Clay for cleaner water
Demonstration of the efficiency and feasibility of clay technology in removing and managing harmful algal blooms of freshwater
Cyanobacterial harmful algal blooms (HABs) have become an increasing environmental concern worldwide. Using clay aggregation to control HABs is a common method implemented in marine environments around the globe. However, this approach hasn't been explored much for treating HABs in freshwater systems within the US. Currently, there are no clear guidelines on how to best apply clay technology, including questions like: a) what is the ideal amount of clay needed to reduce HABs effectively? b) when and for how long should clay be applied in real-world situations? and c) how can we quickly evaluate whether the clay treatment is working over large areas?
A research team led by principle investigator Miki Hondzo has received funding from the US Army Corps of Engineers (USACE) Research and Development Center for an exciting three-year project. The team includes Judy Yang and Ardeshir Ebtehaj of CEGE, plus Cody Sheik (Co-PI) Large Lakes Observatory, University of MN Duluth, Christopher Filstrup (Co-PI), Natural Resources Research Institute, Duluth, and Justin Chaffin (Co-PI), F. T. Stone Laboratory Ohio, Ohio State University) This dedicated, interdisciplinary team of researchers will explore innovative ways to evaluate how effective and cost-efficient clays can be in removing HABs and their soluble toxins.
The investigations will be carried out at three diverse testing sites: the Stone Laboratory in Ohio during Summer 2025, Camden Pond in Minnesota in Summer 2026, and Lake Erie in Ohio in Summer 2027. Each location presents unique HAB species, water chemistry, and different physical and environmental conditions. Clay technology shows promising potential for high HAB and toxin removal when applied correctly. Plus, it can be locally sourced, has a low environmental footprint, and can be scaled to address HAB issues across various affected areas.
Graduate students, including Yuan Li, Lucas Burnette, and K. Denesh, worked with Hondzo to conduct field experiments at the Stone Laboratory on Lake Erie from August 24 to August 31, 2025. Under controlled field experiments in fifteen 600-gallon bioreactors, the research team confirmed the findings of the laboratory measurements at the St. Anthony Falls Laboratory.