Diagram from sewage treatment plan for Philadelphia, 1912
Southwest Sewage Treatment Plant under construction, 1949
Emscher Tank Installation at Essen Nord, Germany
Volume of Sludge from 1,000,000 Gallons of Sewage
Diagram Showing Rate Between Bulk of Wet Sludge and Its Percentage Moisture
Sludge Drying Beds, Essen Nord, Germany
Grit Chamber, Essen, Germany
Effects of Expansion of Gas Bubbles in Enscher Sludge Shown in Right-Hand Cylinder
Sludge Presses for Grease Recovery, Bradford, England
Drain water from sludges obtained from sedimentation, septic and Emscher tanks