Development and operation of innovative scum to biodiesel pilot-system for the treatment of floatable wastewater scum

A novel process was developed for the biorefining of floatable wastewater scum and other waste oils from water treatment facilities into biodiesel and other value-added bio-products. To test the scalability and commercial potential of the technology, a 7000 l/year pilot-scale system was designed and built. Scum from a wastewater treatment facility, located in St. Paul, Mn, was collected and converted into methyl esters (biodiesel) according to the process chemistry. All of the incoming and outgoing process streams were sampled, tested, weighed and recorded to calculate both the process efficiency and product quality. Data from the pilot-scale system operation was compared to laboratory results and the theoretically expected values for each individual unit operation. The biodiesel was tested using a third party laboratory and confirmed it met all of the US EPA's test requirements for commercial-grade biodiesel.