Simultaneous ozone and granular activated carbon for advanced treatment of micropollutants in municipal wastewater effluent.

ABSTRACT

The main objective of this study was to compare the efficacy of ozone (O3) and O3 with granular activated carbon (GAC) (O3/GAC) at pilot-scale for the enhanced removal of micropollutants (MPs) from wastewater effluent. The results revealed enhanced removal of tris (2-carboxylethyl) phosphine (TCEP), sucralose, and meprobamate during the O3/GAC treatment experiments compared to the sum of their removal during isolated ozonation and GAC adsorption experiments. The long-term O3/GAC experiment showed the promotive effect of GAC substantially decreased after 20 h of O3 exposure. This decreased performance correlates with changes to GAC surface properties caused by O3. After 6 h of operation, O3 initially led to an increase in Brunauer-Emmett-Teller (BET) surface area on the GAC improving the elimination level of investigated MPs (except N-nitrosomorpholine (NMOR)). However, after 20 h of exposure, O3 ultimately caused structural damages to the GAC surface, decreased the BET surface area in the final stages of the experiment, and a 4-fold increase in O1sC1s ratio on the GAC surface was observed due to an increase in surface acidic functional groups caused by O3 treatment.