Granted Patent
Utility
US 4,093,539 · App. 05/685,723
Activated sludge treatment of wastewater
Inventor:
Carmen F. Guarino
Patented Case
View Patent ↗
Granted: Jun 6, 1978
Filed: May 12, 1976
Inventor
Carmen F. Guarino
Assignee (at issue)
AUTO-TROL LIMITED
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.