Engineering and Applied Science Research (Aug 2021)
Removal of dissolved organic matter in sugar mill effluent by catalytic ozonation with activated carbon (O3/GAC)
Abstract
This study investigated removals of dissolved organic carbon (DOC) in natural surface water mixed effluent (NW-EFF) of sugar mill factory using O3, granular activated carbon (GAC) and O3/GAC as catalytic ozonation. Effects of O3 flowrate and GAC dose on reductions of DOC and ultraviolet absorbance at 254 nm (UV254) were examined. The DOC removals by O3/GAC were the most efficient (85.5% – 88.0%), while those of O3 and GAC were 41.2% – 61.7% and 0.6% – 14.2%, respectively. The UV254 removals by O3/GAC were 99.8%–99.9%, while those of O3 and GAC were 92.7% – 97.2% and 4.9% – 28.5%, respectively. In O3 experiment, the increases of ozone flowrate decreased the DOC removal. In O3/GAC, during the first 60-min reaction time, the DOC removals by GAC doses of 0.1 g/L and 1.0 g/L were about the same drastic reductions of DOC observed at GAC dose of 2.5 g/L. After 60-min reaction time, the DOC concentrations gradually decreased at the same rate towards the end of the experiment for all GAC doses. The O3/GAC reduced approximately 50% of specific ozone consumption compared to the O3 alone for the same DOC removal. The enhancement factors (R) of all GAC doses are greater than 1.0 indicated that GAC doses have synergistic effects on the removal of DOC in NW-EFF. The O3/GAC reduced the electrical energy per order (EEO) approximately 30% – 55% of those by the O3 process. The present study shows that the O3/GAC is suitable for treatment of NW-EFF of sugar mill factory due to DOC removal and energy efficiencies.
