Removal of micropollutants using biological treatment systems remains a challenge, since conventional bioprocess systems require adaptations to provide more advanced treatment. An ambient temperature upflow anaerobic sludge blanket (UASB) reactor was employed, followed by a two-stage (saturated and unsaturated) vertical subsurface flow (VSSF) constructed wetland (CW) system, to treat domestic wastewater from a nearby settlement and investigate the occurrence and fate of 10 contaminants of emerging concern (CECs) in decentralized, non-conventional treatment systems. The integrated UASB—two-stage CW system achieved high performance regarding abatement of target CECs across all periods. Removal efficiencies ranged from 78% ± 21% (ketoprofen) to practically 100% (2-hydroxybenzothiazole). The pilot system was found to be robust performance-wise and provided enhanced treatment in comparison to a conventional wastewater treatment plant operating in parallel. Most of the target CECs were successfully treated by UASB, saturated and unsaturated CWs, while ibuprofen, bisphenol A and diclofenac were mostly removed in the unsaturated CW. Environmental risk assessment revealed that triclosan poses a significant ecological risk to algae during treated wastewater disposal into the aquatic environment. Additionally, cumulative risk quotient indicated that the potential for mixture toxicity should be carefully considered across all trophic levels.

In a world threatened by water scarcity, the use of non-conventional water sources, as reclaimed wastewater, for irrigation purposes is a promising option. Nonetheless, a suitable water treatment strategy must be implemented to reduce the concentration of emerging contaminants such as pharmaceutically active compounds (PhACs). Upflow anaerobic sludge blanket (UASB) technology is characterized by lower sludge production, lower energy demand as well as lower construction and operational costs compared with conventional activated sludge systems. In this work, the efficiency of a UASB system coupled to a constructed wetland (UASB-CW) was evaluated for the removal of pharmaceuticals present in urban wastewater on a Greek Island in a Mediterranean area suffering from water scarcity. Results showed that influent wastewater (IWW) concentrations in summer doubled in fall (238 856 ng L⁻¹ and 95 057 ng L⁻¹, respectively). The UASB reactor achieved a high removal efficiency for PhACs, particularly for acetaminophen (the most concentrated PhAC in the IWW), with removal rates of 88% in fall and 90% in summer, while exhibiting lower removal rates for other PhACs. The CW, however, decreased the concentration of most pharmaceuticals. The overall removal rate of the system ranged between 64% (summer) and 69% (fall) of the total IWW concentrations. Upon irrigation with reclaimed water, the impacts on the aquatic and terrestrial ecosystems were also considered. Effluent dilution and/or further polishing treatment would be necessary to better eliminate the contaminants and prevent any risk to the environment.