  The removal of organic micropollutants (OMPs) has been investigated in
constructed wetlands (CWs) operated as bioelectrochemical systems (BES). The
operation of CWs as BES (CW-BES), either in the form of microbial fuel cells
(MFC) or microbial electrolysis cells (MEC), has only been investigated in
recent years. The presented experiment used CW meso-scale systems applying a
realistic horizontal flow regime and continuous feeding of real urban
wastewater spiked with four OMPs (pharmaceuticals), namely carbamazepine (CBZ),
diclofenac (DCF), ibuprofen (IBU) and naproxen (NPX). The study evaluated the
removal efficiency of conventional CW systems (CW-control) as well as CW
systems operated as closed-circuit MFCs (CW-MFCs) and MECs (CW-MECs). Although
a few positive trends were identified for the CW-BES compared to the CW-control
(higher average CBZ, DCF and NPX removal by 10-17% in CW-MEC and 5% in CW-MFC),
these proved to be not statistically significantly different. Mesoscale
experiments with real wastewater could thus not confirm earlier positive
effects of CW-BES found under strictly controlled laboratory conditions with
synthetic wastewaters.
