Role of a constructed wetland to humify effluent organic matter from a wastewater treatment plant

Abstract

The degree of aromaticity or hydrophobicity in wastewater effluent organic matter (EfOM) increases during flow-through constructed wetlands connected directly to a wastewater treatment plant (WWTP), as identified using fractionation followed by analysis methods, with respect to major biopolymers (polysaccharides, amino sugars, protein, polyhydroxy aromatics, and lignins). In this study, WWTP effluent and wetland EfOM were fractionated using preparative high-performance liquid chromatography (prep-HPLC) with both UV and RI detectors, and then, their physical and chemical properties were characterized using UV/Vis, high-performance size exclusion chromatography (HPSEC), 3D fluorescence, and pyrolysis-GC/MS (Py-GC/MS). WWTP and wetland EfOM were separated into three fractions (peak #1-3), using prep-HPLC, through C-18 and size exclusion mechanisms. Results of specific UV absorbance (SUVA), 3D fluorescence, and Py-GC/MS analyses indicate that relative aromaticity/hydrophobicity of organic matter are in the order of peak #3 > peak #2 > peak #1, which also represents order of molecular weight (MW) (peak #1 > peak #2 > peak #3)