Living Filter at Penn State (image) American Society of Agronomy Share Print E-Mail Caption The Living Filter at Penn State encompasses 600 acres of land split between two separate sites. Both contain agricultural and forested areas. This is the Astronomy site. Credit Photo credit Zachary Larson. Usage Restrictions Please use with story only Share Print E-Mail 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.