Drinking water treatment plants remove large particles like dirt, while killing pathogens that can make us sick. Although these processes make the water safer to drink, they are not designed to remove many organic pollutants that are present in low concentrations and can lead to negative health effects when consumed. Dr. Christina Remucal, Assistant Professor of Civil and Environmental Engineering at University of Wisconsin-Madison, is using fundamental chemistry to study contaminant transformation, photochemistry, and reactive oxidant production in both engineered (drinking water treatment) and natural (lakes/rivers) systems. As she researches the fate of chemicals in the aquatic environment, she aims to develop new ways to remove chemicals from drinking water through natural processes.

Common water contaminants include pesticides added to fields or urban environments, and pharmaceuticals and personal care products that pass through us to wastewater treatment plants, ending up in the environment. With her team of chemists and engineers, as well as collaborations with colleagues, Dr. Remucal’s research includes extensive study about what happens when these chemicals end up in our water. In a natural environment, such as a lake or river, they explore how fast degradation happens through reaction with sunlight, and whether or not the contaminants turn into less toxic compounds when they degrade. Concerning drinking water, she and her team are investigating new ways to degrade chemicals that are not removed well by conventional drinking water treatment processes. These chemicals include endocrine-disrupting compounds, which can turn male fish into female fish, and are bioactive at the same levels found in the environment. Some of these novel water treatment processes can also be used in developing countries to disinfect water at the household level, potentially providing safer water to millions of people that do not have access to it. 

Current projects include:

The formation of disinfection by products during chlorine photolysis - Dr. Remucal and her team are studying a new water treatment application that takes advantage of the existing drinking water infrastructure to remove contaminants and chlorine-resistant pathogens by shining light on chlorine disinfection units. With her research into this advanced drinking water treatment system, Dr. Remucal is not only investigating the fundamental chemistry processes involved in contaminant removal, but exploring how the formation of disinfection by-products changes. These potentially cancer-causing products are formed when chlorine, the most common water disinfectant in the U.S., is used to kill pathogens in water. Understanding the formation of disinfection by-products is critical to the safety of the new drinking water treatment process. In addition, this new water system can also be used as a point-of-use treatment application in developing countries, where millions of people lack access to safe drinking water. One way an individual may treat their water is through solar disinfection, which involves putting water in plastic bottles and placing it in the sun. Dr. Remucal’s research could speed up this sunlight-based water treatment process, making it more reliable for people that depend on it to keep their water safe to drink. 

Photodegradation of pesticides and pharmaceuticals in lakes and rivers – Pesticides applied to fields or urban environments can be transported to lakes and rivers, while wastewater effluents and animal operations are sources of pharmaceuticals. Many of these chemicals are bioactive at low concentrations and their presence in aquatic systems is a concern for both humans and the ecosystem. Dr. Remucal is studying what happens when these chemicals come in contact with sunlight, how quickly they degrade, and which products they form.

Manganese oxides for contaminant removal - Found in the soil, these naturally occurring minerals can be used to degrade certain pollutants. Because they are naturally highly active, Dr. Remucal posed the question, “Can we use these minerals to remove contaminants from stormwater?” When it rains, the rainwater picks up everything in its path, such as pesticides from lawns and chemicals on cars, and often flows straight into a lake or river. Dr. Remucal and her team are investigating ways to direct stormwater through green infrastructure, such as a manganese oxide-based reactive infiltration systems, reducing contaminant loads before the runoff hits surface water.