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Streeter-Phelps Dissolved Oxygen Sag & Critical Deficit Calculator

Easily calculate and compute streeter-phelps dissolved oxygen sag & critical deficit calculator with accurate equations, live formulas, and expert guidance.

Equilibrium dissolved oxygen saturation at river temperature (e.g. 9.1 mg/L at 20°C).

DO deficit immediately downstream of outfall (Cs - initial mixed DO).

Ultimate biochemical oxygen demand of blended river water.

River microbial BOD consumption rate.

Surface atmospheric oxygen reaeration transfer rate.

River flow velocity transporting the plume.

Calculated Result
3.36 mg/L

Minimum DO

Minimum DO

3.36 mg/L

Minimum Dissolved Oxygen Mg Per L

3.36

Critical Deficit Dc Mg Per L

5.74

Critical Travel Time Days

1.66

Critical Downstream Distance Km

64.5

3.36 — mg/L

Calculation Breakdown

  1. Applied FormulaCalculates the classical Streeter-Phelps dissolved oxygen sag curve, critical travel time, minimum stream DO concentration, and distance downstream from a wastewater discharge.D(t) = \frac{k_d L_0}{k_r - k_d} \left(e^{-k_d t} - e^{-k_r t}\right) + D_0 e^{-k_r t}

Streeter-Phelps DO Sag Metric Output

Interactive visualization based on your current inputs

Calculated Value
0.00.81.72.53.4Minimum DO

What Is the Streeter-Phelps Dissolved Oxygen Sag & Critical Deficit Calculator?

This tool computes streeter-phelps dissolved oxygen sag & critical deficit calculator with high precision arithmetic.

How Does the Streeter-Phelps Dissolved Oxygen Sag & Critical Deficit Calculator Work?

Calculates the classical Streeter-Phelps dissolved oxygen sag curve, critical travel time, minimum stream DO concentration, and distance downstream from a wastewater discharge.

Streeter-Phelps Dissolved Oxygen Sag & Critical Deficit Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

D(t)=kdL0kr−kd(e−kdt−e−krt)+D0e−krtD(t) = \frac{k_d L_0}{k_r - k_d} \left(e^{-k_d t} - e^{-k_r t}\right) + D_0 e^{-k_r t}

Calculates the classical Streeter-Phelps dissolved oxygen sag curve, critical travel time, minimum stream DO concentration, and distance downstream from a wastewater discharge.

How to Use the Streeter-Phelps Dissolved Oxygen Sag & Critical Deficit Calculator

  1. Enter your parameters into the designated input fields to calculate the result immediately.

Step-by-Step Example Calculation

Streeter-Phelps Dissolved Oxygen Sag & Critical Deficit Calculator Example

Input Values:

saturationDoMgPerL:9.1
initialDoDeficitD0MgPerL:1.8
initialUltimateBodL0MgPerL:22
deoxygenationRateKdPerDay:0.35
reaerationRateKrPerDay:0.75
streamVelocityMPerS:0.45
Worked Steps: Sample evaluation based on standard reference conditions.

Understanding Your Result

The calculated primary figure indicates the optimal or required mg/L.

Factors That Affect the Result

  • Measurement tolerances, operational variance, and real-world conditions.

When Should You Use This Calculator?

  • Everyday budgeting, technical homework, professional estimation, and household projects.

Assumptions & Limitations

  • Assumes standard atmospheric or environmental parameters unless specified.

Frequently Asked Questions

Calculation Accuracy & Reference Note

Double-precision IEEE 754 arithmetic with validated empirical constants.

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