The Aeration of Activated Sludge Mixtures

Citation

Okun, Daniel Alexander and Bonell, John Arthur (1938) The Aeration of Activated Sludge Mixtures. Master's thesis, California Institute of Technology. doi:10.7907/9g8w-eq70. https://resolver.caltech.edu/CaltechTHESIS:07182023-191820603

Abstract

The purpose of this investigation is to establish, to the extent possible, the effect of degree aeration on several characteristics of a sewage-sludge mixture: principally, the oxygen utilization by an activated sludge after varying periods of aeration, with varying amounts of air supplied; and secondly, the effect of aeration periods of activated sludges on clarification and dissolved oxygen content.

The work was performed at the Tri-City Sewage Treatment Plant, in Alhambra, California (commonly referred to as the Pasadena Sewage Treatment Plant). Tests were run on samples taken from the new aeration and clarification unit used in conjunction with the original activated sludge plant. These tests were made in the laboratory of the plant.

Tests were begun in January, 1938 and continued until May, 1938, with one interruption, that caused by the floods of early March. The operation of the plant was affected considerably by this flood, and normalcy was not restored until the middle of May. However, the school year necessitated the termination of testing in early May.

Unlike most experimental work, the time the tests are performed is in the case of tests run on actual sewage flows extremely important. Early morning flows are small and weak, rising sharply during later morning hours in both quantity of flow and strength of sewage. But due to the exigencies of scheduled work at the Institute, it was not possible to be at the plant at the requisite hours regularly. There were several occasions where we deemed it necessary to run our tests for twelve consecutive hours, but these were seldom possible. The effect of the change in flow and strength, together with other time factors are treated later in the paper.

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