Granted Patent
Utility
US 4,290,884 · App. 06/179,239
Nitrification-denitrification system
Inventor:
Mikkel G. Mandt
Patented Case
View Patent ↗
Granted: Sep 22, 1981
Filed: Aug 18, 1980
Inventor
Mikkel G. Mandt
Assignee (at issue)
Clevepak Corporation
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.