![Black-and-white image showing several cubic measurements of various types](https://waterhistoryphl.org/wp-content/uploads/volume-of-sludge.jpg?w=300)
![Black-and-white image showing several cubic measurements of various types](https://waterhistoryphl.org/wp-content/uploads/volume-of-sludge.jpg?w=300)
![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 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 image showing a man standing in a large concrete half-pipe](https://waterhistoryphl.org/wp-content/uploads/thomas-run-sewer-outlet-under-construction.jpg?w=300)
Thomas Run sewer outlet during construction
![Black-and-white image of a table with numbers in columns](https://waterhistoryphl.org/wp-content/uploads/bacteria-in-delaware-river-torresdale-filters-1913.jpg?w=300)
Historic resources from our archives - images, maps, documents, and more.