# Presentation: 705914

## Dissolved Oxygen Processes

- Processes and Equations Implemented in WASP7 Eutrophication Module

## Eutrophication - DO Interactions

## DO Balance Processes 

- DO Balance Processes

## Streeter-Phelps with SOD

## Detritus

- Fraction * Detritus Dissolution

**Sources**

**Sinks**

**User Specifies**

**User Specifies**

**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

**BOD2**

**BOD3**

- BOD Decay * Theta ** T-20

## CBOD

## Model Parameters for BOD

## Sediment Oxygen Demand

## Simulated SOD

## Reaeration

## Reaeration Options

- 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

| Polluted State | A |
| --- | --- |
| Gross | 0.65 |
| Moderate | 1.0 |
| Slight | 1.6 |
| Clean | 1.8 |

- Water Quality Coefficient

| 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 | 0.75 |
| Sharp-crested straight slope face | 1.00 |
| Sharp crested vertical face | 0.80 |
| Sluice gates | 0.05 |

- Dam Type Coefficients

## Wind Driven Reaeration

**10 Meters Above **
**Water Surface**

**Wind Speed m/sec (Time Function)**

**Air Temperature ****°C (Time Function)**

**Water Temperature ****°C (Segment Parameter and/or Time Function)**
**Simulated by Hydrodynamic Model**

**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"**

**KA****Wind**

## Slide 20

## Modified Streeter-Phelps

**DO**

**CBOD****1**

**CO****2**

**Reaeration**

**Settling**

**Sediment Oxygen **
**Demand**

**Carbonaceous **
**Deoxygenation**

***Sediment***

**NBOD****2**

**NO****3**

**Nitrogenous **
**Deoxygenation**

**Settling**

- 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

**DO**

**BOD****1**

**CO****2**

**Reaeration**

**Settling**

**Sediment**** ****Oxygen**** **
**Demand**

**Carbonaceous**** **
**Deoxygenation**

**NH****3**

**Settling**

**NO****3**

**Org-N**

**Phyto**

**Photosynthesis**
**Respiration**

**Nitrification**

**Mineralization**

## Linear DO Balance Input

## Measuring Photosynthesis & Respiration