A chain for the treatment of oilfield produced waters: case study and experimental analysis

Produced water are salty and organic polluted waters that are drilled out during the extraction of oil. Typically, these waters are re-injected into the extraction well, without any treatment or valorisation. In this work, a more sustainable and environmental friendly solution is proposed consisting of an innovative PWs treatment scheme: Assisted Reverse Electrodialysis (ARED) is used to reduce the PWs salinity to make them compatible with the downstream Sequencing Batch Moving Bed Biofilm Reactor (SBMBBR), aimed at removing the organic content. To this purpose, a 20-cell pair ARED unit was continuously operated for 24 hours to desalinate PWs down to a target concentration of 20 g L -1 of NaCl. Then, the desalinated stream was treated in a 50 L bioreactor and an abatement up to 40 % of the Total Petroleum Hydrocarbon (TPH) was achieved