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Comparison of emerging contaminants in receiving waters downstream of a conventional wastewater treatment plant and a forest-water reuse system
Citation:
McEachran, A., M. Hedgespeth, S. Newton, R. McMahen, M. Strynar, D. Shea, AND E. Guthrie Nichols. Comparison of emerging contaminants in receiving waters downstream of a conventional wastewater treatment plant and a forest-water reuse system. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH. Ecomed Verlagsgesellschaft AG, Landsberg, Germany, 25(13):12451-12463, (2018).
Impact/Purpose:
Water availability and quality are expected to be adversely affected by adverse weather events and population pressures (Ingram et al. 2013; Trenberth 1999). Therefore, the ability to regulate water availability and improve water quality will become increasingly important with continued human population growth. One approach to regulating water availability and improving water quality is the use of forest-water reuse (FWR) systems (Braatz and Kandiah 1996; Isosaari et al. 2010). FWR systems are slow-rate irrigation systems that treat municipal, industrial, and agricultural wastewaters through infiltration into forest soils and groundwater (Crites 1984; Crites et al. 2014). These systems are lower cost and less energy intensive than conventional wastewater treatment systems of similar size, provide ecosystem service benefits via wood production and carbon storage, and effectively manage regulated nutrients, metals, and organics (Agency 2006; Crites 1984; Pound and Crites 1973). However, these systems are dependent on land availability and application rates are subject to precipitation and weather. The management of regulated nutrients in groundwater and receiving waters (Nichols 2016; Pound and Crites 1973; Shifflett et al. 2014) and hydrological implications (Birch et al. 2016; Crites 1984; Hutchins et al. 1985) of FWR systems are more defined than the characterization of contaminants of emerging concern (CECs). CECs in irrigated wastewater and receiving waters at FWR systems has only recently been assessed (McEachran et al. 2017a).
Description:
Forest-water reuse (FWR) systems treat municipal, industrial, and agricultural wastewaters via land application to forest soils. Previous studies have shown that both large-scale conventional wastewater treatment plants (WWTPs) and FWR systems do not completely remove many contaminants of emerging concern (CECs) before release of treated wastewater. To better characterize CECs and potential for increased implementation of FWR systems, FWR systems need to be directly compared to conventional WWTPs. In this study, both a quantitative, targeted analysis and a nontargeted analysis were utilized to better understand how CECs release to waterways from an FWR system compared to a conventional treatment system. Quantitatively, greater concentrations and total mass load of CECs was exhibited downstream of the conventional WWTP compared to the FWR. Average summed concentrations of 33 targeted CECs downstream of the conventional system were ~ 1000 ng/L and downstream of the FWR were ~ 30 ng/L. From a nontargeted chemical standpoint, more tentatively identified chemicals were present, and at a greater relative abundance, downstream of the conventional system as well. Frequently occurring contaminants included phthalates, pharmaceuticals, and industrial chemicals. These data indicate that FWR systems represent a sustainable wastewater treatment alternative and that emerging contaminant release to waterways was lower at a FWR system than a conventional WWTP.
