


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

Effects of Expansion of Gas Bubbles in Enscher Sludge Shown in Right-Hand Cylinder

Thomas Run sewer outlet during construction

Bacteria in Delaware River, Torresdale Filters, 1913
