Activated sludge systems are the most widely used biological wastewater treatment processes all over the world. The main working principles of an activated sludge system are the oxidation of biologically degradable wastes by microorganisms and the subsequent separation of the newly formed biomass from the treated effluent. Separation by settling is the most troublesome stage of an activated sludge process. A decrease in the efficiency of the separation of microbial biomass from the treated effluent causes a decrease in the overall efficiency of the treatment plant. The efficiency of the separation process is related to the bioflocculation, which can be briefly defined as the aggregation of the bacteria into flocs through flocculation. Bioflocculation depends on the extracellular polymers (EPS) that are produced by microorganisms. The operating conditions of the activated sludge system is a key determinant of the synthesis of EPS and bioflocculation. The main objective of this study is to find out the effect of magnesium ions on the bioflocculation process under phosphorus deficient and sufficient conditions. In order to achieve this aim, the effects of magnesium ion in 4 different concentrations (0.9, 5, 10 and 20 meq/L) are investigated in semi continuous reactors. The reactors are operated at a mean cell residence time of 8 days and 20&ordm / C temperature. When reactors are confirmed to be at steady state, several sets of analysis are conducted. In particular, the surface chemical parameters including EPS and its components, electrical charge, and hydrophobicity as well as physical properties such as settlability, filterability, viscosity, floc strength, and turbidity are examined. It has been understood that phosphorus deficiency causes severe filamentous bulking under magnesium rich conditions. Increasing the phosphorus concentration in the influent can cure this problem. After the sludges are cured some granular structures were observed in the microscopic investigations and they are thought to be polyphosphate granules in which microorganisms tend to accumulate phosphorus when they find the adequate source after a starvation period. To consider the reactors operated at phosphate present conditions, it has been found that EPS increases with increasing influent magnesium concentration. However, protein type EPS (EPSP) exhibits a sharper increase when compared to the carbohydrate type EPS (EPSC) indicating the selective attitude of magnesium ions to protein type of polymers. It has been understood that the increase in the influent magnesium concentration results in an increase in dewaterability and zone settling velocity, and a decrease in the viscosity. Hydrophobicity was found to exhibit a maximum value at 10 meq/L magnesium fed sludge and then it dropped back. Surface charge values also made a minimum at 10 meq/L reactor and then no change occurred at the increase of the magnesium concentration to 20 meq/L. Finally, COD values were found to increase with the increasing magnesium concentration due to the increasing EPS.

Submitted by Rosangela Silva (rosangela.silva3@unioeste.br) on 2018-06-04T12:54:41Z No. of bitstreams: 2 Maico Chiarelotto.pdf: 2629121 bytes, checksum: 037737b1c57a75a63919895d3bb0c89e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-06-04T12:54:41Z (GMT). No. of bitstreams: 2 Maico Chiarelotto.pdf: 2629121 bytes, checksum: 037737b1c57a75a63919895d3bb0c89e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-02-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The composting of agro-industrial waste from the production broiler helps minimizing the environmental, economic, and social impacts caused by such waste. In addition, the final product is an organic compost which can be used in vegetable production. The reduction of the time of stabilization of this waste is linked to the optimization of the conduction of the composting process, through the control and monitoring of physical-chemical parameters and the use of residues of urban tree trimmings, as bulking agent and carbon source. The reduction of composting time can consequently lead to a reduction in production costs, reducing the area required at the plant, as well as lower costs with fuel and labor. Therefore, the objective of this study was to determine the effects of the reduction of composting time on the main process control parameters and on the variables of interest for the agricultural use of the organic compost. The times of the stabilization process evaluated were 35, 63, and 95 days. The effects of time reduction, as well as the quality of the final compost in the stages of stabilization, maturation, and storage, were determined by the following parameters: reduction of mass, volume and organic matter, temperature, pH, EC, losses of N, P, and K, CEC, CEC:TOC ratio, carbon, phosphorus, potassium and soluble polyphenols, and FTIR. With the aid of the statistical techniques of comparison of averages and analysis of main principal components, it was possible to infer about the feasibility of the production of organic compost stable in 35 days of process, presenting CEC of 55.6 cmol kg-1, soluble carbon of 1.00 % and germination index of 140.9%. In addition, the characteristics of the final composition obtained at the 35-day process, are in accordance with the requirements defined by the Brazilian Ministry of Agriculture Livestock and Supply. It was concluded that the reduction of the stabilization time to 35 did not adversely affect the control parameters of the agroindustrial waste degradation process. All the organic compost produced in 35, 63, and 95 days of process presented characteristics of stabilized compost, being suitable for agricultural use. / A compostagem de resíduos agroindustriais provenientes da cadeia produtiva do frango de corte auxilia na minimização dos impactos ambientais, econômicos e sociais causados por estes resíduos. Além disso, resulta como produto final um composto orgânico que pode ser utilizado na produção vegetal. A redução do tempo de estabilização destes resíduos está atrelada à otimização da condução do processo de compostagem, por meio do controle e do monitoramento de parâmetros físico-químicos e da utilização de resíduos de poda de árvores urbana, como agente de volume e fonte de carbono. A redução do tempo de compostagem pode gerar, consequentemente, redução nos custos de produção, diminuindo a área necessária na usina, bem como menor custo com combustível e mão-de-obra. Portanto, objetivou-se determinar os efeitos da redução do tempo de compostagem nos principais parâmetros de controle do processo e nas variáveis de interesse para o uso agrícola do composto orgânico. Os tempos do processo de estabilização avaliados foram 35, 63 e 95 dias. Os efeitos da redução do tempo, bem como a qualidade do composto final nas fases de estabilização, maturação e armazenamento, foram determinados por meio dos parâmetros: redução de massa, volume e matéria orgânica, temperatura, pH, CE, perdas de N, P e K, CTC, relação CTC:COT, carbono, fósforo, potássio e polifenóis solúveis, e FTIR. Com auxílio das técnicas estatísticas de comparação de médias e análise de componentes principais, foi possível inferir sobre a viabilidade da produção de compostos orgânicos estáveis em 35 dias de processo, apresentando CTC de 55,6 cmol kg-1, carbono solúvel de 1,00% e índice de germinação de 140,9%. Além disso, as características da composição final obtida aos 35 dias de processo, estão de acordo com os requisitos definidos pelo Ministério da Agricultura Pecuária e Abastecimento. Conclui-se que a redução do tempo de estabilização para 35 não afetou negativamente os parâmetros de controle do processo de degradação de resíduos agroindustriais. Todos os compostos orgânicos produzidos em 35, 63 e 95 dias de processo apresentaram características de composto estabilizado, sendo adequado para uso agrícola.

The purpose of this research was to uncover factors responsible for the prolific growth of various filamentous microorganisms in the bulking activated sludge at the Hoechst Celanese wastewater treatment plant. First, futile attempts were made to isolate the filamentous bacterium, <i>Nostocoida limicola II</i>, from activated sludge for purposes of its characterization. Chemostat and batch experiments were also performed in an effort to determine conditions favoring its growth, but the filament’s growth could not be sustained in any of the conditions provided. Second, several CSTRs were operated in which single cationic concentrations were varied to try to isolate the actual effects of the different cations on activated sludge microorganisms. Though the objectives of these CSTR experiments were not accomplished because bulking conditions could not be maintained in the reactors, insight was gained as to possible factors significantly impacting filamentous growth. A full-scale study followed, in which microbial population shifts in the activated sludge at the Hoechst Celanese wastewater treatment plant were tracked with changes in the operating conditions at the plant. The results of this study suggested the existence of relationships between the abundances of certain filaments and DO concentration and/or F/M ratio in the activated sludge environment. To isolate the individual effects of these two factors on activated sludge microorganisms, two modified batch studies were performed. The results of these studies indicated that the growth of most of the filaments present in the Hoechst Celanese activated sludge is primarily affected by F/M ratio, though DO concentration strongly impacts the growth of some. The findings in the DO and F/M experiments were combined with the findings in the full-scale study to estimate DO concentration and/or F/M ratio ranges in which growth of the following activated sludge filamentous organisms may be favored: <i>Haliscomenobacter hydrossis</i>, <i>Microthrix parvicella</i>, <i>Nocardia species</i>, <i>Nostocoida limicola II</i>, and Types 0041, 0581, 1851, and 1863. / Master of Science

Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnolgy, Durban University of Technology, 2007 xviii, 143 leaves / Activated sludge flocs are responsible for flocculation, settling and dewaterability. It is important to maintain the growth off loc-forming bacteria for efficient sludge settleability and compaction for good quality effluent. Filamentous bacteria on the other hand are believed to provide rigid support network or backbone upon which floc-forming bacteria adhere to form stable activated sludge flocs (Wilderer et al., 2002; Ramothokang et al., 2003). Filamentous bacteria can also be detrimental to the process when they outgrow floc-forming bacteria. Morphologically filamentous bacteria are at an advantage as they have higher outward growth velocity and can extend freely to bulk liquid substrate. Proliferation of filamentous bacteria causes foaming and bulking (Martins et al., 2004). Although chemical alleviation measures to circumvent bulking are present, they are symptomatic (Chang et al., 2004). Eikelboom (1975) developed the first identification keys for the classification of filamentous bacteria that is primarily based on morphological characteristics and microscopic examination. Although very useful, this type of identification has its limitations. For instance some filamentous bacteria can change morphology in response to changes in the environment and although some of them can be morphologically similar they may vary considerably in their physiology and taxonomy (Martins et al., 2004). A vast number of filamentous bacteria are still very poorly understood which could be due to the problems of cultivation due to their slow growing nature and maintenance of cultures (Rossetti et al., 2006). This limitation necessitates a molecular approach to resolve the taxonomy of filamentous bacteria as it is a culture-independent technique which is highly accurate. This project was undertaken to verify the identity of pure cultures of filamentous bacteria isolated previously through the application of molecular techniques. The 16S rDNA are conserved regions in bacterial cells and they can be extracted and specific nucleic acid fragments amplified. Denaturation gradient gel electrophoresis enabled the separation of fragments of identical length but different size and served as an indication of purity (Muyzer et al., 1993).

Le foisonnement filamenteux est un problème récurant dans de nombreuses stations d'épuration à boues activées. L'objectif de ces travaux est d'améliorer la compréhension des mécanismes physiologiques et moléculaires impliqués dans la filamentation des microorganismes, afin de pouvoir orienter de futures stratégies de lutte contre le phénomène de bulking. Sphaerotilus natans, qui peut croître réversiblement sous forme monocellulaire ou filamenteuse, a été utilisée comme bactérie modèle pour cette étude. Différents types de cultures, ainsi que des suivis par cytométrie en flux et marquage au cFDA/SE, ont montré que les diverses souches de S. natans adoptent des morphologies différentes et que les filaments croissent par divisions cellulaires successives et non par un chaînage des bactéries. Une analyse par RT-QPCR a mis en évidence que l'expression du gène sthA augmente fortement après induction de la filamentation et reste ensuite à un niveau élevé. Une comparaison de l'expression protéique des formes monocellulaire et filamenteuse, par LC-MS-MS, a permis d'identifier des protéines impliquées dans la filamentation, et notamment dans la synthèse de la gaine. La concentration intracellulaire en ARNr, mesurée par RT-QPCR, varie durant la croissance de S. natans et d'autres microorganismes, entraînant une diminution importante de l'intensité du marquage FISH, mesurée par cytométrie en flux. L'utilisation de la technique FISH pour quantifier des microorganismes est donc remise en question, d'autant plus dans des matrices aussi complexes que les boues activées. Ces observations mettent également en doute l'hypothèse, émise en utilisant ce mode de quantification, d'une déstructuration des filaments consécutive à un retour à des conditions de culture plus favorables.

Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnolgy, Durban University of Technology, 2007 xviii, 143 leaves / Activated sludge flocs are responsible for flocculation, settling and dewaterability. It is important to maintain the growth off loc-forming bacteria for efficient sludge settleability and compaction for good quality effluent. Filamentous bacteria on the other hand are believed to provide rigid support network or backbone upon which floc-forming bacteria adhere to form stable activated sludge flocs (Wilderer et al., 2002; Ramothokang et al., 2003). Filamentous bacteria can also be detrimental to the process when they outgrow floc-forming bacteria. Morphologically filamentous bacteria are at an advantage as they have higher outward growth velocity and can extend freely to bulk liquid substrate. Proliferation of filamentous bacteria causes foaming and bulking (Martins et al., 2004). Although chemical alleviation measures to circumvent bulking are present, they are symptomatic (Chang et al., 2004). Eikelboom (1975) developed the first identification keys for the classification of filamentous bacteria that is primarily based on morphological characteristics and microscopic examination. Although very useful, this type of identification has its limitations. For instance some filamentous bacteria can change morphology in response to changes in the environment and although some of them can be morphologically similar they may vary considerably in their physiology and taxonomy (Martins et al., 2004). A vast number of filamentous bacteria are still very poorly understood which could be due to the problems of cultivation due to their slow growing nature and maintenance of cultures (Rossetti et al., 2006). This limitation necessitates a molecular approach to resolve the taxonomy of filamentous bacteria as it is a culture-independent technique which is highly accurate. This project was undertaken to verify the identity of pure cultures of filamentous bacteria isolated previously through the application of molecular techniques. The 16S rDNA are conserved regions in bacterial cells and they can be extracted and specific nucleic acid fragments amplified. Denaturation gradient gel electrophoresis enabled the separation of fragments of identical length but different size and served as an indication of purity (Muyzer et al., 1993).

Au cours du temps, les cavités souterraines sont soumises à un vieillissement et plusieurs types de dégradation peuvent apparaitre. Les anciennes exploitations souterraines, parfois constituées d’un ou plusieurs niveaux, n’ont, sans doute, pas été conçues pour être stables à long terme. Elles ont été réalisées à une époque où n'existaient pas d'enjeux en surface, de zones de travaux, ce qui permettait d’éviter de se préoccuper des mouvements de sol induits. Elles ont pu quelquefois être totalement ou partiellement remblayées, mais pas de manière systématique. L’effondrement d'une cavité souterraine engendre la déconsolidation des niveaux supérieurs des terrains de recouvrement. Ces mécanismes peuvent provoquer en surface deux types de désordres : un affaissement ou un fontis. L'affaissement et le fontis peuvent provoquer des graves dommages aux structures et aux infrastructures en surface mais aussi mettre en péril la sécurité des populations. Les travaux de cette thèse s’articulent autour de l’étude du foisonnement, du fontis et de sa propagation dans les terrains de recouvrement.Les objectifs de cette thèse sont doubles : tout d’abord il s’agit d’étudier le foisonnement de la roche lors d’un effondrement de toit de carrières souterraines ; ensuite il s’agit de modéliser la propagation du fontis dans les terrains de recouvrement et ainsi hiérarchiser les paramètres associés à ce phénomène.La première partie de cette thèse repose sur une étude bibliographique qui récapitule les méthodes d’exploitation, méthodes d’analyse de stabilité de carrières souterraines, méthodes de prévision de la hauteur d’effondrement et estimation de foisonnement. A l’issue de cette synthèse bibliographique l’étude s’est focalisée sur les carrières souterraines à faible profondeur exploitées par chambres et piliers. Ainsi, la modélisation numérique par la méthode des éléments discrets (MED) a été choisie pour analyser l’instabilité des toits de carrières souterraines.La seconde partie s’intéresse au développement d’un modèle numérique qui a pour objectifs : d’une part, le développement d’un Programme de Discrétisation des Massifs Rocheux (PDMR) qui constitue le préprocesseur du logiciel STTAR3D et le développement d’un code permettant le calcul du coefficient de foisonnement des débris de l’effondrement. D’autre part, l’implémentation des lois de comportement sur STTAR3D.La troisième partie consiste à déterminer, d’une part les caractéristiques physico-mécaniques d’échantillons prélevés dans la carrière de la Brasserie (Paris-France), qui a été choisie pour une tester le modèle développé et d’autre part, les deux paramètres de la loi de comportement utilisée pour modéliser les contacts à savoir  et µ.Enfin, la dernière partie de ce travail est constituée des simulations numériques pour lesquelles les paramètres de la loi de comportement mesuré expérimentalement ont été introduits dans STTAR3D. Dans la première étude numérique menée, on s’intéresse à l’effet de la hauteur de chute, du rayon de l’ouverture initiale du fontis et du degré de fracturation sur le foisonnement des décombres, ainsi qu’à l’effet de la variation du foisonnement sur la hauteur de l’effondrement et sur l’affaissement. Dans un second temps, on réalise un modèle de la carrière de la Brasserie dont on calcule le comportement par simulation numérique afin d’obtenir l’affaissement en surface et la hauteur de l’effondrement qui sont comparés aux observations in-situ / Over time, the underground cavities are subjected to aging and several types of degradation can occur. The old underground cavities have probably not been designed to be stable over the long term. They have sometimes been totally or partially backfilled, but not in a systematic way. The collapse of a mine causes deconsolidation of the upper levels of the overburden. These mechanisms can cause two types of disorders on the surface: subsidence or sinkhole. Subsidence and sinkhole can cause severe damage to structures and infrastructures in surface, but also jeopardize the safety of the population.The work of this thesis revolves around the study of rock's bulking, sinkhole and its spread in the overburden. The aims of this thesis are twofold: firstly, to study the bulking of rock during the roofs mine collapse; Secondly, modeling the spread of the sinkhole in the overburden and thus to prioritize the parameters associated with this phenomenon.The first part of this thesis is a bibliographical study which summarizes the methods of exploitation, methods of analysis of stability of underground quarries, methods of prediction of the height of collapse and estimation of the bulking factor. At the end of this bibliographic synthesis, the study focused on shallow underground quarries operated by rooms and pillars. Thus, numerical modeling using the discrete element method (MED) was chosen to analyze the instability of roofs of underground quarries.The second part focuses on the development of a numerical model with the following objectives: on the one hand, the development of a Rock Mass Discretization Program (RMDP) which constitutes the preprocessor of the STTAR3D software and the development of a Code allowing calculation of the bulking factor of the rubble of collapse. On the other hand, implementation of the behavior laws on STTAR3D.The third part consists of determining, on the one hand, the physicals and mechanicals characteristics of samples taken from the quarry of the Brasserie (Paris-France), which was chosen to test the model developed. On the other hand, determining of parameters of the behavior law used for modeling the contacts, namely “” and “μ”.Finally, the last part of this work is made of numerical simulations for which the parameters of the behavior law measured experimentally have been introduced in STTAR3D. In the first numerical study, we investigate the effect of fall height, the radius of the initial opening of the sinkhole and the fracturing degree on the bulking of the rubble, as well as the effect of variation of the bulking on the collapse height and on the subsidence. In a second step, a model of the Brasserie’s mine is realized, the behavior of which is studied by numerical simulation in order to obtain the subsidence on the surface and the collapse height, which are compared with the in-situ observations

SANITATION, PUBLIC HEALTH AND THE ENVIRONMENT The approach to sanitation worldwide should be ecologically sustainable, i.e. concerned with protection of the environment. This means that sanitation systems should neither pollute ecosystems nor deplete scarce resources. It further implies that sanitation systems should not lead to degrading water or land and should, where possible, ameliorate existing problems caused by pollution. More research and better designs are needed. Human excreta can be rendered harmless, and toilet designs that do this in harmony with agricultural and social customs hold promise for the future. Problems with conventional sanitation systems have been shown to include inadequate institutional capacity to deal with the sanitation process, a fixation with providing either a full waterborne system or a VIP toilet, the social acceptability of various systems, and the perception that dry, on-site sanitation systems are inherently inferior. The basic purpose of any sanitation system is to contain human excreta (chiefly faeces) and prevent the spread of infectious diseases, while avoiding damage to the environment. An alternative sanitation technology known as urine-diversion (UD) performs these functions with fewer operational and maintenance problems than those associated with conventional VIP toilets, (for example, it is a major and expensive operation to desludge full pits, which is not the case with UD toilets as the vaults can be quickly and easily emptied using hand tools) and also provides a free, easily accessible and valuable agricultural resource for those who wish to use it. This technology represents one aspect of an approach, or philosophy, termed “ecological sanitation” or “ecosan.” Key features of ecosan are prevention of pollution and disease caused by human excreta, treatment of human excreta as a resource rather than as waste, and recovery and recycling of the nutrients. In nature, excreta from humans and animals play an essential role in building healthy soils and providing valuable nutrients for plants. Conventional approaches to sanitation misplace these nutrients, dispose of them and break this cycle. UD systems have been successfully implemented in many countries, including South Africa where more than 60 000 of these toilets have been built since 1997. However, despite much research having been carried out internationally and locally, various questions still remain, particularly on the health aspects of operation, maintenance, and excreta use or disposal. Not enough is known about the dehydrating processes taking place inside the faeces vault, and there is still disagreement on safe retention periods and microbiological stability of the final product. The roles of dryness, pH, temperature and time in pathogen destruction also need to be further clarified. In addition, it is critically important that toilet users are able to operate and maintain their systems easily and safely, particularly while emptying the vaults and recycling or otherwise dealing with the contents. Engineers need to understand and take all these issues into consideration before they can properly design and implement sustainable UD sanitation systems. It is therefore important to develop guidelines for sanitation practitioners that set out best practices for construction and operation of UD toilets. Construction recommendations are important because good construction facilitates easy operation, and also promotes rapid pathogen destruction. Easy operation in turn directly influences the health risks associated with removing faecal material from the vaults. Handling of faecal material is an aspect inherent in the operation of UD ecological sanitation systems, because emptying of the vault is usually done using hand tools. If the faecal material is also used for agricultural purposes then further handling must of necessity take place. As such, there is a health concern, both for the person(s) handling the material and for the wider public who may be consumers of the fertilised crops. It is therefore necessary that these health concerns be quantified, in order that proper regulation may take place. <b<CONCLUSIONS FROM THE LITERATURE REVIEW The primary aim of sanitation is to prevent the transmission of excreta-related diseases. However, with all sanitation systems there is a risk of disease transmission related to the handling or use of the end product. Therefore, even a well functioning system could enhance pathogen survival and lead to an increased risk of disease transmission for those handling the end products or consuming crops fertilised with them. A greater understanding of pathogen die-off in dry sanitation systems is required where handling and/or use of excreta are expected. Pathogen destruction in dry sanitation systems, particularly in the vaults of urine-diversion (UD) toilets, is mainly dependent on storage time, pH, temperature, humidity, moisture content, organic content of the faecal material, and type of bulking agent added. It is of utmost importance to ensure that the material is safe to handle. This implies that the primary treatment in the vault should, as far as possible, ensure the required level of safety. While much research has been carried out internationally into pathogen destruction in the vaults of UD toilets, the same cannot be said of South Africa. There is also a wide range of results and conclusions, with recommended storage times varying from six months to two years. Construction and operational guidelines are required in order to assist practitioners in these and other respects. Sound management practices could play an important role in reducing the health risks involved in emptying the vaults of UD toilets and the disposal or further use of faecal material. From the public health viewpoint, it is necessary to reduce, as far as possible, the risk of handling faecal material. To do this, a better understanding of the factors influencing pathogen die-off in the vaults is required. FOCUS OF THIS THESIS The primary aim of this thesis is to investigate the efficacy of various methods aimed at enhancing pathogen destruction in the vaults of UD toilets, with the aim of (a) establishing the best combination of factors/methods, in particular the vault storage period required, and (b) producing guidelines for the construction, operation and regulation of these systems. The overall purpose of the research is to establish safety criteria for handling of faecal material from UD toilets. FIELD TRIALS: MICROBIOLOGICAL EFFECTS ON FOOD CROPS FERTILISED WITH FAECAL MATERIAL FROM URINE-DIVERSION TOILETS Recycling excreta to soils reduces the need for chemical fertilisers; however, pathogens are recycled to humans if improper agricultural practices are followed. Concerns about using faecal material include higher pathogenic content in developing countries compared to that in developed countries. This material, as well as that from other sanitation alternatives in small-scale systems, demands more personal involvement from the users (including handling), which constitutes a higher human exposure level compared to that from conventional piped systems. Nevertheless, it is considered that where the material can improve agricultural productivity, it can contribute to improving the nutritional status of the population, thus improving public health. Although ecosan technology is spreading all over the world, and with it the recycling of excreta to soils, only a few researchers have addressed the problems associated with the revalorization practice or documented the pathogen die-off. Moreover, little data about the microbial quality of ecosan faecal material from developing countries (where the health risks are the highest) are available. The objective of this research was thus to investigate the potential health risks of using faecal material in agriculture by determining the pathogen uptake on the surfaces of the edible portions of the crops. Faecal material of between one and three months old was extracted from a number of UD toilets in the eThekwini (Durban) municipal area. This was used primarily for the experimental work described in the next section, but for the purposes of this particular experiment it was first left in a heap in the open air for a further four months. Thereafter it was used as a soil amendment in the cultivation of spinach and carrots. Detailed microbiological tests were conducted on this material as well as on the in situ soil before sowing and after harvesting, on the irrigation water, and on the harvested crops. Applying different rates of material to spinach and carrots, two common edible crops, it was found that the bacteria and fungi content were only noticeable for the higher application rates (>35t/ha), while the helminth ova content varied, both in leaves and stems, depending on the quantity of material applied. Helminth ova content was, for both crops, more prevalent in leaves, suggesting that the ova adhere preferentially to plants rather than soil. It was thus illustrated that there is a health implication involved in growing edible crops in soils amended with ecosan biosolids. Even if in this case the spinach and carrots were cooked before consumption, normal handling of the crops during harvesting and preparation could have caused infection if personal hygiene was unsatisfactory. It is therefore important that crop growers and consumers, as well as proponents of biosolids use, are aware of the storage and treatment requirements for ecosan biosolids before these are applied to soils where crops are grown. DETAILED INVESTIGATION INTO VAULT PROCESSES It is hypothesised that the most advantageous approach to pathogen destruction in a UD toilet vault is to maximise the effects of various environmental factors, e.g. high pH, high temperature, low moisture, type of bulking agent and storage time. In order to quantify these effects a field experiment was set up consisting of 12 UD toilet vaults, each with a different combination of faeces and bulking agent (soil, ash, wood shavings, NaOH or straw), ventilation (ventpipe / no ventpipe) and vault lid material (concrete, metal or perspex). Faecal material was obtained from UD toilets in the eThekwini area, as described above. Temperature probes, which were connected to a data logger, were inserted in the heaps and the logger monitored over a period of nearly 10 months. This enabled a number of graphs to be drawn illustrating the effect of the above parameters on heap temperature over the experimental period. During the coldest week in winter the mean heap temperatures averaged 16,8°C, while the minimum and maximum averaged 14,8°C and 18,8°C respectively. During the warmest week in summer mean heap temperatures averaged 27,6°C, while the minimum and maximum averaged 25,6°C and 29,3°C respectively. In addition, samples were taken at various intervals from each vault as well as from the main heap of faecal material that was left exposed to the elements. The samples were subjected to microbiological testing in order to quantify the pathogen die-off over time for each vault as well as for the main heap. In the vaults, total coliform reduced by 3 log10 (99,9%) at between 130 and 250 days, faecal coliform between 100 and 250 days, and faecal streptococci from 125 days and longer. In the main heap, these times varied from 115 days for both total and faecal coliform to 140 days for faecal streptococci. Viable Ascaris ova were reduced to zero between 44 and 174 days in the vaults and by 44 days in the main heap. The conclusions drawn from the xperimentation were the following: <ul> <li>Influence of ventpipe Ventilation of the vault by means of a ventpipe does not result in any meaningful difference in either the vault temperature or rate of pathogen die-off.</li> <li>Influence of vault lid material The lid material, and by inference also the material of the vault walls, has no significant effect on the temperature of the heap or the associated pathogen die-off.</li> <li>Type of bulking agent While the type of bulking agent used does not significantly influence the temperature of the faecal material, it does have an effect on the rate of pathogen die-off. The ordinary soil mix was seen to give the best results, and this was ascribed to the effect of competing microorganisms in the soil itself.</li> <li>Influence of sunshine and rain The main heap of material (faeces/soil mix) that was exposed to the elements performed among the best in terms of pathogen die-off. Apart from the influence of competing microorganisms in the soil on the pathogens as described above, this good performance was also ascribed to the effect of UV radiation and alternate wetting/drying and heating/cooling cycles, which suggests that open-air exposure is likely to provide the best treatment.</li></ul> Comparing the results of this research with other local and international research, it appears that there is a great deal of convergence in the results. It is concluded that vaults of UD toilets should be sized for a storage period of 12 months from last use. RECOMMENDATIONS FOR CONSTRUCTION, OPERATION AND REGULATION OF URINE-DIVERSION TOILETS The standard of UD toilets in South Africa varies greatly. While there are many good examples of the technology, there are also many that have been ill-conceived and are badly built and poorly operated. Project implementers are responsible for the quality of sanitation schemes and should be equipped with the necessary information to oversee the process. The guidelines are aimed at providing implementers with, firstly, the necessary technical information to build good quality UD toilets and, secondly, the basic operation and maintenance tasks that should be conveyed to the toilet owners. Basic regulatory guidelines for the responsible authorities are also given. The guidelines are intended to be a stand-alone document and some repetition of information from earlier chapters is thus unavoidable. The technology of urine diversion is introduced, followed by basic design and construction guidelines, including drawings, for the superstructure and vault of a UD toilet. Both single- and double-vault toilets are discussed. A number of photographs are also provided, illustrating good and bad building practices. Further aspects discussed are requirements for urine pipes and ventilation. Operation and maintenance of UD toilets are subsequently covered. Topics discussed are dehydration, odour, fly control, cleaning of the pedestal, disposal of anal cleansing material, urine collection and disposal, clearing of blockages in urine pipes, and faeces management. The above guidelines are aimed at designers, builders and toilet users. However, organisations responsible for administering public and environmental health, such as Departments of Health, Environmental Affairs, etc, as well as the local and regional authorities that actually implement the sanitation schemes, should become actively involved in regulating the operation of UD toilets, particularly the removal and disposal of faecal material. Some regulatory guidelines are therefore also included to assist these organisations to set uniform (high) standards in their respective jurisdictions. RECOMMENDATIONS FOR FURTHER RESEARCH RELATED TO THIS THESIS It is deemed important that the field trials conducted in the various vaults as described earlier are repeated in other climatic areas, for example a hot and dry area, as it is likely that different results regarding recommended minimum storage periods will be obtained. This should be supplemented by trials involving co-composting of the faeces mix with other organic material, in order to compare the efficacy of this method with the dehydration process. Further, vault lids made of PVC should be tested for enhancing heat gain in the vaults. Finally, long-tem measurements of heap pH should be made in order to ascertain if high pH amendments (wood ash, lime, etc) do in fact maintain their initial pH level. Additional field trials, similar to those described earlier for spinach and carrots, should be undertaken with a view to making recommendations regarding maximum application rates of faecal material. These should consist of food crops where the edible portions are either in or near to the soil, such as beetroot, onion, potatoes, tomatoes, etc. Trials involving urine should also be considered in order to determine the most advantageous application rate for the various crops. Another important topic is recommended for further research on the subject of UD toilets. At present, virtually all the UD toilets built in the country have been for communities on the lower end of the income scale and who previously had no formal sanitation facility at all or, at best, an unimproved pit toilet. Research carried out by CSIR in a number of communities has revealed people’s resistance to handling their faecal material, while in others it has not been a problem. There is often a general viewpoint in a village that “the municipality must take the faeces away.” However, willingness has also been expressed in some villages to pay for a faeces removal service. For instance, this has borne fruit in an area of Kimberley with UD toilets where householders pay a local resident to remove the faecal material on a regular basis. This is done by means of a wheelbarrow, and the material is stockpiled at a nearby approved facility from where it is destined for co-composting with other municipal waste. However, this has not yet been attempted on a large scale in an area with hundreds, or even thousands, of UD toilets. While a theoretical desktop study has been carried out on the feasibility of setting up a large-scale faeces collection concern, such an enterprise does not yet exist in the country. It is suggested that one be set up utilising a horse- or donkey-drawn cart in a village, or group of villages, with sufficient UD toilets available to ensure that a viable business can be conducted. The cooperation of the particular local authority will be required. If successful faeces collection/disposal services could be established in areas with UD toilets it would greatly enhance the social acceptability, and therefore the viability, of this sanitation technology. / Thesis (PhD(Civil Engineering))--University of Pretoria, 2008. / Civil Engineering / unrestricted

As hard rock mining progresses into higher stress mining conditions through either late stage extraction or mining at depth, the rock mass is driven not just to the peak strength, but often well into the post-peak until complete ‘failure’ occurs and easier mining conditions become evident. Limited research has been accomplished in identifying the transition of the rock mass and its behaviour into the post-peak and this research investigates this behaviour in detail. As the rock mass progressively fails, fractures are initiated through intact rock and extension and shear failure of these and pre-existing features occurs. Associated with this failure are microseismic events, which can be used to give an indication of the strength state of the rock mass. Based on an analogy to laboratory testing of intact rock and measurement of acoustic emissions, the microseismicity can be used to identify, fracture initiation, coalescence of fractures (yield), localization (peak-strength), accumulation of damage (post-peak) and ultimate failure (residual strength) leading to aseismic behaviour. The case studies presented in this thesis provide an opportunity to examine and analyse rock mass failure into the post-peak, through the regional and confined failures at the Williams and the Golden Giant mines, both in the Hemlo camp in Northern Ontario, Canada. At the Williams mine, the progressive failure of a sill pillar region into the post-peak was analysed; relating the seismic event density, combined with numerical modelling and a spatial and temporal examination of the principal components analysis (PCA), to characterize the extent, trend and state of the yielding zone, which formed a macrofracture shear structure. Observations of conventional displacement instrumentation, indicates regional dilation or shear of the rock mass occurs at or prior to the point of ‘disassociation’ (breakdown of stable PCA trends) when approaching the residual strength. At the Golden Giant mine, the complete process from initiation to aseismic behaviour is monitored in a highly stressed and confined pendent pillar. The PCA technique, numerical modelling and focal mechanism studies are used to define significant stages of the failure process, in which a similar macrofracture structure was formed. Temporal observations of key source parameters show significant changes prior to and at the point of coalescence and localization.

As hard rock mining progresses into higher stress mining conditions through either late stage extraction or mining at depth, the rock mass is driven not just to the peak strength, but often well into the post-peak until complete ‘failure’ occurs and easier mining conditions become evident. Limited research has been accomplished in identifying the transition of the rock mass and its behaviour into the post-peak and this research investigates this behaviour in detail. As the rock mass progressively fails, fractures are initiated through intact rock and extension and shear failure of these and pre-existing features occurs. Associated with this failure are microseismic events, which can be used to give an indication of the strength state of the rock mass. Based on an analogy to laboratory testing of intact rock and measurement of acoustic emissions, the microseismicity can be used to identify, fracture initiation, coalescence of fractures (yield), localization (peak-strength), accumulation of damage (post-peak) and ultimate failure (residual strength) leading to aseismic behaviour. The case studies presented in this thesis provide an opportunity to examine and analyse rock mass failure into the post-peak, through the regional and confined failures at the Williams and the Golden Giant mines, both in the Hemlo camp in Northern Ontario, Canada. At the Williams mine, the progressive failure of a sill pillar region into the post-peak was analysed; relating the seismic event density, combined with numerical modelling and a spatial and temporal examination of the principal components analysis (PCA), to characterize the extent, trend and state of the yielding zone, which formed a macrofracture shear structure. Observations of conventional displacement instrumentation, indicates regional dilation or shear of the rock mass occurs at or prior to the point of ‘disassociation’ (breakdown of stable PCA trends) when approaching the residual strength. At the Golden Giant mine, the complete process from initiation to aseismic behaviour is monitored in a highly stressed and confined pendent pillar. The PCA technique, numerical modelling and focal mechanism studies are used to define significant stages of the failure process, in which a similar macrofracture structure was formed. Temporal observations of key source parameters show significant changes prior to and at the point of coalescence and localization.