Friday, February 21, Purdue University’s Environmental and Ecological Engineering (EEE) welcomed Diane M. McKnight to campus for the Association of Environmental Engineering & Science Professors (AEESP) Distinguished Lecturer Conference. EEE sponsored this event with Purdue’s Center for the Environment as well as co-hosts from Bradley University, Illinois Institute of Technology, IUPUI, Purdue Fort Wayne, Purdue Northwest, Rose-Hulman Institute of Technology, University of Illinois, University of Illinois at Chicago, and University of Notre Dame. 

The full day of events brought together individuals in the field of environmental engineering to share their research findings through presentations and poster sessions. The morning presentation sessions were divided into four tracks: waste streams, climate change, resource recovery, and air quality; and were given by 12 faculty members from the different hosting institutions. Dr. Abigail Engelberth of Agricultural and Biological Engineering and EEE presented “Evaluating End-Use Potential for Process Food Waste” as she explored various upgrading schemes for processing food waste. Dr. Brandon Boor of Lyles School of Civil Engineering and EEE presented, “How do People Shape the Chemical Composition of Indoor Air?” His presentation highlighted a recent study investigating how people influence the VOC composition of indoor air in an open-plan office.

After lunch students gathered in the Memorial Union Ballroom for the poster session. Around 40 students from the different hosting institutions displayed their posters and answered questions as attendees made their way around the room. Interestingly, there were a handful of posters printed on fabric instead of the typical paper.

The day concluded with Diane McKnight's keynote lecture, “Trouble Ahead, Trouble Behind: Acid Mine Drainage and Climate Change in the Rocky Mountains.” McKnight is a Professor in the Department of Civil, Environmental and Architectural Engineering, a member of the Environmental Engineering program faculty, and a Fellow of the Institute of Arctic and Alpine Research at the University of Colorado. Her research focuses on the coupling of hydrology and water quality in streams and lakes, and the consequences for aquatic ecosystems and water supplies. She began her career as a research hydrologist with the U.S. Geological Survey, studying the biogeochemistry of lakes in the blast zone of Mt. St. Helens and acid mine drainage streams and pristine alpine lakes in the Rocky Mountains. She participated in designing ecological aspects of the National Water Quality Assessment Program of the USGS. Since 1992, she has conducted research on stream ecosystems as part of the McMurdo Dry Valleys Long-Term Ecological Research (MCM-LTER) project in Antarctica. 

Her presentation focused on the weathering of disseminated pyrite in the country rock and in mining workings generates acidic, metal-enriched water that drains into streams and rivers in the Rocky Mountain watersheds. This overall process is referred to as acid rock drainage (ARD). ARD is a long-term and pervasive environmental problem in the Rocky Mountains and the Sierras, which provide water supply for communities and agriculture throughout the south western US. Contamination has not abated since the mining boom ended about 70 years ago, largely because these contaminants are continuously generated from the exposure to oxygen of pyrite in the mine workings and tailings. Typically these streams have high dissolved concentrations of toxic metals, such as Zn, Cu, Cd and Pb, and their streambeds are covered with iron and aluminum oxides. These streams and rivers support species-poor aquatic ecosystems, and fish are typically absent. A study in an ARD stream system that drains into Dillon Reservoir, a water supply for Denver, Colorado, has found that acidity and concentrations of metals and rare earth elements have been steadily increasing in the summer and fall over the past several decades. Another trend is that mountain resorts have been pursuing a “four seasons resort” approach to adapt to changing climate, and less reliable winter snowpack for skiing. ARD thwarts these plans by constraining the use of stream water for snowmaking and impacting summer recreation, such as fishing and rafting. In addition to general environmental concerns, this situation has focused attention on remediation of abandoned mines which is inherently challenging, as illustrated by the difficulties in remediating the Gold King Mine near Durango, CO. One issue for state and federal agencies and watershed stakeholders’ groups is determining which of the many abandoned mines in a catchment are the main ARD sources, and which of these are suitable for remediation. Addressing the ARD problem in mountain catchments will require a convergent research approach that integrates understanding of hydrology, water quality and aquatic ecosystem processes within a regulatory and water resources framework.

View McKnight's full presentation.