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Thesis (M.S.)—University of Nebraska—Lincoln, 1971. Department of Civil Engineering.


Copyright 1971, the author. Used by permission.


The results of this study show that alum applied to the aeration tank of a complete-mixing activated sludge systems operating near a pH of 7.5 is effective in approximately 90 percent P removal at an A1:P dosage of 1.5:1.

BOD removal is not significantly affected by addition of alum to the activated sludge unit.

Higher life forms are adversely affected by alum to the extent that nearly a complete absence of viable protozoa exist with alum concentrations in excess of 170 mg/l.It appears that flocculation by aluminum precipitates replaces the clarification role of protozoa in the settled effluent.

Domestic wastewater and a glucose-glutamic acid substrate behave essentially the same in regards to biological and chemical efficiencies under the operating conditions of this study.

Although settling rate of the mixed liquor suspended solids reduces slightly by increasing alum addition, the ability to settle is not significantly affected.

Influent alkalinity is not a valid parameter for calculating anticipated buffer residual in an alum treated activated sludge system. Effluent alkalinity of the untreated system should be used.

Advisor: Mark J. Hammer