Masters Theses


"The purpose of this investigation was to study the effects of nickel on the microbial population of activated sludge, to establish a relationship between effluent quality and changes in microbial population, and to determine the fate of nickel applied. Five one liter fill and draw activated sludge units were fed settled domestic sewage and received constant daily nickel doses of 1-10 mg/l, and a 50 mg/l slug dose applied after 27-30 days of operation. The parameters used were the chemical oxygen demand (COD) of the effluent and membrane filtered effluent, mixed liquor and effluent total suspended solids, mixed liquor volatile suspended solids, mixed liquor and effluent nickel concentrations, mixed liquor and effluent microbial counts, and mixed liquor oxygen uptake. It was found that nickel concentrations in the range of 1-10mg/l: (a) caused an increase in effluent COD resulting from the presence of a large amount of organic suspended solids; (b) increased the number of bacteria, both dead and viable, discharged in the effluent; (c) discouraged the growth of rotifers (except for the 1 mg/l dose) and free swimming ciliated protozoa and encouraged the growth of stalked protozoa. About one-half of the nickel introduced was lost in the effluent, while considerably more was released following the addition of a slug dose; this could account for the recovery of activated sludge from slug doses. The absence of free swimming protozoa appeared to be responsible for the deterioration of the effluent"--Abstract, page [i].


Grigoropoulos, Sotirios G.

Committee Member(s)

Wixson, Bobby G.
Siehr, Donald J.
Wulfman, David S., 1934-2013


Civil, Architectural and Environmental Engineering

Degree Name

M.S. in Civil Engineering


United States. Federal Water Pollution Control Administration


University of Missouri at Rolla

Publication Date



iv, 103 pages

Note about bibliography

Includes bibliographical references.


© 1967 Virgil Eugene Carr, All rights reserved.

Document Type

Thesis - Open Access

File Type




Subject Headings

Microbial populations
Nickel -- Environmental aspects
Sewage -- Purification -- Activated sludge process

Thesis Number

T 2014

Print OCLC #


Electronic OCLC #