Office of Air Quality Planning and Standards 

US EPA Research Triangle Park 

109 T.W. Alexander Drive 

Research Triangle Park, NC 27711 

SEWAGE SLUDGE INCINERATOR (SSI) SITE VISITS

WITH THE CITY OF GREENSBORO (NC) &

HAMPTON ROADS SANITATION DISTRICT (VA) 

December 15 & 16, 2009 

MEETING ATTENDEES: 

December 15, 2009 City of Greensboro 

U.S. EPA

Office of Air Quality and Planning Standards

Amy Hambrick 

Ketan Patel 

Toni Jones 

Larry Elmore 

Ron Myers 

Charlene Spells 

Office of Water

Maria Gomez-Taylor 

NATIONAL ASSOCIATION OF CLEAN WATER AGENCIES

 Chris Hornbeck 

 Bob Dominak

CITY OF GREENSBORO T.Z. OSBORNE PLANT

Martie Groome Cornell Hailey Walter King 

Wally Kling Bradley Flynt 

Allan Williams Alicia Goots 

Don Howard Michael Adcock 

December 16, 2009 Hampton Roads Sanitation District 

U.S. EPA

Office of Air Quality and Planning Standards

Amy Hambrick 

Ketan Patel 

Office of Water

Maria Gomez-Taylor 

NATIONAL ASSOCIATION OF CLEAN WATER AGENCIES

 Chris Hornbeck 

 Bob Dominak (North East Ohio Regional Sewer District)

HAMPTON ROADS SANITATION DISTRICT

Mark Feltner Bob Jones 

Mike Parsons Ken Sands

Jeff Lane Christel Dyer 
SUMMARY: 

The site visits served as an information session for EPA representatives to see one fluidized bed and two multiple 

hearth sewage sludge incinerators in working operation. Facility representatives showed EPA how the waste water 

treatment process and sludge incineration process were linked. EPA was also able to see each units respective 

control configurations. 

Site Visit Schedule 

December 15, 2009 

7:45 AM Depart for RTP 

9:30 AM Arrived at T.Z. Osborne WWTP - Greensboro, N.C. (City of Greensboro) 

 - This plant has one fluidized bed incinerator 

12:00 PM Lunch and begin driving to Williamsburg, VA 

December 16, 2009 

8:00 AM Williamsburg WWTP - Williamsburg, VA (Hampton Roads) 

- This plant has two multiple hearth incinerators in which skimmings (i.e., grease, scum, 

floatable plastics removed from the wastewater) are being burned with the plant's biosolids. 

11:00 AM Lunch 

12:00 PM Newport News, VA 

Boat Harbor WWTP - Newport News, VA (Hampton Roads) 

- This plant has two multiple hearth incinerators that are equipped with advanced VenturiPak 

scrubbing systems. 

2:00 PM Tours complete. Drive back to RTP. 

6:00 to 7 PM Return to RTP 

 
“We protect public health and the waters of 

Hampton Roads by treating wastewater 

effectively.”
Hampton Roads Sanitation District

— Year Created: 1940 

— Type of Agency: Political subdivision of the 

Commonwealth of Virginia 

— Service Area: 17 counties and cities 

— Population Served: 1.6 million 

— Governing Body: Governor-appointed commission 

— Collection System: More than 500 miles of pipes, 6-66 

inches in diameter 

— Pump Stations: 104 

— Treatment Plants: 9 major plants in Hampton Roads and 4 

smaller plants on the Middle Peninsula 

— Combined Capacity: 231 million gallons per day (MGD)

— EPA approved Pretreatment Program
HRSD Williamsburg WWTP

EPA & NACWA Facility Site Visit December 16th, 2009
HRSD Williamsburg WWTP

— Liquids Management

— Secondary treatment facility 

— MGD Permitted Flow 22.5 MGD

— Typical plant flow 10-12 MGD w/2 MGD from brewery

— Chemical-physical-biological treatment techniques

— Preliminary treatment (bar screens, aerated grit, and 

septage unloading), primary clarification, oxidation 

towers, intermediate clarifiers, aeration basin, 

secondary clarifiers, disinfection and de-chlorination 

(NaOCL & NaHSO3)

— Final effluent discharged to the James River
HRSD Williamsburg WWTP

— Solids Handling & Incineration

— Screenings and grit (landfill)

— Solids drawn from liquids processes are gravity and belt 

thickened (biosolids holding tanks); centrifuge 

dewatering, screw conveyor, multiple heart furnaces 

(MHFs), and ash silo.

— Two identical nine hearth MHFs each @ 36 DTD

— ID fan, wet scrubbers (pre-cooler, venturi & 

impingement tray)

— Supplemental fuels: natural gas and fuel oil

— Autogenous burn assisted by high BTU side stream waste 

solid (trap grease)

— MHF automation improvements
MHF Incineration
MHF & Off Gas System
Williamsburg’s MFHs

— 1 of 2 MHFs ~ running 24/7, 7204 DT burned 2008

— Top hearth temp 1250F, 1500F “burn zone”

— 28% average dewatered total solids content

— Nov. `09 THC 44 ppm & cake solids 503 metals 

(mg/Kg) <8 As, <2.0 Cd, 42 Cr, 7 Ni, & 13 Pb

— Metals removal thru scrubbers 90%+ except Cd 85%

— 503 metals & THC limits are consistently met

— Post stack testing, T5 PM limit met via minimum 

scrubber water flow rates & < 20% opacity standard

— 18 cubic yards/day of Ash
Williamsburg’s Air Emissions

— 2008 MHF actual air emissions (TPY):

— PM 0.8, SO2 175, NOx 18, VOC 6, CO 113, HAPS 0.8 

— 2008 plant wide actual air emissions (TPY):

— PM 0.9, SO2 175, NOx 24, VOC 12, CO 115, HAPS 1.4 

— Odor control packed tower chemical wet scrubbers 

that help us meet the State odor rule

— Diesel engine emergency generator so we maintain 

Class 1 reliability
Williamsburg Plant Tour

— Any pre-tour questions or requests?

— E-files including plant info, stack tests, T5 permits, etc

— Williamsburg MHF walk through

— Post-tour discussion & lunch order 

— Drive to HRSD Boat Harbor

— Boat Harbor plant overview, discussion over lunch

— Boat Harbor MHF walk through

— Post-tour discussion

HRSD Boat Harbor WWTP

— Liquids Management

— Secondary treatment facility 

— MGD Permitted Flow 25 MGD

— Typical plant flow 12-13 MGD

— Biological & physio-chemical treatment techniques

— Preliminary treatment/Headworks (bar screens, grit 

removal, and septage unloading), primary clarification, 

aerobic reactors, secondary clarifiers, disinfection and 

de-chlorination (NaOCL & NaHSO3)

— Final effluent discharged to the James River
HRSD Boat Harbor WWTP

EPA & NACWA Facility Site 

Visit December 16th, 2009
HRSD Boat Harbor WWTP

— Solids Handling & Incineration

— Screenings and grit (landfill)

— Solids drawn from liquids processes are floatation 

thickened (biosolids holding tanks); centrifuge 

dewatering, screw conveyor, belt conveyor, multiple 

heart furnaces (MHFs), and ash silo.

— Foreign biosolids storage (FBS) hopper (Nansemond 

plant)

— Two identical eight hearth MHFs each @ 43 DTD

— ID fan, advanced wet scrubbers Von Roll System (venturi

& impingement tray)

— Supplemental fuels: natural gas and fuel oil

— MHF automation improvement project

8

7

6

5

4

3

2

1

TO STACK

ODOROUS AIR

COOLING AIR FAN

COOLING AIR FAN FROM 

OFF LINE FURNACE USED 

AS DILUTION AIR

BHTP ORIGINAL FURNACE CONFIGURATION

Linked Dampers

Controlled Master Slave

Yokogowa

Controller 

YS 170 

Used 

Manual

Operation

only

Yokogowa

Controller 

UT 550

Induced Draft

TC

TC

Yokogowa

Temperature 

Recorder

02

02 

Display
BHTP Multiple Hearth Furnace Automation 

1. The Controlled master damper from the off line furnace was removed and put 

on the end of the on line furnace’s return air pipe where it previously had a 

blind flange. For the sake of description, it’s being called the ‘Relocated 

Damper’.

2. A guard was fabricated and installed on the open end of the damper for safety.

3. A signal wire from the 02 sensor at the breach section was run to the 

Yokogowa YS 170 that drove the on line furnace’s ‘Controlled Master 

Damper’. The original control wire to the on line furnace’s ‘Controlled 

Master Damper’ was disconnected and a new control wire was run from the 

Yokogowa YS 170 down to the ‘Relocated Damper’. The Operators can now 

establish an O2 set-point on the Yokogowa YS 170 and it now regulates the 

‘Relocated Damper’ to achieve the set-point. 

a. Hearth 7 has been fitted with 3 automated modulating air doors. These 

doors are also controlled by the Yokogowa YS 170 that controls the 

‘Relocated’ damper. The air doors modulate with the damper position I.e. 

if the damper is 50% open, the air doors are 50% open.

This reconfiguration was modeled after WBTP’s and was accomplished 

with their input and direction.

BH MHF automation (cont.)

b. Hearth 6 has been fitted with 3 semi-automatic air doors. If additional air 

is needed, the Operator can open all three by turning a switch that is mounted 

on the control panel. These dampers are either fully open or fully closed.

4. An additional thermocouple signal wire run from the thermocouple on the 

breach section to the ‘Existing’ Yokogowa UT 550 that controls the burners on 

hearth #4. The thermocouple on hearth #4 that used to send a signal to the 

Yokogowa UT 550 for burner control was disconnected. The Operators can 

now establish a set-point for the breach temperature and the ‘Existing’

Yokogowa UT 550 will adjust the hearth #4 burners up or down to achieve it.

5. A new Yokogowa UT 550 controller was purchased and installed as a safety 

device to shut down the burn on hearth #4 if the hearth #4 temperature 

exceeds 1,800 deg. F. This new controller receives it’s signal from the hearth 

#4 thermocouple. When the temperature in hearth #4 gets to 1,600 deg. F, it 

drives the ‘Existing’ Yokogowa controller to zero burn.

6. The new Yokogowa UT 550 cost $750.00

7. The new thermocouple wire cost $240.00

8. The damper relocation and control hook-up took about one day.

9. The burner control feature took about a day and a half.

10. The air doors were fabricated in-house for approximately $840.00
8

7

6

5

4

3

2

1

TO STACK

ODOROUS AIR

COOLING AIR FAN

COOLING AIR FAN FROM 

OFF LINE FURNACE USED 

AS DILUTION AIR

BHTP FURNACE RECONFIGURATION

Linked Dampers

Controlled Master is OPEN 

is OPEN

Slave is CLOSED Yokogowa

Controller 

YS 170

Induced Draft

Slave damper from 

off line furnace

Yokogowa

Controller 

UT 550 

controls 

Hearth 4

burners 

based 

on breach 

temp.

New

Yokogowa

Controller 

UT 550

Safety 

Feature 

to shut down 

the burn

Yokogowa

Temperature 

Display/

Recorder

02

02 

Display

AUTOMATIC 

MODULATING AIR DOOR

SEMI-AUTOMATIC AIR 

DOOR

TC

TC
Boat Harbor MHF Natural Gas Usage

Boat Harbor MHFs

— 1970’s Envirotech, Inc.

— 1972 original construction permit

— 2000 Title V permit 

— PM 0.14 grains/dscf, Hg 3200 grams/day

— Yr 2000 stack tests (PM & Hg)

— PM 0.025 grains/dscf, Hg 25 grams/day

— 2007 stack test of new advanced scrubbing system

— Von Roll “Ring Jet”wet scrubbing system

— PM 0.018 grains/dscf, Hg 25 grams/day

— MHFs also meet Part 503e incineration requirements
Williamsburg’s MFHs

— 1970’s Envirotech, Inc.

— 1972 original construction permit

— 2000 Title V permit 

— PM 0.14 grains/dscf, Hg 3200 grams/day

— Yr 2000 stack tests (PM & Hg)

— PM 0.025 grains/dscf, Hg 25 grams/day

— 1993 Part 503e incineration

— Self implementing rule (no permits)

— Performance standards (metals & THC)

— < metals site specific conc. & < 100 ppm THC mon. ave.
Boat Harbor MHFs

— 1 of 2 MHFs ~ running 24/7, 8078 DT burned 2008

— Top hearth temp 950F, 1250F “burn zone”

— 24% average dewatered total solids content

— Nov. `09 cake solids 503 metals (mg/kg) <11 As, <2.0 

Cd, 44 Cr, 63 Ni, & 184 Pb

— Metals removal by wet scrubbers is ~ 90-99%

— * Metals emitted orders of magnitude below 503 limits

— Nov.`09 THC 48 ppm & normally below the THC 

limit

— Post stack testing, T5 PM limit met via minimum 

scrubber water flow rates & < 20% opacity standard

— 15 cubic yards/day of ash This slide has been corrected per 12/16/09 email from Mark Feltner.
Boat Harbor’s Air Emissions

— 2008 MHF actual air emissions (TPY):

— PM 0.68, SO2 193.8, NOx 20.2, VOC 7, CO 125, HAPS 0.8 

— 2008 plant wide actual air emissions (TPY):

— PM 0.75, SO2 194, NOx 24.2, VOC 11.5, CO 126, HAPS 1.4 

— Odor control packed tower chemical wet scrubbers 

that help us meet the State odor rule

— Diesel engine emergency generator so we maintain 

Class 1 reliability