M.S.

In nearly all chemical industries the problem of wastes is one of importance, and in any scientific study of waste disposal, the concept of the B.O.D. of the waste is vital. The B.O.D. is usually measured by an arbitrary standard test procedure, but may be determined by manometric measurement of the free oxygen utilized. In either case, the B.O.D. determination requires at least 24 hours. Since the free oxygen involved in the B.O.D. of a waste is utilized in metabolic processes of various microorganisms present, an increase in the number of microorganisms lowers the time required for oxidation of the wastes. In this investigation, the B.O.D. of several wastes was determined by measuring the change in the oxygen uptake of high concentrations of microorganisms because of the presence of the waste. These determinations involved a modification of the resting cell technic used in conjunction with direct Warburg technics. High concentrations of washed cells were prepared and small amounts of the waste added. A control was prepared with distilled water. The effects of waste concentration, bacterial concentration, and temperature were studied. The wastes studied included raw sewage, blowdown liquor and total mill wastes from a semichemical pulp mill, and effluent from an anaerobic, sewage-blowdown liquor digester. The concentrations of microorganisms used ranged from 3.4 to 17.0 milligrams of dry bacterial cells in a total volume of 2.5 milliliters of a 0.05 molar phosphate buffer at a pH of 6.8. The manometric B.O.D. was determined at 30°C. The manometric B.O.D. remained constant at 1,785 parts per million for 1:50 and 1:125 volumetric dilutions of the effluent. The manometric B.O.D. remained constant at 10,200 parts per million for volumetric dilutions ranging from 1:125 to 1:1000 for a sample of the blowdown liquor. The manometric B.O.D. of sewage, blowdown liquor, and mixtures of the two wastes was determined. The values obtained were compared with the standard five-day B.O.D. The manometric B.O.D. of the sewage and the blowdown liquor was 413 parts per million and 13,760 parts per million, respectively. The standard five-day B.O.D. of the sewage and the blowdown liquor was 495 parts per million and 37,800 parts per million, respectively. The manometric B.O.D. of 1:1 by volume mixture of the two wastes was 9,900 parts per million, while the standard five-day B.O.D. was 31,200 parts per million. / Master of Science

Low-grade pyrolusite manganese ore from the Paint Bank deposits of Virginia was prepared for flotation by grinding to different degrees of fineness. The coarsest size was a 28 Tyler Mesh and the finest was 100 Tyler mesh. Under size products of the grinding were as fine as minus 200 Tyler Mesh. Flotation tests were run on the ore in a Denver Sub-A Flotation Cell of 500 gram capacity. Each run was made with an amount of ore closely approximating this capacity. The flotation reagents were added in a definite order allowing three minutes between each addition. A conditioning period of fifteen minutes followed the addition of the reagents in each case. Crude tallol was tested as a collecting agent for the manganese dioxide in the ore, with auxiliary reagents. Runs were made varying the amounts of tallol, pine oil, frother, sodium silicate silica depressor, and the hydrogen ion concentration was varied with either sulphuric acid or hydrated lime. Crude oleic acid from tallol was also tested as a collecting agent for the manganese dioxide in the ore, with auxiliary reagents. Runs were made varying the amounts of crude oleic acid, sodium silicate depressor, and the hydrogen ion concentration was varied with either sulphuric acid or hydrated lime. Sulphonated tallol was also tested as a collecting agent, but the preliminary results did not seem to justify continuing with an extensive investigation. The grade of concentrate was fairly high but the yield of concentrate was less than two per cent of the original head sample. The crude oleic acid was found to be a better collector than the crude tallol, although neither one had much effect on the grade of the concentrate obtained. Sodium silicate had no beneficial action on the grade of concentrate, and with the crude oleic acid, it had a definitely deterrent effect. It was indicated that this was due to its coating the silica with a film of manganese dioxide, thus causing the silica to be collected as a particle of manganese dioxide. The sodium silicate was found to be useful in increasing the per cent recovery of concentrate. Pine oil, while not having any affect on the grade of concentrate, was effective in increasing the yield of concentrate. In general, an acid medium was found conducive to obtaining high grade concentrates, but this was more than offset by the low yields encountered. An alkaline medium was found to give the best overall recovery of the manganese dioxide. It was also indicated that the ore should be crushed through at least 35 mesh, and preferably 65 mesh, in order to obtain the greatest recovery. / Master of Science

M.S.

No description available.

No description available.

Phylogenetic hybridization and phenotypic fingerprinting were applied to the analysis of bacterial communities in wastewater treatment systems. These approaches were aimed at (i) developing monitoring tools able to foresee operational problems, and (ii) providing the rationale to optimize the operation of bioreactors. The work presented is intended to first describe the community found in two reactors treating pulp and paper mill effluent, and second evaluate the possibilities of these techniques with respect to the development of new monitoring tools. / Phylogenetic membrane hybridization showed that the bacterial communities were dominated by Alpha and Beta Proteobacteria, a structure probably linked to the low F:M ratio. Other important factors determining the community structure were the proportion of COD in the high molecular weight fraction, the sludge age, phosphate addition, and the concentration of specific compounds (alcohols, phenols, volatile fatty acids) in the influent. The community structure partly determined the sludge characteristics demonstrating its potential value in the assessment of reactor performance. The results obtained by phylogenetic membrane hybridization suggest that the probes used in a monitoring tool would not need to be targeted to the species level to provide relevant information. However, they also suggest that the technique is more sensitive to changes in population density as opposed to changes in bacterial metabolism. / Phenotypic fingerprinting measured a smaller difference between the communities of the two reactors studied than what was measured by phylogenetic membrane hybridization. However, differences in heterotrophic activities observed between the two communities were linked to differences in influent composition.

Sappi is one of the leading producer and supplier of Eucalyptus pulp to the world market. It is also a great contributor to South Africa economy in terms of employment opportunity to the rural people through its large plantation and export earnings. Pulp mills production of quality wood pulp is mainly affected by the supply of non uniform raw material namely Eucalyptus tree supply from various plantations. Improvement in quality of the pulp depends directly on the improvement on the quality of the raw materials. Knowing factors which affect the pulp quality is important for tree breeders. Thus, the main objective of this research is first to determine which of the anatomical, chemical and pulp properties of wood are significant factors that affect pulp properties namely viscosity, brightness and yield. Secondly the study will also investigate the effect of the difference in plantation location and site quality, trees age and species type difference on viscosity, brightness and yield of wood pulp. In order to meet the above mentioned objectives, data for this research was obtained from Sappi’s P186 trial and other two published reports from the Council for Scientific and Industrial Research (CSIR). Principal component analysis, cluster analysis, multiple regression analysis and multivariate linear regression analysis were used. These statistical analysis methods were used to carry out mean comparison of pulp quality measurements based on viscosity, brightness and yield of trees of different age, location, site quality and hybrid type and the results indicate that these four factors (age, location, site quality and hybrid type) and some anatomical and chemical measurements (fibre lumen diameter, kappa number, total hemicelluloses and total lignin) have significant effect on pulp quality measurements. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

The South African forestry industry has contributed significantly to the economic growth of the country by the planting of trees and the processing of these trees for the export market. With the increased demand for wood chips, the wood chip industry is concerned that the plantation resource that is currently available may not be adequate to fulfil the production required for future wood chip export. The purpose of this study is to examine the trends in wood chips exports from the Port of Durban and to examine the stability and growth of private pulpwood production in Southern KwaZulu-Natal. The forestry pulp and paper sector and its related downstream manufacturing enterprises is an important part of the KwaZulu-Natal economy. Eucalyptus and wattle timber are used to manufacture pulp and are exported in the form of wood chips. The Durban Wood Chipping facility is aimed at the export of wood chips from Durban to pulp and paper manufacturers in Japan. The methodology used in this study included questionnaires and semi-structured interviews that were held with the respondents involved in the forestry industry. A questionnaire was sent electronically to 119 participants being the total population of timber farmers that supply NCT Durban Wood Chips. A total of 33 respondents completed the questionnaire resulting in a 27.73% response rate. Three key personnel, with a strong forestry background, belonging to NCT Forestry Cooperative limited were selected as participants for the qualitative aspect of the study. The findings of the study showed that wood chips exports have increased from the Durban facility between 2006 and 2011. This came from recent research literature as well as data from NCT Durban Wood Chips (PTY) LTD. Dominant challenges faced by the farmers were land reform, transportation costs and municipal rates. Land claims, road infrastructure, economics (cost vs income) and demand for timber were the most challenging factors affecting private timber production into the future. The qualitative and quantitative results confirm that timber production is definitely increasing and hence contributing to stability of private pulpwood production in Southern KwaZulu-Natal. / Thesis (MBA)-University of KwaZulu-Natal, Westville, 2011.

Thesis (Ph.D.)--University of Waikato, 2007. / Title from PDF cover (viewed March 19, 2008) Includes bibliographical references (p. 99-118)