Impact of reclaimed water on select organic matter properties of a receiving stream-fluorescence and perylene sorption behavior.

Surface water samples obtained from the Bull Run tributary upstream and downstream of the Upper Occoquan Sewage Authority(UOSA) advanced wastewater reclamation facility (WRF) were characterized by fluorescence excitation-emission matrix (EEM) spectroscopy, and sorption coefficients (Kmoc) of macromolecular organic carbon isolates were quantified by fluorescence quenching. The EEM data revealed a signature fluorescence distribution in the downstream samples that was attributed to the presence of proteinlike material. The Kmoc values for upstream samples were consistently and significantly higher than those of corresponding downstream samples. There was a moderate correlation (R2 = 0.67) between log Kmoc and the molar extinction coefficient at 280 nm (E280) and a strong correlation (R2 = 0.96) between Kmoc and the proteinlike fluorescence region for macromolecular isolates with negligible quantum yields. This study demonstrates that organic matter downstream of the UOSA-WRF has unique fluorescence and perylene sorption characteristics compared to those of upstream organic matter during summer baseflow conditions. This implies that wastewater treatment facilities, including those advanced facilities designed to reclaim wastewater for indirect potable reuse, can influence the composition and behavior of organic matter in a receiving stream.