Geoscience Reference
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Mn 2+ , Fe 2+ , S 2− start. When the oxygen concentration exceeds this specified value,
reduced anaerobic byproducts are oxidized.
Dissolved oxygen kinetics in CE-QUAL-ICM 56 and HEM-3D 90 are similar to
EUTRO5 except that the two former models also consider the oxidation of inorganic
substances such as sulfide. In the predictive sediment submodel, sulfide and methane
can stay in the sediment layer, be exported to the water column, or be buried into
deeper sediment. If not buried into deeper inactive sediment, the sulfide and methane
will exert an oxygen demand either in the sediment or in the water column.
4.1.5.4.1 Dissolved Oxygen
The mass balance equation for dissolved oxygen given in EUTRO5 is given
C
t
C
KC Ck
C
KC C
64
14
(
T
20)
(
T
20)
6
=
kC C
(
)
k
θ
6
θ
6
144
2S
6
dd
5
12
12
1
+
+
12
44443
BOD
4444
6
12
444 4
44444
NIT
6
3
Reaeration
Oxidation
Nitrification
SOD
32
12
48
14
32
12
(
T
20)
(
T
20)
θ
+
G
+
a
(
1P
)
C
k
θ
C
(4.34)
S
P
1
nc
NH3
4
1
R
1
R
4
D
144
12
443
44
1
44444
2
44444
3
Sediment Oxygen
Demand
Respiration
Phytoplankton Growth
where
C 6
=
dissolved oxygen concentration [mg O 2 l −1 ]
k 2
=
reaeration rate constant at 20
°
C [day −1 ]
C S
=
dissolved oxygen saturation concentration [mg O 2 l −1 ]
k d
=
deoxygenation rate constant at 20
°
C [day −1 ]
θ d
=
temperature coefficient [none]
T
=
water temperature [
°
C]
K BOD
=
half-saturation constant for oxygen limitation [mg O 2 l −1 ]
C 5
=
carbonaceous biochemical oxygen demand (CBOD) concentration
[mg O 2 l −1 ]
k 12
=
nitrification rate constant at 20
°
C [day −1 ]
θ 12
=
nitrification temperature coefficient [none]
K NIT
=
half-saturation constant for oxygen limitation of nitrification [mg O 2 l −1 ]
C 1
=
ammonium nitrogen concentration [mg N l −1 ]
SOD
=
sediment oxygen demand [g m −2 day −1 ]
D
=
depth of segment [m]
θ S
=
SOD temperature coefficient [none]
G P 1
=
specific growth rate constant of phytoplankton [day −1 ]
P NH3
=
preference for ammonium uptake term [none]
C 4
=
phytoplankton carbon concentration [mg C l −1 ]
k 1 R
=
phytoplankton respiration rate constant at 20
°
C [day −1 ]
θ 1 R
=
phytoplankton respiration temperature coefficient [none]
a nc
=
nitrogen to carbon ratio [mg N mg −1 C]
 
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