Final Notes from Site Visit at Allegheny Energy ’s Hatfield’s Ferry Steam Electric Plant on February 3 , 2010

EPA conducted a site visit at Allegheny Energy ’s Hatfield’s Ferry Steam Electric Plant (Hatfield’s Ferry) located in Masontown, PA on Wednesday

, Fe bruary 3, 2010 to learn about the operations at the plant

, including the operation of the flue gas desulfurization ( FGD ) wastewater treatment system

. Table 2 identifies the site visit participants.

Plant Overview

**•** Hatfield’s Ferry operates three coal

- fire d electric generating units

. T able 1 below contains some general i nformation on the current operation of each steam electric generating unit.

Table 1 . Hatfield's Ferry Steam Electric Plant Units Operation

Unit Installation
Da te Gross Net Capacity

(MW) Particulate Control NOx Control SO 2 Control
1 1969 570 ESP (cold

- side) Overfire air FGD ( June 2009 )
2 1970 570 ESP (cold

- side) Overfire air FGD ( October 2009 )
3 1971 570 ESP ( cold

- side) Overfire air,
SNCR FGD (October 2009)

**•** On average

, Hatfi eld’s Ferry burned 3.6 million tons of coal per year from 1993

- 2009. All three units burn a blend of approximately 75% bituminous and 25% powder river basin ( PRB ) coals

. Currently the coal blend has approximately 2 .3 % sulfur and 0.06

- 0.15 % chloride s

. T he FGD systems are designe d for coal s with up to 4% sulfur ; therefore, depending on coal prices

, Hatfield’s Ferry will li kely switch to burning coal with hig her sulfur content in the future

. Based on this expectation, Hatfield’s Ferry stated t hat they will probably burn 100% bituminous coal in another year or two.

**•** Hatfield’s Ferry receives c oal and limestone shipments via barge.

**•** Fly ash is handled dry and sent pneumatically to a silo . From the silo

, dry fly ash is either transported by truck to the landfill or by barge to be sold for beneficial

reuse. Currently, dry fly ash is being used for mine reclamation projects. Hatfield’s Ferry has used dry fly ash handl ing systems since the plant began operating.

**•** Hatfield’s Ferry handles the b ottom as h using a wet system

. The plant sluices the bottom ash to h ydro bins for dewatering . Overflow from the hydro bins is transferred to the concrete ash settling basins. From the settling basins, t he wastewater is neutralized with calcium hydroxide to a pH of 6

- 9 and sent to the lagoons. The bottom ash dewatered in the hydrobins is put directly into truck and most of it is sold

.Page 2

**•** The plant has two lagoons , which are lined with clay

. Only one lagoon is in service at a time, while the other lagoon i s cle a n ed out. H atfield’s Ferry switches the operation of the lagoons approximately every two years

.

**•** Hatfield’s Ferry operates an on

- site landfill, which is not lined. However, t he plant is expanding the landfill and the new portion will be lined with a synthetic liner. The new landfill will hold all FGD waste . All leachate from the new landfill will be transported to a five acre leachate storage impoundment (LSI) . Leachate will be monitored for solids and metals and discharged to the river. The landfill was originally de signed to last 20

- 30 years. However, because the plant is adding
FGD gypsum to the landfill, the plants expects that the landfill will only last

seven years.

**•** The landfill is built over a strip mine. Acid mine drainage from this strip mine is treated with a passive wetland treatment system. Wastewater is pumped from t wo collection sumps to an equilibration pond. The wa ter flows through the wetland where m etals such as iron, aluminum, and manganese are removed . Manganese is removed by manganese oxidizing bac teria which grows on the limestone bed in the treatment system. The wetland discharge s to a pond , which then discharges to Little Whitney creek via outfall 007.

**•** Coal pile runoff is sent to the ash settling basins for treatment

.

Flue G as Desulfurization S ystem

**•** Hatfield’s Ferry uses recycled lagoon water to make up a maximum of 50% of the

water for the FGD system. The remainder of the make

- up comes from the
Monon gahela River . Hatfield’s Ferry can only use up to 50% lagoon water because it is hard to contro l the pH above this percentage

. The plant uses lagoon

water as make

- up because Penn sylvania Department of Environmental Protection (DEP) requested that the plant limit their discharge flow. All wastewater generated at the plant

, except for FGD wastewater

, is sent to the lagoon. This includes ash sluice water, floor drain wastes, and boiler wash water.

**•** The FGD s are all limestone forced oxidation system s. They were designed by
B abcock & W ilcox and have two dual flow t rays. One tray is located about six feet above the flue gas inlet. The second tray is located six feet above the first tray. The first level of spray headers are located six feet above the second tray. The system has five spray headers. The plant typically operates only four of the five spray he aders at a time.

**•** Hatfield’s Ferry operates three ball mills

, one per unit

, to crush the limestone. The limestone preparation process is designed to produce a limestone slurry with 28% solids ; however, the limestone slurry is typically around 22

- 25% solid s.

**•** All three FGD systems have a design sulfur dioxide removal efficiency of 95% and an actual sulfur dioxide removal efficiency of 97

- 98%

.Page 3

**•** Hatfield’s Ferry blows d own from the FGD scrubber based primarily on the level of solids. Once the solids concentr ation reaches 21 percent solids

, the plant blows down to reduce the solid level to approximately 16

- 17 percent . The plant also monitors the chloride level in the absorber s; h owever, by maintaining the correct level of solids, the plant maintains an adequat e chlorid e s level in the absorber at around 10,000 ppm without the need for additional blowdown . For all three units, blow down from the absorbers occurs in six hour increments with four to five hours i n between each blowdown

.

**•** Blow down from each absorb er is sent directly to a set of primary hydro cy clone s (one for each unit). Underflow fr om each primary hydrocyclones is sent to one of four vacuum filters for dewatering gypsum. Each unit has the ab ility to transfer the gypsum to two vacuum filters, which allows blowdown and dewatering to

occur even if one of the vacuum filter s is undergoing maintenance. Filtrate from the vacuum filters is transferred to the reclaim tank. Overflow from the primary hydrocyclone s is either sent to the secondary hydrocyclone s or sent to the reclaim water tank , which is recycled back to the absorbers . Secondary hydrocyclone underflow is transferred to the reclaim tank

, while secondary hydrocyclone overflow goes to the wastewater treatment system.

**•** The plant is designed to produc e commercial grade gypsum, but the plant does not have any contracts in place to sell the gypsum

. The dewatered gypsum contains less than 1 0% moisture

. The plant is not washing the gypsum to remove chlorides because the plant is not marketing gypsum . Addit ionally, the plant has a limit on the average FGD discharge flow rate for the month, which cannot exceed 160

gpm. Plant personnel stated that i f the plant washed the gypsum, the flow additional water would cause them to be above th e flow rate limit. The g ypsum is transported to an on

- site landfill via truck. Wastewater collected in the sump from the gypsum pile is transported to the lagoons.

**•** Ther e are sample points to collect the secondary hydrocyclone overflow off each of the three secondary hydrocyclone s. However, there is no sample point in which to collect the combined secondary hydrocyclone overflow.

FGD Wastewater Treatment System

**•** A simplified diagram of the FGD wastewater treatment system at Hatfield’s Ferry is included as A ttach ment 1

.

**•** In June 2 009, Hatfield’s Ferry began sending wastewater to the FGD wastewater treatment system . The wastewater treatment system first discharged on June 30, 2009.

**•** The secondary hydrocyclone overflow is firs t collected in the equilization (EQ) tank. Wastewater ente ring this tank typically contains 3

- 5 percent solid s

. Primarily overflow from the secondary hydrocyclone s ent ers into the EQ tank. The EQ tank also holds other wastewater

, including treated FGD wastewater and wastewater from the sumps in the FGD waste water treatment building

. Hatfield’sPage 4

Ferry recycles t reated FGD wastewater back to the EQ tank to keep the EQ tank at a sufficiently high level to keep the agitator operating and flow continually running through the wastewater treatment system

. Sumps in the was t ewater treatment system include filter backwash and filtrate from the filter presses that dewater the sludge from the clarifiers

. Sumps from the dewatering area can also empty into the EQ tank. Sumps in the limestone preparation area do not empty into the EQ tank.

**•** From the EQ tank

, FGD wastewater flows into the bottom of reaction tank 1. Hatfield’s Ferry adds l ime to the top of the tank to increase the pH from 5.5 S.U. (pH in the absorber) to 8.5

- 9.0 S.U

. The plant uses s ervice water is used to create th e hydrated lime on site

. The plant also adds o rganosulfide (Nal met 1 689 at the bottom of reaction tank 1

.

**•** The ove rflow from reaction tank 1 flows to reaction tank 2. The plant adds f erric chloride t o the top of th e reaction tank.

**•** The overflow from react ion tank 2 enters a box, which splits the flow to two solids contact clari fiers. Just prior to split ting the stream

, Hatfield’s Ferry adds a polymer to the wastewater

. At the time of the site visit, one clarifier was out of service and being repaired be cau se the lining was peeling off ; therefore, Hatfield’s Ferry is sending all wastewater to the other clarifier. The solids contact clarifier contains a large cone in the center, which is open at the bottom. Wastewater is pumped into the center of this cone . S olids settle down to the bottom of the clarifier. In order for wastewater to exit the clarifier, it must go out the bottom of the center cone and then return back to the surface. This process encourages solids to remain at the bottom of the clarifier. Slud ge scraper arms at the bottom of the clarifier move the solids to the center hopper where it can be removed from the clarifier.

**•** Hatfield’s Ferry the majority of the clarifier solids is sent to the dewatering tank and then pumped to filter presses to crea te sludge cake with 75% solids. The remainder of the clarifier solids are recycled back to reaction tank 1 to act as nucleation sites for the solids entering the system. Th e dewater e d solids are transferred to the landfill with the gypsum. The filtrate fr om the filter presses is collected in the filtrate sump, which is transferred to the EQ tank.

**•** T he overflow from the clarifier is transferred to continuous backwash gravity filters, which use sand as the filtration media. Hatfield’s Ferry adds hydrochlori c acid to the wastewater prior to the filters to raise the pH to 7.0 S.U. The backwash from the continuous backwash gravity filters is transferred to the filtrate sum p.

**•** After passing through the gravity filters, the treated wastewater is sent to the

treat ed wastewater storage tank. Wastewater in this tank is either recirculated back to the EQ tank or discharged.

**•** The plant takes composite and grab samples at a sample tap off of the treated wastewater storage tank. This sample point only collects wastewat er that is beingPage 5

discharged and does not include wastewater that will be recirculated back to the EQ tank.

**•** Discharge from the wastewater treatment system is not continuous; this is largely because treated wastewater is sent back to the beginning of the t reatment system in order to make sure that wastewater is circulating through the system at all times. The plant attempts to keep the average daily discharge lower than 1 6 0 gpm because the average monthly discharge flow rate cannot exceed 160 gpm (a limit

s et by the plant’s NPDES permit). Plant personnel stated that at any individual time, the plant may have no flow leaving the FGD wastewater treatment system, while at other time s , the discharge flow could be 600 gpm. The average daily discharge flow from th e FGD wastewater treatment system (IMP

- 306) is typically about 120 gpm.

**•** Treated FGD wastewater (internal outfall 306) and lagoon wastewater (internal outfall 206) are combined and discharged via the final outfall 006. The plant monitors outfall 006 for pH

, total dissolved solids (TDS), total suspended solids ( TSS ) , oil and grease, cadmium, thallium, selenium, flow, mercury, and sulfate. Hatfield’s Ferry has limits for oil and grease, mercury, cadmium, thallium, selenium, TDS, TSS, and sulfate.Table 2 . Si te Visit Attendees

Name Organization (Representing) Telephone E

- mail

Bill Cannon Allegheny Energy 724

- 838

- 6018 wcannon@allegheneyenergy.com

Randy Jones Allegheny Energy, Hatfield’s Ferry 724

- 966

- 3016 rjones4@alleghenyenergy.com

Wayne Lingenfeller Alleg heny Energy 724

- 838

- 6457 wlingen@alleghenyenergy.com

Donna Hill Southern Company/UWAG 205

- 257

- 5234 dbhill@southernco.com

Josh Hall EPA 202

- 566

- 1002 hall.josh@epa.gov

TJ Finseth Eastern Research Group 703

- 633

- 1698 thomas.finseth@erg.com

Becky Schwantes Eastern Research Group 703

- 633

- 1715 becky.schwantes@erg.com