The results obtained from the tests carried out with a 25% inlet/
75% outlet mixture (Fig. 3A–G) showed a good removal performance
by D. polymorpha due to the bio-filtration effect, probably
because of the suitable concentration of the suspended matter. The
removals obtained for each ME tested through the
filtering activity
of bivalves were always greater than those related to the natural
sedimentation evaluated in controls. In fact, for the majority of the
analyzed MEs, the contribution of the zebra mussel
filtration was
evident, since the differences between the removal percentage