Activated Sludge Manual
and risk as a means to demonstrate its pragmatic merit. In fact, the Worcester system was
designed and installed under a performance-based contract based on effluent quality.
The patent situation for activated sludge became even more complex in 1915 when Leslie
Frank, a U.S. Public Health Officer, obtained an American Patent (#1,139,024) which
covered much the same material as the Jones and Attwood claims. (Frank, 1915) Frank,
however, dedicated his patent for "activated sludge" (the misspelling reflects Frank’s
terminology) to all U.S. citizens. Hence, at this point, there were two different patent
entities dealing with activated sludge. Aside from these legal claims, Flowler’s own
standing as the originator of activated sludge was also being disputed by Clark at
Lawrence. (Clark, 1915; Mohlman 1938; Greeley, 1945) However, despite this confusion
regarding the legal status and origination of activated sludge, the American engineering
community pushed ahead with its technical application.
In late 1914, Jones and Attwood, Ltd. Warned American engineers and cities that they
should use caution regarding patent infringements. (Hatton, 1916) And when American
engineers took credit for certain innovations which transgressed into their (i.e. Jones and
Attwood, Ltd) patented procedures (e.g., Clarence Hurd’s announcement of the spiral-
flow aeration pattern being used at Indianapolis), they were quickly rebuffed by the Jones
and Attwood group. (Hurd, 1929; Sandford, 1929) But as more and more plants were
built, municipal concerns about patent problems and complications diminished.
This mood quickly changed, though, with a suit filed by Activated Sludge, Ltd. (the
licensed patentee for Jones and Attwood, Ltd.) against Chicago in the late 1920’s.
(Anonymous, 1933) Additional suits against Milwaukee, Cleveland, Indianapolis, and
several smaller cities soon followed. Legal rulings on all of these cases took several
years, during which time the sanitary engineering profession seriously reassessed the
prospects for near-term activated sludge utilization. In 1933, District Judge Geiger ruled
that Milwaukee had, indeed, violated patents held by Activated Sludge, Ltd.
(Anonymous, 1934a,b) An appeal was submitted, but in October, 1934 the Supreme
Court declined to rule against this decision.
In reflecting upon this outcome, Bloodgood (1982) indicated a belief that the District
Judge ruled against Milwukee moreso because of their outspoken lawyer than the
involved legal details. Whatever the case, the infringement ruling immediately rippled
throughout the country. Several existing plants quickly shut down to avoid monetary
fines, including the original San Marcos, Texas facility. (Otts, 1982) Many others chose
to continue their use of the activated sludge process based on a royalty fee of 25 cents per
capita. Amongst the 203 plants, Kappe (1938) reported that 150 were licensed by
Activated Sludge, Ltd. (Kappe, 1938) As for the large number of communities planning
to install new activated sludge plants, most simply elected either to build an alternative
system (oftentimes a trickling filter) or to wait until the applicable patents expired (e.g.
Washington, D.C. was a prime example).
Milwaukee and Chicago appear to have suffered the largest losses with each being fined
just under one million dollars (Activated Sludge, Inc., 1946) In Milwaukee’s case, these
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