Wastewater (IMAGE) Penn State Caption In general, the study revealed that the Penn State Wastewater Treatment Plant effectively removed acetaminophen and caffeine and exhibited seasonal variability in the removal efficiency of the other compounds. The activated sludge component of the plant was the most effective step for reducing contaminant concentrations. Credit Penn State Usage Restrictions Non commercial use only License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.