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 th e information collected during the site visit.
Table 1 identifies the site visit participants. The presentation that the Chesterfield personnel gave during the site visit is pr ovided as Attachment 1.

Plant Overview

 Chesterfield is the largest fossil-fueled power station in the Dominion System. The plant operates six electric generati ng units, four of which are ba seload coal-fired units. The plant’s net generating capacity is 1,650 MW , which includes 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 Control

3 1952 101 Cold-side
electrostatic 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 installed
in 2002 6 1969 660 Baghouse (reverse pulse jet fabric filter) Low-NOx
burners
SCR installed
in 2004 LSFO FGD
scrubber online in

2008

7 1990 201 N/A Steam Injection N/A

8 1992 204 N/A Steam Injection N/A

 Chesterfield operates three ponds at the site. Two of the ponds are wet ponds- 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 metals pond is not li ned. The lower ash pond has a capacity of 242 million gallons and receives liquid-borne ma terials for treatment prior to discharge. The third pond- the upper ash pond- is a dry pond that is currently going through closure.The “upper ash pond” was initially constructed as a wet pond in 1983, but beganthe closure process in 2002. The uppe r ash pond no longer receives liquid-borne materials, and the plant is in the process of closing the pond using ash. Neither the lower nor the upper ash pond are lined.

 Chesterfield burns bituminous coal in genera ting 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 strives to keep approximately 30 days worth
of coal on site. Chesterfield burns a pproximately 10,000 tons of coal per day.

 Chesterfield has two coal piles on site, 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 constructing an FGD system for Units 3, 4, and 5 and after the FGD begins operating, each of the units will switch to using high sulfur coal. The following table provides some of the typical ch aracteristics for the two diffe rent 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 . Each unit (system) consists of one
combustion turbine and one steam turbine. These units have the capability to burn #2 fuel oil and/or natural gas. The units can burn the oil and natural gas individually or at the same time. Both combined cycle system s operate as peaking un its, typically cycling up and down depending on demand (cycles ever y 3 to 6 hours); however, plant personnel stated that because natural gas has been so cheap recently, the units have predominantly been burning natural gas and have been operating continuously. Plant personnel also stated that the natural gas burned in the units is required to contain less than one-half percent sulfur.

 Plant personnel stated that generally the only wastewaters generated from Units 7 and 8 are once-through cooling wate r and boiler blowdown. Th e once-through cooling water for Units 7 and 8 is discharged to the Jame s River via Outfall 001. The boiler blowdown is transferred to the station’s sump system, which is then transferred to the lower ash pond. A picture of Chesterfield’s permitted outfalls and a water balance diagram is
included as Attachment 2 to this memorandum.

 Chesterfield also operates onc e-through cooling systems for the coal-fired units. The once-through cooling water for Unit 3 is di scharged via Outfall 002 and the once-through cooling water for Units 4, 5, and 6 is discharged via Outfall 003.

 Chesterfield chlorinates th e cooling water for biofouli ng control on each unit for two hours a day. Chesterfield operates a dechlori nation system on the discharge end of the once-through cooling systems, which consists of injecting sodium bisulfite into the waterstream. Chesterfield stated th at they over-inject the sodium bi sulfite to guarantee that all
the residual oxidants are consumed.

 Chesterfield operates low-NOx burners on each of the coal-f ired units (Units 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 Unit 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 ammonia, for use in the SCRs, is delivered to Chesterfield via truck and stored in tanks. Plant personnel stated th at the SCRs use approximately 38,000 pounds of ammonia a day.

 Plant personnel stated that th e SCRs operated for 3 years befo re 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; therefor e, 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 have not decided if the cat alysts will be regenerated or replaced.

 Chesterfield switched to year-round operati on of the SCRs beginning in 2008. Plant personnel stated that the S CR target NOx reduction is a pproximately 90 percent.

 Chesterfield stated that they have not s een a big impact on the fly ash or the ash pond discharges since the installation of the SCRs. Chesterfield st ated that they had done some modeling of the potential impacts on ammonia disc harges from the ash pond as a result of installing the SCRs. More information about this modeling is provided as Attachment 3. The final report detailing the plant’s investig ation of ammonia adsorption on fly ash due
to the installation of SCRs is included as Attachment 4.

 Units 3, 4, and 5 each operate a cold-side ESP, which achieve a 96 to 99 percent removal of particulate matter. Unit 6 operates a reverse pulse jet fabric filter baghouse, which achieves greater than 99 percent removal of particulate matter. Chesterfield previously operated an ESP on Unit 6, but the plant instal led the baghouse in Apri l 2008 to decrease the particulate and mercury emissions for th e unit. Plant personne l estimated that the installation of the baghouse and FGD syst em will reduce mercury emissions by 90 percent; however, they noted that they do not ha ve plans to replace any of the other ESPs.

 Chesterfield operates the Marsulex Clean St ack technology on Unit 6, which inject lime into the flue gas to control sulfur trioxide emissions which lead to the formation of blue plume. The lime is injected into the ductw ork, upstream of the baghouse. The station does not currently have plans to inst all this technology on Units 3, 4, 5.

 Chesterfield operates once-through cooling systems on all six electric generating units. The plant uses the James River as the sour ce 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 s ubmitted its permit renewal application onMay 28, 2009. Chesterfield personnel stated that they do not expect any to changes to the permit limits or monitoring requirements, even with the installation of the new FGD
system.

FGD System

 Chesterfield 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 trays increase the contact time be tween 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 tr ays are included as Attachment 5 to this
memorandum.

 Chesterfield is currently constructing a s econd 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 sulfur 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 permanen t covering. Although the limestone pile is covered, plant personnel stated that occasio nally a limestone pile runoff stream is generated. The limestone pile runoff is collect ed in the yard sumps and transferred to the ash pond.

 Chesterfield operates two ball mills to crush the limestone to the correct size for use in the limestone slurry. Chesterfield personne l stated that the ba ll mills are typically operated during the night shift.

 The limestone slurry from the ball mills is tran sferred to a classifier to remove the large limestone particles before transferring the slu rry to the limestone storage tanks. The large limestone particles are recy cled 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 dioxide re moval efficiency. The auxiliary equipment (e.g. pumps and piping) was also installed for the organic acid addition. However, personnel stated that the organi c acid tank has never been fill ed and they do not have any plans to use organic acid in the FGD system.

 Chesterfield uses the effluent from the Proc tor’s Creek wastewater treatment plant as the FGD system make-up water, which includes ma ke-up to the scrubber, mist eliminator washes, and limestone preparation. The Procto r’s Creek plant provide s Chesterfield with 1 to 1.5 MGD for use in FGD system. Plan t 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. Wastewater from the Procto rs Creek WWTP is discharged to the James River through two pipes, which run along a Chesterfield County easement through Dominion property just we st of the station’s barge slip. The wastewater for reuse at CPSis diverted from the two discharge pipes via a pumping station located on Dominion property adjacent to the County’s discharge pi pes. The station installed self cleaning
screens to address the growth of algae on the discharge structure associated with the
Proctors Creek WWTP and also within Dominion’s sump that receives the WWTP effluent. This algae used to slough off and cl og the strainers that are located downstream from the sump but prior to the FGD proce ss. The station does not pre-treat Proctor’s Creek effluent prior to use in the FGD. The station monitors the flow of the effluent, but does not monitor any other parameters. Proc tor’s Creek WWTP effl uent characteristics
are consistent that the James River water. There were no design requirements unique to
the FGD units at Chesterfield that enabled the plant to use the effluent from the wastewater treatment plant in their FGD system.

 The typical solids concentration in the FGD system is 14 to 20 percent and the typical chlorides concentration is 19,000 to 25,000 ppm. Plant personnel stated that 25,000 ppm
is the maximum allowable chlorides concentra tion for the materials of construction in the
FGD scrubber. Chesterfield blows down fr om the FGD system once every 12 hours for approximately 10 to 12 hours to maintain accepta ble solids and chloride concentrations in the FGD system.

 The blowdown from the FGD system is transf erred 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 sec ondary hydroclones. The underflow from the primary hydroclone, whic h is approximately 70 percent solids, is
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 Proc tor’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 percen t. The filtrate from the vacuum belt filter is either transferred to the reclaim tank and recycled back to the FGD scrubber or transferred to the FGD wastewater treatment system.

 Chesterfield markets the gyps um 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 percent moisture and less than 100 ppm chlo rides. The gypsum from 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. Chesterfiel d transports approximately 10,000 tons per month of gypsum to U.S. Gypsum. Chesterf ield maintains approximately 9,000 tons of on-site gypsum storage.

 The overflow from the primary hydroclones can be transferred to the secondary hydroclones 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 operati ng, the 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 th e 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 ei ght hours of the day. The equalization tank
also receives the filtrate from the wastewat er treatment filter press and water collected from the sumps of the wastewater 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 6 to the memorandum.

 Currently, the FGD wastewater treatment syst em is not operating co ntinuously 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 wastewater from the equalization tank is transferred to the desaturation tank, where lime is added to adjust the pH of the wastew ater. The desaturation tank also receives a
small amount of underflow from the downstr eam clarifier. The target pH in the desaturation tank is 9.0 S.U. The lime slurry added to the desaturation tank is 2.5 percent
solids.

 The FGD wastewater is transferred from the de saturation 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 chloride 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 DensaDeg clarifiers. Chesterfield adds Nalclear polymer 7768 to the reactor vessels to aid in the settling of the solids. Ferric chloride is generally added to the heavy metal tank, but th e station has the abil ity to add it to the
reactor vessel too. The wastewater in the react or vessel is forced to flow downward and then overflows into the DensaDeg clarifier.

 Chesterfield has two identical DensaDeg clarifiers that operate in parallel. Because only one FGD system is currently operating, Chesterf ield only needs to opera te one clarifier at a time, but once the second FGD system begins operating, the plant will operate both clarifiers. The DensaDeg clarifier contains a layer of inclined, triangle-shaped lamella tubes which increase the settling area of th e clarifier and thereby improve its settling efficiency. The overflow from th e clarifiers is transferred to the effluent tank. Most of
the underflow from the clarifie rs is transferred to the sludge storage tank and then dewatered in a filter press, but some of the underflow is recy cled back to the desaturation tank. The dewatered sludge is transported by tr uck 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. Chesterfie ld adds hydrochloric
acid to the effluent tank to lo wer the pH to between 8.40 and 8.45 S.U. Chesterfield also monitors the turbidity and c onductivity 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 and Wastewater Treatment

 Chesterfield operates wet fly ash and wet bottom ash handling systems on Units 3, 4, 5,
and 6.

 Chesterfield markets some of the bottom ash ge nerated at the plant to Agglite, who uses it
to make cinder blocks. Chesterfield transf ers the bottom ash sluice water to lower ash pond, where the some of the bottom ash is collect ed and transferred off-site for beneficial

reuse.

 Chesterfield personnel stated that they are una ble 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 percen t. Because of this high LOI, the fly ash at Chesterfield is currently unmarketable as a Portland Cement replacement material. To market the ash in Virginia, the LOI cannot be above 5%.

 The fly ash from the coal-fired units is co llected 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 pulle d to a separator where high pre ssure water is injected and mixed with the fly ash. This high pressure wa ter 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 effluent from the metals pond, which receives metal cleaning and low-volume wastewaters, boile r blowdown, coal pile runoff, and the
effluent from the FGD wastew ater treatment system. Chesterfield does not add any chemicals to the ash pond; how ever, the plant has added coagulants to the pond in the
past.

 The lower ash pond has a channel prior to th e open area of the pond where the ash sluice streams are fed, which allows for initial sett ling of the solids. Chesterfield uses a backhoe to pull the solids out of the channe l to dewater. These dewatered solids are trucked to the upper ash pond for disposal. Additionally, Cheste rfield occasionally dredges the solids in the lo wer ash pond and transfers them to the upper ash pond.

 The effluent from the lower ash pond is discharged via Outfa ll 004. Chesterfield monitors the lower ash pond discharge for pH, TSS, dissolved oxygen, total phosphorus, total nitrogen, ammonia as N, TOC, total pe troleum hydrocarbons, o il and grease, nitrate and nitrite, and organophosphate.

 Chesterfield personnel st ated 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 consider ed converting to dry fly ash handling systems; however, because the coal-fir ed 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 space limited and it would be difficult to install additional equipment, due to the ne wly installed baghouse and two FGD systems (plus associated auxiliary equipment).

Chesterfield Upper Ash Pond (Pond Closure)

 The upper ash pond was initially constructe d as a wet pond in 1983; however, the pond began filling with ash solids and the in 2002, Chesterfield decided to begin closing the pond instead of dredging and di sposing of the solids.

 To complete the closure of the pond, Chesterfie ld takes the dewatered ash from the lower ash pond and places it in the upper pond/dry storage facility.

 The upper pond is only permitted to receiv e fossil fuel combustion by-products; therefore, the plant is not allowed to dispos e of the FGD wastewater treatment solids in the upper pond.

 At the time of the site vis it, the height of the upper as h pond was approximately 90 feet above elevation. Chesterfield expects that the upper pond will reach its capacity in another 10 years after it rises an additional 90 feet in elevation.

 The upper pond is covered with soil and vege tation to protect against wind and water erosion. The runoff from the upper pond is coll ected in drainage di tches and transferred to the retention pond. When Chesterfield is expecting a big storm, the plant has the ability to 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 discharge is not continuous. If the retention pond overflows due to a large storm event, the overflow will automatically discharge via Outfall 005. As a general rule, the station discharges from Outfall 005 once per year. Th ere is no leachate collection system for the upper pond closure.

 Chesterfield has eigh t groundwater monitoring sites for the upper as h pond. Chesterfield personnel stated that gr oundwater levels have not shown a need for any action. The plant monitors the groundwater wells for the follo wing species: arsenic, barium, cadmium, chromium, hexavalent chromium, copper, iron, lead, manganese, mercury, molybdenum, selenium, silver, vanadium, zinc, ammonia, chlo ride, nitrate, sulfate, TDS, total hardness, conductivity, and pH. The groundwater measur ements are taken quarterly. The most recent groundwater monitoring data is provided as Attachment 7.

Metal Cleaning Wastes

 Chesterfield performs compressor washes for each of the combined 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. The station generally uses a product called Simple Green. Once the cleaning is complete, the solution is drained and transferred tothe metals pond. This cleaning proc ess generates 100,000 to 150,000 gallons of
wastewater for each wash.

 Chesterfield has not performed a chemical metal cleaning on the heat recovery steam generator, but the plant has cleaned the fire side of the boiler tube s with a carbon dioxide blasting media to remove scaling and rust.

 Chesterfield performs a chemi cal cleaning of the waterside of the coal-fired boiler tubes approximately once every 5 years. This pr ocess consists of adding an EDTA solution (which is similar to citric acid) to the boile r tubes and circulating the solution through the system. After the cleaning, the solution is drained from the bo iler tubes and sent off site for treatment/disposal.

 Chesterfield cleans the fireside of the coal -fired boiler tubes approximately 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 tran sferred back to the sumps and then to the metals pond.

 Chesterfield performs a chemi cal cleaning of the coal-fired steam turbines approximately 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 being transferred to the ash pond.Table 1. Site Visit AttendeesNameOrganization (Representing)TelephoneE-mailRichard T. Elder, Jr.Dominion Resources 804-796-6000 ricky_elder@dom.comDawn K. GarberDominion Resources804-796-6350 dawn.k.garber@dom.comJason WilliamsDominion Resources(804) 796 6166 jason.s.williams@dom.comKen RollerDominion Resources(804) 2733494 kenneth.roller@dom.comCarissa AgneseDominion Resources(804) 796 6048 carissa.r.agnese@dom.comOula ShehabDominion Resources(804) 273-2697 oula.k.shehab-dandan@dom.comJosh Hall EPA/Office of Water (202) 566-1002 hall.josh@epa.govRon Jordan EPA/Office of Water(202) 566-1003 jordan.ronald@epa.govMary Ellen Levine EPA/Office of Water(202) 564-5487 levine.maryellen@epa.govPooja Parikh EPA/Office of Water (202) 564-0839 parikh.pooja@epa.govLemuel Walker EPA/Office of Water(202) 566-1077 walker.lemuel@epa.govJezebele AliceaVirellaEPA/Office of Water (202) 566-1755 alicea.jezebele@epa.govCuc Schroeder EPA/Office of Water(202) 566-2397 schroeder.cuc@epa.govT.J. Finseth ERG (Contractor to EPA) (703) 633-1698 thomas.finseth@erg.comBecky Schwantes ERG (Contractor to EPA)(703) 633-1715 becky.schwantes@erg.comLydia Lambert ERG (Contractor to EPA)(703) 633-1646 lydia.lambert@erg.com