Sludge Valorization from Biofloc-Based Aquaculture Systems for Bioremediation of Crude Oil-Contaminated Sediment

Abstract

This paper describes the potential valorization of sludge waste generated from aquaculture using biofloc system for bioremediation purpose. Three sets of mesocosms were artificially contaminated by 5 % of crude oil (v/v) representing a control, inoculated mesocosm with a commercial hydrocarbonoclastic consortia and a treatment that correspond to the use of sludge from floc-forming consortia. Samples of each mesocosms were taken at 0, 2, 4, 7, 14, 21, 42 and 56 days as well as sediment background to assess abiotic losses due to hydrodynamic force and possible contamination of sediment by the three set of experiments. The results showed significant differences of hydrocarbons removal among the treatments when it was confronted with the different consortia communities exposed through the time and coursetimes. In terms of hydrocarbons removal all treatment reached removal ca. 60 % (w/w) of pollutants at the end of experimentation but the removal performance was different during the first 14 days. The significant results of this study were to support the hypothesis that indigenous bacteria can be used as bioremediation agent but needed more adaptation time compared to the mesocosms that have been inoculated by exogenous bacteria. Both hydrocarbonoclastic and sludge waste from aquaculture were shown to be readily active as starter for biodegradation. Such condition will be beneficial to the mitigation of future oil spills in the study area which are located in the narrow strait where maritime transportation is frequent.