Thursday, June 2, 2011

Phosphorus Removal in Activated Sludge Process (by PAOs)

In Anaerobic Treatment Tank

1. Polyphosphate accumulating organisms (PAOs) decompose polyphosphate (PP) and produce orthophosphoric acid (called orthophosphates)

2. By decomposing, PAOs gain energy and assimilate organic substances (volatile fatty acid, acetate). It is accumulated in PAOs body as polyhydroxoalkanoate (PHA) (called polyhydroxybutyrate, PHB)

In Aerobic Treatment Tank

3. PAOs decompose PHA which earlier stored in their body

4. By decomposing, PAOs gain energy (live and grow) and uptake orthophosphoric acid and accumulate in PAOs body as PP

5. Phosphorus element being discard from system through wasting (WAS) PAOs from final sedimentation tank.