(Chapra, L23, L24) 1 Loading & Overflow Model L = P + 116 - - PowerPoint PPT Presentation

Lecture #19 Streeter-Phelps: Nitrogen, Photosynthesis/Respiration

(Chapra, L23, L24)

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Updated: 30 October 2017

Loading & Overflow Model

David A. Reckhow CEE 577 #6 2

From Chapra (pg 538)

P L qs = + 116 12 . .

Extended Streeter Phelps

David Reckhow CEE 577 #18 3

( ) ( ) ( ) ( )

( )(

) ( )

( )(

)

t k t k n a n Nd n t k a n Nd n t k t k r a r d d t k a r d d t k a B t k t k n a No n t k t k r a

• d

t k

• a

n a a r a a a n a r a

e e k k k S k e k k S k e e k k k S k e k k S k e k H S R P e e k k L k e e k k L k e D D

− − − − − − − − − − − −

− − − − + − − − − + −       + + − + − − + − − + = 1 1 1

'

#1 #2 #3 #5 #6 #4

General Model Kinetics

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Dissolved Oxygen CBOD

K1 K3

Atmosphere

K2

NBOD

KN1

SOD

K4

(Ka) (Kd) (Ks)

Loading & Overflow Model

David A. Reckhow CEE 577 #6 5

From Chapra (pg 538)

P L qs = + 116 12 . .

Mechanistic Algal Model

David Reckhow CEE 577 #21 6

Organic N

β3

NH3 NO2 NO3

β

1

β2 σ4 σ3

Chlorophyll a

(Algae)

Org-P Diss-P

α µ

1 F

α µ

1

1 ( ) − F

α µ

1

α ρ

1

α ρ

2

α µ

2

α µ

3

α ρ

4

β4

σ5 σ2

σ1

General Model Kinetics with algae

David Reckhow CEE 577 #21 7

Dissolved Oxygen CBOD

K1 K3

Atmosphere

K2

Organic N

β3

SOD

K4

NH3 NO2 NO3

β

1

β2 α β

5 1

σ4 σ3

(Ks) (Ka) (Kd) Chlorophyll a

(Algae)

Org-P Diss-P

α µ

1 F

α µ

1

1 ( ) − F

α µ

1

α ρ

1

α ρ

2

α µ

2

α µ

3

α ρ

4

β4

σ5 σ2

σ1

2 6β

α

General Model Kinetics with N species

David Reckhow CEE 577 #18 8

Dissolved Oxygen CBOD

K1 K3

Atmosphere

K2

Organic N

β3

SOD

K4

NH3 NO2 NO3

β

1

β2 α β

5 1

σ4 σ3 α β

6 2

Nitrogen Modeling

 Organic Nitrogen (N4)

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dN dt A N N

4 1 3 4 4 4

= − − α ρ β σ

Org-N settling rate (d-1) Org-N hydrolysis rate (d-1) Algal biomass (mg/L) Algal respiration rate (d-1) Fraction of algal biomass which is nitrogen (mg- N/mg-A)

Nitrogen Modeling (cont.)

 Ammonia Nitrogen (N1)

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dN dt N N z F A

1 3 4 1 1 3 1 1

= − + − β β σ α µ

Org-N hydrolysis rate (d-1) Rate of biological

• xidation of

ammonia (d-1) Benthos release rate (g-N/m2/d) Fraction of algal-N uptake from ammonia Specific Algal growth rate (d-1) Fraction of algal biomass which is nitrogen (mg- N/mg-A)

Nitrogen Modeling (cont.)

 Nitrite (N2)

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dN dt N N

2 1 1 2 2

= − β β

Rate of biological

• xidation of

ammonia (d-1) Rate of biological

• xidation of

nitrite (d-1)

Nitrogen Modeling (cont.)

 Nitrate (N3)

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( )

dN dt N F A

3 2 2 1 1

1 = − − β α µ

Rate of biological

• xidation of

nitrite (d-1) Specific Algal growth rate (d-1) Fraction of algal biomass which is nitrogen (mg- N/mg-A) Fraction of algal-N uptake from ammonia

Nitrogen Modeling (cont.)

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Time (days) Org-N NO3 NH4 NO2 Concentration (mg/L)

Nitrogen Modeling (cont.)

 Inhibition of Nitrification at low D.O.

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CORDO e KNITRF D O = −

−

1

* . .

f e

nitr k

• nitr

= −

−

1

EPA Chapra

Nitrification correction factor Nitrification inhibition coefficient (0.6-0.7 L/mg)

Impact of nitrification inhibition

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D.O. (mg/L) fnitr 10.0 Travel Time D.O. 1.0 With inhibition Without inhibition

 To next lecture

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