July 16, 2009

TJ Finseth

ERG 14555 Avion Parkway, Suite 200 Chantilly, VA 20151

Reference : Covanta Fairfax, Inc.

EPA/ERG Tour on 7/21/2009

Dear Mr. Finseth,

I am the Environmental Compliance Specialist for Covanta Fairfax, Inc and will be assistin g you in providing information about the facility as it relates to wastewater discharge. I have included a description on the following pages of the facility operation and will be available to answer any questions that you have prior to your visit next Tue sday. Due to the recent installation of the Reverse Osmosis (RO), some of the current water information may need clarification with our Chief Engineer, Michael Blackwelder.

Plant Description

Covanta Fairfax is located on an approximately 23

- acre site wit hin the boundaries of the I

- 95 Landfill. The area is approximately 1.75 miles from US Highway 1 on Furnace Road in the vicinity of Lorton, Virginia and approximately 25 miles southwest of Washington D.C. Covanta Fairfax owns and operates the I

- 95 Energy/R esource Recovery Facility (I

- 95 E/RRF) under an agreement with Fairfax County, Virginia. The I

95 E/RRF is a nominal 3000

- ton per day refuse

- fired electric generating facility. The I

- 95 E/RRF has operated continuously since it began commercial operation in June 1990. The facility consists of four

nominal 750 TPD refuse

- fired boilers and two 63.8

- megawatt turbine generators, along with ancillary equipment. The facility processes 3000 TPD of municipal solid waste for a population of more than 900,000

in t he Washington, D.C. suburbs of Fairfax County. Air pollution control equipment consists of spray dryer absorbers for acid gas reduction, fabric filter baghouses for particulate removal, a carbon injection system for mercury control and a selective non

- cata lytic reduction system for reduction of nitrogen oxides. The heat energy produced during the combustion of municipal solid waste is converted into electricity that is sold to Virginia Dominion Power Company.

Waste is delivered to the facility via refuse t rucks. The refuse trucks enter the facility through a controlled access gate and proceed to a weigh station. The weigh station determines the total tonnage of waste delivered and, when applicable, the total amount of unacceptable waste rejected. Once th rough the weigh station, the trucks proceed to the tipping bays located within the enclosed tipping hall to deposit the waste in the refuse pit, or temporarily onto the tipping floor. Several loads a day are dumped onto the tipping floor, in

order to allow the loads to be inspected for unacceptable waste. Unacceptable waste is deposited into a large drop box inside the tipping hall. The rejected waste is subsequently transported to an appropriate disposal site. All acceptable waste is pushed into the refuse pit using a front

- end loader. Waste from the refuse pit is mixed, stockpiled and deposited into the furnace feed hoppers by overhead cranes. The refuse pit and tipping hall are maintained at a slightly negative pressure by the combustion air fans (forced draft fans) that draw air from the building. This design feature provides effective odor control. Waste accepted at the facility is primarily municipal solid waste, which includes household, commercial and institutional waste.

Waste is continuously fed into the combustion units from the feed hoppers through refractory

- lined feed chutes. The combustion units are integrated reciprocating grate stokers and top supported, single pass, membrane waterwall boilers equipped with superheaters and economizers. A sophisticated combustion controls package maintains optimal combustion efficiency minimizing the formation of combustion

-dependent pollutants. Design (nominal) steaming rate for each combustor is 205,625 lbs/hr. Natural gas, used as auxiliary fuel in the boilers during start

- up and shutdown, is received by pipeline.

The combustion air is divided into underfire and overfire air. The underfire air is heated in a steam coil then evenly distributed below the stoker grate before entering the combustion zone. Underfire air cools the grates, aids in the suspension of the waste for combustion, and provides combustion air. Overfire air, which is added above the stoker grate at the front and rear walls of the combustor, assures complete combustion of volatile

off

- gases.

The combined high

- pressure superheated steam generated by the four combustion units is piped to either of two turbine generators. Total energy generation capacity at rated combustion rates is 80 MW. Plant load is approximately 10 MW. The balance of the electricity generated is sold to Virginia Dominion Power Company.

The combined bottom ash and fly ash is conveyed away from the waste combustors and fabric filters (baghouses) by a series of different conveyors. All conveyors are either located w ithin buildings or are otherwise enclosed. The ash is combined in the proprietary Martin Ash Discharger and is conditioned with water as both a cooling agent and as a dust suppression agent. The combination of these two design/work practices effectively l imits fugitive dust generation. Dewatering of the ash is accomplished by gravity, by the squeezing action of an ash extractor ram and by a vibrating pan. Oversize material (>10 inches) is removed from the ash stream by a grizzly scalper in a separate outbu ilding. The remaining ash is sent through a series of sizing screens in the residual ash building. Appropriately sized ash is further processed through a non

ferrous metal processing unit (the non

- ferrous system, which was not operational for a period, is currently being brought back into service) to remove valuable non

- ferrous metals for recycling. Ferrous metal is separated from the ash stream, as well. Recovered ferrous and non

- ferrous material is/will be removed from the site by truck. Ash residue is loaded into covered trucks for removal to the I

- 95 Landfill operated by Fairfax County.

Much of the air pollution control equipment is located adjacent to the boiler building to the south. This equipment includes the four spray dryer absorbers, four bagho uses, associated screw conveyers which convey collected fly ash back into the boiler building to the ash discharges, a carbon storage silo, two pebble lime storage silos, lime slurry tanks, quench reactors and associated equipment. The continuous emissions monitoring system (CEMS) shelter is also located in this area. The dolomitic lime silo that stores lime for ash conditioning is also located in this area. Activities in this area include deliveries of pebble lime, carbon and dolomitic lime to the storage silos, and maintenance of the carbon system, lime system, baghouses and fly ash screw conveyors.

Pebble lime, carbon and dolomitic lime are pneumatically conveyed from delivery trucks to the appropriate storage silos. Conveying air is vented through a fa bric filter (baghouse) mounted on the top each storage silo. Collected dust discharges back into the storage silo. Pebble lime is typically delivered eighteen times per month. Carbon is delivered one to two times per month. Dolomitic lime deliveries are r eceived four times

a week.

The 19% aqueous ammonia storage tank (used to store ammonia for the NO X control system) is located to the west of the boiler building inside secondary containment. Ammonia is delivered five times a week.

Note: Covanta Fairfax h as recently installed a Reverse Osmosis System that eliminates much of the following information in this paragraph referencing a demineralizer. We are presenting this information

to illustrate the ongoing improvements in internal water management at the fa cility. Covanta Fairfax has a demineralizer treatment system for boiler feed water. The demineralizer system and the sulfuric acid and sodium hydroxide (caustic) storage tanks associated with its use are located inside the demineralizer building

on the fir st floor along the west wall. The tanks are located inside concrete containment areas. From the secondary containment any spilled material would be pumped into the neutralization tank. Treated effluent from the neutralization tank is regulated pursuant to SIU Wastewater Discharge Permit #A51109 and isdischarged to the Norman M. Cole POTW. The fill ports for the acid and caustic tanks are located outside along the west wall of the demineralizer building within secondary containment.

Exhaust steam from the turbine is condensed to water. The water used to condense the steam is pumped to the facility’s cooling towers, which are located along the south roadway opposite the APC area. The chlorine generator used to treat the cooling water is located inside the ch lorine generator building, which is adjacent to the cooling towers to the east. The tanks for sulfuric acid and biocide used to treat the cooling water are located inside the demineralizer building.

Excess water and ash from cleaning and maintenance acti vities drains into floor trenches located in the boiler building and in the APC area. These floor trenches drain into sumps and subsequently to the two settling basins located in the APC area. Solids settle to the bottom of the settling basins. Water is pu mped from the settling basins to the ash discharges to provide quench water for the ash residue. Ash and sediment from the trenches and the settling basin is disposed of either with the combined ash residue or with the refuse in the main storage pit.

Proc ess wastewater from the facility consists of boiler blowdown, cooling tower blowdown, neutralization tank batch discharges and sanitary sewage from facility buildings. These wastewaters, along with effluent from the Fairfax County Landfill, are pumped from a lift station located to the east of the administration building to the POTW.

Water Permits

**•** SIU Waste Water Discharge (Norman M . Cole POTW

- Fairfax County).

**•** VPDES Direct Discharge Non

- Contact Cooling Tower Water (Inactive as project is on hold)

.

**•** VPDES General Industrial Storm Water Management (Include s required SWPPP).

Other Environmental Permits

**•** PSD / Air

**•** Title V / Air

**•** Solid Waste

Please contact Scott Drew if you have any questions. Looking forward to meeting you on Tuesday.

Regards, Joseph Herrmann Environmental Compliance Specialist

### Facility Aerial View

### Facility Site Plan

### Water Source and Use

Average quantity of water received and wastewater discharged daily :

### Basic System (Prior to RO in stallation) Parshall flume.

1800 ft3/13500 

### gal

Pum p vault.

4320 ft3/32,400 

### gal Lift Station P umps

. 3’” solids sewage pump. 480V,25A,3P,60hz,20hp

450GPM at 75’head

Manholes

Neut T ank B asket



### Turb bldg

sump. Sanitary 

### Fairfax County

Landfill

POTW

Piping vault

720 ft3/5400 gal Cooling Tower
Blowdown