REMOVAL OF HUMIC SUBSTANCES BY OXIDATIVE AND COAGULATION PROCESS

摘要

The effect of reduction of the humic substances (HS) content in natural waters through processes of oxidation and coagulation was studied.The humic substances were extracted from the lake Mandra and the samples obtained were analysed before/after oxidation and coagulation.The oxidation was carried out with chlorine and hydrogen peroxide,while the coagulation process-with ferrous sulphate,ferric chloride and aluminum sulphate.The effect of oxidation and coagulation was controlled by direct humic substances measurement,permanganate oxygen demand (POD) and IR.The results obtained show that H_2O_2 can be considered as a better choice compared to chlorine since it gave better purification effect for HS.Among the coagulants studied the highest effect on organic matter removal was obtained by A1_2(SO_4)_3.18H_2O.The IR-spectra obtained show that the humic substances are decomposed during their oxidation to produce substances of lower molecular weight and higher concentration of COOH and OH groups.The humic acids are removed during the coagulation,but fulvo acids and low molecular weight compounds remain.