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

Eutrophication - DO Interactions

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

Streeter-Phelps with SOD DO BOD1 CO2 Reaeration Settling and Deposition of Organic Matter Sediment Oxygen Demand Carbonaceous Deoxygenation Sediment

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 °

Sources & Sinks

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

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

CBOD

Model Parameters for BOD

Sediment Oxygen Demand

Simulated SOD

Reaeration

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

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

Reaeration Coefficients

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)

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

Wind Driven Reaeration Jour. of Env Eng, Vol. 109, NO.3, PP.731-752, 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

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

Nitrogenous BOD

Modified Streeter-Phelps Input

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

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

Linear DO Balance Input

Measuring Photosynthesis & Respiration