In South Africa, wastewater disposal in the wine and distilling industry is undergoing a profound transformation as a result of fundamental changes in regulations and license requirements. To deal with this problem conventional Waste Stabilisation Ponding systems have been used by the industry together with irrigation and evaporation disposal practises. Although effective in the evaporation and containment disposal functions, these pond systems are generally not properly designed and/or managed, resulting in overloading and, at times, the generation of seriously offensive odour problems. Preliminary studies on the feasibility of utilising the Advanced Integrated Wastewater Ponding System as a core treatment technology in winery wastewater treatment were conducted. Results indicated that specific problems had to be addressed before successful ponding treatment could be achieved. This research programme undertook an investigation of the performance of a demonstration ponding system treating household sewage, which formed the basis of the research due to limited experience reported on ponds treating wine industry wastewaters. Malfunctions identified were in correlation with the preliminary winery waste ponding survey, which included unstable fermentation pit functions and inadequate nutrient removal. Retrofitting the fermentation pit with a nylon net across the rising water column resulted in improved retention of active anaerobic sludge, especially during periods of system start-up and/or organic overloading. An investigation into nutrient removal utilising algal biomass provided a valuable contribution towards development of an independent nutrient removal system. Harvested algal biomass was passively manipulated to release polysaccharides under anoxic conditions, with subsequent use as a carbon source by denitrifying organisms. Following denitrification, the still viable algal cells were introduced into a High Rate Algal Pond raceway for photosynthetically produced alkalinity. This high pH environment resulted in induced calcium phosphate mineral formation and subsequent precipitation, as well as effective ammonia stripping from the water. Based on the novel positive research outcomes a decision was made to proceed to the construction of a pilot-scale integrated ponding system treating wastewater from a wine lees factory. The system linked the Anaerobic Baffle Reactor, for pre-treatment, with the improved Advanced Integrated Wastewater Ponding System. The potential of this system has shown that a Waste Stabilisation Ponding system can be engineered to treat wine industry wastewaters and thereby effectively reduce the organic and nutrient loads, by using low-cost retrofitted upgrading unit operations. Valuable algal biomass may also be recovered as a by-product of the treatment process.

The hydrolysis of complex organic heteropolymers contained in municipal wastewater to simpler monomers by extracellular hydrolytic enzymes is generally considered the rate-limiting step of the biodegradation process. Previous studies of the Recycling Sludge Bed Reactor (RSBR) revealed that the hydrolysis of complex particulate organics, such as those contained in primary sludge (PS), was enhanced under anaerobic biosulphidogenic conditions. Although the mechanism was not fully understood, it appeared to involve the interaction of sulfide and sludge flocs. The current study was conducted using a 3500 ml laboratory-scale RSBR fed sieved PS at a loading rate of 0.5 kg COD/m³.day and an initial chemical oxygen demand (COD) to sulfate ratio (COD:SO₄) of 1:1. There was no significant accumulation of undigested sludge in the reactor over the 60-day experimental period and the quantity of SO₄ reduced indicated that the yield of soluble products from PS was at least as high as those reported previously for this system (> 50%). In the current study, the specific activities of a range of extracellular hydrolytic enzymes (L-alanine aminopeptidase, L-leucine aminopeptidase, arylsulphatase, α-glucosidase, β- glucosidase, protease and lipase) were monitored in a sulfide gradient within a biosulphidogenic RSBR. Data obtained indicated that the specific enzymatic activities increased with the depth of the RSBR and also correlated with a number of the physicochemical parameters including sulfide, alkalinity and sulfate. The activities of α- glucosidase and β-glucosidase were higher than that of the other enzymes studied. Lipase activity was relatively low and studies conducted on the enzyme-enzyme interaction using specific enzyme inhibitors indicated that lipases were probably being digested by the proteases. Further studies to determine the impact of sulfide on the enzymes, showed an increase in the enzyme activity with increasing sulfide concentration. Possible direct affects were investigated by looking for changes in the Michaelis constant (Km) and the maximal velocity (Vmax) of the crude enzymes with varying sulfide concentrations (250, 400 and 500 mg/l) using natural and synthetic substrates. The results showed no significant difference in both the Km and the Vmax for any of the hydrolytic enzymes except for the protease. The latter showed a statistically significant increase in the Km with increasing sulfide concentration. Although this indicated a direct interaction, this difference was not large enough to be of biochemical significance and was consequently not solely responsible for the enhanced hydrolysis observed in the RSBR. Investigation into the floc characteristics indicated that the biosulphidogenic RSBR flocs were generally small in size and became more dendritic with the depth of the RSBR. Based on the above data, the previously proposed descriptive models of enhanced hydrolysis of particulate organic matter in a biosulphidogenic RSBR has been revised. It is thought that the effect of sulfide on the hydrolysis step is primarily indirect and that the reduction in floc size and alteration of the floc shape to a more dendritic form is central to the success of the process.

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

Please read the abstract in the front section of this document / Dissertation (MSc (Microbiology))--University of Pretoria, 2006. / Microbiology and Plant Pathology / unrestricted

The culture of the floating aquatic plant, duckweed (Lemna minor), as an agent of domestic sewage treatment was studied in a clarification lagoon at Duncan, British Columbia, during the summer of 1986. Duckweed was grown in plastic fabric tanks (3700 L volume, 1.85 m deep, 2.25 m² water surface area) receiving 290 L of sewage per day or 12.8 d hydraulic retention time. Three treatments were tested: cropped duckweed, uncropped duckweed, and no duckweed. Water quality, plant growth and tissue composition were monitored on the basis of weekly sampling. Removals of VSS, COD, total-N and total-P were greater in the presence than in the absence of duckweed. Unmeasured imports of N and P masked the effect of plant uptake on reducing nutrient concentrations in the tank effluents. Sustainable duckweed yields were possible at both cropping rates, despite a severe infestation of aphids. Dry matter yields of 2.0 g/m².d and 6.4 g/m².d were obtained at the 15%/week and 50%/week cropping rates, respectively. Duckweed contained 6.1 - 6.4% N and 1.1 - 1.4% P (dry wt.). Plant harvest removed 0.14 g N/m².d and 0.03 g P/m².d at the 15%./week and 0.31 g N/m².d and 0.07 g P/m².d at the 50%/week cropping rates. Cropping increased the fraction of total-N and total-P loading that could be removed via plant uptake. Performance of the experimental treatments is analyzed in the light of concentration data, mass balances, and mass flux estimations. Possible sources of unmeasured N and P imports are discussed, and recommendations for future research are provided. The results suggest that duckweed may hold promise under certain conditions as a means of polishing sewage lagoon effluent. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

M.Sc. / Please refer to full text to view abstract

Ph.D. (Chemistry) / Phosphorus in the form of phosphate needs to be removed from the aqueous environment as it is primarily responsible for eutrophication of water bodies. In an attempt to limit the discharged of phosphorus into the aqueous environment, the phosphate discharge limits for wastewater treatment plants have been decreased. These limits are not easily or economically met by current phosphorus removal technologies. In addition phosphorus is a non-renewable resource. To ensure the ongoing quality of water bodies and security of food production it is vital that phosphate in water be removed and recovered. In order to address these issues, novel hybrid metal oxide ion exchange resins based on Fe(III), Cu(II), Mn(IV and Ti(IV) oxides have been prepared and their phosphate adsorption characteristics determined.

Made available in DSpace on 2017-06-01T18:20:38Z (GMT). No. of bitstreams: 1 dissertacao_ricardo_francisco.pdf: 1013747 bytes, checksum: 1378e1904be81342e7cf1b3a4c0a7516 (MD5) Previous issue date: 2007-12-01 / The objective of this study was to elaborate and to develop strategies for the design of a pilot plant of an Upflow Anaerobic Sludge Blanket - UASB. In the design of UASB type reactors, mainly those that deal with effluent of low concentration, the sizing is made by the hydraulical load criterion, and not for the organic load. In this case, the ascending velocity in the decantation and digestion compartments starts to be of basic importance higher velocities result in the loss of biomass of the system, reducing the process stability. As consequence, the height of the reactor must be reduced, increasing its transversal section, in order to guarantee the maintenance the upward velocity of the adequate ranges. In for the project of an UASB pilot reactor, with didactic purposes, the functions of each component of the reactor had been studied, identifying to them the necessary fluid dynamic characteristics to the good performance of the set. Simple mathematical models are presented to guarantee ranges of upward and sedimentation velocities of the liquid and solid phases, respectively. For the gaseous phase important operational parameters had been identified, mainly in the stages of start-up and shutdown. As one of the consequences of the study a computational program of sizing for a pilot UASB is presented in Matlab® language. The program is simple, interactive and provides simulation of hydraulical parameters of the reactor. With aid of support tools as pilot unit and of simulation program, it can be made forecasts of an operation adjusted for UASB reactors in commercial scale / O objetivo deste estudo foi elaborar e desenvolver estratégias para o projeto de uma planta piloto de um reator anaeróbico de fluxo ascendente (RAFA), também denominado reator anaeróbico de manta de lodo (UASB - Upflow Anaerobic Sludge Blanket). No projeto de reatores do tipo UASB, principalmente aqueles que tratam esgotos de baixa concentração, o dimensionamento é feito pelo critério de carga hidráulica, e não pela carga orgânica. Neste caso, a velocidade ascendente nos compartimentos de digestão e de decantação passa a ser de fundamental importância - velocidades excessivas resultam na perda de biomassa do sistema reduzindo a estabilidade do processo. Como conseqüência, a altura do reator deve ser reduzida, aumentando-se a sua seção transversal, a fim de garantir a manutenção das velocidades ascensionais dentro das faixas adequadas. Para o projeto de um reator UASB piloto, com finalidades didáticas, foram estudadas as funções de cada componente do reator, identificando-lhes as características fluidodinâmicas necessárias ao bom desempenho do conjunto. Apresentam-se modelos matemáticos simples para garantir faixas de velocidades ascencionais e de sedimentação das fases líquida e sólida, respectivamente. Como uma das conseqüências do estudo apresenta-se um programa computacional de dimensionamento para um UASB piloto em linguagem Matlab®. O programa é simples, interativo e proporciona estimativas de parâmetros de projeto do reator. Com auxílio de ferramentas de apoio do tipo unidade piloto e programa de simulação, pode-se fazer previsões das dimensões adequadas para UASB em escala comercial

Thesis (DTech (Chemistry))--Cape Peninsula University of Technology, 2016. / The use of ozone as an advanced oxidation process is gathering wide spread attention with the major limitation to its application being its cost of operation and design considerations. While the general approach of most researches is to buttress the already known fact of the efficacy of the process, little attention is given to studying the by-products of ozone reactions with organics. The aims of this study were to investigate the efficacy of the ozonation process for removing recalcitrant phenolics: phenol, 2-chlorophenol (2CP), 4-chlorophenol (4CP) and 2,4-dichloropheno (2,4DCP) from aqueous medium with a view of understanding various reaction pathways of the process and identifying possible intermediates and residual compounds using liquid chromatography-mass spectrometry (LC-MS). The choice of the selected chlorophenols would also elucidate the role of the positioning of the chlorine atoms in determining reaction rates, pathways and subsequent mechanisms and by-products. Sequel to this, oxy-hydroxy iron in β-phase (β-FeOOH, akaganite) and various β-FeOOH bonded composites on support metal oxides (Al2O3, NiO and TiO2) were prepared via hetero-junction joining, and explored as a possible promoter to improve the efficiency of the ozonation process. Apparent first order reaction rates constants of tested phenolics was in the order 2,4-DCP > 2-CP > Phenol > 4-CP, irrespective of the tested pH. The individual rates however increased with increasing pH. The position 4 chlorine atom was found to be least susceptible to hydroxylative dechlorination. Catechol intermediate and pathway was identified as the major degradation pathway for phenol and 2-CP, while 4-chlorocatechol pathways were more important for 4-CP and 2,4-DCP. The formation of polymeric dimers and trimers by all compounds was pronounced at alkaline pH. Heterogeneous catalytic ozonation using β-FeOOH reduced ozonation time for 4-CP by 32%. Mechanism for β-FeOOH/ozone catalysis showed that the catalyst suffered reductive dissolution in acidic pH and the kinetics of 4-CP removal using the catalyst was best described using a two stage kinetic model. The first stage was attributed to heterogeneous catalysis of ozone breakdown on β-FeOOH surface generating faster reacting radicals, while the second stage was due to homogeneous catalysis by reduced Fe2+ ions in solution. β-FeOOH stabilized on NiO at a 5% ratio exhibited superior catalytic property compared to the other tested composites. Characterization by high-resolution transmission electron microscopy (HRTEM) affirmed a β-FeOOH-NiO bonded interfaced composite which was stable as a iv catalyst over four (4) recycle runs. The mechanism of operation of the composite was via an increased ozone breakdown to radicals as monitored via photoluminescence experiments. The composite material produced satisfactory results when tested on real wastewater samples. Results from this study contribute to the current understanding on reaction mechanisms for ozone with phenols and chlorophenols, for the first time monitoring time captured intermediates via liquid chromatography-mass spectrometric method, which preserves the integrity of reaction intermediates. Also this study proposes heterogeneous catalysts; β-FeOOH and β-FeOOH bonded composites as possible improvements for simple ozone based water purification systems.

Biological nutrient removal (BNR) systems employ engineered biological processes—including nitrification, denitrification, and biological phosphorus removal—to remove nutrients from wastewater. Since their original implementation, BNR systems have adapted to challenges, such as the presence of inhibitory compounds and demands for more energy- and resource-efficient wastewater treatment. Advancements in alternative BNR technologies made in response to these demands have highlighted the metabolic versatility of microbial communities present in BNR systems. This versatility is also observed in the expanded capacity of BNR systems to remove not only human-derived carbon, but also complex trace organic emerging contaminants (ECs). Based on conventional monitoring alone, the roles of specific bacteria and metabolic mechanisms in the removal of nutrients and ECs remain unclear. A detailed understanding of the actors and mechanisms in BNR systems can be attained through application of molecular biology tools, including those targeting community (a) structure and potential function through DNA analysis and (b) extant function through RNA analysis. This dissertation encompasses three objectives, which seek to link detailed molecular-level information to the performance and metabolic versatility of several nutrient-removing communities. The first objective was to assess the utility of gene expression assays to indicate and predict nitrification inhibition by toxic heavy metals based on functional responses of nitrifying bacteria. Through this assessment, it was found that genes related to both catabolic and anabolic pathways could be used as indicators of nitrification inhibition. The second objective was to investigate the effects of reactor operating conditions on simultaneous nitrogen and phosphorus removal by examining the microbial community structure and metabolism of a survey of full-scale BNR systems. A variety of BNR configurations and operating conditions, all capable of sustained nutrient removal, selected for different nitrogen- and phosphorus-removing communities. The activity of these communities was also dependent on configuration and operating conditions, as indicated by analysis of gene expression. Finally, the third objective was to examine the expanded capacity of BNR systems to attenuate ECs by investigating the removal of the EC bisphenol A (BPA) by microbial communities involved in nutrient removal. Communities derived from both full-scale and lab-scale systems were capable of biodegrading BPA, though each community was uniquely influenced by reactor processes and BPA exposure conditions. Results from this work also offered insights into the utility of assessed genes as biomarkers for metabolic activity and the importance of accurately characterizing in-situ responses of BNR systems. In both lab-scale and full-scale studies, certain genes demonstrated increased sensitivity to nutrient-removing activity. At lab-scale, observed differences between inhibition of ammonia oxidation through discrete and continuous Cu(II) exposure indicated that conventional short-term, ex-situ batch assays may underestimate inhibition in a parent reactor of interest. The benefit of gene expression assays to accurately reflect in-situ responses was also examined in full-scale BNR systems removing both nitrogen and phosphorus. Findings from full-scale BNR systems revealed the long-term effects of changes to process configurations on microbial community structure and activity. Despite differences in operating conditions and the resulting nitrogen- and phosphorus-removing communities, a variety of configurations sustained nutrient removal. Long-term effects were also characterized in the context of EC removal. Differences in BPA degradation rates and microbial community profiles in lab-scale mixed culture communities after extended BPA exposure showed the lasting influence of both reactor processes and BPA exposure conditions. Assessment of microbial community structure was also used to identify BPA-degrading bacteria. Results from each of the three objectives could be used in the development of biomarkers to assess and predict (1) process upsets or inhibition, (2) nutrient removal process performance, or (3) capacity for EC removal. Integrating analysis of microbial community structure and function with reactor performance monitoring and mechanistic modeling that includes such advanced knowledge holds the potential to not only guide effective operation of BNR systems, but also identify opportunities for more efficient and even concomitant nitrogen, phosphorus, and EC removal.