James M. Ebeling, Ph.D. Aquaculture Engineer

An Engineering Analysis of the Stoichiometry An Engineering Analysis of the Stoichiometry of Autotrophic, Heterotrophic Bacterial Control of Autotrophic, Heterotrophic Bacterial Control

of Ammonia-Nitrogen in Zero-Exchange Productionof Ammonia-Nitrogen in Zero-Exchange Production

James M. Ebeling, Ph.D. James M. Ebeling, Ph.D. Aquaculture EngineerAquaculture Engineer

Michael B. Timmons, Ph.D.Michael B. Timmons, Ph.D.ProfessorProfessor

Dept. of Bio. & Environ. Eng.Dept. of Bio. & Environ. Eng.Cornell UniversityCornell University

James J. Bisogni, Ph.D.James J. Bisogni, Ph.D.ProfessorProfessor

School of Civil & Environ. Eng.School of Civil & Environ. Eng.Cornell UniversityCornell University

6th International Conference on Recirculating Aquaculture6th International Conference on Recirculating Aquaculture

IntroductionIntroduction

Ammonia-nitrogen

NH4+

-N NO2--N

Ammonia Oxidizing Bacteria

Photoautotrophic(green-water systems)

HeterotrophicHeterotrophic(zero-exchange systems)

NH4+

-N C5H7O2N

BacteriaBacteria

Autotrophic(fixed-cell bioreactors)

NO2- -N NO3

--NNitrite Oxidizing Bacteria

NH4+

-N CC106106HH263263OO110110NN1616PP

AlgaeAlgae

Cinorganic / N Ratio Corganic / N Ratio


““New Paradigm”New Paradigm”

Zero-exchange Systems “Belize System”Zero-exchange Systems “Belize System”

ShrimpShrimp – – high health, selectively bred SPF stockhigh health, selectively bred SPF stock

FeedFeed – – high protein feeds combined with carbon supplementationhigh protein feeds combined with carbon supplementation

Water managementWater management – – zero water exchange, recycling water between cropszero water exchange, recycling water between crops


??? Understanding of the ‘Removal System’??? Understanding of the ‘Removal System’

• PhotoautotrophicPhotoautotrophic• AutotrophicAutotrophic• HeterotrophicHeterotrophic• Some Combination!Some Combination!

Impact on Water Quality!!!!Impact on Water Quality!!!! Management Strategies!Management Strategies!

““New Paradigm” New Paradigm” ???? ????


Ammonia ProductionAmmonia Production

In general:In general:

PPTANTAN = F * PC * 0.092 = F * PC * 0.092

where:where: PPTANTAN = Production rate of total ammonia nitrogen, (kg/day) = Production rate of total ammonia nitrogen, (kg/day)

F = Feed rate (kg/day)F = Feed rate (kg/day)

PC = protein concentration in feed (decimal value)PC = protein concentration in feed (decimal value)

For marine shrimp:

PTAN = F * PC * 0.144


Nitrogen Removal Pathways

Extensive Pond

• Photoautotrophic

• Autotrophic

• Heterotrophic

• Other Mysterious Ways

NH4+-N CO2 Alkalinity

VSSAlgae

VSSAuto

VSSHetero

CO2

Alkalinity

O2

Corganic

NO3--N

TraceNutrients



Intensive Pond • Photoautotrophic• Autotrophic

• Heterotrophic

• Other Mysterious Ways

NH4+-N CO2 Alkalinity

VSSAlgae

VSSAuto

VSSHetero

CO2

Alkalinity

O2

Corganic

NO3--N

TraceNutrients

Algae Based Systems



Recirculation Systems


• Autotrophic• Heterotrophic

• Denitrification

NH4+-N O2 Alkalinity

VSSAlgae

VSSAuto

VSSHetero

Alkalinity

CO2

Corganic

NO3--N

TraceNutrients

NO2--N

Fixed-film Bioreactors



Zero-exchange


• Autotrophic

• Heterotrophic

• Denitrification

NH4+-N O2 Alkalinity

VSSAlgae

VSSAuto

VSSHetero

Alkalinity

CO2

Corganic

NO3--N

TraceNutrients

Suspended Growth Systems


PhotoautotrophicPhotoautotrophic (algal based systems)(algal based systems)

Biosynthesis of saltwater Biosynthesis of saltwater algaealgae:: Nitrate as nitrogen sourceNitrate as nitrogen source

16 16 NONO33-- + 124 + 124 COCO22 + 140 H + 140 H22O + O + HPOHPO44

2-2- → →

CC106106HH263263OO110110NN1616PP + 138 + 138 OO22 + 18 + 18 HCOHCO33--

Ammonia as nitrogen sourceAmmonia as nitrogen source

16 16 NHNH44++ + 92 + 92 COCO22 + 92 H + 92 H22O + 14 O + 14 HCOHCO33

-- + + HPOHPO442-2- → →

CC106106HH263263OO110110NN1616PP + 106 + 106 OO22


PhotoautotrophicPhotoautotrophic (algal based systems)(algal based systems)

Consumes C organic C inorganic N

Consumables Stoichiometry (g) (g) (g) (g)

NH4+-N 1.0 ----- ----- 1.0

Carbon Dioxide 18.07 g CO2/ g N 18.07 ----- 4.93 -----

Alkalinity 3.13 g Alk/ g N 3.13 ----- 0.75 -----

Yields C organic C inorganic N

Products Stoichiometry (g)(g) (g) (g)

VSSAlgae 15.85 g VSSA / g N 15.85 5.67 ----- 1.0

Oxygen 15.14 g O2/ g N 15.14 ----- ----- -----


Autotrophic - NitrificationAutotrophic - Nitrification

Biosynthesis of Biosynthesis of Autotrophic bacteriaAutotrophic bacteria:: NH4

+ + 1.83 O2 + 1.97 HCO3- →

0.024 C5H7O2N + 0.976 NO3- + 2.9 H2O + 1.86 CO2

The major factors affecting the rate of nitrification include:

• ammonia-nitrogen and nitrite-nitrogen concentration • carbon/nitrogen ratio• dissolved oxygen • pH• temperature• alkalinity• salinity


Autotrophic - NitrificationAutotrophic - Nitrification



NH4+-N 1.0 ----- ----- 1.0


Oxygen 4.18 g O2/ g N 4.18 ----- ----- -----


Products Stoichiometry (g) (g) (g) (g)

VSSA 0.20 g VSSA / g N 0.20 0.106 ----- 0.025

NO3--N 0.976 g NO3

--N /g N 0.976 ----- ----- 0.976

CO2 5.85 g CO2/ g N 5.85 ----- 1.59 -----


Heterotrophic BacteriaHeterotrophic Bacteria

The major factors affecting the rate of nitrification include:

• ammonia-nitrogen• carbon/nitrogen ratio• dissolved oxygen • pH• temperature• alkalinity• salinity

Biosynthesis of Biosynthesis of Heterotrophic bacteriaHeterotrophic bacteria:: NH4

+ + 1.18 C6H12O6 + HCO3- + 2.06 O2 →

C5H7O2N + 6.06 H2O + 3.07 CO2


Heterotrophic BacteriaHeterotrophic Bacteria



NH4+-N 1.0 ----- ----- 1.0

C6H12O6 15.17 g Carbs/ g N 15.17 6.07 ----- -----


Oxygen 4.71 g O2/ g N 4.71 ----- ----- -----

Yield C organic C inorganic N


VSSH 8.07 g VSSH / g N 8.07 4.29 ----- 1.0

CO2 9.65 g CO2/ g N 9.65 ----- 2.63 -----


Impact of C/N Ratio

Autotrophic Heterotrophic

inorganic carbon as alkalinity

organic carbon from the feed

(109 g C organic /kg feed)@ 35% protein

organic carbon from the feed plus supplemental carbohydrates

C/N Ratio

Clabile /N ~ 2.2

C/N ~ 8-10

35.6% Heterotrophic 64.4 % Autotrophic

Clabile /N ~ 6.2

C/N ~ 12-16

Clabile /N ~ 0

Corganic/N ~ small

100% Heterotrophic 100 % Autotrophic

(Recirculation System withexcellent solids removal)


StoichiometryStoichiometry

Photoautotrophic System

16 NO3- + 124 CO2 + 140 H2O + HPO4

2- → C106H263O110N16P + 138 O2 + 18 HCO3-

50.4 g N * 15.8 g VSS/ g N

= 800 g VSSphotoautotrophic

0.063 gN/gVSSA 0.358 gC/gVSSA

50.4 g NVSS 286 g CVSS

Conversion of 1 kg of feed @ 35% protein

6th International Conference on Recirculating Aquaculture6th International Conference on Recirculating AquacultureConversion of 1 kg of feed @ 35% protein



NH4+-N 50.4 ----- ----- 50.4

Carbon Dioxide 18.07 g CO2/ g N 911 ----- 249 -----

Alkalinity 3.13 g Alk/ g N 158 ----- 37.9 -----



VSSAlgae 15.85 g VSSA / g N 800 286 ----- 50.4

O2 15.14 g O2/ g N 763 ----- ----- -----

Photoautotrophic (Pond intensive system)


StoichiometryStoichiometry

50.4 g N * 0.20 g VSS/ g N

= 10.1 g VSSautotrophic


1.25 g NVSS 5.35 g CVSS

+ 49.2 g NO3-N + 80.1 g CO2

Autotrophic System

Conversion of 1 kg of feed @ 35% protein


Autotrophic (Intensive Recirculation System)



NH4+-N 50.4 ----- ----- 50.4


Oxygen 4.18 g O2/ g N 211 ----- ----- -----



VSSA 0.20 g VSSA / g N 10.1 5.35 ----- 1.25

NO3--N 0.976 g NO3

--N /g N 0.976 ----- ----- 49.2

CO2 5.85 g CO2/ g N 295 ----- 80.1 -----

85.6 g CAlk / 50.5 g N C/N ratio of 1.7 and TOC is very, very small


Zero-exchange System (no Carbon Supplementation)

Heterotrophic and Autotrophic Components

1 kgfeed * 0.36 kg BOD/kg feed * 0.40 kg VSS/ kg BOD =

= 144 g VSSheterotrophic

0.124 gN/gVSSH 0.531 gC/gVSSH


+ 47.1 g CCO2 = 123.6 g C

108.2 g Cfeed 15.4 g CAlkalinityAssume that the heterotrophic bacteria out compete the autotrophic bacteria.

Heterotrophic Component: Organic Carbon from Feed




Excess Ammonia-nitrogen:50.4 g NH3-N - 17.9 g NVSS = 32.5

g NA

Autotrophic Component: Inorganic Carbon Alkalinity

32.5 g N * 0.20 g VSS/ g N

= 6.5 g VSSautotrophic



+ 31.7 g NO3-N + 55.4 g CAlk


Heterotrophic Bacteria Consumes C organic C inorganic N

Stoichiometry (g) (g) (g) (g)

NH4+-N 0.356 * NT 17.9 ----- ----- 17.9

C6H12O6 feed 15.17 g Carbs/ g N 272 108.9 ----- -----


Autotrophic Bacteria Consumes C organic C inorganic N


NH4+-N 0.644 * NT 32.5 ----- ----- 32.5


C organic C inorganic N

Total Consumed Consumes (g) (g) (g)

NH4+-N 50.4 g N ----- ----- 50.4

C6H12O6 272 g Carbs 108.9 ----- -----

Alkalinity 293 g Alk ----- 70.8 -----




Heterotrophic Bacteria Yields C organic C inorganic N


VSSH 8.07 g VSSH / g N 144 76.5 ----- 17.9

CO2 9.65 g CO2/ g N 174 ----- 47.4 -----

Autotrophic Bacteria Yields C organic C inorganic N


VSSA 0.20 g VSSA / g N 6.5 3.45 ----- 0.81

NO3--N 0.976 g NO3-N/g N 31.7 ----- ----- 31.7

CO2 5.85 g CO2/ g N 189 ----- 51.7 -----

C organic C inorganic N

Total Products Yields (g) (g) (g)

VSS 150.5 g VSS 80.0 ----- 18.7

NO3--N 31.7 g NO3-N ----- ----- 31.7

CO2 363.4 g CO2 ----- 99.1 -----



460 g Cfeed / 50.5 g N C/N ratio of 9




83%

62%

50%

64%

69%72%

75%77%

23%25%

28%31%

36%

41%

17%

38%

50%

59%

0%

20%

40%

60%

80%

100%

12.4% 15% 20% 25% 30% 35% 40% 45% 50% 55%

Heterotrophic Bacteria

Autotrophic Bacteria

Percent removal of ammonia-nitrogen by Heterotrophic or Autotrophic Process as a function of % Protein


Excess Ammonia-nitrogen:50.4 g NH3-N - 17.9 g NVSS = 32.5 g NA

32.5 g N * 8.07 g VSS / g N

= 262 g VSSheterotrophic

0.124 gN/gVSSH 0.531 gC/gVSSH

32.5 g NVSS 139 g CVSS

+ 85 g C CO2 = 225 g C

197 g Cs 28 g CAlkalinity

Carbon Supplement

Zero-exchange System (Carbon Supplementation)

Carbohydrate is 40% Carbon 492 g carbs

6th International Conference on Recirculating Aquaculture6th International Conference on Recirculating Aquaculture(460 g Cfeed + 197 g Ccarb ) / 50.5 g N C/N ratio of 13



NH4+-N 50.4 ----- ----- 50.4

C6H12O6 15.17 g Carbs/ g N 765 306 ----- -----


Oxygen 4.71 g O2/ g N 237 ----- ----- -----

Yield C organic C inorganic N


VSSH 8.07 g VSSH / g N 407 216 ----- 50.4

CO2 9.65 g CO2/ g N 487 ----- 133 -----



Supplemental Carbohydrate as percentage of feed ratefor heterotrophic metabolism of ammonia-nitrogen to microbial biomass

6%

17%

28%

38%

60%

71%

82%

93%

49%

0%

20%

40%

60%

80%

100%

15 20 25 30 35 40 45 50 55

Feed Protein (%)

Supp

lem

enta

l Car

bohy

drat

e .

(% o

f fee

d) .



Research Trial #1 – C/N RatioResearch Trial #1 – C/N Ratio

StockingStocking 3.6 gm mean weight3.6 gm mean weight 150 shrimp / m150 shrimp / m22

Treatment (Sucrose)Treatment (Sucrose) ControlControl 50 % of Feed Rate50 % of Feed Rate 100% of Feed Rate100% of Feed Rate

4x12 Juvenile Production Tanks

DosageDosage 100% carbon Demand100% carbon Demand 200% of carbon Demand200% of carbon Demand


Research SystemResearch Systemy =0.90 gms/wk

R2 = 0.98

2.0

4.0

6.0

8.0

10.0

12.0

0 10 20 30 40 50 60 70Days

Mea

n W

eigh

t (gm

s) .

Control

50% C Demand

100% C Demand

4x12 System with sludge settling tank,automatic feeders, bacterial floc

Weekly Growth – about 0.9 gm/wk


Water Quality ParametersWater Quality Parameters

• Dissolved OxygenDissolved Oxygen• SalinitySalinity• TemperatureTemperature• pHpH• AlkalinityAlkalinity• TSS/TVSTSS/TVS

• TANTAN• NONO22 –N –N

• NONO33 –N –N

• Total NitrogenTotal Nitrogen• Total Organic CarbonTotal Organic Carbon


Water Quality SummaryWater Quality Summary

DO Temp Salinity pH TAN NO2-N NO3-N Alkalinity

(mg/L) (Cº) (ppt) (mg/L) (mg/L) (mg/L) (mg/L)

Control 6.1 29.5 4.8 7.78 1.15 0.13 54.7 183StDev: 0.4 0.5 0.4 0.20 1.06 0.15 29.0 49

50% of Feed 5.7 29.8 4.5 8.15 1.06 0.38 7.7 328StDev: 0.9 0.9 0.4 0.14 0.26 1.0 3.3 22

100% of Feed: 5.3 29.4 4.7 8.19 1.36 0.60 1.9 360StDev: 1.5 0.2 0.2 0.18 0.81 1.1 0.8 24


Water Quality Parameters - Water Quality Parameters - Dissolved OxygenDissolved Oxygen

4x12 Tanks: Dissolved Oxygen (mg/L)

0.0

2.0

4.0

6.0

8.0

10.0

5/17/04 5/27/04 6/6/04 6/16/04 6/26/04 7/6/04 7/16/04

Dis

solv

ed O

xyge

n (m

g/L

) .

Control

50% Feed

100% Feed


Water Quality Parameters - Water Quality Parameters - TemperatureTemperature

4x12 Tanks: Water Temperature (Deg. C)

27.0

28.0

29.0

30.0

31.0

5/17/04 5/27/04 6/6/04 6/16/04 6/26/04 7/6/04 7/16/04

Tem

pera

ture

(Deg

C)

.

Control

50% Feed

100% Feed


Water Quality Parameters - Water Quality Parameters - pHpH

4x12 Tanks: pH

7.00

7.50

8.00

8.50

9.00

5/17/04 5/27/04 6/6/04 6/16/04 6/26/04 7/6/04 7/16/04

pH

Control

50% Feed

100% Feed


Water Quality Parameters - Water Quality Parameters - TANTAN

4x12 Tanks: Ammonia-nitrogen (mg/L)

0.00

0.50

1.00

1.50

2.00

5/17/04 5/27/04 6/6/04 6/16/04 6/26/04 7/6/04 7/16/04

TA

N (m

g/L

)

Control

50% Feed

100% Feed


Water Quality Parameters – Water Quality Parameters – NONO22- N- N

4x12 Tanks: Nitritie-nitrogen (mg/L)

0.00

0.10

0.20

0.30

0.40

0.50

5/17/04 5/27/04 6/6/04 6/16/04 6/26/04 7/6/04 7/16/04

Nit

rite

-nit

roge

n (m

g/L

) .

Control

50% Feed

100% Feed


Water Quality Parameters – Water Quality Parameters – NONO33- N- N

4x12 Tanks: Nitrate-nitrogen (mg/L)

0

20

40

60

80

100

5/17/04 5/27/04 6/6/04 6/16/04 6/26/04 7/6/04 7/16/04

Nit

rate

-nit

roge

n (m

g/L

) . Control

50%Feed

100% Feed


Water Quality Parameters – Water Quality Parameters – AlkalinityAlkalinity

4x12 Tanks: Alkalinity (mg/L CaCO3)

50

100

150

200

250

300

350

400

5/17/04 5/27/04 6/6/04 6/16/04 6/26/04 7/6/04 7/16/04

Alk

alin

ity

(mg/

L C

aCO

3) .

Control

50% Feed

100% Feed


Solids ManagementSolids Management

Solids Management:Solids Management:

• Settling conesSettling cones


Settling BasinsSettling Basins

Sedimentation: AdvantagesSedimentation: Advantages• Simplest technologiesSimplest technologies• Little energy inputLittle energy input• Relatively inexpensive to install and operateRelatively inexpensive to install and operate• No specialized operational skillsNo specialized operational skills• Easily incorporated into new or existing facilitiesEasily incorporated into new or existing facilities

18

D)(gV

2pp

s

Sedimentation: DisadvantagesSedimentation: Disadvantages• Low hydraulic loading ratesLow hydraulic loading rates• Poor removal of small suspended solidsPoor removal of small suspended solids• Large floor space requirementsLarge floor space requirements• Resuspension of solids and leechingResuspension of solids and leeching


Settling BasinsSettling Basins

Design to minimize turbulence:Design to minimize turbulence:

vs = 0.0015 ft/sec

Q = flow (gpm)

vo = 0.00076 ft/sec


Autotrophic/Heterotrophic ModelAutotrophic/Heterotrophic Model

ControlTank "A"

Initial Final TSS Removed % RemovedDay (mg/L) (mg/L) (gms)24 466 210 666 55%43 487 260 590 47%56 462 263 517 43%

Mean: 591


50% of FeedTank "C"

Initial Final TSS Removed % RemovedDay (mg/L) (mg/L) (gms)11 379 218 419 42%22 441 134 798 70%34 449 206 632 54%42 441 242 517 45%52 482 218 686 55%60 485 313 447 35%

Mean: 583

Heterotrophic Model Heterotrophic Model (50% feed)(50% feed)


100% of FeedTank "B"

Initial Final TSS Removed % RemovedDay (mg/L) (mg/L) (gms)

7 381 165 562 57%13 448 220 591 51%20 604 192 1071 68%25 569 304 689 47%28 490 219 705 55%32 445 208 616 53%35 422 187 611 56%40 507 185 837 64%45 520 264 666 49%49 490 254 614 48%54 463 350 294 24%58 673 587 224 13%62 579 338 627 42%

Mean: 623



TSS Production ModelTSS Production Model

Solids Production Model:Solids Production Model: autotrophic/heterotrophicautotrophic/heterotrophic

heterotrophicheterotrophic



• allocated the daily feed organic carbon to heterotrophic bacterial production, allocated the daily feed organic carbon to heterotrophic bacterial production,

• calculated VSScalculated VSSHH, [, [VSSVSS

HH = feed g/m = feed g/m33 day * 0.36 g BOD/g feed * 0.40 g VSS day * 0.36 g BOD/g feed * 0.40 g VSSHH / g BOD] / g BOD]

• calculated amount of ammonia-nitrogen assimilated in the VSScalculated amount of ammonia-nitrogen assimilated in the VSSHH, [, [TANTAN

HH = 0.123 * VSS = 0.123 * VSSHH] ]

• subtracted TANsubtracted TANHH from the daily TAN from the daily TAN

feedfeed produced, produced,

[TAN[TANfeedfeed = feed g/m = feed g/m33 day * (0.35 * 0.16 * 0.9)] day * (0.35 * 0.16 * 0.9)]

• allocated excess ammonia-nitrogen to autotrophic bacterial consumption, allocated excess ammonia-nitrogen to autotrophic bacterial consumption,

[TAN[TANAA= TAN= TAN

feedfeed – TAN – TANHH]]

• determined VSSdetermined VSSA A [VSS[VSS

AA = TAN = TANAA * 0.20 g VSS * 0.20 g VSS

AA/g N]/g N]

• calculated Total VSS and TSS.calculated Total VSS and TSS.



• allocated the daily feed carbon to heterotrophic bacterial production, allocated the daily feed carbon to heterotrophic bacterial production,

• calculated VSScalculated VSSHH, [, [VSSVSSHH = feed g/m = feed g/m33 day * 0.36 g BOD/g feed * 0.40 g VSS day * 0.36 g BOD/g feed * 0.40 g VSSHH / g BOD] / g BOD]

• calculated amount of ammonia-nitrogen sequestered in the VSScalculated amount of ammonia-nitrogen sequestered in the VSSHH, [, [TANTANHH = 0.123 * VSS = 0.123 * VSSHH] ]

• subtracted from the daily TANsubtracted from the daily TANfeedfeed produced, [ produced, [TANTANfeedfeed = feed g/m = feed g/m33 day * (0.35 * 0.16 * 0.9)] day * (0.35 * 0.16 * 0.9)]

• allocated excess ammonia-nitrogen to additional heterotrophic bacterial production, allocated excess ammonia-nitrogen to additional heterotrophic bacterial production,

[[TANTANH+H+= TAN= TANfeedfeed – TAN – TANH H ]]

• determined VSSdetermined VSSH+H+ [VSS[VSSH+H+ = 8.07 g VSS = 8.07 g VSSHH/g N * g N]/g N * g N]

• calculated Total VSS and TSS.calculated Total VSS and TSS.



•allocated the daily feed carbon to heterotrophic bacterial production,

•calculated VSSH, [VSSH = feed g/m3 day * 0.36 g BOD/g feed * 0.40 g VSSH / g BOD]

•assumed all of the sucrose carbon was converted into bacterial biomass(sufficient nitrogen available)

•determined VSSdetermined VSSH+ H+ [VSSH+ = g sucrose/m3 day * 0.56 g VSSH/g sucrose]

•calculated Total VSS and TSS.


4x12 System: Total Suspended Solids Management - Control

y = 14.7 mg/L day

R2 = 0.92

y = 14.3 mg/L day

R2 = 0.93

y = 14.4 mg/L day

R2 = 0.87

y = 13.8 mg/L day

R2 = 0.94

50

150

250

350

450

550

0 7 14 21 28 35 42 49 56 63

Days

TS

S (

mg/

L)



4x12 System Total Suspended Solids - 50% of Feed

y = 29.1mg/L dayR2 = 0.93

y = 23.5 mg/L day R2 = 0.88

y = 27.4 mg/L dayR2 = 0.93

y = 35.5 mg/L dayR2 = 0.99

y = 21.8 mg/L dayR2 = 0.91

y = 38.1 mg/L dayR2 = 0.95

50

150

250

350

450

550

0 7 14 21 28 35 42 49 56 63

Days

TS

S (

mg/

L)



4x12 System Total Suspended Solids - 100% of Feed

y = 53.7 mg/L day9

R2 = 0.96

y = 87.8 mg/L day

R2 = 0.96

y = 77.1 mg/L day

R2 = 0.99

y = 81 mg/L day

R2 = 0.99

y = 52.2 mg/L day

R2 = 0.98

50

200

350

500

650

0 7 14 21 28 35 42 49 56 63

Days

TS

S (

mg/

L)



Water Quality Management – C/N RatioWater Quality Management – C/N Ratio

0.0

2.0

4.0

6.0

8.0

10.0

7/18/04 7/25/04 8/1/04 8/8/04

Suga

r (k

g)

0.0

0.5

1.0

1.5

Nit

rite

(mg/

L-N

) .

Sugar (kg)

Nitrite (mg/L)

Impact of carbon supplementation (or lack of) on nitrite-nitrogen


Water Quality Parameters - Water Quality Parameters - TOCTOC

TOC for 4x12 System: Control, 50% and 100% Feed

y = 1.10 mg/L day

R2 = 0.97

Control

0

20

40

60

80

100

120

5/17/04 5/27/04 6/6/04 6/16/04 6/26/04 7/6/04 7/16/04

TO

C (m

g/L

-C)

.

Control

50% Feed

100% Feed


Water Quality Parameters - Water Quality Parameters - TNTN

0

50

100

150

200

250

300

0 10 20 30 40 50 60 70

Nit

roge

n (m

g/L

-N)

.

T otal Nitrogen - Model

T otal Nitrogen - FeedT otal Nitrogen - Experimental Data

Measured T otal Nitrogen

0

50

100

150

200

250

0 10 20 30 40 50 60 70

Nit

roge

n (m

g/L

-N)

.

Total Nitrogen - Model

Total Nitrogen - FeedTotal Nitrogen - Experimental Data

Measured Total Nitrogen

Mass balance on nitrogen for the autotrophic/heterotrophic system without carbon supplementation and with periodic harvesting of excess bacterial biomass

Impact of carbon supplementation at 50% of the feed as sucrose on the system with excess bacterial biomass and nitrogen being periodically removed from the system


Conclusions

Further work is needed to characterize the impact on Further work is needed to characterize the impact on production system performance at various C/N ratios.production system performance at various C/N ratios.

Alternative forms of Carbon need to be evaluated for Alternative forms of Carbon need to be evaluated for effectiveness and economics.effectiveness and economics.

Fundamental research is needed on carbon assimilation and Fundamental research is needed on carbon assimilation and conversion efficiency for heterotrophic bacteria.conversion efficiency for heterotrophic bacteria.

Development of optimal strains of bacteria for zero-exchange Development of optimal strains of bacteria for zero-exchange systems. systems.


Conclusions

““New Paradigm”New Paradigm” Zero-exchange systemsZero-exchange systems Mixed-cell racewaysMixed-cell raceways SPF, low salinity growoutSPF, low salinity growout

““Engineering Sustainability”Engineering Sustainability”

Organic CarbonOrganic Carbon + Nitrogen + Nitrogen → → Bacterial BiomassBacterial Biomass


AcknowledgementsAcknowledgements

Research was supported by the Agriculture Research ServiceResearch was supported by the Agriculture Research Service of the United States Department of Agriculture, of the United States Department of Agriculture,

under Agreement No. 59-1930-1-130under Agreement No. 59-1930-1-130 and Magnolia Shrimp LLC, Atlanta Georgiaand Magnolia Shrimp LLC, Atlanta Georgia

with special thanks to Miami Aqua-culture, Inc., Dan Spotts.with special thanks to Miami Aqua-culture, Inc., Dan Spotts.

Opinions, conclusions, and recommendations are of the authorsOpinions, conclusions, and recommendations are of the authors and do not necessarily reflect the view of the USDA.and do not necessarily reflect the view of the USDA.

All experimental protocols involving live animals were in complianceAll experimental protocols involving live animals were in compliance with Animal Welfare Act (9CFR) and have been with Animal Welfare Act (9CFR) and have been

approved by the Freshwater Institute Animal Care and Use Committee.approved by the Freshwater Institute Animal Care and Use Committee.


Questions?Questions?

James M. Ebeling, Ph.D. Aquaculture Engineer

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