Effects of UV irradiation on humic acid removal by ozonation, Fenton and Fe0/air treatment: THMFP and biotoxicity evaluation

► Fe0/air rapidly and effectively removed HA within 9 min and its COD, biotoxicity and THMFP were low. ► THMFP of ozonation-treated solution was much higher than those of Fenton-treated and Fe0/air-treated solutions. ► UV irradiation during ozonation and Fenton oxidation enhanced HA removal, but did not reduce the THMFP of the treated solutions. ► Fe0/air treatment with UV irradiation obviously increased the THMFP of the treated solution. ► The relationship between biotoxicity and chloroform in the chlorinated solution was insignificant.