Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4391703 | Marine sewage treatment with biological filter | — | 1983-07-05 |
| 4337151 | Method and apparatus for pulsed timed control for sludge return line | — | 1982-06-29 |
| 4317723 | Sewage treatment | Walter Rapp | 1982-03-02 |
| 4268389 | Sewage treatment | Walter Rapp | 1981-05-19 |