Improved combined chemical and biological treatments of olive oil mill wastewaters

A novel system was investigated, finalized to reduce the impact of highly polluting wastewaters, and
based on combined actions of catalytic oxidations and microbial biotechnologies. Olive oil mill
wastewaters (COD 10 000-100 000 mg O2/L) were oxidized up to 80-90% by stoichiometric amounts
of dilute hydrogen peroxide (35%) and in the presence of water soluble iron catalysts, either Fe(II) or
Fe(III), at concentrations up to 1% w/w and more, i.e., much larger than those reported for conventional
Fenton processes. In the combined action, the mineralization activity of a selected microbial consortium
was used to degrade residual volatile and nonvolatile organic compounds into CO2 and biomass.
The results of this search could suggest an improved operational methodology capable to reduce
the potential impact of wastewater.