During the crude oil extraction processes, for each barrel of oil turns out an equivalent of 3 barrels of
wastewaters on average. These wastes are known as Produced Waters (PWs) and their dramatic impact on
the environment has attracted the attention of researchers in order to find an economic and efficient method for
their treatment. Dealing with PWs is not easy: the long exposure with oil increases their hydrocarbon fraction,
while the contact with the underground wells increases their concentration in salts and minerals. The direct
discharge of PWs into the sea is obviously not allowed by law and PWs are usually re-injected into the well.
The present work deals with a novel and innovative treatment chain (including assisted reverse electrodialysis
(ARED) as dilution step) able to reduce both the salinity and organic content of PWs. The innovative scheme
includes an ultrafiltration unit as pre-treatment, upstream an ARED unit for the PW dilution. Once the salinity
level has been reduced down to a value affordable for a bioremediation step, PWs are sent to a bio-reactor,
where the organic compounds are digested. Finally, a reverse osmosis unit is used to recover water from the
treated PWs and to recycle it as diluted stream in the ARED unit. A techno-economic model was purposely
developed in the present work to assess the economic feasibility of the proposed scheme. Preliminary results
suggest that the treatment costs are lower than 5 € m-3
PW and fully competitive with current PWs treatment
technologies