Three-dimensional excitation-emission matrix fluorescence spectroscopy and fractions of dissolved organic matter change in landfill leachate by biological treatment

The water quality improvement of landfill leachate after sequencing batch reactor (SBR) activated sludge process were evaluated by chemical oxygen demand (COD), dissolved organic matter (DOM) fractions, and three-dimensional excitation-emission matrix (EEM), from which the new understanding was obtained. The results indicated that less than 14 % COD was removed by SBR. The EEM of leachate and SBR effluent showed that HPO-A and TPI-A were appeared in the peak C, while the HPI, HPO-N, and TPI-N could not be found due to dilution. Although humic acid appeared in peak C, not all the organic materials in peak C are humic acid. And because landfill leachate is a kind of complicated wastewater, therefore, only EEM cannot efficiently reflect the water quality.