Abstract
De facto (or indirect) wastewater reuse is the practice of extracting from surface water bodies which are impacted by treated wastewater (TWW) for anthropogenic use. The extent to which surface water bodies in the Netherlands are impacted by TWW is poorly understood, and the distribution of de facto reuse even more so. This study addresses these knowledge gaps, with a focus on reuse for agricultural irrigation. This is achieved via a novel application of the Water Framework Directive (WFD) Explorer water quality model, allowing for the distribution of different flow components—namely TWW and flow from transboundary rivers—to be discerned for the national surface water network. When paired with data on surface water extractions for irrigation, this identifies notable areas of de facto reuse. Results show that during dry conditions, TWW is a significant flow component in many surface water bodies, particularly in smaller streams located close to WWTPs. De facto reuse is indicated as widespread, with several key areas identified in which extractions are from impacted surface water bodies. This study represents a first attempt to directly link TWW emissions to agricultural irrigation, highlighting a mechanism by which wastewater-associated contaminants can propagate through the hydrological system.
Highlights
Wastewater, following treatment processes, is generally discharged into surface water bodies, whereupon it is transported and diluted
Via “following the water”, this study aims to determine whether treated wastewater (TWW) makes up a significant flow component for surface water bodies in the Netherlands and provide a first estimate of the extent to which de facto wastewater reuse is occurring in agricultural irrigation
A national scale water quality model is used to simulate the partitioning of flow components within surface water bodies and the transport of TWW through the surface water network
Summary
Wastewater, following treatment processes, is generally discharged into surface water bodies, whereupon it is transported and diluted. TWW discharge helps to maintain environmental flow capacities in surface water bodies [4] and to recharge shallow aquifers [5] It is, likely that in areas where surface water bodies are highly impacted with wastewater, water quality concerns are an issue. Contaminants found in TWW include pathogenic microorganisms (concentrations in the range of 10−1–105 [cfu l−1), nutrients (nitrates and phosphates, 100–102 [mg l−1]), heavy metals (10−1–102 [μg l−1]) and endocrine disruptors (10−2–102 [μg l−1]) [6] The presence of these in surface water bodies may lead to problems meeting WFD chemical water quality targets, negative impacts on ecology [7] and reduced societal functions [2]. This is highly dependent on subsurface characteristics and hydrological conditions [8,9], but is indicated by studies which find a range of TWW-related pharmaceuticals and personal care products in groundwater samples [10]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call