1. Dissolved Oxygen Processes
Processes and Equations Implemented in WASP7 Eutrophication Module
WASP7 Course

2. Eutrophication - DO Interactions

3. Photosynthesis and Respiration
DO Balance Processes
Reaereation
CBOD1
CBOD2
CBOD3
Phytoplankton
Periphyton
Dissolved
Oxygen
Sediment
Demand
Detritus
Death
Dissolution
Photosynthesis and Respiration
Organic Decay

4. Streeter-Phelps with SODDO
BOD1
CO2
Reaeration
Settling and Deposition of
Organic Matter
Sediment Oxygen
Demand
Carbonaceous
Deoxygenation
Sediment

5. Sources Sinks Detritus User Specifies Boundaries & Loads
Fraction * Detritus Dissolution
Phytoplankton
Death * Carbon Content
Detritus
CBOD1
CBOD2
CBOD3
Periphyton
Death * Carbon Content
Model Calculated
Dissolution = Dissolution Rate * Theta ** Temp – 20 °

6. Sources & Sinks

7. BOD in WASP Best to convert BOD to Ultimate BOD Values
Three BOD Classes
Fast, Medium, Slow (Labile to Refractory)
Biotic (Algae/Benthic Algae), Abiotic, WWTP
Varying Decay, F Ratios based on Sources

8. BOD1 DO BOD2 BOD3 BOD Decay * Theta ** T-20 Boundaries & Loads
Phytoplankton
Death * Carbon Content
BOD2
Periphyton
Death * Carbon Content
BOD3

9. CBOD

10. Model Parameters for BOD

11. Sediment Oxygen Demand

12. Simulated SOD

13. Reaeration

14. Reaeration Options Global Reaeration Segment Specific Reaeration
Setting to Zero WASP Selects
This Sets Rate for Segment
User Specifies which Equation
This options sets the rate for the whole network
Specify Dam Characteristics
Global Reaeration
Segment Specific Reaeration
User Defined
User Selections
Covar’s Method
Dam Reaeration

15. Reaeration Options Rivers & Streams O’Connor-Dobbins Churchill Owens
U (mps)
H (m)
Ka (per day)

16. Reaeration Coefficients

17. Dam Reaeration Where: r = ratio of deficit above and below the dam
H = difference in water elevation (meters)
T = water temperature (°C)
a = water quality coefficient
b = dam-type coefficient
(Chapra, 1997)

18. Dam Reaeration Water Quality Coefficient Dam Type Coefficients
Polluted State A
Gross
0.65
Moderate
1.0
Slight
1.6
Clean
1.8
Dam Type b
Flat broad-crested regular step
0.70
Flat broad-crested irregular step
0.80
Flat broad-crested vertical face
0.60
Flat broad-crested straight-slope face
0.75
Flat broad-crested curved face
0.45
Round broad-crested curved face
Sharp-crested straight slope face
1.00
Sharp crested vertical face
Sluice gates
0.05

19. Wind Driven Reaeration
Jour. of Env Eng, Vol. 109, NO.3, PP ,
June 1983, Author: D.J. O'Connor, TITLE: "Wind Effects on
Gas- Liquid Transfer Coefficients"
Wind Speed m/sec (Time Function)
10 Meters Above
Water Surface
Air Temperature °C (Time Function)
KAWind
Water Temperature °C (Segment Parameter and/or Time Function)
Simulated by Hydrodynamic Model

21. Modified Streeter-Phelps
Reaeration
NO3
CO2
NBOD2 DO
CBOD1
Nitrogenous
Deoxygenation
Carbonaceous
Deoxygenation
Settling
Settling
Sediment Oxygen
Demand
Sediment
1 use BOD1; 2 use BOD2

22. Nitrogenous BOD

23. Modified Streeter-Phelps Input

24. Temperature Dependency
Where: KT
The value of variable at the local temperature, T (°C)
The value of the variable at 20 °C Ө
The empirical constant for each temperature dependent system variable, user specified

25. Linear DO Balance NO3 CO2 Org-N NH3 DO BOD1 Phyto Reaeration
Mineralization
Org-N
NH3 DO
BOD1
Nitrification
Carbonaceous
Deoxygenation
Phyto
Photosynthesis
Respiration
Settling
Settling
Sediment Oxygen
Demand

26. Linear DO Balance Input

27. Measuring Photosynthesis & Respiration