Page 21 - Simplified Wastewater Treatment Fundamentals_BNR
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Biological Nutrient Reduction (BNR)
Biological phosphorus removal
Biological phosphorus removal is achieved by stressing specialized bacteria, placing them in an anaerobic
fermenting tank prior to being returned to an Aeration Basin.
When stressed, the bacterial cells (known as Polyphosphate Accumulating Organisms, or POA) burn
polyphosphate as an energy source, depleting the cell’s reserves. PAO’s consist of 2 kinds of common
bacteria, bacillus and pseudomonas.
