BOD Progression in Soluble Substrates
-III- Short-Term BOD and Bio-Oxidation
Solids Production
A. W. BUSCH and N. MYRICK1
Assistant Professor and Research Associate, Respectively
Department of Civil Engineering
The Rice Institute
Houston,   Texas
This paper is the third in a series reporting results obtained in an investi-
tation of the biochemical degradation of organic compounds. The study was
initiated on the postulation that there is no essential difference in the progression of bacterial growth over the broad range of environments encountered in
industrial waste treatment and water pollution control. Thus there should be
basic parameters relating the areas of pollution measurement, waste
"strength," biological treatment, and receiving water self-purification. Investigators have generally approached these problems as separate entities.
This paper presents theoretical and experimental evidence, supported by
mathematical and biochemical formulations of the interrelation of these areas
of study.
It should be noted that the ultimate objective of this investigation is sufficient basic knowledge to permit formulation of an experimental procedure
for a short-term BOD test broadly applicable to organic wastes of interest in
water pollution control.
THEORY
The first paper(l) in this series presented experimental data in support of
the postulated theory regarding BOD progression in soluble substrates. The
theory states that the process of biological oxidation of soluble organic substrates involves (a) conversion of the food material into cell substance with
varying degrees of synthesis, and (b) utilization of stored decomposition products and cell substance. In this process a plateau of oxygen utilization representing conversion of all substrate or bacterial cells occurs in from 12 to 48
hrs (depending on the analytical environment) and has a characteristic value
for a specific substrate. This plateau should afford a much more valid point
for determining total load or ultimate oxygen demand than does the conventional five-day incubation. It was also pointed out that the only difference
between the BOD bottle and the activated sludge process is concentration and
hence time.
The second paper(2) reported an attempt to attain the ultimate BOD
through respiration only, by blocking the assimilatory processes. This work
served to verify the theory of BOD progression by producing plateau values
representing a greater percentage of the ultimate BOD although an additional
lag period was induced at critical concentrations of assimilation inhibitors.
1 Current address:   Department of Civil Engineering, Washington University,
St. Louis, Missouri.
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