The primary goal of the MAR? project was the valorization of hydrocarbon based-sludge destined to the production of additives for marine remediation and biomass for energetic purposes, by means of specific biotechnological processes. Such sludge, obtained as a by-product of the refining of hydrocarbon rich-wastewater derived by recovered oil spillage after treatment to obtain fuel oil, currently represents a waste for disposal. The project aimed at developing a multi-stage treatment process for the production of an innovative product to be used in marine remediation of oil spills. Such a product was obtained by fatty acids extracted from microalgae and an inert waste as supporting material. The experimental activities showed that the MAR? additive was able to clean polluted hard surfaces and hydrocarbon compounds floating on water, with the important advantage to remove completely iridescences.
During the project the following specific multi-stage process steps were developed:
- The first step is represented by the aerobic biodegradation of a mixture of waste composed by the hydrocarbon sludge and hydrocarbon-rich wastewater deriving from an industrial wastewater treatment plant. The bioremediation process was carried out by specific bacteria consortia selected during the project. Prototyping trials demonstrated that the bioremediation was able to reduce the organic carbon amount of 52,5%.
- The second step is represented by the process for growing and harvesting specific microalgae capable to produce fatty acids, using a culture medium composed by the exhausted wastewater deriving from the previous bioremediation process. The microalgae in such conditions, under light irradiation, can grow reaching 5-10 g/L of biomass containing from 40 to 50% of fatty acids.
- The extracted fatty acids after a specific chemical reaction are transformed into a reactive hydrophobic and oleophilic component used to perform a surface functionalization of another chemically inert waste. The product obtained is the MAR? additive used for the successful recovery of oil spillage on soil and water.
The closed cycle of the MAR? process which used hydrocarbon-rich waste deriving from marine remediation activities to produce an additive to be used for marine remediation is environmentally more sustainable than the disposal of the hydrocarbon-rich waste, as demonstrated in the project by Life Cycle Assessment, showing a decrease of environmental impacts more than 40% of the traditional waste disposal scenario.
