 Forced Oxidation Gypsum (FOG) Plant.................................................................. 5 4.4 Waste Disposal Area (WDA) .................................................................................. 6 4.5 Little Blue Run (LBR) Impoundment...................................................................... 7

5.0 References ................................................................................................................. ...... 11

Appendix A LIST OF ATTENDEESii LIST OF FIGURES

Page

Figure 4-1. Flow Diagram for Unit 1 and 2 Scrubbers.................................................................. 8

Figure 4-2. Flow Diagram for Unit 3 Scrubber ............................................................................. 9

Figure 4-3. Flow Diag ram for FOG Plant.................................................................................... 101 1.0 S ITE V ISITED AND D ATE

FirstEnergy Generation Corp. Bruce Mansfield Power Plant 128 Ferry Hill Road Shippingport, PA 15077

October 19, 2007

2.0 A TTENDEES

Appendix A lists the attendees.

3.0 B ACKGROUND AND O BJECTIVES

Section 304(m) of the Clean Water Ac t (CWA) requires EPA to develop and publish a biennial plan that esta blishes a schedule for the annual review and revision of national effluent limitations guidelines and standards (E LGs) required by CWA section 304(b). During EPA’s 2005/2006 review of ELGs, EP A determined that the Steam Electric Power Generating Point Source Category (40 CFR Part 423) is the second-largest discharger of toxic-weighted pollutants. EPA’s analyses indicated that the to xic-weighted loadings are predominantly driven by metals present in wastewater discharges, and that the waste streams contributing the majority of the metals are associated with air pollution co ntrols. Other potential s ources of metals include coal pile runoff, metal/chemical cleaning wastes , coal washing, and certain low volume wastes.

In presenting the findings of the 2005/2006 study, EPA noted certain data limitations affect the Agency’s estimate of the potential hazard posed by discharges from this category and, therefore, EPA determined that fu rther review of these discharges during the 2007/2008 ELG planning cycle is warra nted. Due to the limited resources and time available for conducting this study, EPA is concentrating its efforts for the 2007/2008 study on better characterizing pollutant sources and available pollution control t echnologies/practices for the pollutants responsible for the majority of the toxic-weighted pollutant loadings from steam

electric facilities. This will focus the review on wastewater discharges from coal-fired power plants.2 EPA intends to review overall plant ope rations and better un derstand the various wastewater sources present at steam electric plants . This review is expected to largely focus on ash handling wastes, wet flue gas desulfurizati on (FGD) wastes, coal p ile runoff, and final

effluent.

EPA conducted a site visit to the Firs tEnergy Generation Corp. Bruce Mansfield Power Plant (Bruce Mansfield) on October 19, 2 007. The purpose of the visit was to gather information about the plant’s operations, the wast ewater discharges from the plant, and the wastewater management practices us ed to control the discharges.

4.0 P LANT D ESCRIPTION

4.1 Overview of Plant Operations

Bruce Mansfield began operation in 1976, when Unit 1 came on line. Unit 2 began operation in 1977 and Unit 3 began operati ng in 1980. Each unit has a capacity of 824 megawatts (MW), for a plant total generating cap acity of 2,472 MW. The Bruce Mansfield plant is located in Shippingport, PA along the Ohio River.

All three generating units at Bruce Mansfi eld have coal-fired boilers. The plant burns more than 24,000 tons of bituminous coal daily when operating at full capacity. The coal is delivered to the plant by barge and rail from mines in Ohio, Pennsylvani a, and West Virginia. The plant receives both high and lo w sulfur coal, which it then blends to achieve the desired

sulfur level of 2.8- 3.2 percent sulfur.

All three units have selective catalytic reduction (SCR) for NOx control and add

sodium bisulfite downstream of the SCR for SO 3 control. For units 1 and 2, the flue gas from the boilers first passes through the SCR, after which sodium bisulfite is added. The flue gas then passes through the air preheater a nd then enters the scrubbers. Th e plant refers to the processes from the SCR through scrubbers as the Air Qual ity Control System, or AQCS. For unit 3, the flue gas from the boiler passes through the SCR (and sodium bisulfite addition), then the air preheater, followed by the ESP and then the sc rubber. The SCRs are currently operated only3 during ozone season (April through September), but will start operating year-round in January 2009. Flue gases from units 1 and 2 are emitte d through four separate flues (two per unit) through a single 950-foot chimney. Unit 3 flue ga ses are emitted throug h a separate 600-foot chimney.

All units operate inhibited-oxidation, magnesium-enhanced lime wet flue gas desulfurization (FGD) systems. The calcium sulf ite produced in the scrubbers is converted to gypsum in a separate process, which occurs at wh at the plant refers to as the Forced Oxidation Gypsum (FOG) Plant. The first phase of the FOG Plant was started in 1999; the second phase began operation in 2006.

Fly ash is removed from unit 3 by a cold side electrostatic precipitator (ESP). The fly ash is transferred pneumatically from the hoppers to an ash silo, and th en wet sluiced to the Waste Disposal Area (WDA) where it is combined w ith other wastes. No ESPs are installed on units 1 and 2, so fly ash from these units is captu red in the scrubbers. The fly ash from units 1 and 2 is subsequently removed in a process downs tream from the scrubbers and transferred to the

WDA where it combines with other wastes. At the WDA, wet fly ash from all units is commingled with fines thickener underflow from the FOG process. These wastes are mixed with lime and a stabilizing agent, and then disposed of in the Little Blue Run (LBR) impoundment.

The plant operates three 410-foot natura l draft cooling towers. The towers each process cooling water at a rate of approxi mately 310,000 gpm. The total annual water withdrawal for the three cooling towe rs in 2007 was 21,331 million gallons.

4.2 Flue Gas Desulfurization ( FGD) System

All three generating units operate in hibited-oxidation, magnesium-enhanced lime wet FGD systems to control the emission of sulf ur dioxide from the plant. The scrubbers on

units 1 and 2 are venturi scrubbers manufactur ed by Chemico and achieve approximately 97-99 percent SO 2 removals. These scrubbers each have 6 absorber modules. The unit 3 scrubber is a4 horizontal spray design manufactured by Pullman-K ellogg; it has 5 parall el absorber modules and achieves approximately the same level of SO 2 removal. The unit 3 scrubber was shutdown for a maintenance outage during the site visit and is being modified to increase its SO 2 removal capacity. Slaked lime (calcium hydroxide) is used as the FGD sorbent in all three scrubbers. The magnesium present in the lime is present na turally (not added by special processing); the plant purchases lime meeting certain specificatio ns that include magnesium content. Makeup water for the scrubbers is either water recycled from the thickener overflow, or water from the Low Dissolved Solids Pond. For a general descri ption of the FGD process and the chemical reactions involved, see Section 3.2.1.6 of the Interim Detailed Study Report for the Steam Electric Power Generating Point Source Category

.

Calcium sulfite produced in scrubbers is oxidized to gypsum in a separate process, which occurs at the FOG plants. A ll calcium sulfite from the scrubber blowdowns is sent to the FOG plants for processing, unless the FOG plants are shutdown or in an upset condition. Calcium sulfite not processed by the F OG plants is sent to the WDA for treatment, then pumped to the LBR impoundment. According to company literature, at full capacity each scrubber can produce up to 4 mgd of calci um sulfite slurry (blowdown) daily.

Unit 1 and 2 scrubbers

Unit 1 and 2 scrubbers use the same pro cess operations in parallel. There is no ESP on units 1 and 2, so fly ash from these units is captured in the scrubber. The scrubbers operate with continuous blowdown of a mixture of calcium sulf ite and fly ash. The blowdown

rate is controlled to maintain the desired solids concentration in the scrubbers. Plant personnel stated that 4-6 percent solids is the ideal scr ubber concentration, although the scrubbers typically operate at 6-8 percent solids. Scrubber blow down flowrate is not monitored by the plant.

The scrubber blowdown is sent to a th ickener for solids removal. Thickener overflow is returned to the scrubber as makeup water or used as wash water for the mist eliminators. Thickener underflow (calcium sulfite and fly ash) is sent to a holding tank, then pumped to hydroclones to separate fly ash from the calcium sulfite. Fly ash is removed in the hydroclone underflow as a concentr ated slurry (approximately 30 pe rcent solids) and sent to the5 WDA at 500-900 gpm where it combines with fly ash from the other units and fines thickener underflow from the FOG plant. The hydroclone ove rflow (mostly calcium su lfite) is sent to the FOG plant at 500-900 gpm, where it is converted to gypsum. See Figure 4-1 for a flow diagram

of the unit 1 and 2 scrubbers.

Unit 3 scrubber

Unit 3 has a cold side ESP (CS-ESP) upstream of the scrubber which removes most fly ash prior to the flue gases entering the scrubber. The fly ash is pneumatically transferred from the ESP hoppers to a silo; the fly ash is then sluiced from the silo to the WDA using water from the FOG waste sumps. Unit 3 th ickener underflow can be used as a source of fly ash sluice water through the premix sy stem when the FOG is not in service.

The unit 3 scrubber blowdown solids concen tration is similar to Unit 1 and 2 scrubbers; the blowdown is sent to a thickener. Thickener overflow is returned to the scrubber as makeup water or used as wash water for the mist eliminators. Thickener underflow (calcium sulfite) is sent (23-24 percent so lids at 500-700 gpm) to the FOG pl ant where it is converted to gypsum. See Figure 4-2 for a flow diagram of the unit 3 scrubber.

4.3 Forced Oxidation Gypsum (FOG) Plant

Calcium sulfite produced in the scrubbers is oxidized to gypsum in an additional process, which occurs at the FOG Plants. Th e first FOG plant initially began operating in 1999 and had a capacity to process calcium sulfite fr om Unit 3 scrubber, as well as a portion of the calcium sulfite from Units 1 and 2. In 2006, FOG plant #2 began operating and the plant now has the capacity to process all calcium sulfite generated in th e plant’s scrubbers. The primary reason for installing and expanding the FOG plants was to reduce the volume of wastes being

sent to the Little Blue Run im poundment, thus extending the operat ing life of the impoundment. Plant personnel estimate that th e capacity of Little Blue Run impoundment would have been exhausted within 7 years if the FOG plant had not been expanded.6 Calcium sulfite slurry from units 1, 2 a nd 3 is combined in a mix tank, along with recycle streams from the hydroseparator underflow. Slurry from the mix tank is sent to a series

of oxidation reactors. Th e slurry enters the top of the reactor vessel and air is introduced at the

bottom of the reactor. Sulfuric ac id is added to the r eactor to dissolve the calcium sulfite and, in a rapid reaction, the forced oxidati on process forms calcium sulfate crystals which drop to the bottom of the reactor where they are removed.

The calcium sulfate removed from the reacto rs is sent to hydroseparators to wash residual fly ash from the gypsum. The hydroseparat or underflow (gypsum) is sent to belt filter presses where it is dried to a pproximately 10 percent moisture, then transferred by conveyor to an adjacent National Gypsum Company plant where it is made into wallboard. The hydroseparator overflow is sent to a fines thickener.

Underflow from the fines thickener is sent to the WDA mix tank where it combines with fly ash and FOG plant wastewaters. Most of the fines thickener overflow (less than 1 percent solids) is recycled within the proc ess for use as wash water in the hydroseparators.

Excess volumes of fines thickener overflow not us ed as hydroseparator wash water (referred to as the “clear water stream” or dilution water) are pumped to twin storage tanks before being pumped to the Little Blue Run impoundment at an average rate of 400-600 gpm. See Figure 4-3 for a flow diagram of the FOG Plant.

4.4 Waste Disposal Area (WDA) Wet fly ash from all units is commingled with wastewater from the FOG process, as well as any calcium sulfite not converted to gypsum, in a mix tank. Lime and a stabilizing agent (formerly referred to by the trade name of Calcilox) are added to the wastes in the mix tank. The resulting mixture is then pumped thro ugh 7 miles of underground piping to the Little Blue Run impoundment for disposal . The typical wastewater fl owrate from the WDA to the LBR impoundment is 3,000 gpm. The stabilizi ng agent is a byproduct generated by steel mill operations. Other wastes sent to the WDA include settled material from the Low Dissolved Solids Pond (actually two ponds).7 4.5 Little Blue Run (LBR) Impoundment

The LBR impoundment is an 1,100-acre unlined impoundment, which is formed by a 485-foot dam and described in company lite rature as the largest earth and rockfill embankment dam in the eastern U.S. The LBR impoundment receives wet fly ash and FGD wastes (via the FOG plant) from units 1, 2 and 3. Other sources to the LBR impoundment are stormwater runoff and certain impoundment s eepages that are pumped back into the impoundment. Discharges from the LBR impound ment first pass through the Stilling Basin, where pH is adjusted if necessary prio r to discharge to the Ohio River.8 Figure 4-1. Flow Diagram for Unit 1 and 2 Scrubbers9 Figure 4-2. Flow Diagram for Unit 3 Scrubber10 Figure 4-3. Flow Diagram for FOG Plant11 5.0 R EFERENCES

1. U.S. EPA. 2006. Interim Detailed Study Report for the Steam Electric Power Generating Point Source Category . EPA-821-R-01-015. Washington, DC. November. DCN 01923.Appendix A

LIST OF ATTENDEESA-1Table A-1. List of AttendeesNameOrganization (Representing)TelephoneE-mailRick Sprecker FirstEnergy Generation – Bruce Mansfield Plant (724)643-2212 spreckerr@firstenergycorp.comRobert Kish FirstEnergy Generation – Bruce Mansfield Plant (724)643-6852 kishr@firstenergycorp.comDave Brunberg FirstEnergy Generation – Bruce Mansfield Plant (724)682-6907 dbrunberg@firstenergycorp.comScott Brown FirstEnergy Generation (330)384-4643 browns@firstenergycorp.comJosh Hall EPA/Office of Water (202) 566-1002hall.josh@epa.govRon Jordan EPA/Office of Water(202) 566-1003 jordan.ronald@epa.govEphraim King EPA/Office of Water (202) 566-0430 king.ephraim@epa.govKareen Milcic Pennsylvania DEP(412) 442-4033 kmilcic@state.pa.usJeffrey Jones Pennsylvania DEP (724) 847-5279 jefjones@state.pa.usDonna Hill Southern Company (205) 257-5234 dbhill@southernco.com