Improvement of coagulation-flocculation process using anionic polyacrylamide as coagulant aid

Area of Science:

• Environmental Engineering
• Water Treatment Technologies
• Chemical Engineering

Background:

• Slaughterhouse wastewater presents significant treatment challenges due to high organic load and suspended solids.
• Physicochemical treatment, specifically coagulation-flocculation, is a common method for treating such effluents.
• Optimizing coagulant aid and process parameters is crucial for efficient removal of pollutants.

Purpose of the Study:

• To evaluate the effectiveness of anionic polyacrylamide as a coagulant aid in slaughterhouse wastewater treatment.
• To determine the optimal conditions (pH, dosage, stirring) for coagulation-flocculation using ferric sulphate, aluminium sulphate, and polyaluminium chloride.
• To assess the impact of anionic polyacrylamide on floc settling velocity and pollutant removal.

Main Methods:

• Coagulation-flocculation experiments were conducted on slaughterhouse wastewater.
• Anionic polyacrylamide was used as a coagulant aid with ferric sulphate, aluminium sulphate, and polyaluminium chloride.
• Process parameters including pH, coagulant/aid dosage, stirring speed, and time were optimized.
• Key parameters monitored included chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended solids (TSS), particle size, nutrient levels, and residual metal concentrations.

Main Results:

• Anionic polyacrylamide significantly increased floc settling velocity when used with ferric sulphate or polyaluminium chloride.
• Optimal pH, coagulant, and coagulant aid doses were determined for efficient treatment.
• The study successfully optimized the coagulation-flocculation process for slaughterhouse wastewater.
• Measurements of particle number and size, sludge volume, nutrients, and residual metals provided a comprehensive assessment.

Conclusions:

• Anionic polyacrylamide is an effective coagulant aid for enhancing the settling characteristics of flocs in slaughterhouse wastewater treatment.
• The combination of anionic polyacrylamide with ferric sulphate or polyaluminium chloride offers a promising approach for improving the efficiency of physicochemical wastewater treatment.
• Optimization of process parameters is essential for maximizing pollutant removal and achieving desired water quality.