ODOR AND CORROSION CONTROL IN SEWERAGE SYSTEMS PowerPoint Presentation
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: 358703Embed code:
Download this presentation
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
SOUTHEAST SYMPOSIUM ON CONTEMPORARY ENGINEERING TOPICS (SSCET
University of New Orleans
Odor and corrosion control technology
Problems and solution in NO metropolitan area
Pure oxygen injection
Applications and case studiesSlide3
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
Sulfide Generation in Sewers
Condensate: Location of H
S oxidizing bacteria
Anaerobic slime layer
H2S is released from solution as gas (rotten egg odor)
Corrosion of moist pipe surface
H2S + O2
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
MAJOR H2S CORROSION TARGET AREAS
Gravity concrete or cast iron sewersPump stations and force mainsTreatment facilitiesSlide8
Maintain DO > 0.5 mg/L.
Keep dissolved sulfides (DS) less than 0.1 (difficult and costly to achieve) to 0.3 mg/L.
S in the air at less than 3 to 5 ppm.
Increase pipe crown pH to 4.0 or higherSlide9
TECHNIQUES AVAILABLE TO CONTROL H2S CORROSION
HYDROGEN SULFIDE CONTROL AT ORLEANS PARISH
Significant amount of sulfide generation
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-
The unit cost is roughly
$25,000 per MGD treated.
BEST METHOD: PURE OXYGEN INJECTION
A more cost-effective
S control system
is wastewater super-
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
oxygen injection system. (
Typical installation of the ECO
pure oxygen injection system at a raw sewage pumping station (Source: ECO
ADVANTAGES OF PURE OXYGEN INJECTION
Wastewater remains aerobic through the treatment
Wastewater arrives partially treated to the treatment plant
Modern technology makes this system cost effective
Examples of positive results:Slide17
S levels in the Laguna Beach force main
, WEF/A&WMA, 2008Slide18
levels in the Laguna Beach force
main after pure oxygen injection. Source
, WEF/A&WMA, 2008Slide19
H2S in the sewer headspace near Gulf Pond force main discharge, Milford, Conn.Source: Bradstreet and Smith, WEFTEC 2012Slide20
Cost of pure oxygen injection systems
Unit annual cost =
Unit annual cost =
Trinity River Authority,
TX (primary clarifiers, 150 MGD): Unit
annual cost =
and corrosion control
is close to one
-fifth of the cost
HYDROGEN SULFIDE CONTROL AT JEFFERSON PARISH
Jefferson Parish tried iron salts addition on West Bank
At Marrero WWTP got black precipitate (Fe
S) all over the plant
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 programSlide22
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
F6-5 Cleary & W. Napoleon
F6-11 Houma & W. Napoleon
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
30,790.0 gpm2.89 fps
E5-4 Transcontinental & W. Metairie3384.6 gpm42.6 ft
34,174.6 gpm2.69 fps
SCHEMATIC DIAGRAM OF THE EAST BANK SEWAGE PUMPING SYSTEM
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.
Inject pure oxygen into sludge