Basic Wastewater Operator Practice Exam

Calculate F:M ratio given: Influent BOD5 = 290 mg/L, Influent flow = 5.0 MGD, Aeration basin MLSS = 2650 mg/L, Aeration basin volume = 0.8 MG.

1. 0.01

2. 0.11

3. 0.68

4. 0.06

The correct answer is: 0.68

To calculate the F:M (Food to Microorganism) ratio, you need to understand that it provides a measure of the amount of organic material available to the microorganisms in the aeration basin. The formula for the F:M ratio is: \[ F:M = \frac{BOD \, (mg/L) \times Flow \, (MGD)}{MLSS \, (mg/L) \times Volume \, (MG)} \] First, to plug in the values accurately, it's beneficial to convert units where necessary: 1. **Influent BOD5**: 290 mg/L 2. **Influent flow**: 5.0 MGD 3. **Aeration basin MLSS**: 2650 mg/L 4. **Aeration basin volume**: 0.8 MG Now, let's calculate: - The total influent BOD5 entering the aeration basin per day can be calculated as follows: \[ \text{Total BOD5} = 290 \, mg/L \times 5.0 \, MGD = 290 \, mg/L \times 5.0 \, MGD \times 8.34 \, (conversion