Notes from Site Visit at JEA’s Northside Generating Station on April 8, 2014

EPA conducted a site visit at JEA’s Northside Generating Station (Northside) located in 

Jacksonville, FL on April 8th, 2014 to learn about the operations at the plant, specifically the 

dense slurry ash transport system. These notes describe the information collected during the site 

visit. Table 2 identifies the site visit participants. Plant process flow diagrams, provided by JEA 

in preparation for the site visit, are included as Attachment 1 to these notes. Additionally, a 

material flow diagram of the dense slurry system is included as Attachment 2 to these notes. 

Plant Overview

 JEA Northside operates two circulating fluidized bed (CFB) boilers, Units 1 and 2. Units 

1 and 2 are base load units that burn a mixture of petroleum coke and coal and each have 

a gross capacity of 310 megawatts (MW). JEA Northside operates one stand-alone steam 

turbine generating unit, Unit 3. Unit 3 is a cycling unit that burns oil and gas and has a 

gross capacity of 540 MW. Table 1 contains some general information on the three steam 

electric generating units:

Table 1. Plant Summary

Unit Fuel

Capacity 

(MW) Fly Ash Bottom Ash FGD

NOx 

Control FGMC

1* Coal: Bituminous 

Petroleum Coke

Gas: Natural gas 

and Landfill gas

310 Dry pneumatic 

transport to fly 

ash silo, 

transported by 

dense slurry 

system to 

landfill

Dry mechanical 

and pneumatic 

transport to 

bottom ash silo, 

transported by 

dense slurry 

system to landfill

Spray 

Dryer 

Absorber

SNCR None

2* Coal: Bituminous 

Petroleum Coke

Gas: Natural gas 

and Landfill gas

310 Dry pneumatic 

transport to fly 

ash silo, 

transported by 

dense slurry 

system to 

landfill

Dry mechanical 

and pneumatic 

transport to 

bottom ash silo, 

transported by 

dense slurry 

system to landfill

Spray 

Dryer 

Absorber

SNCR None

3 Gas: Natural gas 

and Landfill gas

Oil: No. 6 Fuel Oil

540 None None None Low 

NOx 

burner

None

*CFB boilers.

 Unit 1 and Unit 2 were originally commissioned in 1966 and 1972, respectfully. Unit 3 

was commissioned in 1978. In 2002, JEA Northside repowered Units 1 and 2 with the 

Department of Energy’s (DOE) “clean coal” grant. The addition of the two CFB boilers 

doubled JEA Northside’s generation and reduced sulfur dioxide (SO2) emissions by 10 

percent.

 The JEA Northside plant covers approximately 88 acres and lies adjacent to JEA’s St. 

John’s River Power Park Plant (SJRPP). The two plants operate independently of each
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other; however, they have a combined National Pollutant Discharge Elimination System 

(NPDES) permit. As described in the NPDES permit, the only water that is shared 

between the two plants is the make-up water for the SJRPP natural draft cooling towers. 

The make-up water is withdrawn from the Northside discharge canal and the blowdown 

from the cooling towers is returned to the Northside discharge canal just downstream of 

the SJRPP intake structure.

 At JEA Northside, the two by-product storage areas account for approximately 21 acres 

of the JEA Northside property and the ponds account for approximately nine acres.

 Units 1 and 2 burn a combination of petroleum coke (from Texas or Venezuela) and coal 

(from Colombia). JEA Northside burns approximately 1.4 million tons of petroleum coke 

and 200,000 tons of coal per year. Currently, the fuel blend for one unit is 70 percent 

petroleum coke and 30 percent coal. The other unit burns a fuel blend that is 60 percent 

petroleum coke and 40 percent coal. Fuel blending for each unit can vary from 100% coal 

to 100% petcoke, and any mixture of percentages between those ranges. The fuel 

blending is based on the availability of petroleum coke and coal at the plant.

 There are two fuel domes which collectively store approximately 12 days worth of 

petroleum coke and coal. All fuel at JEA Northside is delivered by barge.

 Units 1 and 2 run continuously. It takes approximately 16 hours to start up the units.

Natural gas is the only fuel used for start up of Units 1 and 2. Gas is used to achieve a bed 

temperature of 900oF to facilitate a solid fuel permissive. At 1400oF a solid fuel “latch” is 

achieved and gas is removed from the units. Additionally, natural gas can be used for 

intermediate or peak operation schedules for Units 1 and 2. The units can co-fire up to 10 

percent natural gas.

 The internal circulating temperature within the CFB boilers at full load is approximately 

1650oF. The ideal temperature for the limestone reaction facilitating SO2 capture is 

approximately 1600oF. These units are termed “hotloop” boilers due to the material being 

blown in a loop within.

 JEA Northside adds limestone directly to the boiler for SO2 control. The plant injects 

approximately 450,000 tons of lime into the boilers each year. Additional SO2 is removed 

downstream by the spray dryer absorber (SDA).

 For Units 1 and 2, more bed (bottom) ash than fly ash is generated. Unit 1 and Unit 2 

each produce approximately 700 tons of bed ash and 500 tons of fly ash per day. The 

plant generates approximately 500,000 tons of by-product per year.

 The fly ash is conveyed dry by a vacuum system to the recycle bin, which feeds the 

mixing tank to make the spray slurry. When the upper level indicator on the recycle bin is 

satisfied, ash valves divert the fly ash and pneumatically convey the ash to the fly ash 

silos where it is either sold or transported to the by-product storage area by the dense 
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slurry system (DSS). The bed ash is collected on a mechanical conveyor from underneath 

the boiler. Then, it is blown by pressure to the bottom ash silos where it is either sold or

transported to the by-product storage by the DSS.

 JEA Northside either landfills the DSS by-product offsite or markets it. The by-product 

can be sold as a binder for other landfills, remediation sites, or pond closures. The byproduct can also be sold for interim cover or secondary road cover.

Spray Dryer Absorber (SDA)

 The flue gas (and entrained fly ash) from Units 1 and 2 exits the top of the CFB boilers 

and travels through the economizer and air heater ducting, where some fly ash falls out of 

flue gas stream and is collected into hoppers. 

 The rest of the fly ash and flue gas enters the SDA and is sprayed with fly ash slurry

(there is no lime directly added to the SDA). The fly ash slurry is made up of some fly 

ash that was collected in the baghouse and reuse water. A mixing tank at the ground level 

continuously mixes the fly ash slurry used in the SDA. The fly ash slurry is pumped to a 

storage tank at each unit prior to being sprayed into the SDA. The high temperature of the 

flue gas dries the slurry (all water evaporates) and reacts with remaining sulfur 

compounds in the flue gas to produce gypsum. The SDA has a SO2 removal efficiency of 

99.9 percent.

 Any solids that drop down in the bottom of the SDA are collected and recycled back to 

the process in the fly ash slurry.

 The only wastewater discharges associated with the SDA are a result of cleaning 

operations. The SDA cleaning operations include flushing out pumps twice a shift and 

high pressure water blasting the absorber once per year. General cleaning is conducted 

once daily to mitigate ash dust and control any ash accumulation. The water associated 

with the cleanings is sent to the baghouse sump. The baghouse sump is flushed with 

approximately 100 gallons of re-use water per day per unit when the pump cycles off. 

The water is then sent to a precipitation basin, followed by the chemical treatment 

system, before it is discharged to a percolation/evaporation pond or a publicly owned 

treatment works (POTW).

 Other cleaning operations include brushing the spray nozzles (no wastewater is generated 

from this process) twice a day.

Fly and Bed Ash Handling

 After leaving the SDA, the fly ash is collected in fabric filter baghouses. Each fabric filter 

baghouse consists of 1,030 cages which are covered with filter bags to capture the fly 

ash. A pulse air system is used to clean baghouse filter bags. Fly ash is pulsed free from 

the filter bags and drops into one of eight hoppers under the baghouse. The fly ash is 
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pneumatically conveyed to the fly ash silos (Silo 1 and Silo 2) or to the SDA. Silos 1 and 

2 are both equipped with dry unloading spouts for marketing fly ash (road base/sub-base 

and waste stabilization/solidification). The fly ash sent to the SDA building is recycled 

for use in the SDA.

 The bed ash flows out of the bottom of the CFB boilers into a stripper/cooler, which 

removes bed ash material to maintain appropriate furnace bed level. The stripper/cooler 

contains piping at the top through which the fine particles return to the boiler. The 

heavier particles are cooled with air to about 500°F and the bed ash is continuously 

removed from the stripper/cooler by a series of mechanical drag chains to a clinker 

grinder. The clinker grinder breaks-up any bed ash particles too large to pneumatically 

convey before the material drops into a surge hopper. A pneumatic pressure system 

underneath the hopper conveys the remaining bed ash to storage silos (Silo 3 and Silo 4). 

Silos 3 and 4 are both equipped with dry unloading spouts for marketing bottom ash

(road base/sub-base and waste stabilization/ solidification).

 JEA Northside explained that a choke point of the fly and bed ash handling systems can 

be the valves from the hoppers to the silo. These valves are typically replaced once every 

year.

 JEA installed four silos at Northside to handle all of the ash from Units 1 and 2. The 

system was originally designed to have one fly ash and one bed ash silo for each unit. 

Because there are two silos for fly ash and two silos for bed ash there is redundancy 

within the system. Fly ash from either unit can be conveyed to Silos 1 or 2 and bed ash

from either unit can be conveyed to Silos 3 or 4. 

 The silos are emptied as frequently as possible. Both fly ash and bed ash material are 

typically slurried to the by-product storage area when the height of fly ash material stored 

in the fly ash silo reaches 40 to 50 feet.

 From the silos, the fly ash and bed ash is either marketed (and transported offsite using 

rail or truck) or slurried to the by-product storage area by the DSS. From the by-product 

storage area, the ash mixture is either landfilled offsite or marketed.

 JEA Northside determines if the ash will be marketed or slurried to the landfill based on 

market conditions and production. The silos have the dry unloading capabilities for rail 

cars and trucks.

Dense Slurry System

 JEA Northside installed the DSS to transport fly ash and bed ash to a by-product storage 

area in 2002. It took the plant approximately three to five years to get the DSS running 

efficiently. The DSS was designed to have enough capacity to handle all fly and bed ash 

produced from Units 1 and 2. JEA installed the DSS because trucking the dry ash 

material was not feasible due to traffic concerns and the volume of trucks required. JEA 
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also stated that a traditional, lean wet sluicing system was not feasible because the 

amount of limestone in the ash would result in scaling and they did not want to build new

ponds to store ash. 

 United Conveyor Corporation (UCC) designed and delivered the equipment for the DSS. 

The diaphragm (GEHO) pumps were procured from a European-based company. 

 As shown in Attachment 2, pre-mix and mixing tanks are located underneath the fly ash 

and bed ash storage silos. Fly ash is first combined with makeup water, from the POTW, 

underneath the fly storage silo in the pre-mix and mixing tanks. The resulting fly ash 

slurry is then pumped to one of two bed ash mixing tanks located underneath the bed ash 

silos. It is mixed with bed ash and additional makeup water to produce the dense slurry 

transferred to the by-product storage area. The dense slurry is approximately 60 percent 

solids by weight and pumped by one of two high pressure piston diaphragm pumps to the 

by-product storage area through four inch diameter slurry pipes. The by-product storage 

area is approximately one mile away. 

 The system is capable of mixing 220-250 tons of ash per minute. JEA Northside only 

conveys ash from one fly ash silo and one bed ash silo to the by-product storage area at a 

time. 

 The ratio of fly ash, bed ash, and water used in the preparation of the slurry depends on 

the blend of fuel burned and the market for dry fly and bed ash. 

 The preparation of the slurry is a highly exothermic reaction that raises the slurry 

temperature to 190 ̊F. According to plant personnel, the small amount of free water left 

after pumping the dense slurry to the landfill evaporates within a few days in the form of 

steam, resulting in a stable landfill placement of the wet by-products. The material takes 

approximately 48 hours to cure. The resulting by-product material mostly consists of 

limestone, giving it a chalk-like consistency.

 During the DSS start up, JEA Northside had to add dry bed ash to the slurry to meet the 

desired composition in the landfill. That procedure is no longer needed because they have 

adjusted boiler input and the ratio of fly ash, bed ash, and water to have a quick drying 

slurry product. The dried by-product is excavated before being milled and deposited into 

large mounds on the far side of the storage area.

 The dried, milled dense slurry product is tested to ensure it meets minimum strength and 

waste stabilization benchmarks before being marketed and transported off-site via trucks. 

Common uses for this material include, but are not limited to, waste stabilization at 

landfills, remediation sites, and pond closures and road sub-base.

 When JEA slurries ash to the by-product storage area, the DSS runs continuously for 

three to four days (usually once a week). To prevent and manage the build-up of fine 
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particles in the dense slurry pipe, the system is flushed with water recycled from other 

plant processes after each run. The water generated during the flush process stays on the 

by-product storage area and is absorbed into the ash material. The slurry discharge can be 

recirculated within the mixing tanks while flushing the downstream dense slurry line and 

GEHO pumps if necessary.

 JEA Northside explained that a choke point of the DSS is the valves in the DSS. Regular 

maintenance on the system includes rebuilding valves once a year during scheduled 

outages, cleaning the mix tanks after every run (the flushing process), and performing 

maintenance in the silos as necessary when they are empty. A plant operator walks the 

dense slurry transport lines from the mixing tanks to the by-product storage area every 

two hours to ensure there are no maintenance issues. 

 JEA Northside did not mention any climate or geographical limitations for operating the 

DSS. 

By-Product Storage Areas/Landfills

 The dense slurry is pumped to one of two by-product storage areas. One storage area is 

the onsite landfill (the upper by-product storage area) for the dense slurry by-product,

which was brought online in 2002. The landfill stores the product of the dense slurry 

system (a mixture of bed ash, fly ash, and water). The 21-acre landfill is double-lined 

with an HDPE liner and a two foot drainage layer.

 The upper by-product storage area was designed to be operational for a five year period. 

However, the plant has sustained use of the landfill for over 10 years by dredging the byproduct material and disposing of it offsite. The by-product is either marketed or trucked 

to an offsite landfill. JEA Northside sends the slurry by-product to offsite landfills 

because they did not want to permit another landfill area. Initially, the plant had a cell fill 

plan for the upper by-product storage area, but no longer follows it. 

 The dense slurry is directed into one of two 25-30 foot deep pits at the upper by-product 

storage area. The dense slurry pump line discharge is not fixed and can be moved to alter 

the location of the dense slurry discharge at the by-product storage area. The slurry is 

only pumped into one pit at a time, filled until approximately four feet of headroom is 

left, and then the slurry line is directed into the other pit. While one pit is receiving slurry, 

the dried material from the other pit is dredged and prepared for the next slurry. The 

dredged by-product is stacked until it is loaded in trucks for final disposal. 

 At the upper by-product storage area, JEA Northside established a low-permeability 

membrane at start-up by laying down thin layers of slurry and letting dry. The 

permeability of the by-product ranges between 10-3and 10-5cm/sec.
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 The upper by-product storage area is in compliance with its 62-701 permit (Florida 

Department of Environmental Protection) solid waste management facility requirements. 

The permit cycle for the landfill is five years. The base of the upper by-product storage 

area is at an elevation of 15 feet and the maximum permitted elevation is 100 feet. The 

landfill is currently at an elevation of 70 feet. 

 JEA Northside is required to survey the landfill annually and perform semi-annual 

ground water monitoring reports. There are over 30 compliance wells and 10 to 15 

detection wells around the upper by-product storage area. Currently, the plant is dealing 

with one issue at a well where vanadium was detected. JEA Northside suspects that this is 

a result of storm water runoff associated with truck traffic at the landfill. As a result, the 

plant is planning to build a truck washing facility that should be completed in October 

2014. 

 The other, smaller by-product storage area (the lower by-product storage area/EZ Base 

Facility) was constructed after the upper by-product storage area. The storage area is selfdeclared for beneficial reuse and, as such, does not require a liner. The platform for the 

area is seven feet of compacted slurry by-product. Additionally, the storage area has 

berms that were built using the slurry by-product. 

 Plant operators are working on at least one of the by-product storage areas every day. The 

operators are responsible for dredging and stacking the by-product for final disposal and 

the next slurry event. Additionally, they build up the edges of the active slurry pits with 

dry by-product. 

 No transport water is recirculated back to the plant for reuse. All the water used to 

convey the ash is absorbed by the material through a hydration reaction, or is evaporated. 

Leachate for the upper storage area and runoff from rainfall are collected and treated in 

the plant waste water treatment system (see next section).

Leachate Collection

 Around the perimeter of the upper by-product storage area there is a perimeter ditch to 

capture runoff. Additionally, there are four sumps that collect the leachate from the upper 

by-product storage area. The four sumps and the perimeter ditch drain to four doublelined collection ponds.

 The collection ponds have an estimated capacity of 12 million gallons and cover 

approximately 11 acres.

 The water from the collection ponds is not recycled back to the plant process; however, it 

is sent to the plant’s chemical waste treatment system. The chemical waste treatment 

system includes flocculation and the addition of acid for pH control. The effluent from 

the treatment system is sent to percolation/evaporation ponds or to a POTW. Other 

wastewaters combined in the treatment system include other water from other plant 
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sumps, once through cooling water, low volume waste, metal cleaning waste, and ion 

exchange wastewater. 

 JEA Northside samples wastewater effluent at the combined discharge from the chemical 

waste treatment system. Analytes include metals, conductivity, pH, oil and grease, and

total suspended solids (TSS).
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Table 2. List of Attendees

Name Organization (Representing) Telephone E-mail

Matt McClure JEA 904-665-6253 mcclmr@jea.com

Ed Cordova JEA 904-665-7840 corded@jea.com

Steve McInall JEA 904-665-4309 mcinsg@jea.com

C. Shay Hill JEA HillCs2@jea.com

Katie Bizub JEA bizukj@jea.com

Jaclyn Taricska JEA tarijm@jea.com

Farid Zahir JEA 904-665-6576 zahimf@jea.com

James Stancia JEA stanjm@jea.com

Scotty Bichsel JEA bichks@jea.com

John Wiseman JEA wiseje@jea.com

Michael D’Avico JEA davimt@jea.com

Kristen Sealey Golder Associates 352-336-5600 ksealey@golder.com

Ron Jordan EPA 202-566-1003 jordan.ronald@epa.gov

Jezebele Alicea-Virella EPA 202-566-1755 alicea.jezebele@epa.gov
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Table 2. List of Attendees

Name Organization (Representing) Telephone E-mail

Phillip Flanders EPA 202-566-8323 flanders.phillip@epa.gov

Deborah Bartram ERG 703-633-1669 deborah.bartram@erg.com

Elizabeth Sabol ERG 610-344-0829 elizabeth.sabol@erg.com

Ryan Novak ERG 703-633-1668 ryan.novak@erg.com