Ratio Of Bod To Ultimate Given Oxygen Required In Aeration Tank Calculator

Formula Used:

\[ f = \frac{Qs \times (Qi - Q)}{O2 + (1.42 \times Qw \times XR)} \]

Sewage Discharge (Qs):

m³/s

Influent BOD (Qi):

kg/m³

Effluent BOD (Q):

kg/m³

Theoretical Oxygen Requirement (O2):

kg/s

Volume of Wasted Sludge per day (Qw):

m³/s

MLSS in Returned or Wasted Sludge (XR):

kg/m³

Ratio of BOD to Ultimate (f):

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1. What is the Ratio of BOD to Ultimate?

The Ratio of BOD to Ultimate is the ratio of 5 days BOD to ultimate BOD in wastewater treatment processes. It helps in understanding the biodegradability of organic matter and the oxygen requirements for treatment.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ f = \frac{Qs \times (Qi - Q)}{O2 + (1.42 \times Qw \times XR)} \]

Where:

\( f \) — Ratio of BOD to Ultimate
\( Qs \) — Sewage Discharge (m³/s)
\( Qi \) — Influent BOD (kg/m³)
\( Q \) — Effluent BOD (kg/m³)
\( O2 \) — Theoretical Oxygen Requirement (kg/s)
\( Qw \) — Volume of Wasted Sludge per day (m³/s)
\( XR \) — MLSS in Returned or Wasted Sludge (kg/m³)

Explanation: This formula calculates the ratio by considering the BOD removal, oxygen requirement, and sludge characteristics in the treatment process.

3. Importance of BOD Ratio Calculation

Details: Accurate calculation of the BOD ratio is crucial for designing efficient wastewater treatment systems, determining oxygen requirements, and optimizing sludge management processes.

4. Using the Calculator

Tips: Enter all values in the specified units. Ensure sewage discharge, influent BOD, and effluent BOD are positive values. Theoretical oxygen requirement and sludge volumes should be non-negative.

5. Frequently Asked Questions (FAQ)

Q1: What does the BOD ratio indicate?
A: The ratio indicates the proportion of biodegradable organic matter that requires oxygen for decomposition relative to the ultimate oxygen demand.

Q2: Why is 1.42 used in the formula?
A: The factor 1.42 represents the oxygen equivalent of bacterial cells, accounting for the oxygen demand of biomass in the sludge.

Q3: What are typical values for this ratio?
A: Typical values range from 0.6 to 0.8, but can vary depending on wastewater characteristics and treatment efficiency.

Q4: How does sludge wasting affect the ratio?
A: Increased sludge wasting reduces biomass in the system, which may affect the oxygen demand and consequently the BOD ratio.

Q5: Can this ratio be used for process control?
A: Yes, monitoring this ratio helps in optimizing aeration rates and sludge retention times for efficient treatment.