الفهرس 
LITERATURE REVIEWOnly 14 pages are availabe for public view
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Abstract
The progressive exertion of BOD of freshly polluted
waters normally breaks down into two stages : a first stage
in which the carbonaceous material is largely oxidized and
a second stage in which significant amount of nitrification
takes place.
Nitrifying bacteria are usually present in relatively
small numbers in untreated domestic sewage, and their
production rate at 20°C is such that their populations do
not become sufficiently large to exert an appreciable demand
for oxygen until a relatively long period have elapsed in
the regular BOD test. This is attributed to the present of
excess aoncentrations of organia matter which inhibits the
’growth and respiration of nitrifying organisms at the early
stages of incubation period. As the time is elapsed, the
organic matter concentration reduces gradually until its
concentration allow for the respiration and multiplication
of nitrifying organisms.
Therefore, this study was undertaken to gain a complete
understanding on the effect of carbonaceous organic
matter concentration on the activity of nitrifying bacteria.
Accordingly, several experiments were conducted on raw,