Cliff Shierk is a principal engineer with the solid waste permitting group at the Minnesota Pollution Control Agency. He has 15 years of experience in the field of environmental engineering and has worked extensively with landfills, remediation systems, and large environmental cleanup projects. He began his career as a design engineer on a large "lift-and-line" landfill project involving PFAS-laden waste and has been addressing PFAS in landfill leachate and groundwater ever since. Cliff is a registered professional engineer in Minnesota and holds degrees from the University of Illinois at Chicago (M.S.) and the University of Minnesota-Twin Cities (B.C.E.). He has served as a co-leader of the ITRC PFAS Treatment Technologies writing subgroup since 2018.