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Resultados 141-150 de 207
Oxygen consumption in continuous biological culture
1971
O'Brien, Walter J. | Burkhead, Carl E.
To aid in the further development of sewage treatment by activated sludge, a continuous flow automatically recording respirometer was used to study the response of aeration only and aeration with sludge return completely mixed activated sludge systems (CMAS) to step changes in the influent substrate. The experiments were conducted at 25 C with glucose; a mixture of glucose, glutamate, and acetate; and a mixture of sewage solids plus Metrecal. Influent substrate concentrations were doubled in the 3-hour and tripled in the 6-hour mean residence time aeration only experiments without increasing the soluble COD in the effluent. Decreases in the influent substrate concentrations produced rapid decreases in the rate of oxygen utilization. A procedure for calculating the rate of oxygen uptake by a CMAS system at any time during a step transient was developed.
Mostrar más [+] Menos [-]Acid mine drainage formation and abatement
1971
Nuclear techniques in environmental pollution
1971
Water quality control through flow augmentation
1971
Baker, David B. | Kramer, Jack W.
Sampling of glacial snow for pesticide analysis
1971
Stengle, Thomas R. | Lichtenberg, James J. | Houston, Charles S.
Snow samples were taken from the plateau glacier of Mt. Logan, Y.T., Canada during an investigation intent on demonstrating the feasibility of taking such samples from high altitude snowfields for pesticide analysis and developing sampling techniques devoid of contamination. Samples were also taken at a depth of 15 m to determine whether DDT concentration varied with the age of the snow. Pesticide analyses were performed using vapor phase chromatographic techniques. DDT was not detected within the limit of detectability (5 ng/l). Over half the samples were contaminated with PCB's which raised the detectability limit to 10-50 ng/1. The PCB contamination is believed to have come from the sampling auger, as an analysis of rinsings from it seemed to confirm. A sample taken from a depth of 1.5-2.5 m was acidified with distilled nitric acid, when thawed, and analyzed for 19 elements simultaleously using a direct reading emission spectrometer. Four elements were detected: boron at 4 ng/ml, cadmium at 9 ng/ml, chromium at 2 ng/ml, and iron at 47 ng/ml. The high levels of cadmium and especially iron suggest contamination from the alloy steels of the auger.
Mostrar más [+] Menos [-]Phosphorus removal and disposal from municipal wastewater
1971
Connell, Cecil H. (Cecil Hardee)
Environmental pollution by fluorides in Flathead National Forest and Glacier National Park
1971
Carlson, Clinton E. | Dewey, Jerald E.
State-of-art, sugarbeet processing waste treatment
1971
Fischer, James A. | Hungerford, Edward H.
Inorganic sulfur oxidation by iron-oxidizing bacteria
1971
Lundgren, Donald G. (Donald George)
Multi-system biological treatment of bleached kraft effluents
1971
