Effluent BOD Formula:
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Definition: This calculator determines the effluent Biochemical Oxygen Demand (BOD) based on the mass of wasted activated sludge and other wastewater treatment parameters.
Purpose: It helps wastewater treatment professionals estimate the BOD remaining in treated effluent after the activated sludge process.
The calculator uses the formula:
Where:
Explanation: The formula accounts for BOD removal through sludge wasting and endogenous respiration in the activated sludge process.
Details: Accurate effluent BOD estimation is crucial for assessing treatment plant performance and ensuring compliance with environmental discharge regulations.
Tips: Enter all required parameters with appropriate units. Typical values are provided for some fields, but actual plant data should be used for accurate results.
Q1: What is a typical value for Ke?
A: The endogenous respiration rate constant typically ranges from 0.02 to 0.05 per day (about 2.31e-7 to 5.79e-7 per second).
Q2: How do I determine the maximum yield coefficient (Y)?
A: Y is typically 0.4-0.8 mg biomass/mg substrate for domestic wastewater, but should be determined experimentally for specific wastewaters.
Q3: What if my effluent BOD calculation is negative?
A: Negative values suggest an error in input parameters, as BOD cannot be negative. Verify all inputs, especially units.
Q4: How does sludge wasting affect effluent BOD?
A: Increased sludge wasting typically improves BOD removal by increasing the mass of microorganisms treating the wastewater.
Q5: What's the relationship between MLSS and effluent quality?
A: Higher mixed liquor suspended solids (X') generally improve treatment efficiency up to a point, beyond which settling problems may occur.