Army Spc. Luis Montalvo, foreground, demonstrates how a filter catches debris during training to purify water at the water utilities facility in San Lorenzo, Puerto Rico, May 31, 2014. Montalvo is a water treatment specialist assigned to the Puerto Rico Army National Guard's 714th Quartermaster Company, 191st Regional Support Group. Army Spc. Luis Montalvo, foreground, demonstrates how a filter catches debris during training to purify water at the water utilities facility in San Lorenzo, Puerto Rico, May 31, 2014. Montalvo is a water treatment specialist assigned to the Puerto Rico Army National Guard's 714th Quartermaster Company, 191st Regional Support Group. SHARE: Download: Full Size (2.13 MB) Tags: Photo Essays Credit: VIRIN: 601175-W-QNV15-204.jpg Photo Gallery