Browsing by Author "Yemets, Sergiy"
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Item Paleolimnology of the St. Louis River Estuary(University of Minnesota Duluth, 2016-05) Reavie, Euan D; Alexson, Elizabeth; Axler, Richard P; Yost, Chad; Ladwig, Jammi; Nurse, Andrea; Estepp, Lisa; Krasutsky, Pavel A; Kennedy, Kathleen; Yemets, Sergiy; Engstrom, Daniel RThe St. Louis River Watershed which drains to the St. Louis River and its associated estuary near Lake Superior has more than 150 years of human development history since Euro‐Americans first settled there, resulting in critical water quality impacts. In 1987, the U.S. Environmental Protection Agency designated the St. Louis River as an Area of Concern primarily due to that history which entailed inappropriate discharge of untreated wastewater and debris from poor industrial and community practices. The organic matter loading from inadequate treatment of sewage and paper mill products along with the dumping of woody debris from sawmills contributed to low oxygen levels in the river. The result included devastating impacts to the entire food web from the bacteria to vegetation to invertebrates to fish. Concurrently, poorly managed stormwater runoff from this post‐logged, barren landscape contributed excessive loading of suspended sediments resulting in increased turbidity and nutrient concentrations (e.g., phosphorus, nitrogen) to the river. Since then, government and private entities have taken action to restore the water quality in the St. Louis River Estuary, and to eventually remove the eight remaining SLRAOC BUIs. This summary focuses on the research documenting water quality changes over time associated with the excessive loading of sediment and nutrients BUI.Item Peat Derived Anion Exchange Materials for Sulfate Remediation in Mine Pit Water(2023) Yemets, Sergiy; Kolomitsyn, IgorA number of new natural peat derived anion exchange materials were developed in our laboratory. A batch testing of these new anion exchange materials were conducted. Recently we have demonstrated that peat derived anion exchange materials have strong binding affinity to per- and polyfluoroalkyl substances (PFAS). The initial positive results prompted us to investigate their efficiency to remove sulfate anions from mine pit water. Isotherms for chloride to sulfate exchange in a selected material fit Langmuir and Freundlich adsorption models. The practical limiting retention capacity was found to be 108 mg/g for the material (SY2205165) and 167 mg/g for the commercial anion exchange resin (Resinex). The new materials demonstrate their potential for the sulfate removal from the contaminated water sources. Further experiments on evaluation of selected peat lignin derived anion exchange material as well as sulfate selective commercial anion exchange resin in the column environment will be performed for the practical implementation.