The multistage filtration (FiME) is an alternative to accomplish water treatment for small communities, however, as for removal of true color associated to dissolved organic carbon (DOC) or humic substances, it have been questioned or reported as low efficiency. The present research evaluated the removal of humic substances in the FiME using ozone and hydrogen peroxide as a pre-oxidation, using for this indirect parameters how true color, UV absorbance (254nm) and DOC. Five experiments were conducted using four slow filters, from this two were composed the intermediate layer of granulate activated carbon (GAC). The assays were conducted with pre-oxidation alternatives using ozone and hydrogen peroxide in several applications forms. It was obtained good result, as main conclusion were the slow filters with GAC, preceded of oxidation with ozone and hydrogen peroxide in appropriate dosage, presented medium removal of true color of 64%, but that the hydrogen peroxide interfering in the development of the biological layer, in the increase of the head loss, in the turbidity removal, in the coliforms removal and in the humic substances removal.
Humic substances; slow sand filtration; oxidation; ozone; hydrogen peroxide
