Fats, oils and greases (FOGs) from the cooking or preparation of food products in the home, cafes and restaurants or food manufacturing industries are often disposed of down the drain or sink. The material ends up in the sewer, congealing and accumulating on the walls, restricting the flow of wastewater and sewage, and causing blockages and interfering with the proper running of wastewater treatment works. FOGs removed from the sewer are usually sent to land-fill, but this is a loss of a useful raw material as they contain natural fatty acids, which can react with methanol to give biodiesel in the form of fatty acid methyl esters. These wastes, however, are typically extremely degraded and contaminated and therefore difficult to process. The EU-funded BioDie2020 project addressed this challenge by developing a unique feedstock pre-treatment technology for processing extremely degraded FOGs and pre-treating them so that they can be converted into high quality biodiesel. “The biodiesel is analysed against a European standard and then blended with ultra-low diesel and used to fuel buses,” says Martin Kingsley project coordinator and CEO of Argent Energy, an SME specialising in the conversion of waste to road diesel for truck and bus fleet operators.
Successful field trials
The consortium modified Argent Energy’s original pre-treatment plant to improve the throughput of degraded FOGs. They also established a state-of the-art quality control laboratory to monitor and measure the quality of feedstocks, in-process samples as well as the final product biodiesel. In addition, researchers incorporated comprehensive testing protocols, methods and sampling regimes into the daily running of the plant. Project partners also conducted fuel trials, including exhaust emissions and fuel economy monitoring to determine the impact of using the new biodiesel in buses. “The emissions measured from the fuel trials showed no detrimental effects from using highly degraded fats, oils and greases derived biodiesel compared to fossil fuel derived diesel,” Kingsley explains.
Better for the environment
Researchers studied several new technologies, including the installation of a microwave system for conducting ‘mini-plant’ trials to determine how their use can improve the separation of pre-esterification reactions and their subsequent settling time. In addition, the team used ionic liquids to reduce sulfur and acidity levels in diesel - the final product. They also successfully tested and demonstrated a novel technique for removing polyethylene from feedstocks. Key results from the project included a stepwise increase in throughput for processing waste oils via the pre-treatment plant and a decrease in the manufacture of distillation bottom products as the biodiesel refinery increased capacity. Many feedstocks used in the BioDie2020 project are currently being spread over the land, land-filled or incinerated. “Therefore, reducing these scenarios means there is less of an adverse impact on the environment. Furthermore, the creation of an anaerobic soup process to combine wastes generated from using degraded feedstocks as part of the pre-treatment plant upgrade has turned wastes into valuable feedstocks for biogas manufacture,” Kingsley concludes.
BioDie2020, biodiesel, feedstock, FOGs, oils, fats, greases, fatty acid, conversion, Argent Energy, wastewater, microwave, fatty acid methyl esters