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Browsing by Author "Parsons, William A."

Now showing 1 - 11 of 11
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    Bacterial coagulation by a chlorinated solvent
    Blackwell, Richard Lee (Virginia Tech, 1965-08-02)
    This investigation has led to the following conclusions: 1. Good removals of most bacterial species were observed. 2. Increased length of settling time increased the percent removal of pure cultures. 3. The solvent coagulation process worked best at a pH very near the pH produced by the bacteria during growth. 4. There was no advantage in changing from room temperature. S. proper surface active agents aided in the coagulation of bacteria in the solvent ooagulation process. 6. Almost all of the bacteria in suspension after the coagulation process were not viable. 7. Good removals were observed using the solvent coagulation process on mixed cultures. 8. The chlorinated solvent coagulation process shows promise for commercial operations.
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    Crystal seeding for the control of sludge properties
    Judkins, Joseph F., Jr. (Virginia Tech, 1964-10-15)
    The object of this investigation was to determine, by the concept of specific resistance, the effect of certain variables on the filterability of calcium sulfate sludge resulting from lime neutralization of synthetic, return sludge seeded, sulfuric acid samples, The variables investigated were rate of mixing, rate of lime addition, degree of neutralization, return sludge loadings and acid concentration. Mixing rate and lime addition rate are factors effecting the characteristics and filterability of calcium sulfate sludge. Slow lime addition provided a more effective return sludge than did rapid lime addition. Slow sample mixing produced a more filterable sludge than did rapid mixing for a given lime addition rate. The degree of sample neutralization appeared to have only a minor effect on the filterability of the sludge, with the filter ability improving as the final pH of the sample decreased. The sample return sludge dosage appeared to have only a minor effect on the filterability of the resulting sludge with filterability decreasing as return sludge loadings increased. A complete evaluation of the effect of return sludge loading cannot be made, however, until these studies are expanded to include the optimum return sludge loading for the given acid-lime system. The values of specific resistance obtained were influenced by the resistance of the filter paper. For samples with similar dry solids concentration the effect is approximately the same; however, the amount of filter paper interference decrease with increased sample dry solids concentration. For varying acid concentrations there was a minor decrease in specific resistance as the acid concentration, and dry solids concentration, of the samples increased. This decrease was thought to be due to decreasing amounts of filter paper interference rather than improved sludge filterability.
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    The effect of bioxidation on the coagulation of dispersed color
    Laing, Gary Thomas (Virginia Tech, 1967-08-15)
    This thesis shows how the first plan of the Air War Plans Division (AWPD-l) became the most important document in the development of American strategic bombing doctrine in World War II. This plan was not only the first in the Air War Plans Division. but it was the first of its kind in the world. Beyond the history and importance of the plan itself, this study testifies to the success of a handful of dedicated airmen who believed in the power of a strong air force. General Henry H. Arnold deserves tribute for having had the wisdom and foresight to pick a former Air Corps Tactical School (ACTS) instructor to head the AWPD. Finally, the unofficial acceptance of AWPD-l was a triumph for the ACTS itself. Significantly, all four officers ultimately responsible for completing A WPD-l had been instructors at the ACTS.
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    Effect of pH on the denitrification of activated sludge effluent at high oxygen tensions
    Bugg, John Cline (Virginia Tech, 1965-08-05)
    In the recent past more and more attention has been given by sanitary engineers to the problem of nitrogen removal in sewage treatment. This attention is brought about by several problems associated with nitrogen. First, in some locations, such as our southwest United States, there is both an essentially constant supply of water and an increasing demand for water. This calls for water recycling. or reuse, as a means of meeting the demand for potable water. An accumulation of impurities, such as compounds of nitrogen, can limit the recycling of water. One such substance is nitrate nitrogen, which when in excess of ten parts per million can cause the disease methemo-globinemia in bottle-fed infants.
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    An investigation on the removal of escherichia coli by ion exchange resins
    Blair, Thomas Jackson (Virginia Tech, 1957-03-05)
    The purpose of this study was to evaluate the ability of typical cation and anion exchange resins to remove Escherichia coli from water. The objective was to obtain a method of purifying slightly polluted, private well water supplies. The investigation consisted of passing water samples, inoculated with known concentrations of Escherichia coli, through resin columns of known volumes. The resins were subjected to varying Escherichia coli concentrations and cycles of regeneration. The results indicated the anion exchange resin, Amberlite IRA-400, possessed the highest potential for removing Escherichia coli.
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    Lime Stabilization of a Virginia Clay Soil
    Barney, Syed Ishratali (Virginia Tech, 1962)
    The fact that when lime is added to clayey soils same very beneficial results are produced dates back into the remote past. It is not a new development, In the United States lime has been in use since l923. The objective of this study was to determine the effect of increasing soaking time of soil-lime mixtures on the strength, swell potential, and degree of saturation. In order to ascertain the exact composition of clay minerals, X-ray diffraction analysis was run on the soil sample. The analysis showed that the clayey soil contained a large amount of water with a greater percentage of halloysite minerals. The soil, it was concluded, was poorly crystalline and was found to be midway between montmorillonite and kaolinite group.
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    Lime treatment for removal of phosphate from digester supernatant liquor
    Parsons, William A.; Yeh, Hsin Hsing, 1941-; Glennon, James Michael, 1943- (Water Resources Research Center, Virginia Polytechnic Institute, 1967)
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    Mica stabilization with lime, portland cement and lime-calcium carbonate
    Hsieh, Tai-Chou (Virginia Tech, 1964-02-05)
    Research was conducted to study the unconfined compressive strength of a mica soil stabilized with various percentages of lime, Portland cement, and combinations of calcium hydroxide and calcium carbonate. In order to trace the calcium carbonate and calcium hydroxide in the stabilized soil, x-ray diffraction analyses, differential thermal analysis, and thermagravimetric analyses were made. Results show the appearance of calcium carbonate and absence of calcium hydroxide.
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    Removal of microorganisms and proteins from sewage and industrial waste with chlorinated solvents
    Dawson, Herbert Maxwell (Virginia Tech, 1962-08-15)
    Very few sewage and industrial waste treatment effluents are free from microorganisms and proteins. Such discharges require further treatment by the receiving stream and consequently lower stream quality. The object of this investigation was to evaluate chlorinated solvent processes for the removal of microorganisms, proteins, and other substances from sewage and other wastes. Six different chlorinated solvents were added to different waste samples in the ratio (by volume) of five percent solvent and 95 percent waste, mixed and allowed to settle for a specified period of time. The efficiency of the solvent extraction process was evaluated in terms of reduction of suspended solids, biochemical oxygen demand, and by increased weight of residue separable by sedimentation. The results showed that the process produced the following effects on settled sewage. Suspended solids were reduced by 85 percent, the weight of residue separable by sedimentation was increased 33 percent, and the biochemical oxygen demand was reduced 49 percent. The process was less effective for the treatment of raw sewage, trickling filter effluent, sewage lagoon effluent, or for separation of activated sludge. The variables investigated were temperature, pH and the solvent waste system. Temperature and pH appeared to have negligible effects on the extraction efficiency. The solvents employed were; chloroform, ethylene dichloride, chlorobenzene, carbon tetrachloride, trichloroethane, and dichloroisopropyl ether. Solvents with low vapor pressures and wastes with low concentrations of suspended solids appeared to be the most efficient system. The addition of 20 percent of butanol (by weight) to trichloroethane appeared to increase the extraction efficiency of trichloroethane. Bacterial counts made indicated that the solvent extraction process was affecting better than 90 percent removal of microorganisms from the waste samples. More research will be needed to completely evaluate chlorinated solvent processes for the removal of microorganisms, proteins, and other substances from sewage and other wastes.
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    Resolving bacteria with the coulter counter
    Jacobson, Ronald Leslie (Virginia Tech, 1964-08-05)
    Present methods of counting and sizing of bacteria arc usually tedious and often have low statistical validity. The objective of this thesis was to investigate the feasibility of counting and sizing of bacteria with the Coulter Counter and to evaluate orifices which were prepared in this laboratory. Size distributions of Pasteurella multocida and Proteus vulgaris were obtained with the electronic particle counter. These distributions appeared to follow the normal distribution when relative per cent was plotted against diameter, The two modes of the distributions appeared far enough apart to warrant future attempts to separate quantitatively P. vulgaris and P. multocida in mixed suspensions. Size distributions also were obtained for Staphylococcus epidermidis, Sarcina lutea, and Azotobacter. Many variables appeared to be inherent in the electronic particle method of counting biological cells; among these are the biological cells, diluent, and electronic circuitry. Apparently the variability in the electronic circuitry caused the calibration of laboratory orifices to be impossible according to conventional methods.
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    Some mineralogical and physical interpretations of the free- swelling characteristics of montmorillonite-water systems
    Fink, Dwayne Harold (Virginia Tech, 1965-06-15)
    Free-swelling properties of montmorillonites in water systems were studied using X-ray diffraction techniques. Four specimen type montmorillonites (Wyoming bentonite, Otay bentonite, hectorite and nontronite) and several soil clays were selected. In Phase I of the study the differential swelling properties were related to the type of cation on the exchange complex and to variations in the mineralogical properties of the montmorillonites.