The Effect of Nitrification of
Organic Wastes on Waters in the Natural
Environment — I. Effects of Seed
BARRY A. PATRIE, Engineer
Steams and Wheler
Cazenovia, New York
K. KESHAVAN, Associate Professor
FRANKLIN E. WOODARD, Assistant Professor
Civil Engineering Department
University of Maine
Orono, Maine
INTRODUCTION
One of the basic tasks in water pollution control is to evaluate the capacity
of streams to assimilate organic pollution on the basis of oxygen demand data
collected in the laboratory. Every year, millions of dollars are being spent for
this purpose, but, in spite of this, many streams are found with less than the
predicted amount of oxygen. One of the reasons for this discrepancy might be
that nitrification is far more effective in the natural environment than under the
laboratory test conditions. The importance of nitrification and its effects on the
oxygen resources of the stream have been recognized by many investigators (1,2,
3,4, 5,6,7). A recent abstract in the Water Pollution Abstracts (8) pinpointed the
problem of nitrification in the Grand River in Michigan as follows: "It was found
that dissolved oxygen in the stretch below Lansing was significantly affected by
oxidation of organic and ammoniacal nitrogen in the effluent from Lansing sewage works, and it was estimated that the sewage works would have to provide a
very high degree of oxidation of total nitrogen to maintain desirable dissolved
oxygen levels at drought flows. The results of this survey indicated that in such
a stream, where active nitrification is occurring, the nitrogenous BOD can be integrated with the carbonaceous BOD and the oxidation can be assumed to proceed
exponentially."
The above statement tends to confirm the views of many authors who have
maintained that nitrification and oxidation of carbonaceous compounds would proceed simultaneously if the environmental conditions were suitable (1,4,5). This
point of view is in direct conflict with that of the majority of investigators who
have felt that the nitrification would start only after the bulk of the carbonaceous
compounds are oxidized. The proponents of the later theory have pointed out that
in a mixed culture the heterotrophs would suppress the activities of the autotrophic
nitrifying bacteria. This point of view might be true only under certain environmental conditions such as low initial numbers of active nitrifying flora, adverse
pH and temperature conditions and very low concentrations of ammonia. It was
theorized by Keshavan (9) that if the deamination reactions were active in a system, then nitrification could proceed quite significantly provided that the other
environmental conditions were suitable for the nitrifying flora.
The purpose of this research was to investigate the methods by which concurrent exertion of the carbonaceous and nitrogenous oxygen demands might be in-
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