EXHAUSTED COOKING OIL VALORIZATION FOR RAW MATERIAL AND ENERGY RECOVERY

Cooking Oil is a popular food preparation ingredient, especially in Italy. When it become a waste, if not properly disposed, it could represent a significant risk for the environment, having important concerns both by environmental and economic point of view. The main problem is connected with urban exhausted oil waste: in fact, its correct management is strictly regulated for food industries, catering activities and restaurants, while there’s no regulation for household cooking oil that has to be wasted. Thanks to a proper management and appropriate recycling and recovery processes, it can be possible to produce secondary raw materials and a high heating value fuel, saving natural resources and fossil fuel, providing an alternative and renewable source for energy together with some by-products. Exhausted cooking oil is a serious threat for the environment as potential pollutant. It needs to be properly managed and disposed. In fact, if improperly discharged in soil, it could damage the vegetation in nutritive substance hindering; reaching to the aquifers, it prevents the oxygenation, contamining the water; inside the urban sewage systems, oil can produce severe damage to wastewater treatment plants with serious technical and economic consequences. In relation with waste classification, household exhausted cooking oil represent an urban non hazardous liquid waste, EU code 20 01 25, whose production could be quantified in several million of tons per year in Europe (only in Italy about 140-160.000 tons per year). The collection and proper disposal are, at present, really complicated and expensive. In that way it could be necessary to implement and to disseminate good practices for household oil management, thanks to communication activities by the families, improving regulation and arranging a dedicated collection system, together with awarness campaigns carried out by the municipalities. According with Eu directive 2008/98/CE hierarchy in urban waste management and objectives, it’s necessary to consider first of all the possibility to intercept exhausted oil before discharging, in order to recycling a secondary raw material and to recovery energy, at least at 50% of the total amount of oil wasted. Recycling oil has great potential: in Italy about 99% of the oil collected from the dedicated consortium (CONOE) could be recovered, getting recycled products with high added value. Once properly processed in a regeneration treatment plant, exhausted cooking oil becomes a raw secondary material or a renewable energy resource as: mineral lubricating oil for the production of asphalt and bitumen; fuels for power plants of alternative and renewable energy; biodiesel for traction, highly biodegradable fuel; raw material for tannery industry; paraffin and other by-products production. A first useful utilisation of exhausted cooking oil waste for energy could be as motor fuel for cogeneration, which, at present, is one of the most efficient technologies according with a rational use of energy. Oil cogeneration plants have lower impacts than other energy plants in terms of space and land use, noise and smell. Another energy recovery method by exhausted cooking oil is represented by biodiesel production, as valid alternative to fossil fuels utilisation, wich sustainability is definely higher with respect to others. Moreover, the use of biodiesel from waste oil avoids the conflict between food crops and those destinated to biofuel production. Biodiesel production has seen a constant growth in the last ten years, increasing in Europe and Eurasia of 679%, for a total production in 2013 of 10988 thousand TEP, and of 65348 thousand TEP in the world (BP Statistical review of energy 2014). Also consumption of Biodiesel is constantly increasing. That of biodiesel is certainly a growing market, where production from 414 exhausted oil waste can be relevant both from the economic and environmental point of view, but also in order to preserve food sustainability. In both energy recovery method, we are moving inside the European Parliament Directive for the promotion of renewable resources utilisation, according with a promotion of energy security and a reduction of greenhouse gases. In this issue, the state of the art in terms of exhausted cooking oil management and valorization has been carrying out in order to evaluate environmental impacts related with its release to the environment, the environmental impact and the economic damage due to sewage and to its disposal. A Life Cycle Assessment (LCA) approach has been utilized integrated with a Life Cycle Cost evaluation. In that way, a detailed analysis of the entire logistic and supply chain has been done, from collection to mechanical and thermochemical treatment, until its final valorization in terms of secondary material recycling and energy recovery. As first conclusion it can bee seen an absolute advantage of recycling and energy recovery in terms of environmental and economical sustainability.