The Influence of Aluminum on the Flocculation of Activated Sludge with Different Concentrations

The mechanism governing the flocculation of activated sludge (AS) with different concentrations of aluminum was studied in this paper.The AS samples were cultivated in sequencing batch reactors at 22 ℃.The sludge retention times (SRT) was 15 d.The dosages of Al 3+ were 0.00, 0.0625, 0.125, 0.250, 0.500, 1.00, 2.00 and 4.00 meq/L.The experimental results indicated that the dosage of Al 3+ could enhance sludge flocculation, but deteriorate sedimentation.It was also found that as Al 3+ dosage (≤ 2 meq/L) increased, the total interaction energy, and loosely bound extracellular polymeric substances (LB-EPS) content decreased, indicating that the dosage of Al 3+ could enhance sludge flocculation.