Marsesa, RizaMuhdarinaNurhayati2016-05-102016-05-102016-05-10wahyu sari yenihttp://repository.unri.ac.id/xmlui/handle/123456789/8355One of the clays contained in Riau is Cengar clay. This study utilizes Cengar clay as a liquid coagulant. Liquid coagulant was obtained by calcining clay at a temperature of 700 °C for 2 hours and leaching with 0.2 mol H2SO4. Variations for leaching conditions was selected at temperatures of 80 and 100 °C for 2 hours. The liquid coagulant was used in peat water treatment processes with parameters TSS (Total Suspended Solid) and TDS (Total Dissolved Solid). Peat water parameters after treatment were compared to PP 82 of 2001 and PERMENKES/416/Health Minister/PER/IV/1990. The produced liquid coagulants have pH between 7.8 and 8.0, levels Al3+ between 0.3355 and 0452 mg/L, and levels Fe3+ between 0.0795 and 0.115 mg/L. Coagulation processes to peat water by using liquid coagulant reduced parameters TSS between 59.09 and 65.9% and TDS between 3.2 and 18.98% and that peat water after coagulation agree with water quality standards.enPeat waterCengar clayliquid coagulantstudent Paper Post Degree