Notes from Site Visit at Detroit Edison’s Monroe Power Plant on September 23, 2009

EPA conducted a site visit at Detroit Edison’ s Monroe Power Plant (Monroe) located in Monroe, MI on Wednesday, September 23, 2009 to le arn about the operations at the plant. Table 1, located at the end of this me morandum, identifies the site visit participants. Attachment 1 provides the presentation that the Monroe personnel gave during the site visit.

This memorandum describes the informati on collected during the site visit.

Plant Overview

 Monroe is owned by Detroit Edison Company, a subsidiary of DTE Energy. Detroit Edison

was founded in 1903. It is the nint h largest electric utility in the United States with 2.1 million customers and over 11,000 MW of electric power generating capacity, primarily coal

fired. Detroit Edison owns one nuclear plant (Fermi 2).

 The Monroe plant covers 1,200 acres and is surr ounded by Lake Erie and the Raisin River. The Monroe-related property is split into thr ee sections, including the Monroe plant property, the dry fly ash loading area, and the fly ash basin, including th e 200 acres of land south of the fly ash basin. Monroe purchased the 200 acres south of the fly ash basin for possible future use if the basin needed to be expanded. An aerial view of the Monroe plant property is provided as Attachment 2 to this memorandum.

 Monroe employs more than 400 permanent employees and 100 long term contract employees. Monroe also employs about 500- 800 temporary construction employees for various construction projects, incl uding the Environmental Project.

 Monroe produces about 35 percent of DTE Ener gy’s electrical power and 44 percent of its fossil power. Monroe has a net winter electric generating capacity of 3,135 MW, and the net summer capacity is typically about 3,115 MW. Th e plant’s auxiliary power requirement is about 5 percent parasitic load without the flue gas desulfurization (F GD) operation. With the added FGD operation, the auxiliar y power requirement increases to about 6.2 percent. The plant generates about 16 to 18 million MWs per year. The table below contains some general information for each electric generating unit.

Unit Installation

Date Capacity (MW) Fly Ash Handling

System Particulate

Control NOx

Control SO 2 Control

1 1971 817 Dry and wet systems in operation Cold-side

electrostatic precipitator (ESP) Low-NOx burners;

SCR FGD

scrubber planned to

be installed by 2015.

2 1972 823 Wet system in operation at time of site visit; Dry system in operation since Sept. 2009 a Cold-side

ESP Low-NOx burners;

SCR planned to

be installed FGD

scrubber planned to

be installed by 2015.Page 2

Unit Installation

Date Capacity (MW) Fly Ash Handling

System Particulate

Control NOx

Control SO 2 Control

3 1973 823 Wet system in operation; Dry system planned

to be installed in

2013 b Cold-side

ESP Low-NOx burners;

SCR Limestone

forced

oxidation (LSFO)

FGD

scrubber planned to

be operational

in Nov 2009

4 1974 817 Wet system in operation; Dry system planned

to be installed in

2013 b Cold-side

ESP Low-NOx burners;

SCR LSFO FGD

scrubber operational

in June

2009 a – At the time of the site visit, the dry syst em was installed, but not yet operating. The dry system was projected to be in operation in Fall 2009, and as planne d, it began operating in September 2009. b – Although the company signed an agreement that allows a 3 rd party to install a dry system, as of this date the company cannot st ate that there is a likelihood that a dry system will be installed. Among other things, such an installation by a 3 rd party is predicated on the company not electing to burn pet-coke in this unit. As of this date the company has not decided whether it will burn or not burn pet coke in this unit.

 Monroe operates low-NO X burners on each of the coal-fir ed units (Units 1, 2, 3, and 4). Additionally, Monroe operates SCRs on Units 1, 3, and 4. Plant personnel stated that they are planning to install an SCR on Unit 2 in the fu ture. The SCRs on Units 1, 3, and 4 each have four catalyst layers available, but there are typically less than four layers that are loaded. When necessary, these catalyst layers are re placed and are not regenerated on site.

 Monroe’s current plan for reduc tion of mercury emissions incl udes the operation of SCR and FGD systems. Monroe estimates that an S CR and FGD scrubber installed in series is expected to typically reduce about 80 percent of mercury emissions.

 DTE Energy/Monroe participated in a DOE -co-funded pilot study for activated carbon injection (ACI) at Monroe. A ll of the equipment was removed once the study was finished. Monroe stated that injecting activated carbon ups tream of the ESP would preclude the sale of fly ash due to high carbon content, and specifi cally, high activated carb on content. Monroe stated that if they implemented ACI downs tream of the ESP to keep the dry fly ash marketable, a baghouse would have to be instal led. Fuel additives and FGD slurry additives would be considered if additional mercury oxidation is required or re-emissions from the

FGD became an issue. No a dditives are used currently.

 The plant has three coal piles; one contains low-sulfur Powder River Basin (PRB) coal (0.2 to 0.5 percent sulfur); one contains mid-sulf ur eastern bituminous coal (1.2 to 1.6 percent sulfur); and one contains a blend of coal (60 to 70 percent PRB and 30 to 40 percent easternPage 3

bituminous). Monroe estimated that this year th ey have burned closer to 70 percent PRB and 30 percent eastern bituminous coal because recen tly the total cost for obtaining PRB coal is

less than that for eastern bituminous coal. All coal arri ves by rail or lake vessel. At full load, the plant consumes about 32,000 to ns of coal per day and on an average year, burns 8-9

million tons of coal.

 Monroe’s coal pile runoff is not acidic due to the significant amount of PRB coal burned. The runoff is typically between 7 and 8 S.U. (a recent measurement was 7.76 S.U.). Monroe sends the coal pile runoff to a small basi n and then to the bottom ash basin.

 Plant personnel estimated that the distributi on of ash generated from the generating units, calculated based on coal consumption, is a pproximately 20 percent bottom ash, 80 percent fly ash and 1 percent economizer ash. The plan t has no means of measuring any of these ash

steams and the above numbers are estimates base d on literature review of comparable units.

Ash Ponds

 Monroe has two ash ponds, the bottom ash basin (Area 15) and the fly ash basin. Originally, the plant’s fly ash pond and bottom ash pond were both located in Area 15. Area 15 was only used for fly ash disposal as an interim measur e in the early 1970’s, while the fly ash basin was being built. Area 15 has never reached its limits and continues to be used as a bottom ash pond. There are no chemical additions to the ponds.

 The bottom ash basin receives bo ttom ash sluice, coal pile ru noff, effluent from the FGD wastewater treatment system, and low volume wast es. The bottom ash is sluiced to the basin and then dredged and sold or used for roadbe d. Bottom ash sales are infrequent. Effluent from the bottom ash basin is discharged via Outfall 001B to the main discharge cooling canal, and then discharged to Lake Erie via Outfall 001.

 The Monroe 410-acre fly ash basin was construc ted in 1974. The ash basin has never been expanded and is currently at about 2/3 of its volume capacity. The bottom of the basin is about 5 to 10 feet below ground level, and the highest point of the berm is about 35 feet above ground level. Monroe fills about 5 to 10 acres of the pond each year with fly ash. The

estimated end of life for the ash basin is about 20 years from the time of the site visit. This could be extended if more dry fly ash can be sold or decreased if the pl ant is no longer able to sell ash or gypsum. The fly ash basin is license d/permitted by the state as a landfill under the solid waste program.

 Compacted “Lake Erie” clay, the naturally-occurr ing clay in the area, was used to construct the berm of the fly ash basin. The basin is not li ned. Monroe stated that the permeability of the clay makes it an ideal component fo r the bottom and berm of the ash pond. The permeability coefficient of the ash basin emba nkment soils strata ranges from 1.30 X 10(-7) to 2.37 X 10(-8) cm/sec. The permeability coefficien t of the ash basin site soils strata ranges from 1.0 to 2.0 X10(-8) cm/sec. These data ar e based on soil test results from a 1986 ash basin embankment soils investigation and 1995 as h basin site soils i nvestigation. Clay was the only component used to build the fly ash basin, but is not the main component of the bottom ash basin. Permeability verification docum ents were provided to GZA: the other EPA contractor reviewing as h basin construction.Page 4

 The fly ash basin effluent is currently monito red for total suspended solids (TSS), oil and grease with grab samples taken at the end of a discharge canal. Flow is also recorded. The water from the fly ash basin is discharged with an underflow/overflow weir that is controlled by gates. The water flows underground to one of three upwellings and then flows to the monitoring point. The fly ash ba sin effluent is discharged via Outfall 001F to the main discharge cooling canal, a nd then discharged to Lake Erie via Outfall 001. An aerial view of the fly ash basin, with monitoring points and di scharges identified, and a plant water balance are provided as Attachment 3 to this memorandum.

 There is an air quality monito r located near the as h basin that continually monitors for fugitive dust.

 An engineering study of the fly ash basin was co nducted in 2008 (prior to the TVA ash spill), during which the structural integrity of th e pond was analyzed. The 2008 study was focused on the design of a repair plan for the surficial sloughs that ha ve occurred on the exterior of the basin. The 2008 plan was not focused on the st ability of the core of the dike. After the TVA ash spill occurred, Monroe obtained a second opinion, and it was determined that the embankment slope needed to be modified. The second opinion was again focused on the surficial sloughs and identifie d a number of remedial options. The company could have maintained the existing slopes, but recognized that there would be less maintenance with a flatter slope. Ultimately the company chose to modify the embankment slope to both repair surficial sloughs and incur less O & M expense in the future. Monroe operators perform weekly inspections of the fly ash basin to l ook for any visual differe nces concerning the ash basin. DTE Surveyors also use inclinometers and dike movement indicators to inspect the fly ash basin. Every two years, Monroe hires a priv ate contractor to surv ey the ash basin and observe/record any location and depth changes.

Ash Handling

Overview

 Monroe operates wet fly ash and wet bottom ash handling systems on Units 1, 2, 3, and 4. Recently, Headwaters Resources (Headwaters) bu ilt a dry fly ash handling system on Units 1 and 2. The dry fly ash handling system is current ly in operation on Unit 1. Monroe stated that Unit 2 should be in operation by the end of September 2009. As currently planned, Units 3 and 4 will have dry fly ash handling systems installed and operated by 2013. Headwaters may build a dry fly ash handling system on one or both of the remaining Units (units 3 & 4), but will not build a dry system on any unit burning petroleum (pet) coke. The company is currently entertaining a request that it burn pet coke.

 The bottom ash is sluiced to Area 15. Mill rej ects are collected and sluiced with the bottom ash. The bottom ash is dredged and sometimes used or sold for roadbed.

 Headwaters owns and operates the dry fly as h handling system at Monroe. Headwaters

markets the ash to the cemen t/concrete industry for use in ready mix and concrete pipe.

Headwaters has been in the business of ma rketing fly ash since the late 1980’s.

 As the fly ash handling system is currently set up for Units 1 and 2, Monroe has the ability to handle fly ash wet or dry. The dry fly ash handl ing system was not intended to be a completePage 5

wet-to-dry conversion. The current system lacks redundancy and capacity to handle 100 percent of the fly ash dry. Monroe was able to install and bring the dry fly ash handling system on line without any additional outages, ou tside of those regularly scheduled. The dry fly ash handling system was first installed pa rallel to the wet fly as h handling system, and then connected to the wet fly ash handling system during a regularly scheduled outage.

 Monroe produces a class of dry fly ash that is between “C” and “F”. Plant personnel stated that there is high demand for their fly ash. Plant personnel stated th at the loss on ignition (LOI) of their fly ash is typically 1.5 percent.

 The piping of the dry fly ash handling system is routed to pneumatically transfer fly ash to a Headwaters owned and operated 4,000 ton storag e silo, which is 3,100 ft away from the ash silos at the Monroe plant.

 Headwaters operates the dry fly ash truck lo ading area with four on-site employees. Two Headwaters employees, Mr. Mike Dunlap and Mr. Lance Staron, spoke with EPA during the Monroe site visit. The dry fly ash truck load ing area is currently onl y able to handle/load “bone dry” (less than one percen t moisture) fly ash for sale. It is not set up to moisturecondition the fly ash, as would be done for landf illing. Headwaters has sold about 4,000 tons of Monroe’s fly ash from August 6, 2009 to the time of the site visit; local market demand has driven when Unit 1 fly ash has been handled dry. Similarly, market demand will determine whether Unit 2 fly ash will be handl ed dry. The demand for dry fly ash will likely

increase next summer. Headwaters intends to st ock pile the dry fly ash this winter for the

demand next season.

 Headwaters has a rail network acr oss the country for selling/tran sporting dry fly ash and they network locally by truck. The company strate gically placed ash storage silos across the country where ash demand is high. Headwaters looks to expand the dry fly ash sales at

Monroe. Rail would allow Headwaters to ma rket the fly ash where demand is high yearround. Rail loading equipment is already installed at the Monroe plant. To begin operation, this rail loading equipment would need to be co nnected and track would n eed to be installed. Rail loading would increase the staff requirements at the loading facility.

Detailed Fly Ash Handling Operation

 The fly ash from Monroe’s Unit 1 is collected dry in two rows of pr ecipitator hoppers (upper and lower).

 When Monroe operates the wet fly ash handli ng system, economizer and fly ash are pulled dry by a vacuum (using a water ejector/eductor) through a set of pipes that split from the pipes used for the dry fly ash handling system . The ash is then introduced to water for sluicing in slurry tanks. The ash sluice is then pumped from the slurry tanks to the fly ash basin located approximately 3,500 ft from the precipitator.

 When Monroe operates the dry fly ash handling system, only fly ash (no economizer ash) is pulled by vacuum, using mechanical exhauste rs, from the precipitator hoppers to two filter/separators. The filter/separators separate the fly ash from the transfer air, which is exhausted. The fly ash is then dropped into a 150-ton, air-locked tran sfer hopper. The ash is then introduced to the compressed air pressure sy stem that pushes it to th e storage silo at thePage 6

Headwaters loading site. The timed, air-locked transfer hopper allows the system to switch between the negative and positive air pre ssure used to transport the ash.

 The dry fly ash is transported 3,100 ft to the Headwaters loading site. With the current system at Monroe, 3,100 ft is probably the fart hest distance that the ash can be efficiently transported pneumatically. Options to improve th e system include larger blowers or a booster system. With a booster system, bursts of air are strategically placed along the pipe to enhance air flow. Headwaters stated that 4,000 ft is about the maximum dist ance that ash can be transferred pneumatically.

 Headwaters stated that there are two ways to tr ansfer fly ash pneumatical ly. The first is called a dilute system, in which there is a small amount of ash relative to air in the pipe. This system, which is operated at Monroe, offers le ss risk of clogging. The other type of system operates with higher amounts of ash relative to air in the pipe. Although the system ideally transfers more ash through the pipe than the dilute system, it is usually more expensive, slower, less reliable, an d not cost effective.

 From the 4,000-ton storage silo, the ash is pneum atically transferred to a 200-ton loading silo by an air slide and bucket conveyor. The air slide, located at the bottom of the storage silo, is a long piece of fabric membrane, positioned at a specific gradient with air jets underneath

that float and move the ash “dow n the slide”. From the slide, the ash is filled into the bucket conveyor, which can load the silo at 200 tons per hour if necessary. Both the air slide and bucket conveyor are operated under a vacuum sy stem. Any fugitive dust is pulled back into either the main storage silo or the loading s ilo and collected in a ba ghouse at the top of each

silo. There are induced air fans that pull air out of the silos through the filter bags. An air quality monitor is located in the loading area that continually monitors for fugitive dust.

 According to Headwaters, capacity at storage silo is enough to handle about 4 days of ash production at the plant.

 Dry fly ash is transferred from the loading si lo to the trucks pneumatically with a double annular spout. A vacuum is pulled through the ou ter annulus of the spout , creating a tight seal

with the truck. Ash is delivere d through the inner annulus of the spout into the truck. The vacuum captures any fugitive dust and pulls it through the loading silo to the baghouse. It

takes about 1 or 2 minutes for the ash to settle in the trucks before the spout is pulled away.

 Headwaters frequently tests the moisture c ontent of the dry fly ash being loaded. Plant personnel stated that is the fly ash usually contains less that 1 percent moisture.

 The amount of ash that is tran sferred to the trucks is dete rmined by weight. Trucks in Michigan are permitted to haul up to 50 tons. Headwaters estimated that they can load about 25 tons of ash into a truck in 10 minutes, and can load 200 tons from the loading silo into eight trucks.

 Monroe stated that a complete conversion from the current we t/dry fly ash handling system to a moisture-conditioned dry fly ash handling syst em (suitable for landfilling the dry fly ash) would require the following major changes:Page 7

 The 150-ton silos that collect the dry fly ash from the precipitator hoppers

would need to be converted to 500-t on silos to support a completely dry
system.

 Modifying the silo and loading area fo r moisture-conditioning would also be expensive. This modification would in clude adding an exhaust system and doors to the loading area that will provi de enclosure to the transfer space. Additionally, Monroe stated that beca use they burn 70 percent PRB coal, any moisture conditioning would cause the as h to become cementitious in the bottom of the storage silo.

 Transfer of the moisture-conditioned ash to the basin/landfill would be a potential issue. Suggested options in clude truck, pneumatic transfer, or conveyors. State and township permits would be developed to control any fugitive dust and the infrastructure (new roads or piping) used for transport.

 Monroe would also have to develop a nother ash handling system specifically

for economizer ash. The economizer ash cannot be handled with marketable fly ash because the larger size of the economizer ash particles would make the

ash unmarketable to the cement/concrete industry. Economizer ash also

cannot be handled with bottom ash because the trace metals it contains would

not allow Monroe’s bottom ash to meet certain state standards. The bottom ash is currently considered by the Mi chigan Department of Environmental Quality (MDEQ) to be inert and not a solid waste (i.e., does not leach any pollutants above drinking water standards).

FGD System

 Monroe operates one limestone forced oxidatio n (LSFO) FGD scrubber system that services Unit 4. An identical FGD scrubber system has b een installed to servi ce Unit 3. At the time of the site visit the FGD scrubber system on Un it 3 was not yet operating, but as planned it began operating in November 2009. Monroe is cu rrently considering constructing/installing

two additional LSFO FGD sc rubbers that will service Un its 1 and 2 by 2015, depending on

the outcome of the CAIR rule and economic fa ctors. Plant personnel estimate that it takes about 30 months to construct, install, and bring an FGD scr ubber system on line. It took about two weeks from the time Monroe began op erating the Unit 4 FGD system to the time it was at steady state and Monr oe could begin sending wastew ater to the FGD wastewater treatment system. It took about 10 days from that point to “fill” the FGD wastewater
treatment system w ith wastewater.

 The Unit 4 FGD system has four absorber recycl e pumps and four sets of spray headers.

Three of the four are typically operated. The absorber has two trays. Process flow diagrams of the Unit 3 and 4 FGD systems are included in Attachment 4 of this memorandum.

 The Unit 4 FGD absorber is constructed of conc rete block and lined with Stebbins, semplate tile. It is a B&W design.Page 8

 The Unit 4 FGD system achieves a sulfur dioxide removal of greater th an 97 percent. After passing through the Unit 4 FGD system, flue ga s exits through a dual flue chimney stack, which will also service the Unit 3 FGD system when it is operational.

 Monroe receives limestone by boat. The limest one is conveyed to a storage pile. Limestone for the Units 3 and 4 FGD systems is then conveyed to a silo with an 890 ton capacity.

 Monroe has two ball mills on site to crush lim estone to the correct size for use in the limestone slurry. At the time of the site visi t, one was in operation and the other was being prepped for operation. The ball mill crushe s 43 tons of limestone per hour.

 The limestone slurry from the ball mill is tran sferred to a classifier to remove the large limestone particles before the slurry is tran sferred to the limestone storage tank. The large limestone particles are recy cled back to the ball mill for additional processing.

 Monroe has a 600,000 gallon FGD make-up water tank th at holds filtered plant service water. Plant service water, which is intake water from the surrounding Lake Erie (note that this is

not Raisin River water due to a reversal of wa ter flow), is filtered through six multimedia filters to remove any unwanted debris (e.g., stones, zebra mussel larvae). Backwash from these multimedia filters (“FGD pretreatment back wash”) is sent to the bottom ash basin. The

filtered water is used for the limestone slurr y, the FGD absorber mist eliminators, and the vacuum belt filter,

 Monroe maintains a pH of approximately 5 to 6 S.U. in the Unit 4 FGD absorber.

 Monroe does not add any acid additive s to the Unit 4 FGD scrubber system.

 Monroe blows down from the Unit 4 FGD absorb er when the solids concentration in the absorber reaches 21 percent (by weight). Th is blowdown occurs about three times per day for approximately one to one and a half hours. The typical solids concentration in the FGD absorber is 19 to 21 percent and the typical chlorides concentra tion is 9,000 to 12,000 ppm (and always maintained below 12,000 ppm). Plan t personnel stated that 15,000 ppm is the

maximum allowable chlorides concentration acco rding to the design specifications of the

FGD scrubber.

 The blowdown from the FGD system is transf erred to the primary hydroclones for initial solids separation. Four sets of hydroclones are cu rrently in place that can service all four FGD systems, when operational. If the overf low from the primary hydroclones is between 11,000 and 12,000 ppm chlorides, it is sent to the chloride purge tank. If the overflow from the primary hydroclones is between 9,000 and 10,000 pp m chlorides, it is recycled back to the reclaim water tank, from which water is r ecycled back to the absorber. The underflow from the primary hydroclones, which is appr oximately 55 percent so lids (by weight), is

transferred to filter feed tanks and then to the vacuum belt filter.

 Monroe uses a vacuum belt fi lter to dewater the gypsum in to a saleable byproduct. The vacuum used is created with a 500 horsepow er pump. Monroe washes the gypsum with filtered plant service water as the gypsum is applied to the belt filter to reduce chlorides. The

moisture content of the dewatere d gypsum is about seven to eight percent. The filtrate from

the vacuum belt filter is tran sferred to the reclaim tank.Page 9

 Monroe markets the gypsum product and they ar e currently looking to improve their current contract. Monroe anticipates that the gypsum specifications will be less than ten percent moisture and less than 100 ppm chlorides in order for the gypsu m to be used for wallboard. The gypsum produced at Monroe typically c ontains about 30 ppm chlorides. The gypsum

from the vacuum belt filter is transferred to a gypsum storag e building. The gypsum is either sold (Monroe is currently holding some saleable gypsum) or trucked to an offsite landfill at the Sibley Quarry, which is owned by Monr oe. Typically, Monroe sends about four truckloads of gypsum per day to the Sibley Quar ry. The Sibley Quarry landfill is not lined. Groundwater monitoring wells are located around this landfill. Landfill leachate is collected.

 The water in the chloride pur ge tank is transferred to the secondary hydroclones for additional solids separation. The underflow from the secondary hydroclones is transferred to

the reclaim tank and the overflow is transferre d to the wastewater treatment tank. Monroe

sends wastewater from the wastewater treat ment tank to the FGD wastewater treatment system once every three days for approximately two hours.

 Monroe takes grab samples of the influent to the FGD wastewater treatment system from the top of the open wastewater tr eatment tank using a bucket.

FGD Wastewater Treatment System

 The FGD wastewater treatment system opera ted at Monroe was designed by Siemens. Monroe monitors the wastewater treatment syst em at various points (e ffluent of equalization tank, reaction tank #1, effluent of the clarifier, and the final wastewater treatment system effluent) to ensure that it is achieving metals removal according to Siemens’ design specifications. Monroe sends the FGD wastewater treatment samples to a lab for analysis of metals that include, but are not limited to, aluminum, antimony, arsenic, copper, lead, mercury, and selenium.

 The two-train FGD wastewater treatment system operated at Monroe was designed to handle wastewater from all four FGD systems, when installed/operating. When operating at full capacity, Monroe projects that FGD wastewater will be treated 7 days a week and sludge will be treated 5 days a week. Currently, Monroe operates the FGD wastewater treatment system as a batch process. Each train of the wastew ater treatment system was designed to treat 600 gpm of FGD wastewater (each clarifier can handle 1,200 gpm). The current, typical flow rate through the wastewater treatment system is 550 gpm. A process flow diagram of the FGD wastewater treatment system is includ ed in Attachment 5 of this memorandum.

 The FGD scrubber purge (from the wastewater treatment tank) is transferred to the equalization tank of the FGD wastewater trea tment system. The e qualization tank also

receives the filtrate from the wastewater treatm ent filter press, off-spec treated effluent, and water collected from the sumps of the wastewat er treatment system building. The influent flow rate to the Equalization tank is 1200 gpm. The residen ce time in the equalization tank depends on the flow rate that the WWT plant is processing. At a flow rate of 600 gpm the residence time is approximately 12 hours.

 The wastewater treatment system includes a ma intenance tank in case the equalization tank or sludge holding tank is out of service.Page 10

 The wastewater from the equalization tank is tr ansferred to reaction ta nk #1 (the wastewater treatment system includes two of these tanks) wher e lime slurry is added to adjust the pH of the wastewater. Organosulfide is added to target the remova l of certain metals, such as mercury. The target pH in reaction tank #1 is between 8 and 9 S.U.

 The FGD wastewater gravity drains to reacti on tank #2 (the wastewat er treatment system includes two of these tanks) wh ere ferric chlori de is added.

 From reaction tank #2, the wastewater gravity dr ains to the clarifiers (the wastewater treatment system includes two clarifiers). As the water is transferred, AcuTreat® 4355 polymer is added. The total retention time in the clarifiers is about 6 hours.

 From the clarifier, the wastew ater gravity drains into one of five sand gravity filters (continuous backwash). Hydrochlor ic acid is used to adjust th e pH of the wastewater to

between 6 and 8 S.U. as the water is transferred to the sand filters.

 From the sand filters, the water is transferred to the treated wastewater storage tanks (there are two of these tanks) and is sent to the bottom ash basin (A rea 15). On average Monroe’s WWT Plant will discharge to the bottom ash basi n 14 hours a day at a flow rate of 275 gpm. This depends upon the pH falling within a rang e of 6.5 to 9.0 and how much waste water is being sent to the WWT Plant from the FGD system. This effluent is monitored for pH and turbidity. Off-spec treated wastewater is recycled to the equalization tank.

 Monroe takes grab samples of the treated wast ewater downstream of the treated wastewater storage tank on the suction side of the treated wastewater discharge pumps from a fiberglass reinforced plastic (RFP) pipe tap.

 The residence time of the wastewater depends on the flow rate that the WWT facility is processing. At a flow rate of 600 gpm th e residence time is approximately 20 hours.

 Some of the sludge from the clar ifiers is recycled to reaction tank #1 for seeding. The rest of the sludge is transferred to the sludge holding ta nk and then to the sludge conditioning tanks. Monroe dewaters the sludge from the sludge c onditioning tanks using four belt filter presses. As the sludge is loaded onto the belt press, AcuTreat® 4355 polymer is added. The press sandwiches the sludge between tw o rollers to remove moisture . The filtrate from the belt presses is recycled to the e qualization tank. The dewatered sl udge, which is typically about 35 percent moisture, is transferred to four sludge hoppers and trucked off site to a landfill.

Metal Cleaning Wastes

 Monroe cleans each of their four boilers about once every ten years. Monroe uses an acid

wash to clean the boiler tubes. The wastewater from cleaning the boilers is sent to a 6.5 million gallon, open storage tank. Between 1994 and 2001, the plant evaporated chemical metal cleaning wastewater in the Unit 4 boi ler. However, Monroe will no longer be evaporating metal cleaning wastes, because it will poison the SCR catalyst and possibly the FGD. The current practice is to adjust the wa stewater to a pH of 10 using lime, and then agitate it with oxygen in order to meet the permit requirements prior to discharge under the NPDES permit. The two acids used to clean th e boiler tubes are 4% hydroxyacetic acid andPage 11

2% formic acid. The typical boiler volume is approximately 105,500 gallons. Unit 3 was cleaned in November 2009 and generated appr oximately 2.2 million gallons of wastewater, including wash water and rinse water. Unit 2 was cleaned in May 2010 and generated approximately 1.7 million gallons of wastewater , including wash water and rinse water. Exact volumes of metal cleaning wastewater s are not known for earlie r cleanings, but are likely between about 1.7 million gallons a nd 2.5 million gallons. Only chemical metal cleaning wastes are sent to the storage tank. Because it is an open tank, storm water may also

enter the tank

.

 Monroe stated that they only us e water to clean the air heaters. No chemicals are added to the water during this process. The water is sent to the bottom ash basin (Area 15).Table 1. Site Visit AttendeesNameOrganization (Representing)TelephoneE-mailMary HanaEnvironmental Management andResources(313) 235-8704hanamj@dteenergy.comChuck LarlhamEnvironmental Management andResources /Monroe Power Plant(734) 384-2560larlhamr@dteenergy.comClaire JenningsEnvironmental Management andResources /Monroe Power Plant(734) 384-2562jenningsc@dteenergy.comDan CaseyMonroe Power Plant(734) 384-2371caseyd@dteenergy.comDennis LeonardEnvironmental Management andResources(313) 235-8714leonardd@dteenergy.comBrett Mac IntyreEnvironmental Management andResources(313) 235-6922macintyreb@dteenergy.comPaul Tracy Monroe Power Plant (734) 384-6812tracyp@dteenergy.comDonna Hill UWAG/Southern Co. (205) 257-5234dbhill@southernco.comRon Jordan EPA/Office of Water (202) 566-1003jordan.ronald@epa.govJezebele AliceaVirellaEPA/Office of Water (202) 566-1755alicea.jezebele@epa.govSarah Holman ERG (Contractor to EPA) (703) 633-1661sarah.holman@erg.comElizabeth Sabol ERG (Contractor to EPA) (703) 633-1659elizabeth.sabol@erg.com