Outside Sprinkling Filters, Spring Garden Sewage Experiment Station, 1911
In 1911, a sewage treatment experiment station was set up near the old Spring Garden pumping station (along the Schuylkill near the Girard Avenue Bridge), where drinking water filtration experiments had been conducted several years earlier.
As a result of this work, the City's first treatment plant was built in 1912 to keep the raw sewage of several municipal institutions out of Pennypack Creek, which emptied into the Delaware River within reach of water intake points at the Torresdale pumping station. As the Pennypack Works was a prototype the much larger Citywide sewage treatment system then being developed, its operation and performance was closely scrutinized and extensive documentation is available in PWD annual reports from the period.