![Photo of four men standing on the banks of the Schuylkill River on the last day of the Schuylkill Interceptor, December 20, 1956](https://waterhistoryphl.org/wp-content/uploads/Interceptor-Last-Gasp-1956-2004.092.0262.jpg?w=300)
![Photo of four men standing on the banks of the Schuylkill River on the last day of the Schuylkill Interceptor, December 20, 1956](https://waterhistoryphl.org/wp-content/uploads/Interceptor-Last-Gasp-1956-2004.092.0262.jpg?w=300)
![](https://waterhistoryphl.org/wp-content/uploads/1912-sewage-treament-report-frontispiece.jpg?w=300)
Diagram from sewage treatment plan for Philadelphia, 1912
![Southwest Sewage Treatment Plant under construction, 1949 (from Water & Sewer Course Module 7)](https://waterhistoryphl.org/wp-content/uploads/Southwest-Plant-1949-2004.093.0005.jpg?w=300)
Southwest Sewage Treatment Plant under construction, 1949
![Black-and-white photo of industrial tank installation with smokestacks and factories in the background](https://waterhistoryphl.org/wp-content/uploads/emscher-tank-essen-nord-germany.jpg?w=300)
Emscher Tank Installation at Essen Nord, Germany
![Black-and-white image showing several cubic measurements of various types](https://waterhistoryphl.org/wp-content/uploads/volume-of-sludge.jpg?w=300)
Volume of Sludge from 1,000,000 Gallons of Sewage
![Black-and-white image of a graph with several captions](https://waterhistoryphl.org/wp-content/uploads/rate-between-bulk-of-sludge-and-moisture.jpg?w=300)
Diagram Showing Rate Between Bulk of Wet Sludge and Its Percentage Moisture
![Black-and-white photo of a man standing in a long trench](https://waterhistoryphl.org/wp-content/uploads/sludge-drying-beds-essen-nord.jpg?w=300)
Sludge Drying Beds, Essen Nord, Germany
![Black-and-white photograph of a man in a hat standing in a brick trench](https://waterhistoryphl.org/wp-content/uploads/grit-chamber-essen.jpg?w=300)
Grit Chamber, Essen, Germany
![Black-and-white image of two cylinders on a white surface](https://waterhistoryphl.org/wp-content/uploads/emscher-sludge-bubbles.jpg?w=300)
Effects of Expansion of Gas Bubbles in Enscher Sludge Shown in Right-Hand Cylinder
![Black-and-white photo of heavy machinery](https://waterhistoryphl.org/wp-content/uploads/sludge-presses-for-grease-recovery-bradford-england.jpg?w=300)
Sludge Presses for Grease Recovery, Bradford, England
![Black-and-white image of a tray with three compartments and four small glass cylinders](https://waterhistoryphl.org/wp-content/uploads/drain-water-from-sludges-emscher-tank.jpg?w=300)
Drain water from sludges obtained from sedimentation, septic and Emscher tanks
![Black-and-white line graph showing two jagged lines on a grid](https://waterhistoryphl.org/wp-content/uploads/Dissolved-O2-in-Delaware-River.jpg?w=300)