Draft Notes from Site Visit at Dominion Resources’ Chesterfield Power Station on September 2, 2009

EPA conducted a site visit at Dominion Resources’ Chesterfield Power Station (Chesterfield) located in Chester, VA on Wednesday, September 2, 2009 to learn about the operations at the plant. These notes describe the information collected during the site visit.
Table 1 identifies the site visit participants. The presentation that the Chesterfield personnel gave during th e site visit is provided as A ttachment 1

.

Plant Overview

**•** Chesterfield is the largest fossil

- fueled power station in the Dominion System. The plant operates six electric generating units , four of which are baseload coal

- fired units. The plant’s net generating capacity is 1

, 650 MW

, which incl ud es 1

, 245 MW associated with
the coal

- fired units . The table below contains some general information for each electric generating unit.

Unit Installation
Date Net Capacity

(MW) Particulate
Control NOx Control SO 2 3 Control
1952 101 Cold

- side
electrostat ic precipitator ( ESP ) Low

- NOx
burners Limestone forced oxidation (LSFO)
FGD scrubber under construction (will service Units 3, 4, and 5) 4 1960 163 Cold

- side
ESP Low

- NOx
burners
SCR installed
2003
5 1964 321 Cold

- side
ESP Low

- NOx
burners
SCR installe d
in 2002

6 1969 660 Baghouse (pulse jet fabric filter) Low

- NOx
burners
SCR installed
in 2004 LSFO FGD
scrubber online in
2008

7 1990 201 N/A N/A N/A
8 1992 204 N/A N/A N/A

**•** Chesterfield operates two ponds and a landfill on the site . The two ponds are described
as the metals pond and the lower ash pond. The metals pond has a capacity of approximately 19 million gallons and is used to treat pre

- treat low

- volume wastes prior to transferring to the lower ash pond. The lower ash pond has a capacity of 242 million gallons and receives liquid

- borne materials for treatment prior to discharge. The landfill,
referred to as t he “ upper ash pond ” was initially constructed as a wet pond in 1983, but began the closure process in 2002 . The upper ash pond no lon ger receives liquid

- borne
materials , and the plant is in the process of landfilling ash where the pond previouslyexisted . Neither the lower nor the upper ash pond are lined. [QUESTION FOR CHESTERFIELD: Is the metals pond lined?]

**•** Chesterfield burns s ub bituminous coal i n generating units 3, 4, 5, and 6. Most of the coal
used at Chesterfield comes from Appalachian mines. The coal is delivered by train and stored in the plant’s coal pile. Chesterfield keeps 30 days worth of coal on s ite

. Chesterfield b urns approximately 10,000 tons of coal per day.

**•** Chesterfield has two coal piles on s ite , a high

- sulfur and a low

- sulfur coal pile. The high sulfur coal is used in Unit 6 because the unit is serviced by any FGD system. The plant is currently constructi ng an FGD system for Units 3, 4, and 5 and after the FGD begins operating, each of th e units will switch to using high sulfur coal. The following table provides some of the typical characteristics for the two different types of coal burned by the plant

.

Characteristic Low

- Sulfur Coal High

- Sulfur Coal BTU (BTU/lb) 12,500 12,900 Sulfur content (%) <1 1.6

– 3.2 Chlorine content (%) Varies 0.09

– 0.18 Ash content (%) 6

– 13 7

- 12

**•** The coal pile runoff generated by the plant is transferred, untreated, to the lower ash pond.

**•** Units 7 and 8 are combined cycle turbines . These units have the capability to burn #2
fuel oil and/ or natural gas. T he units can burn the oil and natural gas individually or at
the same time. Both combined cycle systems operate as peaking units

, typically cycl ing up and down depending on demand (cycles every 3 to 6 hours) ; however, p lant p ersonnel
stated that because natural gas has been so cheap recently , the units have predominantly been burning natural gas and have been operating continuously. P lant p ersonnel also
stated that the natural gas burned in the units i s required to contain less than one

- half percent sulfur. [QUESTION FOR CHESTERFIELD: How many combustion turbines and steam turbines are associated with each combined cyc le system?]

**•** Plant personnel stated that generally the only wastewaters generated from Units 7 and 8

are once

- through cooling water and boiler blowdown. The once

- through cooling water for Units 7 and 8 is discharged to the James River via Outfall 001. Th e boiler blowdown
is transferred to the yard sump, which is then transferred to the lower ash pond. A picture of Chesterfield’s permi tted outfalls and a water balance diagram is included as
A ttachment 2 to this memorandum.

**•** Chesterfield also operates on ce

- through cooling systems for the coal

- fired units. The

once

- through cooling water for Unit 3 is discharged via Outfall 002 and the once

- through cooling water for Units 4, 5, and 6 is discharged via Outfall 003.

**•** Chesterfield chlorinates the cooling wate r for biofouling control on each unit for two hours a day. Chesterfield operates a dechlorination system on the discharge end of the

once

- through cooling systems, which consists of injecting sodium bisulfite into the waterstream. Chesterfield stated tha t they over

- inject the sodium bisulfite to guarantee that all
the residual oxidants are consumed.

**•** Chesterfield operates low

- NOx burners on each of the coal

- fired units (U nits 3, 4, 5, and
6 ). Additionally, Chesterfield operates SCRs on units 4, 5, and 6

. Plant personnel stated that they do not intend to install a SCR on U nit 3 because it is not considered cost effective. Chesterfield personnel stated that the other SCRs are over

- controlled to compensate for the NOx emissions from Unit 3

.

**•** Anhydrous ammo nia , for use in the SCRs, is delivered to Chesterfield via truck and
stored in tanks. Plant personnel stated that the SCRs use a total of 38,000 pounds of ammonia a day.

**•** P lant p ersonnel stated that the SCRs operated for 3 years before Chesterfield had to add a third layer of catalyst to maintain the NOx removal efficiency. The SCRs are now at capacity for the layers of catalyst; therefore, the plant will either have to replace or regenerate a catalyst layer the next time a new catalyst layer is needed. Plant personnel stated that they ha ve not decided if the catalyst s will be regenerated or replaced

.

**•** Chesterfield switched to year

- round operat ion of the SCR s beginning in 2008. P lant

p ersonnel stated that the SCR target NOx reduction is approximatel y 90 percent.

**•** Chesterfield stated that they have not seen a big impact on the fly ash or the ash pond discharges since the installation of the SCRs. Chesterfield stated that they had done some modeling of the potential impacts on ammonia discharges from the ash pond as a result of installing the SCRs. [ QUESTION FOR CHESTERFIELD: Please provide the results or reports that document effects that the installation of the SCR had on the fly ash and ash pond wastewater characteristics

.

**•** Units 3, 4, and 5 ea ch operate a cold

- side ESP , which achieve a 96 to 99 percent removal of particulate matter . Unit 6 operat es a pulse jet fabric filt e r baghouse , which achieves greater than 99 percent removal of particulate matter. Chesterfield previously operated
an ESP on Unit 6, but the plant installed the baghouse in April 2008 to decrease the particulate and mercury emissions for the unit

. Plant personnel estimated that the installation of the baghouse and FGD system will reduce mercury emissions by 90 percent ; howev er, they noted that they do not have plans to replace any of the other ESPs.

**•** Chesterfield operates the Marsulex Clean Stack technology on Unit 6, which inject lime into the flue gas to control sulfur trioxide emissions which lead to the formation of blu e plume. [QUESTION FOR CHESTERFIELD: Where is the lime injected? Does the plant plan to use the technology on Units, 3, 4, or 5? If so, which ones?]

**•** Chesterfield operates once

- through cooling systems on all six electric generating units. The plant u ses the James River as the source of the once

- through cooling water.

**•** Chesterfield employs approximately 260 workers.

**•** Chesterfield is in the process of renewing its NPDES permit. The current permit will expire on December 9, 2009 . Chesterfield submitt ed its permit renewal application onMay 28, 2009. Chesterfield personnel stated that the y do not expect any to change s to the permit limits or monitoring requirements, even with the i nstallation of the new FGD system

.

FGD System

**•** C hesterfield operates a limestone forced oxidation FGD system for unit 6

. The FGD system has five recirculation pumps and three spray headers

. The FGD system also has a dual flow tray that consists of multiple metal trays with small holes for the gas to pass through. The tr ay s increases the contact time between the sorbent slurry and the flue gas; thereby increasing the sulfur dioxide removal efficiency. A process flow diagram of the FGD system and a picture of the dual flow tray s are included as Attachment 3 to this

memora ndum.

**•** Chesterfield is currently constructing a second limestone forced oxidation FGD scrubber that will service Units 3, 4, and 5. This FGD system is planned to begin operation in the spring of 2011.

**•** Both FGD systems were designed to achieve a sul fur dioxide removal of greater than 95 percent.

**•** Chesterfield receives its limestone via barge. The limestone is conveyed from the barge to the limestone pile, which has a permanent covering. Although the limestone pile is covered, plant personnel state d that occasionally a limestone pile runoff stream is generated. The limestone pile runoff is collected in the yard sumps and transferred to the ash pond.

**•** C hesterfield operates two ball mills to crush the limestone to the correct size for use in
the lime stone slurry. Chesterfield personnel stated that the ball mills are typically operated during the night shift.

**•** The limestone slurry from the ball mills is transferred to a classifier to remove the large limestone particles before transferring the slurry to the limestone storage tanks. The large limestone particles are recycled back to the ball mill for additional processing.

**•** Chesterfield built an organic acid tank to have the capability to add organic acid to the FGD system and improve the sulfur diox ide removal efficiency ; h owever, personnel
stated that the organic acid tank has never been filled and they do not have any plans to use organic acid in the FGD system

. [QUESTION FOR CHESTERFIELD: Is the auxiliary equipment (e.g., pumps and piping) also i nstalled for the organic acid addition?]

**•** Chesterfield uses the effluent f r om the Proctor’s Creek wastewater treatment plant as the FGD system make

- up water, which includes make

- up to the scrubber, mist eliminator washes, and limestone preparation. The Pr octor’s Creek plant provides Chesterfield with 1 to 1.5 MGD for use in FGD system. Plant personnel stated that Proctor’s Creek
effluent will also be used as the make

- up water for the second FGD system when it begins operating. [QUESTION FOR CHESTERFIELD : Does the plant have to do any pretreatment of the effluent from the wastewater treatment system prior to use in the FGD? Are there any parameters of the effluent that the plant monitors? Was the systemdesigned to take the effluent from the wastewater treatment plant and if so were there any design requirements that are unique to the FGD at Chesterfield specifically for this purpose?

**•** The typical solids concentration in the FGD system is 14 to 20 percent and the typical chlorides concentration is 19,0 00 to 25,000 ppm. Plant personnel stated that 25,000 ppm
is the maximum allowable chlorides concentration for the materials of construction in the FGD scrubber. Chesterfield blows down from the FGD system once every 12 hours for approximately 10 to 12 ho urs to maintain acceptable solids and chloride concentrations in the FGD system.

**•** The blowdown from the FGD system is transferred to the primary hydroclone for initial solids separation. The design flow rate of the blowdown to the primary hydroclone is 1, 328 gpm. Some of the overflow from the primary hydroclones , 990 gpm, is recycled back to the scrubber, while the remainder is transferred to the secondary hydroclones.
The underflow from the primary hydroclone, which is approximately 70 percent solids, i s transferred to the vacuum belt filter

.

**•** Chesterfield uses a vacuum belt filter to dewater the gypsum into a saleable byproduct. Chesterfield washes the gypsum as it is applied to the belt filter to reduce the chlorides.
Chesterfield also uses Proctor ’s Creek effluent as the gypsum wash water. The dewatered gypsum typically has a chloride concentration of 70 to 85 ppm and moisture content of six to eight percent

. The filtrate from the vacuum belt filter is either
transferred to the reclaim tank and r ecycled back to the FGD scrubber or transferred to the FGD wastewater treatment system.

**•** Chesterfield markets the gypsum produced to U

. S

. Gypsum in Norfolk. The gypsum specifications for use by U

. S

. Gypsum are that the gypsum must contain less than 10

per cent moisture and less than 100 ppm chlorides. The gypsum f ro m the vacuum belt filters is transferred to a temporary storage area and then conveyed to a barge so it can be transported to U

. S

. Gypsum. Chesterfield transports approximately 10 ,000 tons per month of gypsum to U

. S

. Gypsum . Chesterfield maintains around 9,000 tons of on

- site gypsum storage.

**•** The overflow from the primary hydroclones is transferred to the secondary hydroclone s for additional solids separation. The underflow from the secondary hydroclones is transferred to the reclaim tank and recycled back to the FGD scrubber. The overflow from the secondary hydroclone , FGD scrubber purge, is transferred to the FGD wastewater treatment system.

**•** Once the second FGD system begins operating , t he FGD scrubber purge for the system
will also be sent to the FGD wastewater treatment system

.

FGD Wastewater Treatment System

**•** The FGD scrubber purge is transported to the equalization tank of the FGD wastewater treatment system. The FGD scrubber purge is typically transferred to the equalization tank at 140 gallons per minute for at least eight hours of the day. The equalization tank also receives the filtrate from the wastewater treatment filter press and water collectedfrom the sumps of the wastewa ter treatment system building. The residence time of the equalization tank is approximately 30 minutes. A process flow diagram of the FGD wastewater treatment system is included as Attachment 4 to the memorandum.

**•** Currently, the FGD wastewater treatment system is not operating continuously because the FGD scrubber purge is transferred on an intermittent basis

. Plant personnel expect that the treatment system will operate on a more continuous basis once the second FGD system begins operating

.

**•** The waste water from the equalization tank is transferred to the desaturation tank, where lime is added to adjust the pH of the wastewater. The desaturation tank also receives a small amount of underflow from the downstream clarifier. The target pH in the
desatura tion tank is 9 .0 S.U

. The lime slurry added to the desaturation tank is 2.5 percent
solids.

**•** The FGD wastewater is transferred f rom the desaturation tank to the heavy metals tank. In the heavy metals tank, Chesterfield adds TMT and ferric chloride to the wastewater. TMT is used as a coagulant to pull the heavy metals out of solution and ferric chlor ide is
used as a co

- precipitatant and coagulant. Chesterfield continuously injects 0.3 gallons of TMT per 1,000 gallons of wastewater

.

**•** From the heavy metals tank, the FGD wastewater is transferred to one of the two the
reactor vessels , which are part of the DensaD eg clarifi ers. Chesterfield adds Nalclear polymer 7768 to the reactor vessels to aid in the settling of the solids

. [QUESTION FOR
CHESTERFIELD: Ar e ferric chloride and TMT also added to the reactor vessel? They are shown on the process flow diagram, but we didn’t discuss it during the tour.] The
wastewater in the reactor vessel is forced to flow downward an d then overflows into the
DensaD eg clarif ier.

**•** Chesterfield has two identical DensaD eg clarifiers that operate in parallel. Because only one FGD system is currently operating, Chesterfield only needs to operate one clarifier at a time, but once the second FGD system begins operating, the plant will operate both
clarifiers. The DensaD eg clarifier contains a layer of inclined, triangle

- shaped lamella
tubes which increase the settling area of the clarifier and thereby improve its settling efficiency. The overflow from the clarifiers is transferr ed to the effluent tank. Most of the underflow from the clarifiers is transferred to the sludge storage tank and then dewatered in a filter press, but some of the underflow is recycled back to the desaturation tank. The dewatered sludge is transported by truck to Shoosmith, a local sanitary landfill. The filtrate from the filter press is recycled back to the equalization tank.

**•** The clarifier overflow is transferred to the effluent tank. Chesterfield adds hydrochloric
acid to the effluent tank to lower th e pH to between 8.40 and 8.45 S.U. Chesterfield also
monitors the turbidity and conductivity in the effluent tank. The treated FGD wastewater
is then transferred to the yard sump, which is eventually transferred to the lower ash pond.Ash Handling a nd Wastewater Treatment

**•** Chesterfield operates wet fly ash and wet bottom ash handling system s o n U nits 3 , 4, 5,
and 6.

**•** Chesterfield markets some of the bottom ash generated at the plant to Agglite, w ho use s it
to make cinder blocks. Chesterfield trans fers the bottom ash sluice water to lower ash pod, where the some of the bottom ash is collect ed and transferred off

- site for beneficial

reuse.

**•** Chesterfield personnel stated that they are unable to sell the fly ash because there isn’t a
market for it in the area. Plant personnel also stated that the loss on ignition (LOI) for fly
ash at Chesterfield is typically 10 to 15 percent. [QUESTION FOR CHESTERFIELD: Does the LOI make the fly ash produced at Chesterfield unmarketable?]

**•** The fly ash from the coal

- fired units is collected dry in the hoppers of the baghouse and the ESPs. Chesterfield operates a wet fly ash handling system where the fly ash is pulled out of the hoppers dry and pulled to a separator where high pressure water is injected and
mixed wit h the fly ash. This high pressure water creates the vacuum that pulls the fly ash to the separator. The fly ash is mixed with the sluice water to a 20 percent solids mixture and transferred to the lower ash pond

.

**•** The lower ash pond also receives the eff luent from the metals pond, which receives metal cleaning and low

- volume wastewaters, boiler blowdown, coal pile runoff, and the effluent from the FGD wastewater treatment system. Chesterfield does not add any chemicals to the ash pond; however, the plant added coagulants to the pond in the past.

**•** The lower ash pond has a channel prior to the open area of the pond where the influent streams are fed, which allows for initial settling of the solids. Chesterfield uses a backhoe to pull the solids out of th e channel to dewater. These dewatered solids are trucked to the upper ash pond /landfill for disposal. Additionally, Chesterfield occasionally dredges the solids in the lower ash pond and transfers them to the upper ash pond /landfill

.

**•** The effluent from the lower ash pond is discharged via Outfall 004. Che sterfield monitors the lower ash pond discharge for pH, TSS, d issolved oxygen, total phosphorus, total nitrogen, ammonia as N, TOC, total petroleum hydrocarbons, oil and grease, nitrate and nitrite, an d organophosphate.

**•** Chesterfield personnel stated that cenospheres, which are generated in the boiler, collect on the surface of the lower ash pond and are eventually removed by a contractor.

**•** Chesterfield personnel stated that they are have considered con verting to dry fly ash handling systems ; however, because the coal

- fired units particulate collection systems are not all located in the same area, it presents an issue for where to store the fly ash. Additionally, the plant is indicated that they are spa ce limited and it would be difficult to
install additional equipment , due to the newly installed baghouse and two FGD systems (plus associated auxiliary equipment).C hesterfield Upper Ash Pond (Pond Closure)

**•** The upper ash pond was initially constructed as a wet pond in 1983 ; h owever, the pond began filling with ash solids and the in 2002, Chesterfield decided to begin closing the pond instead of dredging and disposing of the solids.

**•** To complete the closure of the pond, Chesterfield takes the dewatere d ash from the lower ash pond and places it in the upper pond/dry storage facility.

**•** The upper pond is only permitted to receive fossil fuel combustion by

- products; therefore, the plant is not allowed to dispose of the FGD wastewater treatment solids in
th e upper pond.

**•** At the time of the site visit, the height of the upper ash pond was approximately 90 feet above elevation. Chesterfield expects that the upper pond will reach it s capacity in another 10 years after it rises an additional 90 feet in elevatio n.

**•** The upper pond is covered with soil and vegetation to protect against wind and water
erosion. The runoff from the upper pond is collected in drainage ditches and transferred to the retention pond. When Chesterfield is expecting a big storm, the plant will transfer some of the water in the retention pond to the lower ash pond for treatment to allow for additional capacity in the retention pond. Chesterfield has a controlled discharge from the retention pond to the James River via Outfall 005. The dis charge is not continuous. If the retention pond overflows due to a large storm event , the overflow will automatically discharge via Outfall 005

. [QUESTION FOR CHESTERFIELD: How often does the plant discharge from Outfall 005 ? Is leachate collected from the upper pond and if so is it sent to the retention pond? ]

**•** Chesterfield has eight groundwater monitoring sites for the upper ash pond. Chesterfield personnel stated that groundwater levels have n ot shown a need for any action. [QUESTION FOR CHESTERFIEL D : What does the plant monitor for in the groundwater wells? How often are groundwater measurements taken. Please provide the most recent groundwater monitoring data.

Metal Cleaning Wastes

**•** Chesterfield performs compressor washes for each of the combin ed cycle systems two or three times a year. The process consists of filling the compressor with a chemical/water solution and slowly rotating the contents. Once the cleaning is complete, the solution is
drained and transferred to the metals pond. This cl eaning process generates 100,000 to 150,000 gallons of wastewater for each wash . [ Q UESTION FOR C HESTERFIELD : What is the name of the chemical that is used for cleaning the compressors ? ]

**•** Chesterfield has not performed a chemical metal cleaning on the heat recovery steam generator, but the plant has cleaned the fireside of the boiler tubes with a carbon dioxide blasting media to remove scaling and rust.

**•** Chesterfield performs a chemical cleaning of the waterside of the coal

- fired boiler tubes once every 5 years. This process consists of adding an EDTA solution (which is similarto citric acid) to the boiler tubes and circulating the solution through the system. After the cleaning, the solution is drained from the boiler tubes and sent off site for

treatme nt/disposal.

**•** Chesterfield cleans the fireside of the coal

- fired boiler tubes once every 3 to 5 years by power washing them with a fire hose. The plant uses sump water to perform the washing and the wastewater is transferred back to the sumps and then to the metals pond.

**•** Chesterfield performs a chemical cleaning of the coal

- fired steam turbines once every 2 years. The process consists of using an ammonia foaming solution. The wastewater is transferred to the metals pond and treated with lime prior to be ing transferred to the ash pond.Table 1. Site Visit Attendees

Name Organization (Representing) Telephone E

- mail

Richard T. Elder, Jr. Dominion Resources 804

- 796

- 6000 ricky_e lder@dom.com

Dawn K. Garber Dominion Resources 804

- 796

- 6350 d awn.k.garber@ dom.com

Jason Williams Dominion Resources

Ken Roller Dominion Resources

Carissa Agnese Dominion Resources

Oula Shehab Dominion Resources (804) 273

- 2697 oula.k.shehab

- dandan@dom.com

Josh Hall EPA/Office of Water (202) 566

- 1002 hall.josh@epa.gov

Ron Jordan EPA/Office of Water (202) 566

- 1003 jordan.ronald@epa.gov

Mary Ellen Levine EPA/Office of Water (202) 564

- 5487 levine.maryellen@epa.gov

Pooja Parikh EPA/Office of Water ( 202 ) 564

- 0839 parikh.pooja@epa.gov

Lemuel Walker EPA/Office of Water (2 02) 566

- 1077 walker.lemuel@epa.gov

Jezebele Alicea

Virella EPA/Office of Water ( 202 ) 566

- 1755 alicea.jezebele@epa.gov

Cuc Schroeder EPA/Office of Water (202) 566

- 2397 schroeder.cuc@epa.gov

T.J. Finseth ERG (Contractor to EPA) (703) 633

- 1698 thomas.fin seth@erg.com

Becky Schwantes ERG (Contractor to EPA) (703) 633

- 1715 becky.schwantes@erg.com

Lydia Lambert ERG (Contractor to EPA) (703) 633

- 1646 lydia.lambert@erg.com