An Innovative Plant for the Desalination and Treatment of Produced Waters

Produced waters (PWs) are wastewaters that are pulled out with oil during the petroleum extraction. The handling of this water has gained increasing interest from the scientific community in recent years, because of the large volume produced, the presence of pollutant and the high treatment costs. PWs are i) usually re-injected into the wells as method to enhance the oil recovery or ii) disposed as regulated by Authorities. Unfortunately, traditional physical-chemical treatments are too expensive. On the other hand, PWs high salinity represents an issue for intrinsically cheaper biological treatments, as it inhibits bacteria growth and metabolism. In this work, a novel biologically based treatment chain is presented. Assisted Reverse ElectroDialysis ARED is adopted in the chain as a preliminary desalination step devoted to diluting the PWs down to 20 g L−1 before feeding them to a downstream Membrane Bio Reactor MBR for the removal of the organic pollutants. PW desalination in ARED was investigated via experiments in order to validate a purposely developed model. Moreover, a techno-economic model of the treatment chain as a whole plant was developed to estimate the PW treatment cost. Preliminary economic analyses show a specific cost of 2.93 € m−3PW for the best considered scenario, thus making the proposed idea economically attractive and justifying future more in-depth studies.