PENJERNIHAN AIR DENGAN PROSES KOAGULASI DAN FLOKULASI MENGGUNAKAN FERI SULFAT

Coagulation and flocculation processing are the most essential parts of water treatment. Therefore the increasing effectivity and efficiency in these parts will influence all of processess. In coagulation and flocculation processess use a coagulant, to neutralize colloid surface�s charge for forming floc which could settle fast. This research use ferric sulphate as coagulant to sermo�s lake water in Kulon Progo. The raw water contents about 320 ppm colloidal and suspended solid. Observed variables were ferric sulphate dose and pH, use beaker glass and magnetic stirrer. The agitation consist of fast agitation (240 rpm) was conducted in 5 minutes and followed by slow agitation (60 rpm) in 10 minutes then the absorbency value was measured using UV/Visible. From this research, those were obtained optimum ferric sulphate dose 100 ppm and optimum pH=9. The data are used to calculate Sedimentation Constant (kd) that constitute Reynold function. The reseach�s result showed that Sedimentation Constant (kd) would be greater for larger floc diameter. This is caused for increasing floc diameter would enlarge settling velocity and Reynolds Number (Re). in this research relationship between Sedimentation Constant (kd) and Reynolds Number (Re) was found suitable with following equation : kd = 51,98 Re 0,3735 with average error : 9,8