WRS student Elizabeth Boor targets CECs in wastewater research

by Elizabeth Boor
In the Water Resources Center’s Onsite Sewage Treatment Program, graduate student Elizabeth Boor isn’t afraid to get down and dirty. This summer she has been collecting septic tank sludge also known as “septage” as a key component to her thesis research. 

A properly designed septic tank does a wonderful job of treating traditional groundwater pollutants like nitrogen from wastewater. In some instances, it treats water more effectively than a wastewater treatment plant does. However, little is known about septic systems’ ability to treat CECs or “Chemicals of Emerging Concern” from waste. CECs span a range of compounds including personal care products, flame retardants, and pharmaceuticals.

Pharmaceuticals are the target of Boors’ research. She is targeting Ibuprofen, Naproxen, Acetaminophen, Erythromycin-H2O, Azithromycin, and Triclocarban. These medications are found in high concentrations in human waste and are present in septic systems. 

lizzywatering

Boor watered the columns weekly. Each soil column received 640mL of water per week to mimic average rainfall during Minnesota summers.

A septic tank slowly gets filled with solids as it treats wastewater. The solids need to be periodically removed to continue effective treatment. In Minnesota, the solids within the tank are typically applied to crop fields as fertilizer. This is the process Boor is mimicking in a laboratory setting. She has soil columns set up in the University’s greenhouses which have had high and low strength septage applied to them. Each column has wheat growing in it which is watered weekly. 

When the wheat reaches maturity, plant, soil, and “groundwater” (water that flowed through the column) will have been collected and will be run through a mass spectrometer to quantify the concentrations of the pharmaceuticals present. These findings will be immensely helpful in understanding how different compounds transport through crop field systems and into our food sources. CEC are known to build up in our environment over time. Understanding how they move and break down in our environment is an important human health concern.