Peat water is a surface water that’s found in swamp and lowland areas that have characteristics of organic matter, turbidity and high color. One of peat water treatment that can be used by coagulation-flocculation. This study aims to determine the effect of peat sludge addition in coagulation-flocculation process with Coagulant Aluminium Sulfate (Al2(SO4)3) 1%. Peat water was taken in Ri…