Anaerobic co-digestion of cork based oil sorbent and cow manure or sludge

Cork, a material with great economic, social and environmental importance in Portugal, is also a good oil sorbent that can be used in the remediation of oil spills. The oil-impregnated cork can be easily removed, but requires further treatment. In the case of vegetable oil spills, anaerobic digestion may be a potential solution. This study aims to evaluate the effect of adding cork contaminated with sunflower oil as co-substrate in anaerobic digestion processes. Biodegradability assays were prepared with cow manure or sludge from a wastewater treatment plant, in the presence of five concentrations of oil-contaminated cork, between 200 and 1000 mg· L 1 as COD. Maximum cumulative methane production increased with the amount of oily cork up to 41 % and 101 % in the assays with manure and sludge, respectively. Sporadic addition of cork contaminated with vegetable oil during anaerobic digestion of manure or sludge increases significantly the methane production of these processes.