Toxicity attenuation of olive mill wastewater in soil slurries

Olive mill wastewaters (OMW) are endowed with micro- and phyto-toxicity bound to the high polyphenol content. This work focuses on the potentiality of agricultural soil as a natural catalyst to promote polyphenol oxidation and polymerisation and thus detoxify OMW. We have shown that model polyphenols usually found in OMW are fully converted in soil slurries and products show no toxicity to the growth of a typical soil bacterium (B. cereus) and reduced phytotoxicity in germination tests (using the sensitive English cress seeds). Such preliminary data suggest the feasibility of an economically sustainable treatment of OMW in aerated soil slurries.