WSSC Patuxent Water Treatment Plant

WSSC stands for washington suburban sanitary comission. This is their sweitzer lane drinking water treatment plant, "Patuxent Filtration Plant" is written on the side of the building. The supply is the T Howard Duckett reservoir to the north ("Rocky gorge", patuxent river just west of duckett dam)and is pumped uphill to this facility. This is one of the highest points in the area, making pumps to deliver to final customers unnecessary. On a tour of this plant at an open house they had several years ago the guide told me the some of the tanks you see in this picture were made from steel intended for battleship construction during wwII. Many if not all of the tanks have since been demolished and replaced with new ones covered by geodesic dome type structures (southernmost tanks). the two trapezoidal concrete structures you see just to the north are settling ponds for this plant. At the time of the open house, they were using sand/gravel/charcoal filters at at least one stage of the process, and they would prolong the life of these by "backwashing", running thousands of gallons of water in the wrong direction at intervals, removing filtrate that would otherwise quickly clog the filters. the main point i want to emphasize is this is to treat drinking water, not sewage. there is much more complete information at the wssc site available at the link below