Chemical-physical and biological treatment of high salinity wastewaters contaminated by oily xenobiotic compounds

Wastewaters contaminated by xenobioties of oil-bearing origin, generated by various sources and subsequently discharged into the natural environment create a major ecological problem throughout the world because of the persistence and accumulation of these compounds. The main goal of this research is to investigate the effectiveness of a removal process composed of several treatments including physical, chemical and biological phases. Considered watewater are wash-waters originated from the cleaning of ships' fuel tanks (slopes). Beside the presence of refractory compounds, these waters show extremely high salinity levels (up to 25,000 p.p.m.), that limit the possibility of discharge to sewers and address the disposal to the sea. This severely lowers the concentrations limits for most of the "sensible" parameters, such both COD and xenobiotic hydrocarbons, thus requiring a higher level treatment. The research has also led to a proper characterization of the specific wastewater typologies as available scientific data are incomplete or too scattered. The main objective of this work was to investigate the feasibility of treating slop wastewater by sedimentation and chemical coagulation followed by granular activated carbon (GAC) filtration and offline bioregeneration of exhaust carbons. Previous research is far from provide a complete understanding of process design, operation, and performance of GAS bioregeneration systems treating mixtures of biodegradable and nonbiodegradable SOCs such slops are. Experiments on bioregeneration are still in progress and results are thus incomplete and only methods are here presented