6. Nitrification requires the addition of \( 519 \mathrm{mg} / \mathrm{L} \) of caustic soda. The c rate for the process is \( 5 \mathrm{MGD}\left(18,925 \mathrm{~m}^{3} / \mathrm{day}\right) \). What is the chemical A. \( 19,410 \mathrm{lb} / \) day \( (8.812 \mathrm{ka} / \mathrm{d} \)

To solve the problem, we need to calculate the total amount of caustic soda required for the nitrification process based on the given concentration and flow rate. ### Known Conditions: 1. Concentration of caustic soda: \( 519 \, \text{mg/L} \) 2. Flow rate: \( 5 \, \text{MGD} = 18,925 \, \text{m}^3/\text{day} \) ### Step-by-Step Calculation: 1. **Convert the concentration from mg/L to kg/m³**: \[ 1 \, \text{mg/L} = 0.001 \, \text{g/L} = 0.001 \, \text{kg/m}^3 \] Therefore, \[ 519 \, \text{mg/L} = 519 \times 0.001 \, \text{kg/m}^3 = 0.519 \, \text{kg/m}^3 \] 2. **Calculate the total mass of caustic soda required per day**: \[ \text{Total mass} = \text{Concentration} \times \text{Flow rate} \] Substituting the values: \[ \text{Total mass} = 0.519 \, \text{kg/m}^3 \times 18,925 \, \text{m}^3/\text{day} \] 3. **Perform the multiplication**: \[ \text{Total mass} = 0.519 \times 18,925 \] Now, let's calculate this value. Calculate the value by following steps: - step0: Calculate: \(0.519\times 18925\) - step1: Multiply the numbers: \(9822.075\) The total mass of caustic soda required per day is approximately \( 9822.075 \, \text{kg/day} \). 4. **Convert kg/day to lb/day**: To convert kilograms to pounds, we use the conversion factor: \[ 1 \, \text{kg} = 2.20462 \, \text{lb} \] Therefore, \[ \text{Total mass in lb/day} = 9822.075 \, \text{kg/day} \times 2.20462 \, \text{lb/kg} \] Now, let's calculate this conversion. Calculate the value by following steps: - step0: Calculate: \(9822.075\times 2.20462\) - step1: Multiply the numbers: \(21653.9429865\) The total mass of caustic soda required per day is approximately \( 21653.94 \, \text{lb/day} \). ### Final Answer: The chemical requirement for nitrification is approximately \( 21653.94 \, \text{lb/day} \). This value does not match the provided option of \( 19,410 \, \text{lb/day} \). Please verify the input values or the expected output.