Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains ix, 53 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 50-52).

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains viii, 84 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references (p. 65-69).

Thesis (doctoral)--University of Newcastle upon Tyne, 1997. / BLDSC reference no.: DX206801.

In the past, the response of microbial populations to anthropogenic disturbances was studied using conventional methods based on cultivation of microorganisms and on measurement of their metabolic activities (Fantroussi et al., 1999). However, these culturing methods often account for a small proportion of the total microbial community (Ibekwe and Kennedy, 1998; Hill et al., 2000). To overcome this, molecular techniques were developed and these allowed for the analyses of microorganisms in their natural habitats. Analysis of the 16S rRNA molecule and its corresponding gene (16S rDNA) has been the most widely used approach in the last decade (Amman et al., 1995). Although molecular techniques based on PCR have been used to eliminate the bias of culturing methods, they also have their drawbacks (Wintzingerode et al., 1997; Kirk et al., 2004). As another alternative, Garland and Mills (1991) developed a rapid community-level physiological approach to study microbial communities. The use of the community-level approach to microorganisms provided an accurate and meaningful measure of the heterotrophic microbial community by measuring the community’s metabolic abilities (Garland and Mills, 1991). Zak et al. (1994) used the method to study the functional diversity of microbial communities. The approach has been used to study the soil functional diversities in polluted or disturbed environments. Over the years, the application of gypsum in agriculture has received much attention. The gypsum has been used to ameliorate both acidic and alkali soils with elevated amounts of salinity (Suhayda et al., 1997; Sun et al., 2000). In these studies, the application of gypsum lead to changes in the soil chemical properties by causing a drastic increase in the amount of exchangeable calcium and sulphate and reduced the levels of exchangeable aluminium. It has been noted that high levels of aluminium and/or reduced amounts of calcium restrict root elongation and thus hindered the plants ability to access adequate water (Sun et al., 2000). Also, the replacement of sodium ions with calcium ions resulted in the flocculation of soil particles and improved the porous structure and water permeability of the soil (Suhayda et al., 1997). This study revealed that the application of the gypsiferous mine water did not have any negative impact on the bacterial communities. In fact, on average, the bacterial diversities were found to be higher in the gypsum-irrigated soils. This was most evident in pivot Major and Tweefontein, where the gypsum-irrigated soils were more diverse than the control soils. DGGE results from pivot Major and Tweefontein revealed a high level of bacterial diversity in gypsum-irrigated soils, as estimated by the number of dominant bands. Also, the number of heterotrophic bacteria in the gypsum-irrigated soils was one to two orders of magnitude higher than in the control soils. Principal component analysis performed on BIOLOG data showed that in both pivot Major and Tweefontein, the gypsum-irrigated soils were able to utilise a wider range of carbon sources as compared to their control counterparts. The bacterial communities in pivot Four appeared to be steady in both the gypsum-irrigated soils and the control soils. The number of visible DGGE bands was consistent between the gypsum-irrigated and the control soils. The heterotrophic bacterial counts in the gypsum-irrigated soils had an average of 273x106 cfu g-1 soil and those present in the control soils were slightly higher at 380x106 cfu g-1 soil. Principal component analysis revealed no differences in terms of substrate utilisation capabilities among the gypsum-irrigated soils and the control soils. All three techniques revealed no significant difference in community structures between soil profiles at 0-10 cm and 40-60 cm. The lack of difference could be attributed to the crops planted in all three pivots during sampling. The root system of Zea Maysplants enhanced microbial growth by exuding nutrients such as amino acids and sugars. In conclusion, the application of polyphasic approach proved successful in studying the response of soil bacterial communities to gypsiferous mine water. The use of both culture-dependent and culture-independent methods is recommended as the methods compensate each other’s limitations and therefore provide a more detailed description of the community. In this study, the application of gypsiferous mine water did not have an adverse effect on the soil bacterial communities. In fact, the addition of gypsiferous mine water seemed to ameliorate the soil bacterial communities. However, further comprehensive study is needed to determine the response of bacterial communities to gypsiferous mine water over longer periods of time. 16S rDNA sequencing and analysis of DGGE bands should also be done to identify the bacterial species present in the gypsum-irrigated samples. / Dissertation (MSc)--University of Pretoria, 2010. / Microbiology and Plant Pathology / unrestricted

Current mining methods used to extract coal from underground mine workings disturb the natural environment and the existing stable geological structures. As a result, the ingress of water into the mines increases and the quality of the water passing through the mine workings deteriorates, irrespective of the operational status of the mines. Water ingress is generated by regional aquifers, local aquifers, recharge from the surface through rainfall, natural drainage paths on the surface, and surface water bodies. The quality of water in the mines deteriorates as a result of contact with the remaining coal in the mine workings. Mining can therefore cause an increased influx of water into a mine and the degradation of this water. The solution to reducing the impact of mines on the environment is to prevent, or at least reduce, the amount of water entering the mines, and to manage this water to prevent further degradation in water quality. This study focused on afforestation with Eucalyptus viminalis trees to manage or inhibit ingress of water into underground mine workings. The hypothesis of this study was that a change in vegetation, from grassland to fast-growing and potentially high water-using trees like Eucalyptus. could possibly reduce the drainage of water below the root-zone and into the mine workings. The hypothesis was tested by estimating the components of the soil water balance for a grassland site and a Eucalyptus tree site. The research site was situated in Mpumalanga, (260 36' Sand 290 08' E, 1650 m a.m.s.l.), one of South Africa's major coal bearing areas. Although the Secunda area is a treeless environment and conditions are not optimal for forestry, some Eucalyptus species are suited for conditions (frost and periodic droughts) encountered in this area. The soil water balance of grassland and E. viminalis trees were studied through a field experiment and a long-term (30 years) modelling exercise. Total evaporation of the grassland site was estimated using the Bowen ratio energy balance technique. The transpiration of six representative E. viminalis trees were estimated using the heat pulse velocity technique. The soil water storage changes at both sites were determined from the soil water content, estimated using water content reflectometers. Measurements were performed in a smectic clay soil which resulted in measurements difficulties. Vertical cracks were formed under soil drying. To establish the importance of climate and plant growth on the drainage beyond the root-zone, the soil water balance of a grassland and an E. viminalis site were simulated over a 30-year period with the Soil Water Atmosphere Plant (SWAP) model. It was concluded from the comparative field experiment and modelling, that a change in vegetation from grassland to E. viminalis will reduce the drainage of water below the root-zone, especially under above-average rainfall conditions. The reduction in drainage beyond the root-zone at the E. viminalis sites, compared to the grassland site, was demonstrated in the modelling exercise and can be deduced from the total evaporation and soil water storage estimated at both sites. The results from the field experiment confirmed the modelling results and showed that usually there were higher transpiration rates for the E. viminalis tree site, compared to the grassland site. The higher transpiration rates for E. viminalis trees resulted in lower relative saturation of soil layers and lower profile soil water contents at the E. viminalis site, and higher daily soil water storage changes at the E. viminalis site compared to the grassland site. These differences were more pronounced during winter when the grassland was dormant. The results from the modelling exercise showed that an E. viminalis tree stand, with a closed canopy, reduced drainage below the root-zone compared to a grassland. The drainage at the grassland site contributed to up to 54 % of the rainfall, compared to the 43 % at the E. viminalis site. However, under below-average rainfall conditions the annual drainage at both sites, were similar. Further, the absolute magnitude of the drainage was similar to the total evaporation at the grassland site under certain conditions. The results not only suggest that a change in vegetation, from grassland to E. viminalis trees, would reduce the drainage beyond the root-zone, but that it may delay the onset of drainage. Under above-average rainfall conditions, the modelled drainage at the E. viminalis site only exceeded 20 mm, a month later than at the grassland site. The simulation results also showed that under conditions of aboveaverage rainfall, drainage occurs whenever the rainfall exceeds the long-term average rainfall, irrespective of the existing vegetation. However, when the rainfall is belowaverage drainage at both sites are limited to large rainfall events. This simulation showed that over a period of eight years, E. viminalis trees could potentially reduce the drainage by 1235 mm more than grassland, which is equivalent to 1540 m3 ha- I a-I, or 1.54 Me ha- I a-I. The annual average reduction in drainage below the root-zone caused by E. viminalis trees (1.79 Mf ha-1 a-\ is a small reduction when compared to the influx of water into mineworkings. E.g. the influx of water into a bord-and-pillar mine range between 0.5 and 4 Mt d-I per area mined and up to 17000 Mt d-I per area mined under high extraction mining (Hodgson and Krantz, 1998; Hodgson et aI., 2001). This work gave a comprehensive account of the differences in the soil water relations of grassland and E. viminalis trees overlying coal mine working. Few other studies in South Africa compared the total evaporation and soil water relations of grassland and E. viminalis trees in so much detail. State of the art monitoring techniques were used and produced valuable comparison of their use in expansive clay profiles. The work should contribute to management decisions focussed on limiting ingress of water into mine workings. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 2003.

Polluted waters, arising from extensive past and ongoing mining operations in South Africa, pose serious environmental threats to the limited fresh water resource. The long time periods, of decades to centuries, over which decanting mine waters may be expected to flow raises additional concerns about the sustainability of these resources. Responses to the problem have thus increasingly been directed towards the long-term sustainability of mine water treatment technologies (MWTT) as a critical indicator in both their research and development, and application. Bioprocess treatments have been considered in this regard and, among these, the Rhodes BioSURE Process has been investigated in preliminary studies using complex organic carbon wastes as the carbon source and electron donor for the central sulphate reduction unit operation. Although both the mining industry and the related statutory/regulatory authority in South Africa share public commitment to sustainability in the treatment of mine waters, no systematic mechanism has emerged to enable the application of sustainability thinking as a guiding principle in the selection and application of MWTTs, nor in the research and development undertaking. This study undertook the development of a Sustainability Indicator Framework in order to provide a systematic basis for the incorporation of sustainability objectives in MWTT bioprocess development, and specifically to use this framework as an input to the investigation of the scaleup development of the Rhodes BioSURE Process. In the development of the MWTT Sustainability Indicator Framework, an initial survey of industry thinking in this area was undertaken and, based on these outcomes, a detailed questionnaire methodology was developed in order to identify and quantify critical sustainability indicators. These included analysis of environmental, economic, social and technical indicators used in sustainability accounting practice in the industry. Statutory/regulatory sustainability targets in the same categories were derived from State of the Environment Reports (SoER) from Provincial authorities where mining is undertaken in South Africa. A synthesis of industry and SoER values was derived from weighted averages and the Sustainability Indicator Framework based on these outcomes. A Conceptual Decision-Support System, to guide the selection and development of MWTTs, was proposed and also based on these results. In the development of the Rhodes BioSURE Process the use of primary sludge (PS) had been investigated as a potential complex carbon and electron donor source. In this regard the utility operator, and sewage treatment process infrastructure, was identified as potentially meeting aspects of the sustainability objectives identified for MWTT application development. Both the Sustainability Indicator Framework and the Conceptual Decision-Support System provided inputs in the formulation of the experimental programme relating to the scale-up development of the Rhodes BioSURE Process. Based on these outcomes, a series of single- and multi-stage reactor configuration, optimisation and enzymology studies were undertaken at bench-, pilot- and technical-scale operations. These units were operated at hydraulic retention times (HRT) ranging between 22 to 72 hours and at chemical oxygen demand to sulphate ratios (COD:SO[subscript 4]) ranging between 1:1 to 2:1. Studies undertaken in fed-batch, bench-scale reactors confirmed the preliminary feasibility of using established sewage treatment infrastructure as a replacement for novel reactor configurations that had been used in the initial studies. The results further indicated that the hydrolysis of PS occurred at different rates under biosulphidogenic conditions in the different reactor configurations investigated. Scale-up of these findings in multi-stage pilot- (7.4m[superscript 3]) and technical-scale plants (680m[superscript 3]) showed comparable performances between the unit operations in terms of SO[subscript 4] and COD removal. These results indicated no apparent advantages in the uncoupling of hydrolysis and sulphate reduction in separate unit operations as had been suggested in previous studies. Scale-down/scale-up studies were undertaken in a continuously fed single-stage reactor configuration and showed that the process could be effectively operated in this way. Previous proposals that chemical and biological gradients established in the sludge bed of the Recycling Sludge Bed Reactor (RSBR) exercised an influence on the rates of substrate hydrolysis were investigated and the relative activity of α- and β-glucosidase and protease enzymes was measured. Results provided additional support for this hypothesis and it was shown that enzyme assay may also provide a useful tool in process development and monitoring studies. While sulphide recovery, following the sulphate reduction step in the BioSURE Process, was not investigated as a component of this study, the treatment of final effluent or waste spills was identified as an important sustainability requirement given the toxicity of sulphide to human and ecosystem environments. A conventional trickle filter reactor system was evaluated for this purpose and showed close to 100% oxidation to sulphate in a short contact time operating regime. Although residual COD removal was low at ~20% of influent, it is considered that high rate recycle biofilter operation could achieve the COD discharge standard of 75 mg/l. The results of the above studies provided inputs into the design, construction and commissioning of the first full-scale commercial application of the Rhodes BioSURE Process for mine wastewater treatment using sewage sludge as the carbon and electron donor source. An adjacent mine and sewage works have been linked by pipeline and an operational capacity of 10 Ml/day water treated has been established with sulphate reduced from ~1300mg/l to <200mg/l. These developments constitute a novel contribution in the mine waste water treatment field.

Please read the abstract in the section 00front of this document / Dissertation (MSc (Soil Science))--University of Pretoria, 2005. / Plant Production and Soil Science / unrestricted

No description available.

Thesis (M.Ing. (Electrical and Electronic Engineering))--North-West University, Potchefstroom Campus, 2007.

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xiii, 379 p. : ill. (some col.), maps (some col.). Vita. Includes abstract. Includes bibliographical references.