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 .

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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.

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