From Effluent to New Water: Performance Evaluation and Quality Assurance

Abstract

As water reuse becomes increasingly important to satisfy water demand, ensuring the quality of recycled wastewater becomes ever more vital. Pharmaceuticals (PhACs) and alkylphenol polyethoxylates (APEOs) metabolites are two groups of chemicals that are commonly present in treated effluent and have received attention for their demonstrated or potential biological effects. In this paper we present data on the effects of river transport, wetland treatment, and groundwater recharge on the attenuation of these emerging chemicals. Using data from three advanced water treatment plants, we also report on the efficiency of microfiltration, reverse osmosis and ultraviolet oxidation in removing these compounds from advanced treated effluents. With respect to natural attenuation processes, decreases in pharmaceutical concentrations during river transport were likely attributed to sediment sorption and chemical and biological degradation or transformation. Wetland treatment was less efficient when compared to river transport. Groundwater recharge appeared to be an effective removal process (> 99% attenuation) for PhACs and APEO metabolites, although trace levels of the latter can travel substantial distances in the subsurface. With regards to the engineered treatment options, reverse osmosis was capable of almost complete rejection of all PhACs and APEO metabolites analyzed, whereas the performances of microfiltration and UV treatment were much less efficient and consistent.