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 the site visit is provided as Attachment 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 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 SO2 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 lined. The lower ash pond has a capacity of 

242 million gallons and receives liquid-borne materials 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 began 
the closure process in 2002. The upper 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 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 strives to keep approximately 30 days worth 

of coal on site. Chesterfield burns approximately 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 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. 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 systems operate as peaking units, typically cycling 

up and down depending on demand (cycles every 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 water and boiler blowdown. The once-through cooling water 

for Units 7 and 8 is discharged to the James 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 once-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 water 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 water 
stream. Chesterfield stated that 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 (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 that the SCRs use approximately 38,000 pounds of 

ammonia a day. 

 

 Plant personnel 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 have not decided if the catalysts will be regenerated or replaced. 

 Chesterfield switched to year-round operation of the SCRs beginning in 2008. Plant 

personnel stated that the SCR target NOx reduction is approximately 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. More information about this modeling is provided as Attachment 3. 

The final report detailing the plant’s investigation 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 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; however, 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 blue 

plume. The lime is injected into the ductwork, upstream of the baghouse. The station 

does not currently have plans to install 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 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 submitted its permit renewal application on 
May 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 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 trays are included as Attachment 5 to this 

memorandum. 

 

 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 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 permanent covering. Although the limestone pile is 

covered, plant personnel stated 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. 

 Chesterfield operates two ball mills to crush the limestone to the correct size for use in 

the limestone 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 dioxide removal efficiency. The auxiliary equipment 

(e.g. pumps and piping) was also installed for the organic acid addition. However, 

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. 

 Chesterfield uses the effluent from 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 Proctor’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. Wastewater from the Proctors Creek WWTP is discharged to the James 

River through two pipes, which run along a Chesterfield County easement through 

Dominion property just west of the station’s barge slip. The wastewater for reuse at CPS 
is diverted from the two discharge pipes via a pumping station located on Dominion 

property adjacent to the County’s discharge pipes. 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 clog the strainers that are located downstream 

from the sump but prior to the FGD process. 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. Proctor’s Creek WWTP effluent 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 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 hours 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, 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 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 recycled 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 

percent moisture and less than 100 ppm chlorides. 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. Chesterfield transports approximately 10,000 tons per 

month of gypsum to U.S. Gypsum. Chesterfield 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 operating, 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 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 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 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 wastewater 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 

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 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 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 the station has the ability to add it to the 

reactor vessel too. The wastewater in the reactor 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, 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 DensaDeg 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 transferred 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 the 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 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 generated at the plant to Agglite, who uses it 

to make cinder blocks. Chesterfield transfers the bottom ash sluice water to lower ash 

pond, where the some of the bottom ash is collected 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. 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 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 with 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 effluent 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 has 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 ash sluice 

streams are fed, which allows for initial settling of the solids. Chesterfield uses a 

backhoe to pull the solids out of the channel to dewater. These dewatered solids are 

trucked to the upper ash pond for disposal. Additionally, Chesterfield occasionally 

dredges the solids in the lower ash pond and transfers them to the upper ash pond. 

 The effluent from the lower ash pond is discharged via Outfall 004. Chesterfield 

monitors the lower ash pond discharge for pH, TSS, dissolved oxygen, total phosphorus, 

total nitrogen, ammonia as N, TOC, total petroleum hydrocarbons, oil and grease, nitrate 

and nitrite, and 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 converting 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 space limited and it would be difficult to 

install additional equipment, due to the newly installed baghouse and two FGD systems 

(plus associated auxiliary equipment). 

Chesterfield Upper Ash Pond (Pond Closure) 

 The upper ash pond was initially constructed 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 disposing of the solids. 

 To complete the closure of the pond, Chesterfield 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 receive fossil fuel combustion by-products; 

therefore, the plant is not allowed to dispose of the FGD wastewater treatment solids in 

the 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 its capacity in 

another 10 years after it rises an additional 90 feet in elevation. 

 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 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. There is no leachate collection system for the 

upper pond closure. 

 Chesterfield has eight groundwater monitoring sites for the upper ash pond. Chesterfield 

personnel stated that groundwater levels have not shown a need for any action. The plant 

monitors the groundwater wells for the following species: arsenic, barium, cadmium, 

chromium, hexavalent chromium, copper, iron, lead, manganese, mercury, molybdenum, 

selenium, silver, vanadium, zinc, ammonia, chloride, nitrate, sulfate, TDS, total hardness, 

conductivity, and pH. The groundwater measurements 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 to 
the metals pond. This cleaning process 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 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 

approximately once every 5 years. This process consists of adding an EDTA solution 

(which is similar to 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 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 transferred back to the sumps and then to the 

metals pond. 

 Chesterfield performs a chemical 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 Attendees 

Name Organization (Representing) Telephone E-Richard T. Elder, Jr. Dominion Resources 804-796-6000 ricky_elder@doDawn K. Garber Dominion Resources 804-796-6350 dawn.k.garber@Jason Williams Dominion Resources (804) 796 6166 jason.s.williamsKen Roller Dominion Resources (804) 2733494 kenneth.roller@Carissa Agnese Dominion Resources (804) 796 6048 carissa.r.agneseOula Shehab Dominion Resources (804) 273-2697 oula.k.shehab-dJosh Hall EPA/Office of Water (202) 566-1002 hall.josh@epa.gRon Jordan EPA/Office of Water (202) 566-1003 jordan.ronald@Mary Ellen Levine EPA/Office of Water (202) 564-5487 levine.maryellePooja Parikh EPA/Office of Water (202) 564-0839 parikh.pooja@eLemuel Walker EPA/Office of Water (202) 566-1077 walker.lemuel@Jezebele AliceaVirella EPA/Office of Water (202) 566-1755 alicea.jezebele@Cuc Schroeder EPA/Office of Water (202) 566-2397 schroeder.cuc@T.J. Finseth ERG (Contractor to EPA) (703) 633-1698 thomas.finseth@Becky Schwantes ERG (Contractor to EPA) (703) 633-1715 becky.schwanteLydia Lambert ERG (Contractor to EPA) (703) 633-1646 lydia.lambert@