In this study, mainly the total suspended solids (TSS) and COD removal efficiency of coagulation and flocculation processes in the influent of S. Giovanni a Teduccio municipal wastewater treatment plant were evaluated to the Italian water quality discharge limits by defining optimal operational strategy. Fifteen samples were treated by jar-test procedure using Al-2(SO4)(3).18H(2)O, FeCl3.6H(2)O and FeSO4.7H(2)O alone or in combination with Ca(OH)(2) at pH values varying from 4 to 10 for AI(III) and 5 to 8 for Fe(III) salts. Doses of 150 and 450 mg/l of coagulants were chosen. 2 mg/l of Prodefloc((R)) polymer was used as flocculant. COD and TSS contents ranging from 140 to 650 mg/l and 90 to 265 mg/l, respectively, could be observed. The mean value of COD calculated as 316 mg/l represents medium domestic wastewater characteristics. Each coagulant provided high COD and TSS removal efficiency ranging from 45 to 90%. The maximum removal efficiency providing discharge limits was obtained for the combination FeSO4.7H(2)O + Ca(OH)(2) at a concentration of 150 + 50 mg/l at pH 8. Normally 200 mg/l + 60 mg/l at pH values between 8 and 9 were used.