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Correction: Interior Photography of SewersSource: Sewage and Industrial Wastes, Vol. 30, No. 12 (Dec., 1958), p. 1495Published by: Water Environment FederationStable URL: http://www.jstor.org/stable/25033773 .
Accessed: 16/06/2014 04:56
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Vol. 30, No. 12 PREDACIOUS FUNGI 1495
after chlorination, one unit showed an
increase in effluent oxidized nitrogen. The remaining four showed a similar increase four days later. Apparently, chlorination resulted in a major de crease in the population of nitrifying organisms. Their slower regeneration period resulted in a much longer re
covery time than for other active or
ganisms.
Sludge Condition
Activated sludge effluents remained in poor condition during the chlorina tion period. Suspended solids ranged from 20 to 40 mg/1. Mixed liquor solids continued to decrease slowly.
Only one to two days were required after discontinuance of chlorination to obtain a clear effluent. Mixed liquor solids began a rapid rise about two
weeks after chlorination.
Effect on Nitrile-Consuming Organisms
Nitrile assimilation was undeter mined during the period of upset and
recovery because of the nitrogen im balance resulting from sludge destruc
tion. As soon as oxidized nitrogen in
the effluent exceeded nitrogen entering in sewage, nitrile nitrogen oxidation became evident, occurring in one test
unit during the second week after chlorination and, in the three remain
ing units, during the third week after chlorination.
It was apparent that nitrile-consum
ing organisms were not completely de
stroyed by the upset or by subsequent chlorination. Although up to 11 weeks
were required to acclimate a new
sludge to nitrile oxidation, all four test units were effectively metabolizing nitriles within three weeks after chlo rination.
Conclusions
Chlorine dosage used to correct the wild growth apparently was greater than necessary to accomplish the de sired effect. Fewer applications at a lower concentration probably would have destroyed the fungus without
seriously affecting nitrifying organ isms.
In Units 6 and 7, which were not
chlorinated, Zoophagus was still evi dent at a time when the chlorinated units were producing good effluents. The mold was disappearing slowly as if running out of food or because of the large increase in copepods. It is
likely that the population balance would have been restored eventually in the test units without treatment but
good effluents were obtained two to four weeks earlier in the chlorinated units.
Acknowledgment
Photomicrographs, at X 450, were taken by E. N. Bloomhuff.
Reference
1. Duddington, C. L., "The Predacious Fungi and Their Place in Microbial Ecol
ogy." Cambridge University Press, New York, N. Y. (1957).
CORRECTION
In the paper, "Interior Photography of Sewers" (This Journal, 29, 12, 1398; Dec. 1957), the text description on page 1403 referring to Figure 6 is in error in identifying the pipe in the photograph as
being made of vitrified clay. This is an interior photograph of a 36-yr old, 17-in. diameter, concrete pipe.
This content downloaded from 188.72.126.118 on Mon, 16 Jun 2014 04:56:52 AMAll use subject to JSTOR Terms and Conditions