Effects of exposing slimes on rotating disks
409
NITRIFICATION
The effect on nitrification of enriching the atmosphere with oxygen over stage 1 is
evident in Table 1. Nitrification was observed to begin at stage 5, in the first period, while
nitrification moved upstream to stage 3, when operating with enrichment of the
atmosphere over stage 1. In the first period, it required 9 stages to cope with the
oxidation of organics and produce 9 mg/1 of N0 3 -N (N0 2 -N not determined).
Coincidentally, the alkalinity was reduced by 76 mg/1. In the latter period, the same
work was accomplished by 7 stages.
Legend
x T.O.C Mar to Ju 1.15,
1970 normal atmosphere
over all stages
O T.O.C Jul. 16 to Nov.
1970 (excl. Sept.) with
oxygen enrichment over
stage I
AS.O.C Mar. to Jul. 15,
1970 normal atmosphere
over all stages
o SO C. Jul 16 to Nov
Δν
1970 (excl Sept.) with
oxygen enrichment over
over stage I.
4
5
6
Stage No.
Fig. 3
Comparison of profiles of T.O.C. and S.O.C. remaining