Olive mill wastewaters (OMW) are a serious environmental
issue with special impact on the Mediterranean area countries,
like Portugal, where the most part of the world olive oil is
produced. Some strategies have been proposed for these difficult
effluents and the most common practice is the direct deposition
in evaporation basins where biochemical conversion may occur1
even if soaring risks are associated with this approach of
management concerning the often serious issue of contamination
of superficial and underground waters.2 Moreover, depending
on the weather conditions, the collected OMW may not
evaporate making the pond unenviable in the following year