APPLICATION OF A 50:50 COMBINATION OF ALUMINUM SULFATE (AL₂(SO₄)₃) AND PAPAYA (Carica papaya L.) SEED POWDER COAGULANTS ON TSS, COD, AND pH IN KARANG MUMUS RIVER WATER

Abstract

The Karang Mumus River in Samarinda City has experienced declining water quality due to domestic and urban activities, particularly affecting Total Suspended Solids (TSS), Chemical Oxygen Demand (COD), and pH. This study evaluates the effectiveness of aluminum sulfate and papaya seed powder, individually and in combination, in improving river water quality through laboratory-scale coagulation-flocculation using jar tests. Water samples were collected near Perniagaan Bridge, Samarinda. The results showed that aluminum sulfate at an optimum dose of 0.08 g achieved COD and TSS removal efficiencies of 54%, while papaya seed powder at 1 g achieved 91% COD removal and maintained a neutral pH. However, papaya seed powder was less effective in reducing TSS due to residual unsettled organic particles. The combination of both coagulants at a 50:50 ratio achieved the highest COD removal efficiency of 99.7%, with a final pH of 6.62, meeting the applicable pH standard. Nevertheless, the final TSS concentration of 48 mg/L remained above the regulatory limit of 40 mg/L. These findings highlight the potential of combining chemical and natural coagulants to enhance COD removal, although further optimization is required to improve TSS reduction and overall treatment performance.