ABSTRACT Graphs showing biological effect before and after advanced water treatment Water scarcity due to a changing climate and population growth has led to increasing interest in water reuse. The chemical water quality of purified recycled water (PRW) is typically evaluated using targeted chemical analysis, though effect-based methods (EBM) are also recommended for monitoring PRW quality. In the current study a comprehensive test battery of in vitro bioassays was applied to source water (treated wastewater) and PRW from an advanced water treatment plant (AWTP) on a fortnightly basis over a year. Bacterial toxicity, photosynthesis inhibition, aryl hydrocarbon receptor (AhR) activity, estrogenic activity and oxidative stress response were detected in all source water samples. Chemicals contributing to the effect in source water were identified with iceberg modelling based on chemical concentrations and potency data. The response in PRW was mostly undetectable, with low levels of oxidative stress response and (anti)glucocorticoid activity in some samples. AhR activity was observed in three PRW samples above the human effect-based trigger value (humEBT), though the activity was not linked to any AWTP process issues or detected chemicals. Overall, bioactivity in source water and PRW remained fairly consistent over the year for most bioassays, with quarterly or biannual monitoring suggested for routine monitoring.
Neale et al. (Fri,) studied this question.