


Thomas Mill Covered Bridge over Wissahickon Creek (Picturesque America)

Centre Square Water Works, Frederick Graff, Sr. Plans, 1799

Centre Square Water Works, Latrobe Plans, 1799

Grit Chamber, Essen, Germany

Sludge Presses for Grease Recovery, Bradford, England

Drain water from sludges obtained from sedimentation, septic and Emscher tanks

A Day in the Ma’sh – Oil Refinery

Bridge Street Draw, July 26, 1897

Color Diagram of Plan for the Collection, Purification and Disposal of the Sewage of the City of Philadelphia

State Street pipeline construction, 1904
