Coagulation for treatment of swine slaughterhouse wastewater

Abstract

In this study, wastewater taken from the Nam Phong swine slaughterhouse, Ho Chi Minh City, was used to evaluate the treatment efficiency of common coagulants, including Alum (Aluminum Sulfate - Al2(SO4)3.18H2O), Poly-Aluminum Chloride (PAC), and Ferrous Sulfate (FeSO4.7H2O), using a jar-test system. The experiments were conducted using the one-factor-at-a-time method to examine three variables which are pH, stirring speed, and coagulant dosage. The results showed that both Alum and PAC perform over 90% removal of colour, turbidity, COD, and total phosphorus (TP) from slaughterhouse wastewater at pH 7 with a stirring speed of 75 revolutions per minute (RPM) and average coagulant dosages of 450 mg/L for Alum and 550 mg/L for PAC. Meanwhile, under the appropriate conditions of pH equal to 10 and 75 RPM with a chemical dosage of 350 mg/L, COD and TP removal efficiencies by Ferrous Sulfate exceed 87%, but those of turbidity and colour only reach 25%. This finding could be a promising coagulation method as a pre-treatment for the swine slaughterhouse wastewater.