Removal of 1,4-dioxane from landfill leachate by a rotating advanced oxidation contactor equipped with activated carbon/TiO composite sheets.

A rotating advanced oxidation contactor (RAOC) equipped with activated carbon (AC)/TiO composite sheets for 1,4-dioxane removal from biologically treated landfill leachate (BTLL) was developed. The performance of the RAOC in 1,4-dioxane removal was compared to that of a TiO slurry reactor by evaluating the removal efficiencies in pure water (PW) and the BTLL. In the TiO slurry reactor, 1,4-dioxane was hardly degraded in the BTLL during 66 h of treatment because of strong inhibition by coexisting substances in the BTLL. In contrast, the RAOC successfully removed 1,4-dioxane from the BTLL by 89% through adsorption and by 81% through photocatalysis during treatment for 66 h. The ratio of the rate constants for degrading 1,4-dioxane in the BTLL and PW by the RAOC was two orders of magnitude higher than that for a TiO slurry reactor. This shows that the RAOC greatly mitigated the inhibition by coexisting substances in the BTLL. The electrical energy required for 1,4-dioxane degradation in the BTLL by the RAOC was much lower than that required for degradation by the TiO slurry reactor. The results show that the RAOC equipped with AC/TiO composite sheets effectively removed 1,4-dioxane from BTLL.