Currently most used frying oil is treated as waste material and is disposed of in landfill sites, or discharged into sewage systems causing malfunctions in the filters and oil/water separators of wastewater treatment plants. With adequate collection and treatment, such oil can however be recycled into an environmentally friendly biodiesel for transport. This can help meet the requirements of the EU biofuels directive (2003/30/EC), whereby Member States must ensure a minimum proportion of 5.75% of biofuels and other renewable fuels for transport.
The OIL PRODIESEL project’s main objective was to develop an integrated and innovative waste management system for used frying oil collected in Oeiras – a small town located 15 minutes from Lisbon. The project would promote more efficient collection of the used oil from private households, in order to avoid waste disposal to landfill or into the sewage system. The project would also evaluate the opportunities for reusing the residue from biodiesel production. Furthermore, it would promote the use of biodiesel as a viable alternative to diesel – demonstrating energy and cost savings for public transport fleet.
The project achieved its objectives. An integrated system for the collection of used frying oil produced in the domestic sector was developed: a 1 000 litre biodiesel processor prototype and 20 collection containers were built and installed; a fill-up monitoring system was designed and installed for the containers. The project also evaluated the opportunities for the biodiesel produced, which was used in six vehicles for the Oeiras municipality transport fleet.
The results included:
- the conversion of a waste material (used frying oil) into a raw material for biodiesel production;
- improvements in the quantity of used oil collected in the municipality (current figures are 10%/ year);
- more than 11 000 kg of used frying oil was collected during a nine-month period. This represents savings of approximately €4 000 in the maintenance costs of the urban sewage system and sewage treatment plants;
- reductions of emissions using biodiesel in vehicles, compared with diesel (e.g. estimated 15% reductions of CO2 emissions and up to 20% reductions of hydrocarbons. Sulfur dioxide emissions are also reduced (as biodiesel doesn’t contain sulphur); and
- significant decreases in oils and fats (e.g. 52.0 mg/l, compared with 103.2 mg/l) and hydrocarbons concentrations (e.g. 3.3 mg/l, compared with 11.1 mg/l) in the wastewater treatment plant.
Project partner CMO plans to introduce the use of biodiesel in up to 20% of its transport fleet, as a measure to reduce its carbon footprint by 2020. Eleven municipalities are already replicating the OILPRODIESEL collection system for used frying oils produced in the domestic sector. Besides providing a model for the efficient collection of these used oils, this will have a positive impact in the short to medium term implementation in the legislative/regulatory measures concerning biofuels and used frying oil as an alternative raw material. Finally, environmentally friendly technology for the reuse of glycerine was also investigated, as well as the valorisation of other wastes from the process (plastics). Various solutions were found and deliverables produced.