Abstract:
Liquid coagulant was prepared by extraction of Cengar clays by using sulfuric acid with
the variations of acid concentration, extraction time and temperature. Liquid coagulant with a maximum content of Al and Fe are used to reduce the levels of Biochemical
Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) in the peat water. The
results of the coagulation processes were compared to Peraturan Pemerintah (PP) No.
82, 2001 for the management of water quality and water pollution control. The results
showed that the liquid coagulant with a maximum content of Al (mg/L) and Fe (mg/L)
are Al = 23.926; Fe = 34.993 (Al < Fe), Al = 29.368; Fe = 29.993 (Al ≈ Fe) and Al =
28.118; Fe = 26.818 (Al > Fe), respectively. Coagulation testing on BOD and COD
content of peat water has been decreased (i) BOD (36.8%) and COD (66.67%) for the
liquid coagulant Al < Fe, (ii) BOD (28.32%) and COD (50%) for Al ≈ Fe and (iii) BOD
(24.13%) and COD (1.85%) for Al > Fe. Apparently, coagulant Al < Fe has the greatest performance and in accordance with PP. 82 in 2001
