Treatment of Fish Processing Wastewater by Alum and PAM: A Comparative Study on Turbidity, COD, BOD, and Rheological Properties

This research article compares the efficacy of using alum and poly aluminum chloride (PAM) for the treatment of fish processing wastewater. This study aims to determine the effectiveness of each treatment method in reducing turbidity, COD), BOD, and altering the rheological properties of the wastewater.  Batch mode coagulation and flocculation experiments were conducted using lab scale jar test apparatus. The findings indicate that both alum and PAM can significantly reduce turbidity and COD. The highest turbidity removal efficiency of 93% was achieved with alum at a dose of 200 mg/L, while PAM achieved a maximum turbidity removal efficiency of 86% at a dose of 100 mg/L. Alum and PAM achieved the highest BOD5 and COD removal efficiencies at a dosage of 200 mg/L and pH 7.0. However, the removal efficiencies varied at different pH values and dosages. Alum and PAM have significant effect on the rheological properties of fish processing wastewater. The viscosity of settled residual sludge after chemical coagulation is more compared to untreated fish processing wastewater due to aggregation of suspended particles to form larger flocs. This would improve the settling properties of the coagulated sludge. The study concludes that both alum and PAM can be viable options for treating fish processing wastewater, with Alum showing a slight edge over PAM in certain aspects.