 
		 
		 
		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
 
		Water, Water Everywhere – Philadelphia Record, 1937-03-14
 
		Frankford Creek: Sad History of an Urban Stream title page
 
		Outhouse over the Schuylkill near Pottstown
 
		Pegg’s Run, Northern Liberties (Watson’s Annals)
 
		Swimmers at Pier 126, Delaware River, July 15, 1918
