Biological approaches to the treatment of saline oily waste(waters) originated from marine transportation.

Abstract

Oily wastewater generated, in amounts of millions of tons per year, by ships mainly in engine-rooms (bilge waters) and by washing oil tanks (slops) create a major disposal problem throughout the world because of the persistence and accumulation of xenobiotic compounds in the environment. The high salinity levels (up to 25.000 p.p.m.) and the pollutants concentration limit the chances of discharge into the sewer systems and address the disposal of these waste(water)s to the sea. Tightening effluent regulations and consequent high energy and management costs has generated interest in the introduction of biological phases in the treatment of these wastewater. The objectives of this study were to evaluate the feasibility of using biological processes with purposely acclimated microorganism for the treatment of high salinity oily wastewaters (slops). Specifically both the bio-regeneration of the exhaust Granular Activated Carbons (GAC), loaded with a mixture of compounds occurring in slops, and a BioFilm Membrane BioReactor (BF-MBR) application were examined. Results proved the feasibility of using salt-adapted micro-organisms capable of degrading the main pollutants contained in slops.