Enhanced Dewatering of Activated Sludge by Skeleton-Assisted Flocculation Process

Abstract

Sludge dewatering is the fundamental process of sludge treatment. Environmentally friendly and efficient sludge conditioning methods are the premises of sludge to achieve dehydration reduction and resource utilization. In response to sewage plant sludge dehydration, fly ash (FA), polymerized aluminum chloride (PAC), and polymer sulfate (PFS) were studied separately to determine their sludge dehydration performance, and the effects of these three conditioner composite regulations on sludge dehydration properties were studied. Compared to the sludge treated only with conditioner, the average particle size of floc increased and the organic matter content in the filtrate decreased. The sludge dewatering efficiency after the conditioning effect is better than that after conditioning a single conditioner. After PFS conditioning with fly ash, the water content and specific resistance (SRF) of the sludge cake can be reduced to 76.39% and 6.63 × 1010 m/kg, respectively. The moisture content and specific resistance (SRF) of the sludge cake can be reduced to 76.10% and 6.91 × 1010 m/kg, respectively. The pH of the sludge and filtrate changed slightly after PAC conditioning with fly ash coupling. These results indicate that fly-ash coupled with PAC and fly-ash coupled with PFS are expected to become a novel and effective environmental protection combined conditioning method for sludge dewatering.

Environmentally Safe Method for Conditioning and Dewatering Sewage Sludge Using Iron Coagulant, Cellulose and Perlite

“…These values are similar to the effects of PIX 113 sludge conditioning at a dose of approximately 2.0-6.0 mL/L (0.13-0.40 g/g DS). For comparison, Xi et al [57] showed that the use of flu ash in sludge conditioning at a dose of 10-15 g/g DS allows obtaining SRF = 1.03 × 10 11 m/kg and FH = 74%. However, to achieve very low hydration of the dewatered sludge of 68%, a dose of 30 g/g DS was necessary.…”

Advances in Chemical Conditioning of Residual Activated Sludge in China

“…Studies have shown that the larger the D50 (the particle size corresponding to a sample with a cumulative particle size distribution of 50%), the better for sludge dewatering. Xia et al [17] used fly ash in conjunction with polymeric iron sulfate and polymeric aluminum chloride to treat residual sludge and showed that the flocs of the original sludge were relatively fluffy. The addition of complex conditioning agents can neutralize the negative charge on the surface of the flakes and reduce the repulsion between colloidal ions, making it easier for the flakes to collide and aggregate, thereby forming flocculated particles with large particle size and dense structure.…”