Combined coagulation/decantation-ozone/hydrogen peroxide-biological aerated filter process for advanced treatment of bio-treated leachate from Chinese herbal medicine residue.

To reach discharge limit, further treatment of bio-treated leachate from Chinese herbal medicine residue (BLCHMR) was very imperative. In this study, performance of combined coagulation/decantation-ozone/hydrogen peroxide (O/HO)-biological aerated filter (BAF) technology used to further treat BLCHMR was investigated with pilot-scale experiment. Under optimal conditions, the COD (40-44 mg/L) and color (13-17 time) in treated BLCHMR indicated that combined process can efficiently treat BLCHMR. O/HO had good performance not only in mineralization and decomposing of organic matter but also in decolorization of BLCHMR. For dissolved organic matter (DOM), O/HO reacted with non-biodegradable fraction preferentially and oxidized different molecular weight (MW) fractions equally. O/HO-BAF generated more higher MW DOM (namely F2 fraction) than BAF alone. Meanwhile, O/HO mainly influenced the amount and biodegradability on DOM but not the removal rate on DOM. Accordingly, the helpful influence on O/HO perhaps can be owed to the generalized influence on DOM but not the specific influence on improved biodegradability. Finally, inspiring (namely very low) cost (respectively, 0.3419 $/per ton bio-treated leachate and 0.5766 $/Kg COD removed) was achieved in the combined process.