Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4374730 | Process and apparatus for the biological purification of sewage | Alexandru Braha, Klaus Hess, Peter Kroetzsch, Helmut Merkel, Roland Roedl +2 more | 1983-02-22 |
| 4212737 | Processes and apparatus for removing suspended matter from suspensions by filtration through foams | Manfred Dressel, Klaus Hess, Hubert Engelhardt | 1980-07-15 |