O sulfeto de hidrogênio é um gás que pode causar os mais diversos danos se lançado ao meio ambiente devido, principalmente, à sua elevada toxicidade, corrosividade, odores indesejáveis e alta demanda de oxigênio. Atualmente existem diferentes processos físico-químicos estabelecidos para o tratamento desse composto, entretanto são consideradas técnicas onerosas do ponto de vista econômico e ambiental. Os processos biológicos constituem-se como uma alternativa bastante interessante quando comparados aos processos físico-químicos, sendo que a biofiltração é o processo mais amplamente utilizado. Neste trabalho, foram avaliados três tipos diferentes de materiais suporte, sendo um sintético - espuma de poliuretano - e dois orgânicos - fibra de côco e bagaço de cana -, para a biofiltração de uma mistura gasosa contendo \'H IND.2\'S\'. Como inóculo, optou-se pela utilização de cultura mista originária de duas fontes: a) unidade de biofiltro aerado submerso pertencente ao Serviço Autônomo de Água e Esgoto da Cidade de São Carlos, b) unidade de lodos ativados pertencente a São Carlos S/A - Indústria de Papel e Celulose. A adaptação do inóculo foi realizada em meio nutriente específico. Foi observado um período de partida de somente 2 dias nos três sistemas. Com o intuito de avaliar o impacto do aumento progressivo das taxas de carregamento mássico no desempenho dos três biofiltros, os mesmos foram submetidos a taxas de 19, 32, 54 e 70 g/m³.h (concentrações afluentes médias de 184, 328, 526 e 644 ppm para tempo de retenção do gás de, aproximadamente, 50 segundos). As eficiências remoção média em todos os sistemas mantiveram-se sempre acima dos 99,3%. A capacidade eliminação máxima alcançada pelos biofiltros oscilou entre 74 e 80 g/m³.h. As perdas de carga verificadas no ensaio hidrodinâmico foram baixas, variando entre 0,59.\'10 POT.-2\' a 0,68 \'10 POT.-2\' mca, para a velocidade superficial utilizada durante o estudo. O modelo matemático empregado na previsão do desempenho dos sistemas ajustou-se bem aos dados experimentais. Portanto, pode-se concluir que os materiais suportes testados são adequados para a biofiltração de sulfeto de hidrogênio. / Hydrogen sulfide is a gas which has high restrictions regarding to its disposal in the environment, mainly, because of its high toxicity, malodors, high oxygen demand, etc. Currently, there are many different physical-chemical processes established in order to treat this compound, nevertheless they are considered expensive techniques by the point of economical and environmental views. Biological processes are very interesting alternatives when they are compared to the physical-chemical ones, and biofiltration is the most used process. In this work, three different materials as support media were evaluated, - a synthetic one - represented by the polyurethane foam, - two organic ones - represented by coconut fiber and sugar bagasse -, for a biofiltration of a gaseous mixture containing \'H IND.2\'S\'. Microorganisms were obtained from two sources: a) submerged aerated biofilter unit, b) activated sludge unit. Inoculum\'s adaptation was realized in specific nutrient media. It was observed a 2 days start-up period in the three systems. In order to evaluate some impact caused by the progressive increasing of mass loading rate on the biofilters performance, were applied rates of 19, 32, 54 e 70 g/m³.h (average influent concentrations of 184, 328, 526 e 644 ppm to the empty bed retention time of, approximately, 50 seconds). Average removal efficiencies in the systems were always above 99,3%. Maximum elimination capacities reached by the biofilters were in the range of 74 e 80 g/m³.h. Loss pressure verified by the hands of hydrodynamic essays varied between 0,59.\'10 POT.-2\' a 0,68.\'10 POT.-2\' mca, to a superficial velocity utilized during the work. Mathematical model used to predict the performance of the systems fitted reasonably the experimental data. Then, it can be concluded that the three packing materials are appropriated for the hydrogen sulfide biofiltration.

O objetivo deste estudo foi realizar ensaios de adsorção dinâmica, em coluna de leito fixo sem etapa regenerativa, para tal finalidade utilizou-se como adsorventes o carvão ativado comercial e material adsorvente à base de lodo biológico, para o tratamento de sulfeto de hidrogênio em corrente gasosa e obtenção das capacidades de adsorção. O lodo foi obtido de forma bruta em estação de tratamento de efluentes de abatedouro de aves, e tratado por processos térmicos e químicos em laboratório, para a geração de adsorvente. A concentração de H2S alimentada foi de 500 ppm na coluna, presente em duas misturas gasosas, uma com N2 e H2S, e outra mistura simulando o biogás contendo CO2, CH4 e H2S. As concentrações de H2S foram monitoradas por meio de um analisador de gás conectado a saída da coluna. Usou-se a técnica de interpretação das curvas de efluência para a determinação da capacidade de adsorção dos adsorventes estudados. Os resultados obtidos nesse trabalho indicaram que o aparato experimental usado não se mostrou viável para a adsorção com adsorvente à base de lodo. No entanto foi possível aumentar sua área superficial por meio dos tratamentos submetidos, passando de 0,005 g/m² na condição de lodo seco, para 86,4 g/m² depois de tratado. O lodo tratado com ácido sulfúrico mostrou maior capacidade de adsorção para a vazão de 4,0 L/min, apresentando remoção média de 0,21 mg H2S/g lodo. O carvão ativado comercial se apresentou propício para a remoção de H2S nas duas correntes gasosas, apresentando uma capacidade de adsorção média de 2,70 mg H2S/g carvão para a mistura gasosa simulando biogás e 1,26 mg H2S/g carvão para a corrente gasosa formado por nitrogênio e sulfeto de hidrogênio. / The objective of this study was to perform dynamic adsorption tests in fixed-bed column without regenerative stage, for this purpose it was used as adsorbents commercial activated carbon and biological sludge-based adsorbent material, for the treatment of hydrogen sulfide in the gas stream and obtaining the adsorption capacities. The sludge was obtained in raw form in treatment effluent plant from slaughterhouse poultry, and treated by thermal and chemical processes in the laboratory, to generate adsorbent. The concentration of H2S fed was 500 ppm in the column, present in two gas mixtures, one with N2 and H2S, and other mixing simulating the biogas containing CO2, CH4 and H2S. The H2S concentration was monitored by a gas analyzer connected to the outlet of the column. It was used breakthrough curves to determine the adsorption capacity of the adsorbents studied. The results of this work indicated that the experimental apparatus used was not suitable for adsorption with sludge-based adsorbent. However it was possible to increase the surface area through of undergoing treatments, from 0.005 g/m² on dry sludge condition to 86.4 g/m² after treated. The treated sludge with sulfuric acid showed a higher adsorption capacity for the flow rate of 4.0 L/min, with an average removal of H2S 0.21 mg/g sludge. The commercial activated carbon proved itself suitable for the removal of H2S in the two gas streams, with an average adsorption capacity of 2.70 mg H2S/g carbon for the gaseous mixture simulating biogas and 1.26 mg/g carbon for the gaseous stream consisting of nitrogen and hydrogen sulfide.

Orientador: Heloisa Helena de Araújo Ferreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T00:48:21Z (GMT). No. of bitstreams: 1 Mendes_JackelineAmaral_M.pdf: 3206748 bytes, checksum: a2ba24233e4b17f3e6d3d8a4326a499c (MD5) Previous issue date: 2014 / Resumo: Estudos mostram que o sulfeto de hidrogênio (H2S) possui um papel relevante na fisiopatologia de doenças pulmonares. O objetivo deste trabalho foi investigar os mecanismos pelos quais o H2S influência a apoptose, o infiltrado de células inflamatórias, e o remodelamento das vias respiratórias na inflamação alérgica pulmonar. Para isso, camundongos BALB-C foram sensibilizados e desafiados com ovalbunina (OVA). Os camundongos tratados receberam o hidrosulfeto de sódio (NaHS) 30 minutos antes do desafio com OVA (OVA/NaHS). Alguns camundongos sensibilizados receberam salina estéril sem a OVA na ocasião do desafio (grupo salina). A eutanásia dos animais foi realizada 48 horas após o desafio, quando foi coletado o lavado broncoalveolar, para separação imunomagnética de eosinófilos para verificação da apoptose desta célula, e retirados os pulmões. O lobo direito dos pulmões foram homogeneizados para verificação da expressão das proteínas Caspase 3, Caspase 9, Bax, Fas-L e TGF-?1 e para dosagem dos níveis de citocinas. O lobo esquerdo foi fixado no formol para alguns procedimentos de análise histológica. Verificamos o infiltrado inflamatório no parênquima pulmonar pela coloração HE (hematoxilina/eosina) e o colágeno no pulmão utilizando a coloração TM (tricômico de masson). Observamos, também, a apoptose in situ em células epiteliais do pulmão através do ensaio TUNEL (Terminal deoxynucleotidyl transferase dUTP nick end labeling). Por fim, realizamos a imunohistoquímica no pulmão para verificação da expressão das enzimas cistationia-?-liase (CSE) e cistationina-?-sintetase (CBS). Os resultados dos camundongos alérgicos não tratados (OVA) mostraram um aumento do infiltrado inflamatório ao redor dos brônquios e bronquíolos, com prevalência de eosinófilos. O tratamento com NaHS foi efetivo em reduzir este infiltrado inflamatório. No grupo salina não se verificou infiltrado inflamatório. Ao estudarmos a expressão das proteínas Caspase 3, Caspase 9, Fas-L e Bax, observamos que nos animais sensibilizados e desafiados (OVA) a expressão da Caspase 3, Caspase 9 e Bax não sofrem qualquer alteração. No entanto, o tratamento dos animais com NaHS diminui a expressão da Caspase 3, mas não da Caspase 9 e Bax. A expressão do Fas-L é aumentada nos animais sensibilizados e desafiados (OVA) quando comparado ao grupo salina e o tratamento com NaHS diminui essa expressão á níveis semelhantes ao grupo salina. Não foram observadas modificações na apoptose dos eosinófilos isolados dos camundongos alérgicos ou dos tratados com NaHS. Os animais sensibilizados e desafiados apresentaram um aumento da apoptose de células do epitélio brônquico quando comparado ao grupo salina. O tratamento com NaHS foi capaz de reduzir esta apoptose a níveis semelhantes ao grupo salina. Verificamos um aumento dos níveis das citocinas IL-4, IL-5, IL-13 e IL-25 nos pulmões dos camundongos sensibilizados e desafiados, e este aumento foi evitado pelo o tratamento dos animais com NaHS, com exceção da IL-13. A concentração da eotaxina, fator quimiotático de eosinófilos, não sofreu qualquer influência do tratamento com NaHS nos pulmões dos camundongos sensibilizados em resposta ao desafio com OVA. O desafio com OVA aumentou os níveis do IFN-? no homogenato pulmonar, e este aumento foi revertido pelo tratamento dos animais com NaHS a níveis semelhantes aos observados no grupo salina. Os níveis de TNF-? não sofreram alteração do desafio com OVA e nem do tratamento com NaHS. Relacionado ao remodelamento das vias aéreas, não houve formação de colágeno peribronquiolar nos camundongos sensibilizados e desafiados com OVA e nem naqueles tratados com NaHS. O mesmo foi observado na expressão do TGF-?1 que não sofreu influência nem da indução da alergia pulmonar pela OVA nem do tratamento com NaHS. A expressão da enzima CSE tanto no epitélio brônquico como no endotélio vascular estava aumentada nos pulmões dos camundongos alérgicos, e este aumento foi amplificado pelo tratamento com NaHS. Diferentemente da expressão desta enzima, o tratamento com NaHS não modificou a expressão da enzima CBS em nenhuma das estruturas pulmonares estudadas. Em conclusão, nossos resultados sugerem que o H2S tem um efeito protetor no pulmão contra os danos provocados pela alergia. A redução do infiltrado de eosinófilos peribronquiolar pode ser explicada pela diminuição nos níveis pulmonares da IL-4, IL-5 e IL-25, devido à ação do H2S. O H2S também evitou a apoptose e, consequentemente, a destruição do epitélio brônquico, o que contribui para a diminuição da inflamação no processo alérgico pulmonar. A enzima CSE pode estar envolvida neste processo. O H2S possui um importante potencial terapêutico para as doenças alérgicas pulmonares como a asma / Abstract: Many studies show that hydrogen sulfide (H2S) has a relevant role in the pathophysiology of lung diseases. The objective of this study was to investigate the mechanisms by which H2S influence apoptosis, the inflammatory cell infiltrate, and airway remodeling in allergic lung inflammation. To this end, BALB-C mice were sensitized and challenged with ovalbunina (OVA). The treated mice received the sodium hydrosulfide (NaHS) 30 minutes before challenge with OVA (OVA / NaHS). Some sensitized mice received sterile saline without OVA at the time of challenge (saline group). The euthanasia was performed 48 hours after challenge, when it was collected bronchoalveolar lavage for immunomagnetic separation of eosinophils to check this cell apoptosis, and the lungs were removed. The right lobe of the lungs was homogenized for checking the expression of caspase 3, caspase 9, Bax, Fas-L and TGF-?1 protein and for determination of cytokine levels. The left lobe was fixed in formalin for histological analysis. We checked the inflammatory infiltrate in the lung parenchyma by HE staining (hematoxylin/eosin) and collagen in the lung using the TM (Masson trichrome) staining. We also observe in situ apoptosis in lung epithelial cells by TUNEL assay (Terminal deoxynucleotidyl transferase dUTP nick end labeling). Finally, we performed immunohistochemistry in the lung to check the expression of cistationia ?-lyase enzymes (CSE) and cystathionine ?-synthase (CBS). The results of allergy untreated mice (OVA) showed an increase in inflammatory infiltrates around the bronchi and bronchioles, with a prevalence of eosinophils. Treatment with NaHS has been effective in reducing this inflammatory infiltrate. In saline there was no inflammatory infiltrate. By studying the expression of Caspase 3, Caspase 9, Fas-L and Bax proteins, we observed that in animals sensitized and challenged (OVA) the expression of Caspase 3, Caspase 9 and Bax remain unchanged. However, treatment of the animals with NaHS decreases the expression of Caspase 3 but not caspase 9 and Bax. The Fas-L expression is increased in sensitized and challenged (OVA) animals when compared to saline treatment group and NaHS will decrease the expression levels similar to saline group. No changes in apoptosis of eosinophils isolated from allergic mice or those treated with NaHS were observed. The sensitized and challenged animals showed an increase in apoptosis in bronchial epithelial cells as compared to saline group. Treatment with NaHS was able to reduce this apoptosis to similar levels to the saline group. Verified increased levels of IL-4, IL-5, IL-13 and IL-25 in the lungs of sensitized and challenged mice, and this increase was prevented by treating the animals with NaHS, with the exception of IL-13. The concentration of eotaxin, eosinophil chemotactic factor, suffered no influence of treatment with NaHS in the lungs of sensitized in response to challenge with OVA mice. The OVA challenge increased the levels of IFN-? in lung homogenates, and this increase was reversed by treating animals with NaHS levels similar to those observed in the saline group. The levels of TNF-? did not change the OVA challenge nor treatment with NaHS. Related to airway remodeling, there was no formation of peribronchial collagen in mice sensitized and challenged with OVA and not in those treated with NaHS. The same was observed in the expression of TGF-?1 not affected either by the induction of OVA lung allergy or treatment with NaHS. The expression of both enzyme CSE in the bronchial epithelium and the vascular endothelium was increased in the lungs of allergic mice, and this increase was amplified by treatment with NaHS. Unlike the expression of this enzyme, treatment with NaHS did not alter the expression of the enzyme CBS in any of the studied pulmonary structures. In conclusion, our results suggest that H2S has a protective effect against lung damage caused by allergy. The reduced peribronchiolar infiltrate of eosinophils can be explained by the reduction in lung levels of IL-4, IL-5 and IL-25 due to the action of H2S. H2S also avoided apoptosis, and consequently, the destruction of the bronchial epithelium, which contributes to the reduction of pulmonary inflammation in allergic process. The CSE enzyme may be involved in this process. H2S has an important therapeutic potential for allergic pulmonary disorders such as asthma.? / Mestrado / Farmacologia / Mestra em Farmacologia

Orientador: Gilberto De Nucci / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-21T17:28:54Z (GMT). No. of bitstreams: 1 Carvalho_FernandaDelGrossiFerraz_D.pdf: 7417050 bytes, checksum: 077ba1139ebaf6a1ae4c5f1056628f58 (MD5) Previous issue date: 2012 / Resumo: A disfunção erétil (ED) é definida como a incapacidade de alcançar ou manter ereção peniana adequada para a relação sexual satisfatória. O diabetes mellitus (DM) é uma condição associada a inúmeros distúrbios sistêmicos que podem contribuir direta ou indiretamente para o desenvolvimento de ED, como aterosclerose de grandes vasos, doença arterial microvascular, neuropatia autonômica, dislipidemia, hipertensão arterial e disfunção endotelial. ...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: Erectile dysfunction (ED) is defined as the inability to achieve or maintain penile erection sufficient to permit satisfactory sexual intercourse. Diabetes mellitus (DM) is a condition associated with numerous systemic disorders that may contribute directly or indirectly to the development of ED, such as large vessel atherosclerosis, arterial microvascular disease, autonomic neuropathy, dyslipidemia, hypertension and endothelial dysfunction. ...Note: The complete abstract is available with the full electronic document / Doutorado / Farmacologia / Doutora em Farmacologia

Stormwater retention basins are an integral component of municipal stormwater management strategies in North America. The province of Ontario’s Ministry of the Environment and Climate Change obligates land developers to implement stormwater management in their land use and development plans to mitigate the effects of urbanization (Bradford and Gharabaghi, 2004). When stormwater retention ponds are improperly designed or maintained, these basins can fail at improving effluent water quality and may exasperate water quality issues. Intense H2S production events in stormwater infrastructure is a serious problem which is seldom encountered and documented in stormwater retention ponds. This study monitored two stormwater retention ponds situated in the Riverside South community, Ottawa, Ontario, Canada for a period of 15 consecutive months to thoroughly characterize intense hydrogen sulfide (H2S) production in a stormwater retention pond under ice covered conditions during winter operation and during periods of drought under non-ice covered conditions during the summer. Field experiments showed a strong relationship (p < 0.006, R > 0.58, n = 20+) between hypoxic conditions (dissolved oxygen (DO) concentration < 2 mg/L) and the intense production of H2S gas. Ice-capping of the stormwater ponds during winter severely hindered reaeration of the pond and led to significant production of total sulfides in the Riverside South Pond #2 (RSP2), which subsequently resulted in the accumulation of total sulfides in the water column (20.7 mg/L) during winter in this pond. There was a perceived lag phase between the drop in DO and the increase in total sulfides near the surface, which was potentially indicative of slow movement of total sulfides from the benthic sediment into the water column. These high-sulfide conditions persisted in RSP2 from early January 2015 until the spring thaw, in mid-April, 2015. Riverside South Pond #1 (RSP1), the reference pond studied in this work, showed significantly less production of total sulfides across a significantly shorter period of time. Analysis of the microbial communities showed that there was little change in the dominant bacterial populations present in the benthic sediment of the pond demonstrating significant total sulfide production (RSP2) and the pond that did not demonstrate significant total sulfide production (RSP1). Additionally, it was found that locations with the most accumulated sediment had the highest propensity for the production of H2S gas. Furthermore, there was no perceivable community shift in the two ponds throughout the seasons, indicating that the sulfate-reducing bacteria (SRB) in stormwater benthic sediment are ubiquitous, exist in an acclimatized microbial population and are robust. Study of the microbial abundances revealed that SRB represented approximately 5.01 ± 0.79 % of the microbes present in the benthic sediment of RSP2. Likewise, in the stormwater pond which did not experience intense H2S gas production, RSP1, 6.22 ± 2.11 % of microbes were of the SRB type, demonstrating that H2S gas production does not correspond to higher concentrations of SRB or the proliferation of dominant species, but rather is a symptom of increased bacterial activity due to favourable environmental conditions. In addition, this work also covers the kinetics of sediment oxygen demand (SOD), ammonification and sulfate-reduction, and attempts to understand the processes leading to H2S gas production events. In doing so, it was observed that kinetics obtained full-scale field studies were greater than in laboratory kinetic experiments. Laboratory experiments at 4°C identified total SOD, ammonification and sulfate-reduction kinetics to be 0.023 g/m2/day, 0.027 g N/m2/day and 0.004 g S/m2/day, respectively. Meanwhile, kinetics calculated from the field study of stormwater retention ponds for total SOD, ammonification and sulfate-reduction were of 0.491 g/m2/day, 0.120 g N/m2/day and 0.147 g S/m2/day, respectively. It is expected that this difference is due to the depth of active sediment influencing the total rates of production/consumption, making area-normalized daily rates of production/consumption (g/m2/day) unsuitable for the comparison of field and laboratory studies, without some scaling factor. This study also measured supplementary kinetic parameters such as the Arrhenius coefficients and the half-saturation coefficient, to add to existing knowledge of sulfate-reduction.

Hydrogen sulfide (H2S) is a gasotransmitter that has shown cardioprotective effects in the setting of myocardial injury such as acute myocardial infarction (MI) and pressure overload-induced heart failure. However, there are shortcomings in precision and control release from the use of traditional formulations of H2S in the form of inorganic salts. In this thesis, we sought to determine if the novel, orally active, slow-releasing H2S-compound SG1002 plays a role in attenuating MI-induced left ventricular (LV) dysfunction and adverse remodeling. We also evaluated the effect of SG1002 on changes in ECG parameters such as QT interval, in addition to 28-day survival post MI. SG1002 protects against ischemic cardiomyopathy in mice by mitigating LV dysfunction as measured by echocardiography and decreasing LV scar size as measured by histopathological methods. The improvement in survival might be due to the reduction in QT interval prolongation hence lessening the likelihood of forming lethal arrhythmias post MI. Western blot analyses of SG1002 treated mice showed restoration of VEGF levels indicating a pivotal role played by pro-angiogenic signaling in the improvement of cardiac function and attenuation of adverse remodeling. We propose that SG1002 can be a promising pharmacotherapeutic means for the treatment of ischemic heart failure.

The diploma thesis focusses on the elimination of odor in the sewer system. Firstly, the paper contains the research in problematics of the origin, control and risks of the hydrogen sulfide for humans as well as for the sewer system. Secondly, the paper describes methods for hydrogen sulfide removal from water, air and in addition to that the selected sorbents are described in detail. Practical part deals with sorbent testing for hydrogen sulfide removal in laboratory environment. The practical part also follows up the odor in the particular area through sorption on sewer filters. From the measured data and from the results of the laboratory analyzes the consequences of the odor are evaluated and recommendations for the operator are presented.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23181号 / 工博第4825号 / 新制||工||1754(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 高岡 昌輝, 教授 橋本 訓, 准教授 大下 和徹 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Modern landfills produce landfill gas, LFG, on a smaller scale and with limited content of degradable organic materials in the waste. The waste deposit in the Sofielund landfill began in 2005 and the final coverage is not yet commenced. The landfill waste must contain up to 10% decomposable organic materials at most. In a previous experiment on Sofielund landfill in summer 2011, the measurements from four sample wells showed the landfill gas consisted of up to 45% Methane and about 17000 ppm of Hydrogen sulfide, and the rest was only carbon dioxide. During the earlier experiment in 2011 and during 2012 the smell of H2S got offensive periodically and apart from that, concentrations above 1000 ppm are toxic. Previous research, Bottom ash for biogas upgrading, BABIU, shows that bottom ash from municipal solid waste incinerator (MSWI) can effectively reduce CO­­2 and H2S contents of landfill gas. Bottom ash from MSWI can be utilized in upgrading landfill gas and reduce odor problems of landfills with high H2S production. In this study, an area of 15m x 12m was covered with weathered slag from bottom ash with thickness of about 30cm, to examine how this layer can reduce the concentrations of H2S and CO2. Gas samples were taken from depths of 10cm and 15cm below the surface of bottom ash. There were also samples taken from around the slag-covered area. The surface was laid out 5 days before the first measurement was performed. The experiment was carried out for 20 days, 5, 7, 11, 13, 18 and 20 days after establishment of the surface with bottom ash. The intensity of emissions in different parts of the landfill varied from time to time, due to compacting and changing the permeability of the surface, and it shows that LFG flow in the Sofielund is near the lowest limit of it. Considering the results from the tests in 2011 in deep wells, the recent measurements done in this study showed low contents of LFGs. The highest contents of LFGs in the measurements belong to a pipe, which was found in the waste area of the landfill. Those highest contents of LFG were 15.1% methane, 12.1% carbon dioxide, 0.4% oxygen and the hydrogen sulfide did not exceed 2 ppm. This shows that in deeper depths concentrations of LFG is higher than that of the surface and 10cm below the surface. In the slag covered area CO2 content increased day by day from the first day of the measurement to the last day due to carbonation of the slag and its role in CO2 sequestration.  According to the recent measurement, it can be suggested to cover the landfill with a layer of slag as a construction material, to minimize the LFG emissions and the bad smell from H2S. Therefore it can eliminate direct emissions of LFG to the atmosphere by diffusion through the slag layer. This diffusion allows adsorption of CO2 and oxidation of H2S.

Doctor Educationis / Maize (Zea mays L.) is grown globally as an important grain crop in South Africa, United States, China and Brazil and plays a major role in the worldwide economy. In South Africa, the grain is utilised for food consumption, livestock feed, for malting purposes and bioethanol production. Maize contains approximately 72% starch, 10% protein, 4% fat and supplying an energy density of 365 Kcal/100 g. The production of grain crops in South Africa is restricted by various factors such as abiotic and biotic stresses. The fungal genus Aspergillus is one of the most important biotic stresses affecting maize in the country. Aspergillus flavus can contaminate a wide range of agricultural commodities either in storage or field. Hydrogen sulfide appears to have a potential in the mechanism of resistance against pathogen attack by Aspergillus flavus. / 2023