A final cover on a waste impoundment is the main physical barrier between the waste impoundment and the environment designed to protect against physical, chemical and biological factors isolating the waste from the atmospheric environment. Since the early 1990‟s regulators in the United States have started accepting vegetation covers in lieu of the prescriptive covers. Currently in South Africa, data that provide field performance comparisons of alternative vegetation covers are few or non-existent; hence a research program was undertaken by an industrial corporation in South Africa to determine the potential use of vegetation covers. In proposing a practical way forward, the Company (AECI Limited) reached an understanding with the Regulators that a vegetated evapotranspiration (ET) cover, would be acceptable provided that its performance in limiting surface water infiltration (and subsequent leaching) could be quantitatively demonstrated. The overall object of this research was to determine the capability of vegetation cover to limit effluent leaching from a waste impoundment. Analysis of the following sub-objectives were required to address and give answers to this study (1) determine, as accurately as possible a climatic water balance on the vegetation covers, (2) determine the geohydrological properties of the material of the waste impoundment, (3) determine the fate of the water i.e. proportion reused via evapotranspiration as opposed to the proportion infiltrating the waste body beneath the root zone and (4) determine the leaching potential below the waste. The study identifies and evaluates the climatic (above ground) and geohydrological (sub-surface) parameters used to estimate the water balance of the materials for a waste impoundment. The study then utilizes these parameters at the respective sites in a finite-element model, called the HYDRUS-2D model, to simulate the water balance of the material. The simulated water balance results were then compared against collected field data, which provide the evidence of the efficiency of a vegetation cover to limit effluent from the impoundment. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

In the following study, the potential role that microorganisms play in the removal of Mn (II) and Fe (II) was assessed using biofilter sand and water samples collected from a biofiltration system (operated by Umgeni Water in KwaZulu-Natal, Nottingham Road, at the Nottingham combined school, South Africa) treating borehole water containing manganese and iron. Initially the presence of Mn (II) and Fe (II) oxidizing bacteria was demonstrated in the biofiltration system. Thereafter, the contribution of individual microorganisms to the overall removal of manganese and iron was assessed in the laboratory by determining the difference in metal oxidation in the presence and absence of active bacteria at neutral pH, simulating conditions in the biofilter. Controls were run to verify the elimination via physiochemical reactions occurring within the biofiltration system. Finally a diversity snapshot of the bacteria present within the biofilter matrix was established via analysis of a clone library. Viable bacterial counts for the biofiltration system were established using MSVP (minimal salts vitamins pyruvate) medium - plus added manganese sulfate or iron sulfate targeting Mn (II) and Fe (II) oxidizing bacteria - and R2A for heterotrophic bacteria. In the first experimental chapter, batch tests using MSVP were employed to determine manganese oxidation, by measuring the pH and ORP (oxidation reduction potential) in experimental flasks and controls over time. There was a clear drop in pH and a concomitant increase in ORP when an isolated manganese oxidizing strain (designated LB1) was grown in MSVP plus added manganese sulfate, indicating manganese oxidation. Based on physiological characteristics established by the VITEK-2 system as well as by 16S rRNA gene sequence analysis and MALDI-TOF (Matrix assisted laser desorption ionization-time of flight mass spectrometry) mass spectrometry of cell extracts, the isolate was identified as a member of the genus Acinetobacter. EDX (energy dispersive X-ray analysis) analysis of crystals formed in batch culture tests, containing MSVP plus either added manganese or iron sulfate, confirmed the ability of the isolate to oxidize both Mn (II) and Fe (II). The leucoberbelin blue colorimetric assay and batch tests using MSVP both demonstrated that in the presence of the isolated strain, Acinetobacter sp. LB1, the rate of Mn (II) oxidation at neutral pH was enhanced as compared to abiotic controls. In the second experimental chapter the difference in Fe (II) oxidation between biological and abiological systems at neutral pH was determined using batch tests run with Acinetobacter sp. LB1 and Fe (II) in saline. In addition, the rate of Fe (II) oxidation was also determined at acidic pH and at alkaline pH in experimental and control flasks. To determine Fe (II) removal under conditions simulating those in the biofiltration system, batch tests were set up using borehole water freshly collected from the biofiltration system. In order to verify the contribution of native microorganisms in the borehole water to Fe (II) oxidation, these flasks were spiked with bacterial strains isolated from the biofiltration system - Acinetobacter sp. LB1 and Burkholderia sp. strain LB2 - and two known iron oxidizing strains Leptothrix mobilis (DSM 10617) and Sphaerotilus natans (DSM 565) were used to determine the contribution of reference iron oxidizers to Fe (II) oxidation. A separate set of the same flasks with the addition of filter sand was used to qualitatively demonstrate iron oxidation as it would occur within the biofiltration system. The ferrozine assay was employed to quantify the amount of Fe (II) in batch tests employing saline medium and in batch tests employing borehole water. EDX analysis was employed to confirm the presence of Fe (II) in oxidation products in the batch test flask with filter sand spiked with Acinetobacter sp. LB1. In the presence of Acinetobacter sp. LB1 at neutral pH in saline medium, the rate of Fe (II) oxidation was very similar to that in the abiological controls thus demonstrating that the presence of metabolically active microorganisms does not per se enhance the oxidation of Fe (II) like in the case of Mn (II) at neutral pH. Surprisingly, in the heat inactivated control, apparently the highest amount of Fe (II) was oxidized. As expected, at acidic pH very little oxidation of Fe (II) took place and at alkaline pH almost all Fe (II) in the flasks was removed and small amounts oxidized as determined by the amount of Fe (III) produced. Batch tests using borehole water proved that native microorganisms within the biofiltration system were more efficient in the oxidative removal of Fe (II) from the system, in comparison to the reference iron oxidizing strains. In the final experimental chapter, the presence of biofilms with actively metabolizing cells was examined on a pooled sample of biofilter matrix from the manganese and iron filter using CLSM (confocal laser scanning microscopy) image analysis. DNA was extracted from the biofilm material associated with biofilter matrix to establish a diversity snapshot of the bacteria present within the biofilter matrix. ARDRA (amplified “rDNA” restriction analysis) analysis of the clone library revealed the presence of 15 unique OTU’s (operational taxonomic unit) based upon restriction patterns of amplified 16S rRNA genes of a total of 100 randomly selected clones. The majority of the clones were closely related to the genera Nitrospira and Lactococcus. Overall, 42% of the clones were assigned to the phylum Proteobacteria, 13% to the phylum Actinobacteria, 24% to the phylum Firmicutes and 21% to the phylum Nitrospirae. Overall, the results demonstrate that bacteria present within an established biofiltration system at neutral pH can contribute to the oxidative removal of Mn (II) and, apparently only to a smaller degree, to that of Fe (II) present in borehole water and that species within the proteobacterial genus Acinetobacter are potentially involved in the geochemical cycling of these two metals. Keywords: Biofiltration, iron and manganese oxidation, Acinetobacter sp. LB1, batch tests, 16S rRNA, MALDI-TOF MS analysis, Mn (II) and Fe (II) colorimetric assays, EDX analysis, biofilm formation, CLSM image analysis, 16S rRNA clone library Abbreviations: MSVP (minimal salts vitamins pyruvate), ORP (oxidation reduction potential), EDX (energy dispersive X-ray analysis), MALDI-TOF MS (Matrix assisted laser desorption ionization-time of flight mass spectrometry), rRNA (ribosomal RNA), ARDRA (amplified “rDNA” restriction analysis), CLSM (confocal laser scanning microscopy), OTU (operational taxonomic unit) / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

Since the United States Environmental Protection Agency (USEPA) began requiring landfills to implement a leachate collection system in 1991, the proper disposal of leachate has become a growing concern. The potential toxicity of landfill leachate will contaminate groundwater and soil if not managed properly. Research has been made in efforts to manage leachate in a cost-effective, single treatment process. Photocatalytic oxidation is an advanced oxidation process (AOP) which has shown ability to reduce toxicity of an array of leachate constituents including organics, inorganics and heavy metals. The purpose of this manuscript is to scale up the batch scale study of TiO2 photocatalytic degradation of leachate utilizing a pilot scale falling film reactor. In this research project, the use of UV/TiO2 for the removal of chemical oxygen demand (COD), ammonia, alkalinity and color will be studied in order to optimize catalyst dosage, determine pH effects and reaction kinetics and develop preliminary cost estimates. / by Frank Youngman. / Thesis (M.S.C.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnology, Durban University of Technology, 2007 xxi, 117 leaves / The aromatic compounds Polychlorinated Biphenyls (PCBs) are one of the largest groups of environmental pollutants. The greatest concern is the release of PCBs in the water systems by industrial effluent, accidental spillages or leaks. PCBs are able to bioaccumulate in the fatty tissues of animals, fish and humans. The impact on human health due to PCBs has prompted interest in their degradation. The application of microbial degradation of PCBs can transform many PCB metabolites. There are a wide variety of microorganisms that can degrade PCBs or utilise them as sole carbon sources. This study focused on isolating microrganisms from industrial wastewater capable of aerobic degradation of PCBs. The degradation potential of the selected isolates were investigated by using different analytical techniques viz. ultra violet or visible spectrophotometer (UV/Vis), thin layer chromatography (TLC) and gas chromatography electron capture detector (GC-ECD).

Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnology, Durban University of Technology, 2007 xxi, 117 leaves / The aromatic compounds Polychlorinated Biphenyls (PCBs) are one of the largest groups of environmental pollutants. The greatest concern is the release of PCBs in the water systems by industrial effluent, accidental spillages or leaks. PCBs are able to bioaccumulate in the fatty tissues of animals, fish and humans. The impact on human health due to PCBs has prompted interest in their degradation. The application of microbial degradation of PCBs can transform many PCB metabolites. There are a wide variety of microorganisms that can degrade PCBs or utilise them as sole carbon sources. This study focused on isolating microrganisms from industrial wastewater capable of aerobic degradation of PCBs. The degradation potential of the selected isolates were investigated by using different analytical techniques viz. ultra violet or visible spectrophotometer (UV/Vis), thin layer chromatography (TLC) and gas chromatography electron capture detector (GC-ECD).

The objective of this research was to determine if mature landfill leachate could be treated to a level so that it was safe to discharge to the environment. The treatment method was an Advanced Oxidation Process. The process utilized Titanium Dioxide and UV. Three different reactor types were used, falling film, flow through and falling film + Electron Magnetic Oxygen Hydrogen (EMOH). To improve removal pre-treatment with titanium dioxide settling were conducted in conjunction with treatment in a reactor. The best removal was obtained with pre-treatment with titanium dioxide settling, followed by the falling film + EMOH reactor. In 8 hours, removal was 63% for COD, 53% for ammonia, 73% for alkalinity and 98% for calcium hardness. The kinetics found in this experiment show that full treatment times for safe discharge vary between contaminates. For complete removal of all tested contaminates to safe discharge regulations requires 185 hour of treatment. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

Most waste generated in South Africa is sent to landfills for disposal, and although it is confined in specific areas, it can potentially affect both above and below ground water resources, impacting environmental and public health. This is particularly relevant in a country where water supplies are limited and groundwater resources are prone to pollution. The primary objective of this study was to assess the performance of an upflow packed-bed bioreactor purposedesigned for the treatment of leachates produced by landfills in the Durban Metropolitan Area (DMA). The effect of parameters such as the nature of the biofilm support matrix, aeration rate and recycle rate on the efficacy of the system were investigated. Another major aim of the project was to develop a low maintenance technology that could, nonetheless, bioremediate leachate effectively at minimum cost. This aspect of process design is a crucial factor in areas where there is a shortage of both funds and skilled labour. The glass 132 l packed-bed upflow bioreactor was evaluated by measuring its efficiency in terms of chemical oxygen demand (COD) and biological oxygen demand (BOD) reduction and ammonia removal. The bioreactor could be configured as a batch-type system, which was useful for comparing operating conditions; or as a continuous cascade system, which was used to assess its overall performance. Different biofilm support matrices viz. various grades of pine bark, plastic bioballs and ceramic noodles were evaluated in 22 l batch-type reactors. Leachates from five landfill sites were remediated during the course of the study, and only the leachate from Shongweni landfill, which had a remarkably low BOD:COD ratio (0.05), was intractable and could not be successfully treated; even in flask trials designed to test strategies such as augmentation of microflora and biostimulation. The other leachates investigated were from the Umlazi, Marianhill, Bisarsar Road (all general sites) and Bul-Bul Drive (a semi-hazardous site) landfills, all of which were remediated to some degree. Originally, leachate from the Umlazi landfill site was used, but it became unavailable when the site closed enforcing the use of other leachates for the remainder of the investigation. Leachates from Marianhill, Bisarsar Road and Bul-Bul Drive were treated simultaneously in duplicate operating the six-chambered bioreactor in the batchtype configuration. The highest COD removal efficiency (49 %) was obtained in the chambers treating the Bul-Bul Drive leachate, which was therefore used for further investigations. This leachate had the highest BOD:COD ratio and was therefore expected to be the most suited to biological remediation. The bioreactor performed best when plastic bioballs were used as biofilm support matrix with a relatively low level of aeration, although the uncomposted form of pine bark was used initially as the support matrix because it is inexpensive and readily available in South Africa. However, although satisfactory COD reduction (30 – 61 %) and ammonia removal (87 – 98 %) was achieved when the Umlazi leachate was treated, the possibility of compounds leaching out of the bark and affecting the quality of the treated leachate was a concern. Also, pine bark would be prone to mechanical degradation in a full scale operation. Of the other solid support matrices tested using the Bul-Bul leachate, COD removal efficiencies were superior with plastic bioballs (60 %) than with pine bark chips (29 %). The former therefore became the preferred biofilm support matrix. Aeration level did influence bioremediation of the Umlazi landfill leachate since those chambers aerated with an aquarium pump (0.05 – 0.1 litres air/litre leachate/min; 60 % COD removal) performed better than those aerated with a blower (0.6 -0.7 litres air/litre leachate/min; 42 % COD removal) and those that remained unaerated (44 % COD removal). Recycle rate did not significantly affect bioremediation, but the performance of the system was higher when operated in batch mode (up to 60 % influent COD removal), rather than in continuous flow-through (cascade) mode when only 37 % of the influent COD in the Bul-Bul leachate was removed. Under the latter conditions, most of the reduction occurred in the first four chambers and very little biodegradation occurred in the final two chambers. The cascade-mode will require some refinement to enhance the COD removal efficiencies achieved. However, it did eliminate 89 % of the BOD present in the raw leachate, producing a treated effluent with a consistent BOD:COD ratio of 0.05. The COD removal efficiencies achieved covered a wide range from a minimum of 23 % with Marianhill leachate to a maximum of 63 % with leachate from Bul-Bul Drive. These results are comparable with many of those reported by other authors treating landfill leachate. Up to 98 % of the ammonia was removed when the Umlazi leachate was treated. However, ammonia removal from the other leachates tested was erratic. Although the treated leachate from this system could not be released into the environment without further remediation, the reduction in concentration of pollutants would allow its return to the local water supply via a wastewater treatment plant. This was achieved without temperature and pH regulation or addition of extraneous nutrient sources. A cost-effective, low maintenance technology such as this one would be a useful tool for the treatment of effluents such as landfill leachate in countries like South Africa where although water conservation is urgently required, resources for highly sophisticated effluent remediation are often not readily available. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

PhD. (Department of Chemical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / The use of solar photocatalysis for the treatment of aromatic chemicals like phenol in wastewater has attracted significant attention due to the low cost of sunlight. However, sunlight is unreliable since its intensity fluctuates during the day. This drawback can be addressed by supplementing sunlight with artificial UV lamps when the solar intensity reduces. In this work, such a hybrid solar/UV lamp reactor, internally illuminated by the UV lamp and externally by sunlight, was designed. Phenol was used as the model pollutant and the nanophase Aeroxide P25 TiO2 was employed as the photocatalyst and fluidized by compressed air. The catalyst and bubble distribution in the reactor was analysed using computational fluid dynamics (CFD) while the Monte Carlo (MC) method was used to model the light distribution and reaction kinetics. Finally, a lamp controller was designed to specify the required UV lamp output as a function of the solar intensity. The CFD simulation using ANSYS CFX 17 showed that a fairly homogeneous distribution of the catalyst was achieved in the reactor. Consequently, accurate simulations of the light distribution could be achieved without considering the hydrodynamics. The MC models revealed that bubbles did not significantly influence light absorption at the optimum catalyst loading. This showed that air was a good medium for fluidization as it could provide good mixing and oxygen electron acceptor without negatively affecting light absorption. The forward scattering behaviour of the P25 TiO2 and the increase in light attenuation with catalyst loading was confirmed in this work. The optimum catalyst loading in the different reactor configurations was 0.15 g/L (tubular solar), 0.2 g/L (annular solar), 0.4 g/L (annular UV lamp), and 0.4 g/L (hybrid light). This resulted in experimental reaction rates of 0.337 mgL-1min-1 (tubular solar), 0.584 mgL-1min-1 (annular UV lamp), and 0.93 mgL-1min-1 (hybrid light). An analysis of the local volumetric rate of energy absorption (LVREA) and reaction rate profiles along the radial coordinate showed a non-uniformity which worsened with an increase in catalyst loading. The reaction order with respect to the volumetric rate of energy absorption (VREA) indicated that solar illumination resulted in a higher electron-hole recombination as compared to UV illumination. This, combined with the higher intensity of the UV lamp, resulted in a higher reaction rate under UV light as compared to sunlight, demonstrating that the UV lamp could be used to supplement sunlight. For a typical sunny day, a lamp controller was designed that could adjust the UV lamp output as a function of the solar intensity to maintain the reaction rate at a reference level while ensuring less energy consumption than an ON/OFF lamp controller. This work demonstrated the feasibility of hybrid solar/UV lamp photocatalysis reactor which could maintain the advantages of solar photocatalysis while mitigating its drawbacks.