Enrique J. La Motta, Ph.D., P.E.. Professor of Civil and Environmental Engineering. THE . SOUTHEAST SYMPOSIUM ON CONTEMPORARY ENGINEERING TOPICS (SSCET. ). University of New Orleans. September 2014 . ID: 358703
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Presentations text content in ODOR AND CORROSION CONTROL IN SEWERAGE SYSTEMS
Slide1
ODOR AND CORROSION CONTROL IN SEWERAGE SYSTEMS
Enrique J. La Motta, Ph.D., P.E.
Professor of Civil and Environmental Engineering
THE
SOUTHEAST SYMPOSIUM ON CONTEMPORARY ENGINEERING TOPICS (SSCET
)
University of New Orleans
September 2014
Slide2
PRESENTATION OUTLINE
Cause
of H
2
S
odor
and
corrosion
Odor and corrosion control technology
o
verview
Problems and solution in NO metropolitan area
Pure oxygen injection
Applications and case studies
Slide3
Bacteria need oxygen to consume org. matter
MAIN CAUSE OF ODOR
Oxygen sources(order of preference):Oxygen (limited)Nitrate (limited)Sulfate (unlimited)
Slide4
Anaerobic slime layer
SO
42-
Anaerobic bacteria
H
2S
Sulfide Generation in Sewers
Condensate: Location of H
2
S oxidizing bacteria
Anaerobic slime layer
H2S is released from solution as gas (rotten egg odor)
Corrosion of moist pipe surface
H2S + O2
Thiobacillus
sulfuricans
H
2SO4
(EPA Manual)
Slide5
EFFECTS OF SEWER CORROSION
(Vitrified Clay Pipe Manual)
Slide6
RATE OF CORROSION
At H2S concentrations of 20ppm in the headspace,concrete will corrode at a rate of 1 inch in 5 years
(
Clidence
and
Shissler
, 2008)
Slide7
MAJOR H2S CORROSION TARGET AREAS
Gravity concrete or cast iron sewersPump stations and force mainsTreatment facilities
Slide8
TREATMENT OBJECTIVES
Maintain DO > 0.5 mg/L.
Keep dissolved sulfides (DS) less than 0.1 (difficult and costly to achieve) to 0.3 mg/L.
Maintain H
2
S in the air at less than 3 to 5 ppm.
Increase pipe crown pH to 4.0 or higher
Slide9
TECHNIQUES AVAILABLE TO CONTROL H2S CORROSION
Oxidations systems:
Pure oxygen
injection
Air injection
Hydrogen peroxide
Chlorine
Potassium permanganate.
Precipitation systems
Iron salts
Zinc salts
pH elevation
Other methods
Slide10
HYDROGEN SULFIDE CONTROL AT ORLEANS PARISH
Significant amount of sulfide generation
occurs
in the sanitary sewer systems of the New Orleans metropolitan area
.
Orleans Parish produces approximately 120 MGD of municipal wastewater
S&WB has tried hydrogen peroxide and Bio-Kat addition
Roughly 24 MGD is
being treated with Bio-
Kat
The annual
cost
of Bio-Kat
≈
0.6 million
dollars
The unit cost is roughly
$25,000 per MGD treated.
Slide11
BEST METHOD: PURE OXYGEN INJECTION
A more cost-effective
H
2
S control system
is wastewater super-
oxygenation.
Oxygen can be generated in situ using modern technology.
Pure oxygen is injected at selected sewage pumping stations.
High oxygen transfer efficiency (>90%)
Slide12
Typical in situ oxygen generation system using the pressure swing adsorption (PSA) technology (Source: OGSI.)
Slide13
Schematic diagram of the ECO
2
oxygen injection system. (
Clidence
and
Shissler
, 2008).
Slide14Slide15
Typical installation of the ECO
2
pure oxygen injection system at a raw sewage pumping station (Source: ECO
2
web site)
Slide16
ADVANTAGES OF PURE OXYGEN INJECTION
Wastewater remains aerobic through the treatment
plant:
No H
2
S generation
No odors
No corrosion
Wastewater arrives partially treated to the treatment plant
Modern technology makes this system cost effective
Examples of positive results:
Slide17
Untreated H
2
S levels in the Laguna Beach force main
Source:
Clidence
and
Schissler
, WEF/A&WMA, 2008
Slide18
H
2
S
levels in the Laguna Beach force
main after pure oxygen injection. Source
:
Clidence
and
Schissler
, WEF/A&WMA, 2008
Slide19
H2S in the sewer headspace near Gulf Pond force main discharge, Milford, Conn.Source: Bradstreet and Smith, WEFTEC 2012
Slide20
Cost of pure oxygen injection systems
Milford
, Conn
.: Unit
annual cost
=
$
5,400/MGD
Madison,
ME:
Unit annual cost =
$
5,200/MGD
Elk Vale,
SD:
Unit annual cost =
$
5,400/MGD
Trinity River Authority,
Dallas,
TX (primary clarifiers, 150 MGD): Unit
annual cost =
1,700
/MGD
The cost
of super-oxygenation
for H
2
S
and corrosion control
is close to one
-fifth of the cost
of
Bio-
Kat.
Slide21
HYDROGEN SULFIDE CONTROL AT JEFFERSON PARISH
Jefferson Parish tried iron salts addition on West Bank
At Marrero WWTP got black precipitate (Fe
2
S) all over the plant
Got Fe(HO)
3
precipitate at the chlorination chamber
Suspended iron salt addition in 1997.
Severe odor and corrosion problems at the East Bank Wastewater Treatment Plant
UNO has been cooperating with JP by developing a pure oxygen injection program
Slide22
Pure Oxygen Injection At JP East Bank Pumping Station System
Assumptions made to calculate oxygen demand:
Oxygen concentration to meet the oxygen uptake rate = 10 x HRT.
HRT was based on continuous flow at average dry weather flow rate
Oxygen concentration needed to oxidize hydrogen sulfide = 5 x DS at each pumping station.
DS data base was limited.
Calculations were performed, and several changes and adjustments were made.
Final amounts of oxygen to be added are on the next diagram.
Slide23
G6-9 Helios
3340.4
gpm
55.1
ft
0.77 fps
G6-4 Galleria
3795.5
gpm
60.1
ft
7136
gpm
1.27 fps
F6-5 Cleary & W. Napoleon
2966.6
gpm
53.8
ft
10,102.5
gpm
1.79 fps
F6-11 Houma & W. Napoleon
2012.6
gpm
66.4 ft
F6-5 Clearview & W. Napoleon2456.7 gpm46.0 ft
12,115.1 gpm2.15 fps
F6-2 W. Napoleon8065.0 gpm66.64 ft
14,571.8 gpm2.04 fps
E6-7 Transcont. &Vineland8153.3 gpm32.66 ft
3.7 fps
30,790.0 gpm2.89 fps
E5-4 Transcontinental & W. Metairie3384.6 gpm42.6 ft
34,174.6 gpm2.69 fps
EBWWTP
SCHEMATIC DIAGRAM OF THE EAST BANK SEWAGE PUMPING SYSTEM
22,636.8
gpm
2.12 fps
Slide24
SECOND PHASE, JEFFERSON PARISH
Implement the oxygen injection program.
Monitor the successful removal of hydrogen sulfide in the pumping system.
Monitor the remaining odor levels at the EB WWTP.
If odors continue, focus on improving the sludge management system.
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DownloadNote - The PPT/PDF document "ODOR AND CORROSION CONTROL IN SEWERAGE S..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Presentations text content in ODOR AND CORROSION CONTROL IN SEWERAGE SYSTEMS
ODOR AND CORROSION CONTROL IN SEWERAGE SYSTEMS
Enrique J. La Motta, Ph.D., P.E.
Professor of Civil and Environmental Engineering
THE
SOUTHEAST SYMPOSIUM ON CONTEMPORARY ENGINEERING TOPICS (SSCET
)
University of New Orleans
September 2014
Slide2PRESENTATION OUTLINE
Cause
of H
2
S
odor
and
corrosion
Odor and corrosion control technology
o
verview
Problems and solution in NO metropolitan area
Pure oxygen injection
Applications and case studies
Slide3Bacteria need oxygen to consume org. matter
MAIN CAUSE OF ODOR
Oxygen sources(order of preference):Oxygen (limited)Nitrate (limited)Sulfate (unlimited)
Slide4Anaerobic slime layer
SO
42-
Anaerobic bacteria
H
2S
Sulfide Generation in Sewers
Condensate: Location of H
2
S oxidizing bacteria
Anaerobic slime layer
H2S is released from solution as gas (rotten egg odor)
Corrosion of moist pipe surface
H2S + O2
Thiobacillus
sulfuricans
H
2SO4
(EPA Manual)
Slide5EFFECTS OF SEWER CORROSION
(Vitrified Clay Pipe Manual)
Slide6RATE OF CORROSION
At H2S concentrations of 20ppm in the headspace,concrete will corrode at a rate of 1 inch in 5 years
(
Clidence
and
Shissler
, 2008)
Slide7MAJOR H2S CORROSION TARGET AREAS
Gravity concrete or cast iron sewersPump stations and force mainsTreatment facilities
Slide8TREATMENT OBJECTIVES
Maintain DO > 0.5 mg/L.
Keep dissolved sulfides (DS) less than 0.1 (difficult and costly to achieve) to 0.3 mg/L.
Maintain H
2
S in the air at less than 3 to 5 ppm.
Increase pipe crown pH to 4.0 or higher
Slide9TECHNIQUES AVAILABLE TO CONTROL H2S CORROSION
Oxidations systems:
Pure oxygen
injection
Air injection
Hydrogen peroxide
Chlorine
Potassium permanganate.
Precipitation systems
Iron salts
Zinc salts
pH elevation
Other methods
Slide10HYDROGEN SULFIDE CONTROL AT ORLEANS PARISH
Significant amount of sulfide generation
occurs
in the sanitary sewer systems of the New Orleans metropolitan area
.
Orleans Parish produces approximately 120 MGD of municipal wastewater
S&WB has tried hydrogen peroxide and Bio-Kat addition
Roughly 24 MGD is
being treated with Bio-
Kat
The annual
cost
of Bio-Kat
≈
0.6 million
dollars
The unit cost is roughly
$25,000 per MGD treated.
Slide11BEST METHOD: PURE OXYGEN INJECTION
A more cost-effective
H
2
S control system
is wastewater super-
oxygenation.
Oxygen can be generated in situ using modern technology.
Pure oxygen is injected at selected sewage pumping stations.
High oxygen transfer efficiency (>90%)
Slide12Typical in situ oxygen generation system using the pressure swing adsorption (PSA) technology (Source: OGSI.)
Slide13Schematic diagram of the ECO
2
oxygen injection system. (
Clidence
and
Shissler
, 2008).
Slide14Slide15Typical installation of the ECO
2
pure oxygen injection system at a raw sewage pumping station (Source: ECO
2
web site)
Slide16ADVANTAGES OF PURE OXYGEN INJECTION
Wastewater remains aerobic through the treatment
plant:
No H
2
S generation
No odors
No corrosion
Wastewater arrives partially treated to the treatment plant
Modern technology makes this system cost effective
Examples of positive results:
Slide17Untreated H
2
S levels in the Laguna Beach force main
Source:
Clidence
and
Schissler
, WEF/A&WMA, 2008
Slide18H
2
S
levels in the Laguna Beach force
main after pure oxygen injection. Source
:
Clidence
and
Schissler
, WEF/A&WMA, 2008
Slide19H2S in the sewer headspace near Gulf Pond force main discharge, Milford, Conn.Source: Bradstreet and Smith, WEFTEC 2012
Slide20Cost of pure oxygen injection systems
Milford
, Conn
.: Unit
annual cost
=
$
5,400/MGD
Madison,
ME:
Unit annual cost =
$
5,200/MGD
Elk Vale,
SD:
Unit annual cost =
$
5,400/MGD
Trinity River Authority,
Dallas,
TX (primary clarifiers, 150 MGD): Unit
annual cost =
1,700
/MGD
The cost
of super-oxygenation
for H
2
S
and corrosion control
is close to one
-fifth of the cost
of
Bio-
Kat.
Slide21HYDROGEN SULFIDE CONTROL AT JEFFERSON PARISH
Jefferson Parish tried iron salts addition on West Bank
At Marrero WWTP got black precipitate (Fe
2
S) all over the plant
Got Fe(HO)
3
precipitate at the chlorination chamber
Suspended iron salt addition in 1997.
Severe odor and corrosion problems at the East Bank Wastewater Treatment Plant
UNO has been cooperating with JP by developing a pure oxygen injection program
Slide22Pure Oxygen Injection At JP East Bank Pumping Station System
Assumptions made to calculate oxygen demand:
Oxygen concentration to meet the oxygen uptake rate = 10 x HRT.
HRT was based on continuous flow at average dry weather flow rate
Oxygen concentration needed to oxidize hydrogen sulfide = 5 x DS at each pumping station.
DS data base was limited.
Calculations were performed, and several changes and adjustments were made.
Final amounts of oxygen to be added are on the next diagram.
Slide23G6-9 Helios
3340.4
gpm
55.1
ft
0.77 fps
G6-4 Galleria
3795.5
gpm
60.1
ft
7136
gpm
1.27 fps
F6-5 Cleary & W. Napoleon
2966.6
gpm
53.8
ft
10,102.5
gpm
1.79 fps
F6-11 Houma & W. Napoleon
2012.6
gpm
66.4 ft
F6-5 Clearview & W. Napoleon2456.7 gpm46.0 ft
12,115.1 gpm2.15 fps
F6-2 W. Napoleon8065.0 gpm66.64 ft
14,571.8 gpm2.04 fps
E6-7 Transcont. &Vineland8153.3 gpm32.66 ft
3.7 fps
30,790.0 gpm2.89 fps
E5-4 Transcontinental & W. Metairie3384.6 gpm42.6 ft
34,174.6 gpm2.69 fps
EBWWTP
SCHEMATIC DIAGRAM OF THE EAST BANK SEWAGE PUMPING SYSTEM
22,636.8
gpm
2.12 fps
Slide24SECOND PHASE, JEFFERSON PARISH
Implement the oxygen injection program.
Monitor the successful removal of hydrogen sulfide in the pumping system.
Monitor the remaining odor levels at the EB WWTP.
If odors continue, focus on improving the sludge management system.
Inject pure oxygen into sludge
holding
tank.
Slide25Questions?
Slide26Slide27Slide28Slide29Slide30