Oxygen Transfer Capacity under Standard Conditions when Correction Factor is 0.85 Calculator

Oxygen Transfer Capacity Formula:

\[ Ns = \frac{N}{\left(\frac{(DO_{0.85} - DL) \times 0.85 \times (1.024)^{(T-20)}}{9.17}\right)} \]

Oxygen Transferred (N):

kg/s/W

D.O Saturation (DO_0.85):

kg/m³

Operation Dissolved Oxygen (DL):

kg/m³

Temperature (T):

°C

Oxygen Transfer Capacity (Ns): kg/s/W

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1. What is Oxygen Transfer Capacity?

Definition: Oxygen Transfer Capacity is the ability of a system, typically in a wastewater treatment context, to transfer oxygen from the air into the water.

Purpose: It helps engineers design and evaluate aeration systems for wastewater treatment plants and other water treatment applications.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Ns = \frac{N}{\left(\frac{(DO_{0.85} - DL) \times 0.85 \times (1.024)^{(T-20)}}{9.17}\right)} \]

Where:

\( Ns \) — Oxygen Transfer Capacity (kg/s/W)
\( N \) — Oxygen Transferred (kg/s/W)
\( DO_{0.85} \) — D.O Saturation when Correction Factor is 0.85 (kg/m³)
\( DL \) — Operation Dissolved Oxygen (kg/m³)
\( T \) — Temperature (°C)

Explanation: The formula adjusts the measured oxygen transfer rate to standard conditions (20°C, zero dissolved oxygen) using temperature correction and the 0.85 correction factor.

3. Importance of Oxygen Transfer Capacity

Details: Proper oxygen transfer is crucial for biological wastewater treatment processes where microorganisms need oxygen to break down organic matter.

4. Using the Calculator

Tips: Enter the oxygen transferred rate, D.O saturation value (default 3.41455 kg/m³), operation dissolved oxygen level (default 0.00201 kg/m³), and temperature in °C (default 85°C).

5. Frequently Asked Questions (FAQ)

Q1: What is the 0.85 correction factor?
A: It accounts for the fact that actual D.O. saturation in sewage is typically 85% of the theoretical saturation in clean water.

Q2: Why is temperature important in this calculation?
A: Oxygen solubility in water decreases as temperature increases, so we must correct for temperature differences.

Q3: What's a typical D.O saturation value?
A: For water at sea level and 20°C, it's about 9.17 mg/L (0.00917 kg/m³), but varies with temperature and pressure.

Q4: How do I measure oxygen transferred (N)?
A: This is typically measured during aeration system testing using off-gas analysis or other standard methods.

Q5: What units should I use for inputs?
A: Use consistent units - kg/m³ for concentrations, °C for temperature, and kg/s/W for oxygen transfer rates.