Highlighted projects at the Center for Biorefining demonstrate the translation of research into deployable technologies and measurable outcomes, supported by federal, state, and industry investment. These projects address challenges in waste management, food systems, energy production, and environmental protection, with emphasis on scalability and real-world implementation.
Destruct Per/Polyfluoroalkyl Substances (PFAS) in Landfill Leachates
Investigators: Roger Ruan, Paul Chen
Funding agency: LCCMR
Description: Per- and polyfluoroalkyl substances (PFAS) are persistent contaminants widely used in industrial and consumer products and resistant to conventional degradation processes. Their accumulation in landfill leachates poses significant risks to water systems and public health. This project developed integrated treatment strategies combining ion exchange and membrane separation, adsorption using biochar and resin materials, photocatalytic degradation, and algae-based flocculation. These approaches were evaluated individually and in combination to enable both removal and breakdown of PFAS from complex leachate streams. The work establishes a multi-pathway framework for PFAS treatment that supports scalable implementation in landfill systems while reducing environmental release and enabling safer water management.
Development of Continuous Intense Pulsed Light Technology for Non-Thermal Pasteurization of Powdered Foods
Investigators: Roger Ruan, Paul Chen, David Baumler, Chi Chen, Joellen Feirtag, Zata Vicker
Funding agency: USDA NIFA
Description: Powdered foods are widely used but remain susceptible to microbial contamination, with existing decontamination methods often limited by inefficiency or adverse effects on product quality. This project developed a continuous intense pulsed light (IPL) system as a nonthermal pasteurization approach. The system was designed and optimized to control energy input, residence time, and environmental conditions, enabling consistent treatment across different powdered products. Experimental validation demonstrated up to five-log reductions in bacterial populations while maintaining nutritional and sensory quality. Mechanistic studies using molecular biology, microscopy, and metabolomics provided insight into microbial inactivation pathways and process optimization. The resulting system offers a scalable, energy-efficient alternative for improving food safety in powdered food production.
Catalytic Microwave-Assisted Pyrolysis and Gasification of Solid Wastes
Investigators: Roger Ruan, Paul Chen
Funding agency: Xcel Energy, Sun Grants, USDA, DOE, and private companies
Description: Thermochemical conversion of biomass and waste is often limited by product instability, low selectivity, and high processing costs. This project developed microwave-assisted pyrolysis systems coupled with catalytic upgrading to improve process performance and product quality. Bench- and pilot-scale systems were constructed to process a range of feedstocks, including algae, lignin, wood, plastics, and sludge. A two-stage fast microwave-assisted pyrolysis process followed by catalytic upgrading using HZSM-5 demonstrated improved production of aromatic hydrocarbons and enhanced bio-oil stability. Process studies showed that catalyst loading, reactor temperature, and operating conditions significantly influence product distribution and yield. This work advances scalable conversion technologies capable of transforming diverse waste streams into usable fuels and chemical intermediates.
Integrated Biological System for Animal Wastewater Treatment through Utilization
Investigators: Roger Ruan, Paul Chen, Neil Anderson
Funding agency: MNDrive
Description: Animal waste generated from dairy, hog, and poultry production presents significant environmental challenges, particularly nutrient loss and water contamination. Conventional practices such as land application and lagoon storage are increasingly insufficient due to nitrogen losses through volatilization, nitrification, denitrification, and runoff. This project developed a multi-stage integrated system to achieve near-complete treatment and utilization of manure within a closed-loop framework. The system combines thermophilic anaerobic digestion with ammonia and hydrogen sulfide reduction, advanced microalgae cultivation for nutrient removal and biomass production, and hydroponic processes for further polishing of residual nutrients. Biochar filtration steps were incorporated to enhance water quality and enable reuse. The system achieved greater than 98% reduction in COD, nitrogen, and phosphorus, while producing value-added outputs including biofuels, fertilizers, animal feed, and crops. This work demonstrates a scalable pathway for transforming livestock waste management into a resource recovery platform.
Closed-Loop Landfill Management System
Investigators: Roger Ruan, William Lazarus, Andi Sutton, Juer Liu
Funding agency: ESMC, Bridgewater Township
Description: Municipal solid waste in landfills generates environmental challenges including greenhouse gas emissions and contamination of water resources with PFAS, microplastics, and heavy metals. This project develops an integrated system combining leachate treatment, waste conversion, and gas capture into a closed-loop landfill management framework. The approach integrates water treatment technologies, thermochemical conversion processes, and resource recovery strategies. The system is designed to transform landfills into controlled platforms for material recovery and environmental management.
Almond Hull Valorization and Functional Ingredient Development
Investigators: Roger Ruan, Yanling Cheng, Paul Chen, Juer Liu
Funding agency: Almond Board of California
Description: Almond hulls represent a large-volume agricultural byproduct with significant potential as a source of fermentable sugars and bioactive compounds. This project developed processes to convert almond hulls into functional ingredients for food and material applications. Comprehensive safety evaluations, including acute, subchronic, and genotoxicity studies, demonstrated that almond hull-derived products are safe for consumption at relevant levels. Building on this foundation, the project developed phenolic-retaining syrups, functional fibers, and nanocellulose-based materials through optimized processing techniques. This work establishes a pathway for upcycling agricultural residues into high-value products while supporting sustainability in the food industry.
Sustainable Ammonia Production via Nonthermal Plasma
Investigators: Roger Ruan
Funding agency: IHI Corp.
Description: Conventional ammonia production relies on energy-intensive processes with significant carbon emissions. This project develops a nonthermal plasma-based system for ammonia synthesis using renewable electricity. The approach utilizes plasma discharge in liquid to generate reactive hydrogen species directly from water, enabling in-situ hydrogen production and reducing reliance on external hydrogen sources. The system supports long-term electrosynthesis of ammonia in aqueous form. This technology provides a pathway toward decentralized, low-carbon fertilizer production and electrified chemical manufacturing.