By Sara Quam
Treatment of Luverne's murky waters may become more clear with help from a long-term study.
The University of North Dakota, Grand Forks, under the direction of Scott Korum, is studying denitrification in groundwater near the Rock River and Wastewater Treatment Plant. Allen Schlag, a researcher at UND, installed equipment to test for denitrification Monday.
"We've been looking at how aquifers can naturally remove some contaminants," Schlag said.
Denitrification is the natural conversion of nitrate to harmless nitrogen gas. It benefits water consumers by naturally removing nitrates from ground water.
The city hopes the study - that will continue for almost three years - will offer insight about the water before it reaches the treatment stage.
UND has a grant from the U.S. Environmental Protection Agency, the Minnesota Pollution Control Agency, the Minnesota Department of Health and the Minnesota Department of Agriculture to assess the denitrification capacity of aquifers.
Nitrates, the most-common groundwater contaminant, can come from fertilizer and human and animal waste but can also be found when sod is freshly-tilled.
Another portion of the study includes three sites in North Dakota. Schlag said comparing the sites will "help researchers and water managers understand differences in the water chemistry of North Dakota and Minnesota aquifers with similar geologic histories but different geologic compositions."
Schlag said nitrates make a useful subject to study because some organisms use them like oxygen. "When there's no more oxygen, bacteria can use nitrates to breathe and continue to eat other contaminants."
The city's ongoing issue with water treatment has been that the aquifers are shallow and that Luverne has many more wells than most cities its size. The city has more wells to monitor as the water has less soil to filter through before entering the cityÕs treatment plant.
"The study is significant to the city because the test sites are so near the wells," Schlag said.
Schlag hypothesizes that Luverne's water will have a lower denitrification rate than ones in North Dakota. That's because North Dakota's sites in the Red River Valley have water that is usually filtered through sedimentary deposits containing higher levels of organic carbon and a mineral called pyrite - which support the denitrification process. Luverne's aquifer contains more igneous and metamorphic base, which do less of the filtering work.
Schlag will visit the test site several times over the next few months to initiate the experiment and train representatives from the Minnesota Department of Agriculture who will gradually assume sampling duties.
Of the two wells in Luverne, one will be left in its natural state to monitor natural water changes and the other will have increased nitrate content to observe how it affects the natural water chemistry.
At the end of the study, a report with findings will be available.
Schlag has a master's degree in geology, with an emphasis on hydro-geology, and he lectures at UND.