If in Problem 15-6, the amount of alkalinity in the raw wastewater is 305 mg/L as CaCO3,...

If in Problem 15-6, the amount of alkalinity in the raw wastewater is 305 mg/L as CaCO₃, what will the pH be after nitrification? Assume that the CO₂ concentration in the wastewater resulting from BOD oxidation and ammonia nitrification is 25 mg/L. Use the following equation for the estimate:

where pK₁ = 6.38.

Problem 15-6

If the influent ammonium concentration is 21.8 mg/L, estimate the amount of alkalinity (in mg/L) that must be added to buffer the oxidation reaction assuming that a residual alkalinity of 80 mg/L as CaCO₃ is required to keep the pH at approximately 7. Assume the influent alkalinity is 250 mg/L as CaCO₃.