Character of organic matter in soil-aquifer treatment systems

The objective of this study was to investigate the character and fate of bulk organics in reclaimed water used for groundwater recharge via soil-aquifer treatment (SAT). The study design followed a watershed guided approach considering hydraulically corresponding samples of drinking water sources, SAT-applied wastewater effluents, and subsequent post-SAT samples representing a series of different travel times in the subsurface. Water samples were fractionated into hydrophobic acids, transphilic acids, and hydrophilic carbon using a XAD resin-based protocol. Extensive characterization of organic carbon in the different samples was performed using state-of-the-art analytical techniques including excitation–emission matrix fluorescence spectroscopy, size exclusion chromatography, carbon-13 nuclear magnetic resonance spectroscopy ( C-NMR 13 ) , Fourier transform infrared spectroscopy (FTIR), and elemental analysis. During SAT, transphilic and hydrophilic organic matter were preferentially removed. The results...