Treatment of Strong Industrial Wastes In A
Municipal Facility by Aerated Stabilization
WESLEY A. FLOWER, Waste Treatment Engineer
The Miami Conservancy District
Dayton, Ohio 45402
Aerated stabilization, in the extreme sense, is the process provided by nature to treat
organic wastes discharged into surface waters. In this system, we attempt to optimize by
engineering methods those physical, chemical and biological processes which occur
haphazardly in nature. Aerated stabilization is often confused with aerated lagoons, but the
two are distinctly different. Aerated lagoons are probably the closest waste treatment
process to nature's method of purifying streams in that a large body of water is stored and
aerated to maintain a sufficient oxygen content. However, in the system the only real
concern is usually for the dissolved oxygen level, and the suspended solids often settle to the
bottom where anaerobic digestion takes place with release of nutrients and carbonaceous
matter. The aerated stabilization system, on the other hand, though still taking advantage
of the long-term detention typical of aerated lagoons, requires careful consideration of
basin geometry, liquid velocities and dissolved oxygen profiles in order to prevent the
deposition of solids and the subsequent regeneration of nutrients. The system combines the
properties of efficiency and reliability with economy of operation. It was primarily these
considerations which influenced the selection of aerated stabilization as the secondary
treatment process for The Miami Conservancy District's regional treatment plant at
Franklin, Ohio.
BACKGROUND
This somewhat novel approach is not entirely without precedent. In describing the
development of the world's first successful flood control network built by the District early
in this century, Colonel Edward A. Deeds referred to "a new, and sometimes bold approach
from an engineering viewpoint . . ."In looking back at the situation in Franklin in the late
1960's, the need for a "new and bold approach" is evident.
The "blue-collar" community of 10,000 population was served by a 40-year-old,
400,000-gallon-per-day (gpd) trickling filter plant which was in a poor state of repair.
Upgrading to meet minimal discharge requirements then in force was projected to be $1.44
million. In addition, the five paper mills in town generated an average waste load of 110,000
pounds chemical oxygen demand (COD) per day (250,000 P.E.), and a peak load of
1,000,000 pounds COD per day (2,500,000 P.E). The industries were desperate in their
frustration to obtain adequate and economical waste treatment, and the community leaders
were worried about possible loss of the industries upon which the local economy was
heavily dependent. Add to this a strong liquid waste from the city's new solid waste recovery
plant, and a river with seasonally low flow and critical dissolved oxygen problems.
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