Page 17 - Simplified Wastewater Treatment Fundamentals_Advanced Nitrification P2

Advanced Nitrification

Process and Chemically Enhanced Chlorine Effectiveness

This chart depicts the ratio of chlorine needed per unit of NH4. You can

clearly see that as chlorine concentration increases beyond 5 mg/L, free

chlorine residual radically declines. As the Operator continues to

increase dose from 7 to 11 mg/l or more, chlorine residual is regained,

but at a cost.

Peracetic Acid is an effective alternative for chlorine-based oxidizers.

Peracetic Acid is not affected by Nitrites. When applied, Peracetic Acid

can lower effluent pH and must be closely monitored to ensure dose is

achieving kill without overdosing.

Note – The core process solution is to encourage Nitrosomonas and

Nitrobacter growth in the spring with short term higher SRT and to

efficiently remove nitrifiers in the fall by lowering SRT until NO2 and

NO3 levels have diminished.