Fatta-Kassinos has worked in the area of environmental science and authored numerous publications. Her research spans the fields of wastewater treatment and reuse, with a particular focus on Advanced Oxidation Processes (AOP), and on the development, and use of techniques for identifying contaminants of emerging concern in wastewater and crops, as well as antimicrobial resistance in the environment and wastewater technical systems. Among various honors, she is the recipient of the highest national research recognition award, the Nikos Symeonides National Research Award, and most recently was awarded the Noack Laboratorien Outstanding Science Career Award by the Society of Environmental Toxicology and Chemistry (SETAC). She was the Proposer, and Chair of the European COST Action NEREUS ES1403, "New and emerging challenges and opportunities in wastewater reuse" from 2014 till 2018, and later, became the Project coordinator of "Antibiotics and mobile resistance elements in wastewater reuse applications: risks and innovative solutions" (ANSWER) Project.