![Pumping stations after Philadelphia's incorporation, 1854](https://waterhistoryphl.org/wp-content/uploads/1_ConsolidationMap.jpg?w=300)
![Pumping stations after Philadelphia's incorporation, 1854](https://waterhistoryphl.org/wp-content/uploads/1_ConsolidationMap.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)
Volume of Sludge from 1,000,000 Gallons of Sewage
![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 line graph showing two jagged lines on a grid](https://waterhistoryphl.org/wp-content/uploads/Dissolved-O2-in-Delaware-River.jpg?w=300)
Diagram Showing Decreased Amount of Dissolved Oxygen in Delaware River, 1913
![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)
Bacteria in Delaware River, Torresdale Filters, 1913
![Six people and dozens of sandbags performing a load test on a concrete pipe, 1914](https://waterhistoryphl.org/wp-content/uploads/Load-test-concrete-sewer-pipe-1914_20040920278.jpg?w=300)
Pipe Test, 1914
![Photo of Allegheny Avenue Sewer, Pier 126, Delaware River, July 15, 1918](https://waterhistoryphl.org/wp-content/uploads/Pier126-Sewer-AlleghenyAvenue-20040920279-1.jpg?w=300)
Allegheny Avenue Sewer at Pier 126, 1918
![Spring Garden Sewage Experiment Station, used to test water filtration methods](https://waterhistoryphl.org/wp-content/uploads/DR_SpringGardenSewExpSta1911.jpg?w=300)