Influence of iron species and mineral particles added on the advanced oxidation processes (AOP) for the humic acids (HA) removal was elucidated. It was observed that decomposition rate of hydrogen peroxide increased when the modified ferrous ion (M-Fe, of which main species are pre-hydrolyzed ferrous species as FeOH+) was added. Addition of bentonite in the iron-catalyzed oxidation process adversely affected H2O2 degradation. Iron salts, were adsorbed onto the surface of bentonite, suppressed the reaction between iron and H2O2. In contrast, adding glass powder slightly increased the H2O2, degradation rate. In addition, changes in the molecular and structural characteristics of HA and the hydrophobic and hydrophilic fractions of trihalomethanes (THMs) precursors after the Fenton and photo-Fenton oxidation were evaluated by GPC, NMR spectra and Py-GC/MSD.