From Waste to Worth: Ozone Pretreatment as a Platform for Sustainable Resource Recovery
Monday June 30th 2025 at 14:00
Wolfson Building of Mechanical Engineering, Room 206
Abstract:
As global pressures mount around waste accumulation and resource scarcity, advanced oxidation processes- particularly ozone-based treatments- offer promising pathways to transform waste into valuable materials. This seminar presents a series of interdisciplinary investigations into ozone-assisted strategies for upgrading lignocellulosic, textile, and plastic waste streams into functional products.
For lignocellulosic waste, a hydrodynamic venturi reactor was engineered using a “Free model” configuration, allowing unrestricted circulation of particles and achieving nearly 100% ozone utilization. This design improved mass transfer, eliminated the need for off-gas treatment, and significantly enhanced enzymatic hydrolysis yields- up to 65%- while enabling valorization of residual solids into materials suitable for adsorption. This approach supports a scalable, near-zero-waste biorefinery model.
In the treatment of textile waste, ozone was implemented as a post-treatment “polishing” and bleaching step in nanocellulose (NC) production. The process improved NC purity and functional surface properties, while enabling recovery and reuse of sulfuric acid- commonly discarded in conventional protocols- thereby reducing operational costs and environmental hazards.
The third case explores an emerging biotechnological frontier: Plastic waste valorization explored the integration of ozone with fungal biodegradation. Ozone pretreatment increased the hydrophilicity and surface reactivity of nylon, promoting colonization by Trametes versicolor. The resulting fungal biomass shows promise as a protein-rich additive for food or feed, presenting an innovative route for transforming recalcitrant polymers into nutritive resources.
Additional innovations include reactor design optimization for energy efficiency, streaming potential surface characterization, and ozone application for pollutant degradation. Together, these findings demonstrate that ozone pretreatment, when coupled with tailored bioprocessing, provides a flexible and scalable platform to advance circular economy goals, integrating waste management, biotechnology, and sustainable engineering.
Bio:
Barak Halpern is a multidisciplinary environmental engineer and biotechnologist specializing in advanced oxidation processes for waste valorization. His doctoral research at Tel Aviv University, conducted in collaboration with the University of Toronto, Oranim College, and Kinneret College, focuses on ozone-based pretreatment technologies to enhance the biodegradation and upcycling of organic and plastic waste. His work integrates reactor engineering, biotechnology, and circular economy principles to convert waste streams.
A hallmark of his Ph.D. research is the design of an innovative hydrodynamic venturi reactor operating in a "Free model" configuration, which achieves nearly 100% ozone utilization and significantly improves enzymatic hydrolysis efficiency. He has demonstrated the reactor’s scalability in a semi-pilot biorefinery producing disinfectant-grade ethanol during the COVID-19 pandemic. In related projects, Barak has developed processes for recovering and reusing sulfuric acid in nanocellulose production and for accelerating fungal degradation of ozone-treated plastic waste.
Barak has published in high-impact journals (e.g., Cellulose, International Journal of Molecular Sciences) and presented at leading conferences in sustainability, food tech, and polymer recycling. He has received multiple awards, including the Teaching Commendation for excellence in education (2023/2024), the KKL Climate Scholarship, and 2nd place in the Falling Walls Israel Lab competition for his work on agri-plastic waste biodegradation, and participating on Coller 2025 contest.
Beyond the lab, he is an experienced mentor, educator, and social entrepreneur, having led sustainability-focused engineering projects through Engineers Without Borders and student-led initiatives addressing pollution, recycling, and environmental resilience.
