Date:
Bruce Rittmann, PhD
Director, Biodesign Swette Center for Environmental Biotechnology
Regents’ Professor of Environmental Engineering, Arizona State University
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Abstract
The United States has identified a pressing need to find new sources of Critical Metals and Minerals (CMM), which include the Rare Earth Elements, Platinum Group Metals, Gold, Nickel, Lithium, and Copper. Mining, ore processing and refining, and metals recycling generate wastewater streams that contain soluble, oxidized CMM, which are serious pollutants if discharged to aquatic environments. Using hydrogen gas (H2) as the electron donor, certain bacteria are able to convert the CMM to nanoparticles that constitute a novel source of CMM of high economic value. This talk overviews how the H2-based membrane biofilm reactor (MBfR) can be used to form the CMM nanoparticles. The H2-MBfR delivers H2 gas directly to a biofilm growing on the exterior of gas-transfer membranes. The bacteria oxidize the H2 and use the electrons to either directly reduce the PGM and Gold to elemental nanoparticles or to reduced sulfate to sulfide that precipitates to form nanoparticles of REE, Nickel, Lithium, and Copper. The nanoparticles are naturally retained in the biofilm and recovered by periodically harvesting some of the biofilm.
Speaker Bio
Dr. Bruce E. Rittmann is Regents’ Professor of Environmental Engineering and Director of the Biodesign Swette Center for Environmental Biotechnology at Arizona State University. His research focuses on the science and engineering needed to “manage microbial communities to provide services to society.” Services include generating renewable energy, cleaning water and soil, and improving human health. Dr. Rittmann is a member of the National Academy of Engineering; a Fellow of AAAS, WEF, IWA, AEESP, and NAI; and a Distinguished Member of ASCE. Dr. Rittmann was awarded the first Clarke Prize for Outstanding Achievements in Water Science and Technology from the NWRI, the Walter Huber Research Prize and the Simon Freese Award from ASCE, the G.M. Fair Award from AAEES, the Perry L. McCarty/AEESP Founders Award, and the Camp Applied Research Award from WEF. He is the co-winner of the 2018 Stockholm Water Prize. Dr. Rittmann has published over 800 journal articles, books, and book chapters, and he has 21 patents. With Dr. Perry McCarty, Dr. Rittmann co-authored the textbook Environmental Biotechnology: Principles and Applications (McGraw-Hill Book Co.), which is now out in its second edition.