Pilot scale evaluation on ferric floc sludge concentration with pelleting flocculation blanket process

Area of Science:

• Environmental Engineering
• Water Treatment Technologies
• Solid/Liquid Separation

Background:

• High turbidity suspensions pose challenges for efficient solid/liquid separation.
• The Pelleting Flocculation Blanket (PFB) process is a proven method for such applications.
• Ferric flocs sludge concentration requires optimized operational parameters for effective treatment.

Purpose of the Study:

• To conduct a dynamic experimental study on concentrating ferric flocs sludge using the PFB process.
• To optimize the conditioning system and identify key operational parameters for the PFB process.
• To evaluate the impact of various parameters on sludge concentration and effluent quality.

Main Methods:

• Pilot-scale experiments were conducted on ferric flocs sludge with flow rates ranging from 1.3-5.4 m³/h.
• The study investigated the effects of polyacrylamide (PAM) dosage, agitation speed, and water up-flow rates.
• Sludge concentrations from 103-1,154 mg/L were tested to determine optimal conditioning.

Main Results:

• Ideal conditioning was achieved with PAM dosages of 0.3-2.7 mg/L, 10 rpm agitation, and 18-48 m/h up-flow rates.
• Increased polymer dosage improved effluent turbidity and pellet settling; moderate up-flow rates had minimal impact.
• Excessive surface loading negatively affected effluent turbidity.

Conclusions:

• A linear relationship exists between raw sludge concentration and optimal PAM dosage.
• A linear inverse relationship was observed between raw sludge concentration and maximum up-flow rate.
• The PFB process demonstrates effective solid/liquid separation for ferric sludge under optimized conditions.