U of Minnesota Wastewater Treatment Pilot Promises to Turn Scum into pProfit
(University of Minnesota) For University of Minnesota (UMN) researchers, scum is a word packed with profitable promise. College of Food, Agricultural and Natural Resource Sciences (CFANS) professor and Center for Biorefining director R. Roger Ruan and doctoral candidate Erik Anderson are converting scum into high-quality biodiesel.
Scum, a white, muddy byproduct produced in wastewater treatment facilities, presents significant disposal challenges. Typically scum is treated either by anaerobic digestion to produce biogas, which has low energy density, or disposed of in a landfill, which causes many environmental problems. However, the process developed by Ruan and Anderson converts scum to biodiesel that can be directly used in utility vehicles on-site, leading to substantial cost savings.
The patented process not only converts the scum to a higher value product (biodiesel) but also reduces environmental pollutants in both landfills and water systems. As a result, 68 percent of dried and filtered scum can be converted to biodiesel, equivalent to approximately 140,000 gallons of biodiesel and $500,000-600,000 in profit per year. Additionally, the process utilizes available waste heat from water treatment facility.
“Using a free oil source combined with the lack of transportation and handling costs makes a scum to biodiesel process very attractive financially,” said Anderson. “Scum oil is not only free, but is considered a waste material. By converting most of the scum to biodiesel, and part removed as either distillation bottoms or filtered solids, the process saves a majority of the liquid organic scum from a landfill. That’s an immediate savings of more than $150,000 per year in costs associated with landfilling scum at the St. Paul facility, in addition to the revenue generated.” READ MORE