Page 21 - SIMPLIFIED WASTEWATER TREATMENT FUNDAMENTALS_ Advanced Nitrification P1
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Advanced Nitrification
Scenario – Dropping pH and Alkalinity Dosing
This wastewater facility is receiving higher concentrations of influent BOD (335 mg/L) and the mixed liquor pH
has been dropping. Process mixed liquor pH target is 7.2. Today the pH is 6.5 and ammonia concentration in the
final effluent is rising. Influent wastewater flow is 2.35 MGD and the Lab has determined the influent Ammonia
concentration to be 30 mg/L.
As hydrated lime has a 1 to 1 relationship in pounds of alkalinity, 15 – 50-pound bags of lime has been mixed,
with lime slurry being fed into the mixed liquor throughout the day. Is there enough alkalinity being added?
15 x 50 = 750 pounds of lime added
2.35 MGD x 30 mg/L x 8.34 = 588 pounds of Ammonia
588 pounds of Ammonia x 7.14 = 4,198 pounds of alkalinity needed
Answer – No, the Nitrifiers require additional alkalinity (588 lbs of NH4 x 7.14 lbs of Alkalinity needs = 4,198 lbs)
