EVALUATING THE EFFECTIVENESS OF ACCELL FOR ODOR AND CORROSION CONTROL IN

WASTEWATER COLLECTION SYSTEM

Department of Chemical and Natural Gas EngineeringTexas A&M University, Kingsville

BY:

ADEBANJO O. IBIRONKE

SUPERVISORS:

DR. CARL MURPHY (TAMUK)DR. CHARLES GLASS (HOWARD

UNIVERSITY)MANAGER:

MR. HIRAM TANNER (DC WATER)

1

The ProblemOdor

Under anaerobic conditions and absence of other electron acceptors as nitrate, microbiological reactions of sulfate reducing bacteria (SRB) in the sewer biofilm result in sulfate reduction to sulfide.

• SO4= + 8H+ → S= + 4H2O

• S= + 2H+ → H2S (hydrogen sulfide)2

MECHANISM OF H2S GENERATION• On a wastewater profile in

sewer, below the bulk water and next to the submerged wall, a thin layer of biofilm is fully formed after two weeks. The layer is composed mainly of bacteria and inert solids compacted by zooglea -a biologically secreted protein. Here, sulfate reducing bacteria (SRB) within the anaerobic zone strips the sulfate ion (SO4

2-) of its oxygen and uses this as a source of oxygen for digesting organic matter.

3

Hydrogen Sulfide (H2S) is a dense, toxic, colorless gas, that is not only odorous, but, also, very corrosive to infrastructure.

H2S (ppm) Hazard Property

0.1 - 0.3 Detectable

3 - 5 Rotten Egg

10 – 50 Headaches/Nausea

100 –300 Conjunctivitis/Respiratory Irritation (imperceptible to smell)

500 -1000 Immediate Collapse withRespiratory Paralysis

1000-2000 Death

4

Corrosiveness of H2SOn the sewer pipe crown, surface and wall resides aerobic bacteria, mainly thiobacillus. These bacteria thrive on the moist wall of sewers and they oxidize gaseous hydrogen sulfide into sulfuric acid.

● Sulfuric acid readily deteriorates the structural integrity of concrete, iron and steel in the moist, oxidizing atmosphere of a wastewater treatment plant.

● Copper contacts and components of electrical systems will rapidly oxidize to black copper sulfate in the presence of small amounts of hydrogen sulfide.

S= + 2H+ H2SSO4

= -202 S=

H2S + 202 H2SO4

5

Toxicity

• Daily exposure to noxious odors resulting in heightened health risks to employees

• Unpredictable pump systems failures due to structural deterioration of metals

Corrosion• Sewer System Assessment and

Water Facility Plan, 2009 indicated: 88% defect in inspected sewers and 94% defect in manholes.

• Approximately, 7000 linear feet of sewers were found in need of either rehabilitation or replacement.

CONCERNS

6

• Fiscal year 2009 -2018 Capital Improvement Program budget for DC Water, rehabilitation cost of sanitary sewer lines was estimated to $413 million = 11% of the total budget of $3.8 billion.

• Estimates $38B in replacement costs in United States annually in collection and distribution systems due to corrosion

• Water & sewer utility agencies face the same costs as the damage caused by Hurricane Katrina but on an annual basis

COST

7

• Largest Sewer: Northeast Boundary 22 feet by 23’6” near RFK (Robert F. Kennedy) Stadium

• Longest: Potomac Interceptor 50 miles from Dulles International Airport to the Potomac Pumping Station

• Oldest Sewer: Tiber Creek first sections completed in early 1850’s

• Largest Pumping Station: O Street 500 mgd Storm, 45 mgd Sanitary. Built 1908

• 1800 miles Sanitary and Combined Sewers; 600 miles of Storm Sewers

• 9 Sanitary and 16 Stormwater Pumping Stations

• 60 CSO (combined sewer overflows) Outfalls and 95 CSO Structures.

Washington DC Collection System

8

9

• Existing Asset:– Sewers are Longitudinal Dynamic Reactors – BY NOT

TREATING SEWERAGE - FLOW BECOMES ANAEROBIC AND PRODUCES CORROSIVE GASES

– Treatment in Sewers Have Lower CIP (capital improvement program) Impact Versus Building or Modifying Facilities at the Plant

• Treatment in Sewers Is Part of The Solution: – Protect the Environment - Reduce Noxious Odors and

Greenhouse Gases– Protect the Public - Reduce Risk of Sewer Collapse Due to

Corrosion– Protect Assets at Pumping Stations – Reduce Likelihood of Arc

Flash (electric explosion)

To find a Treatment Process for Sewers

10

Accell• Accell is a homogenous, amber

colored, neutral, non toxic liquid with no volatile organic compound or living cell.

• Its is made by Advanced Biocatalytic Corporation (ABC), Irvine, California andSupplied in 55 gallons drums.

• Accell is a product made of protein surfactant complexes (PSC). Basically, activity of synthetic (unnatural, petrochemical) surfactants are enhanced by tightly bonding them with small stress proteins which are released when baker’s yeast is heat shocked.

11

How Accell works?• Protein Surfactant Complexes as flexible linkers that assist in the

solubilization of hydrophobic contaminants.• (PSC) enhances microbial processing by:

hydrolysis H2O dissociates to H+ and OH- in the chemical mechanism of organic matter degradation.

hydroxylation chemical process of introducing hydroxyl group(OH) for organic matter digestion.

• PSC reduces IFT(interfacial tension) thus increases dissolved oxygen uptake

• PSC uncouples bio-oxidation from biomass growth by increasing membrane permeability for H+ thus suppressing change in pH and ATP formation (which supplies stored energy for biomass). All living cells require a continual supply of energy for two main purposes: for the biosynthesis of micro and macromolecules, and for the active transport of ions and molecules across cell membranes. The energy derived from the oxidation of nutrients is not used directly but, by means of a complex and long sequence of reactions, it is channelled into a special energy-storage molecule, adenosine triphosphate (ATP). Instead of utilizing the energy from bioxidation for biomass, it applies the energy toward ion and molecule transfer across its membrane thus enhancing digestion of organic matter.

• Prevents accumulation of Fats, oil and grease by biocleaning. 12

Less demand for oxygen within the system to aid digestion

Less requirement for sulfate (SO4-)reduction to sulfide (S2-)

Efficient utilization of dissolved oxygen within the system to reduce organic matter to CO2

BOD reduction TSS(organic matter) reduction

Stimulate the metabolism activity of bacteria within wastewaterBio-oxidation Biosynthesis

13

Accell ClaimsReduce Wastewater Treatment Plant Pollutants

Cost Effect

90% reduction in Fats, Oils, Grease (FOG) 50% -90% reduction in odor control costs

75% reduction in ammonia 20% - 60% reduction in alum and polymer costs

50% reduction in nitrates/nitrites 15% - 25% reduction in aeration power costs

70% reduction in phosphates 30% -50% reduction in biomass and disposal costs

50% reduction in BOD’s 30% improvement in sludge dewatering properties

95% reduction in H2S 15% - 55% reduction in membrane maintenance

costs.

14

• Documented Success in BP gulf cleanup 2010

• EPA Certified Surface Washing Agent

• NSF Certification for treatment of drinking water

15

• Grab Samples was collected from manhole and tested with Accell.

• Result shows a rapid decrease in dissolved sulfide after 10mins of Accell treatment

• No detectable sulfide after 30mins

Fresh s

ample

Accell

Treated

(1:15

),10m

ins

Untrea

ted 10

mins

Accell

Treated

(1:50

),30m

ins

Untrea

ted 30

mins0

0.2

0.4

0.6

0.8

1

1.2

Sample 1

Sample 2

Sample 3

H2S

PPM

16

Quick Tests1. Laboratory Test

2.Emergency Dosing at Poplar Point

• Manual Screen Cleaning when the automated system malfunctions

• Employees Were Directed to Leave When H2S Exceeded 10 ppm.

• Pumped Accell3 into entering line before entry

• Sawtooth action from Odalogger resulted from this dosing

Point of dosage17

Research Methodology• Add Accell3 at a different rates at Main Pumping Station

– 0.1, 0.2 and 1.9 ppm.• Take grab samples.• Track Performance at 6 Sites along the East Outfall

Sewer.• Measure :

ORP (oxidation reduction potential) ;DO (Dissolved oxygen)pHTSS (Total Suspended Solids); VSS (Volatile Suspended Solids)COD (Chemical Oxygen Demand)Nutrient: H2S, NO3

-N, NH3, PO4-3

18

Location of SitesSite 1

Site 2

Site 3

Site 4

Site 5

Site 6

19

Dosing PointThis is the dosing location of the Accell3 product. (Main PS)

This is the first designated sampling location.

20

Siphon Chamber(Site 2)This is the second designated sampling location.

All wastewater is collected here before it leaves Main Station.

21

Old Gate House (Site 3)The is the third designated sampling location. (East Outfall Line)The structure is located across the river (1/4 mile) from Main PS.

Poplar Point Manhole (Site 4)This is the fourth designated sampling location. (East Outfall Line)-Located a half of a mile from Main Pumping Station.

22

Squeeze Box (Site 5)This is the fifth designated sampling location. Located one mile away from Main Pumping Station.

Structure #4 (Site 6)

This is the six and final designated sampling location.Located three miles from Main Pumping Station.

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Typical H2S

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Average Hydrogen Sulfide Concentration at Six Sites

Site 1 Site 2 Site 3 Site 4 Site 5 Site 60

10

20

30

40

50

60

70

H2S

(ppm

)

Direction of flow

Sites Site 1

Site 2

Site 3 Site 4

Site 5

Site 6

Ave H2S (ppm)

0 0 4.2 3.3 5.3 29

25

Total Suspended Solid

0 1 2 3 4 5 6 7 8 9 10 11 120.0

200.0

400.0

600.0

800.0

1000.0

1200.0

1400.0

1600.0

1800.0

2000.0

7 GDPstructure 16old gate housesqueeze boxsiphon chamberpoplar pointstructure 4

Weeks

PPM

10.5 GPD0 GDP

26

Volatile suspended solids

0 1 2 3 4 5 6 7 8 9 10 11 12 130.000

200.000

400.000

600.000

800.000

1000.000

1200.000

1400.000

1600.000

7 GDP structure16siphon chamberold gate housepoplar pointsqueeze boxstructure4

Weeks

PPM

10.5 GPD0 GDP

0 1 2 3 4 5 6 7 8 9 10 11 12 130.00

20.0040.0060.0080.00

100.00120.00140.00160.00180.00200.00

NO3-N structure16oldgate housesqueeze boxpoplar point

Week

NO3-

N M

g/l

Nitrate

0 GDP 7 GDP 10.5 GDP

27

Phosphate

0 1 2 3 4 5 6 7 8 9 10 11 12 130.00

5.00

10.00

15.00

20.00

25.00

PO4-PStructure 16Old Gate houseSqueeze boxSiphon ChamberPopular PointStructure 4

Week

Mg/

l

0 1 2 3 4 5 6 7 8 9 10 11 120.00

50.00

100.00

150.00

200.00

250.00

300.00

NH3-Nstructure16old gate housesqueeze boxsiphon chamber

Week

NH3-

N M

g/l

Ammonium

10.5 GDP7 GDP0 GDP

10.5 GDP7 GDP0GDP

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ORP•H2S gas is produced at -50 to - 250 mV.

•ORP values reached-300mV during 100+ weather

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

-400

-300

-200

-100

0

100

200

300

structure16 old gate house

sq box siphon chamber

poplar point structure4

Weeks

ORP

(mV)

29

Site 1 Site 2 Site 3 Site 4 Site 5 Site 60

10

20

30

40

50

60

70

80

90

67.3

60.2

67.1 68.9

60.1

71.471.3

76.173.3

69.3 68.2 68.7

81.9

55

72.2

39.8

67.263.2

12.6

43.5

22.620.5

24.5 24.2

TSSVSSPO4-PNO3-N

% re

duct

ion

Reduction (good!)

30

Increase (not good)

Site 1 Site 2 Site 3 Site 4 Site 5 Site 60

20

40

60

80

100

120

TDS

COD

NH3-N

% in

crea

se

Direction of flow

  TDS COD NH3-N

 

Site 1 69.7 32.6 0.9

Site 2 76.5 5.6

Site 3 71.2 42.1 25.9

Site 4 95.9 27.3 3

Site 5 58.1 65.5 56.1

Site 6 68.1 28.7 24.2

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Comparing results to claimsClaim Results (maximum %change)50% reduction in nitrate 43.5% reduction in nitrate as nitrogen

70% reduction in PO4-P 81.9% reduction in PO4-P

76.1% VSS reduction

71.4 % TSS reduction

75% reduction in ammonia 56.1 % ammonia increase50% reduction in BOD 65 % COD increase90% reduction in Fats, Oils, Grease (FOG

FOG (inconclusive)

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Winter study• Maximum H2S of 3 ppm

Winter Period 2011

• Temperature range of 50-600 F

33

FATS, OIL & GREASE (FOG)

• Cause of Sewer Blockages

• Source of H2S• Source of Odor• Major Impact on

Operation &Maintenance Costs 34

Latest attempt at FOG studies

2/11/2012 2/16/2012 2/21/2012 2/26/2012 3/2/2012 3/7/2012 3/12/2012 3/17/2012 3/22/2012 3/27/20120

10

20

30

40

50

60

Screening RoomSiphon Chamber

Oil

and

Gre

ase

mg/

l

> 30 GPD> 5 GPD 0 GPD

• Methodology similar to earlier study but with two monitoring points.• Influent stream = screening room• Effluent stream = siphon chamber.

• Yet to obtain a conclusive set of data.• Need to have more monitoring sites and longer retention time in sewer line.35

Study ConclusionsAccell3 Results

• TSS ,VSS, Phosphate, Nitrate Decreased

• COD, Ammonia, TDS increased.

• pH and DO - No Change • ORP Was Low – No Impact.• H2S Increased with

Distance. • Accell3 Mitigated Indoor

H2S at Main & Poplar Point pumpstations.

• Accell3 Reduce Odors IN Screening Area, Siphon Chamber & Sewer Up to ½ Mile.

• Treatment Feasible• Success Demands

Further Study

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Research 2012-2013Expand Study to Add’l Products/Solutions• ECO2 - Injects Oxygen into Force Mains• STX Catalyts – Inject Catalyts and Peroxide into Force Mains

Rapid Oxidation of Sulfonated Organics• Pri-Sci – Add Iron Salts bind Hydrogen Sulfide, Regenerate

Iron Salts by Adding Peroxide• Accell – In Combination with Oxygen• Magnesium Hydroxide – Raise pH of Sewerage• Microbes

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References• APHA-AWWA-WEF, 2005. Standard Methods for the Examination of Water and

Wastewater, 21st ed. American Public Health Association, Washington, DC, USA• James CC. Sewers and their construction. Drainage problems of the east (a revised

and enlarged of Oritental drainage). Bombay, India: Bennett, Coleman & Company, Ltd., 1917

• Apgar, D.,Witherspoon, J., Easter, C., Bassrai, S., Dillon, C., Torres, E., Bowker, R.P., Corsi, R., Davidson, S., Wolsstenholme, P., Forbes, B., Quigley, C., Ward, M., Joyce, J., Morton, R., Weiss, J., and Stuetz, R., “Minimization of Odor and Corrosion in Collection Systems: Phase 1”, Water Environment Research Foundation, 2007.

• Lee and Reucroft, Vapor adsorption on coal and wood based chemically activated carbons (II) adsorption of organic vapors, 1999.

• Hatamoto Masashi, Tomo Miyauchi, Tomonori Kindaichi, Noriatsu Ozaki, Akiyoshi Ohashi. 2011, Dissolved methane oxidation and competition for oxygen in down-flow hanging sponge reactor for post-treatment of anaerobic wastewater treatment, Bioresource Technology, pp1-6

• Fredrik P. Glasser, Jacques Marchand, Eric Samson. “Durability of Concrete –Degradation Phenomena Involving Detrimental Chemical Reactions”, 2007.

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THANK YOU!!!!!

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