DONALD FRANCIS HEANEY
Engineers in Pittsburgh, PA

4051039, Sep 27, 1977

Apr 26, 1976

5/680421

Donald F. Heaney - Pittsburgh PA

Dravo Corporation - Pittsburgh PA

B01D 2316

210274

There is disclosed an activated sewage disposal plant of the compact or so-called "packaged" type and a method of processing sewage wherein a fast filter is provided through which the effluent liquid from the primary processing is passed, provision being made for backwashing the fast-flow filter from time to time with the backwash being collected in a well or vessel from which it is recycled at a controlled rate to the raw sewage. The entire plant can be embodied in a compact package unit, one common type of which comprises two concentric tanks, the outer one of which is divided into several compartments.

4064050, Dec 20, 1977

Feb 27, 1976

5/662131

Donald F. Heaney - Pittsburgh PA
Delbert L. Boal - Pittsburgh PA

Dravo Corporation - Pittsburgh PA

B01D 2318

210293

A nozzleless, strainerless filter bottom includes a first set of blocks laid end-to-end in spaced parallel rows to define elongated channels. Transverse grooves in the lower surface of the first set of blocks provide communication between adjacent channels. A second set of blocks laid end-to-end in spaced rows which are parallel to and overlap the rows of first blocks form covers for the longitudinal channels. Transverse slots in the lower surface of the second set of blocks form with the upper surface of the first set of blocks passages through which filtrate and backwash fluid may pass without clogging. A pair of laterally spaced longitudinal flanges depending from the lower surface of the second set of blocks extend into the lower elongated channels and bear against the adjacent sides of the first set of blocks to prevent lateral displacement of both sets of blocks. Longitudinal ribs extending upwardly from the upper surface of the first set of blocks give added strength thereto and prevent clogging of the passages with filter media.