Inadequate sanitation is one of the leading causes of water pollution and consequently illness in many underdeveloped countries, including South Africa and, specifically, the Eastern Cape Province, where cholera has become endemic. As modern wastewater treatment processes are often energy intensive and expensive, they are not suitable for use in these areas. There is thus a need to develop more sustainable wastewater treatment technologies for application in smaller communities. The integrated algal ponding system (IAPS) was identified as a possible solution to this wastewater management problem and was investigated for adaptation to local conditions, at the Rhodes University Environmental Experimental Field Station in Grahamstown, South Africa. The system was monitored over a period of nine years, with various configuration adjustments of the high rate algal pond (HRAP) unit operation investigated. Under standard operating conditions, the system was able to achieve levels of nutrient and organic removal comparable with conventional wastewater treatment works. The mean nitrate level achieved in the effluent was below the 15mg.l-1 South African discharge standard, however, nitrate removal in the IAPS was found to be inconsistent. Although the system was unable to sustain chemical oxygen demand (COD) removal to below the 75mg.l-1 South African discharge standard, a removal rate of 87% was recorded, with the residual COD remaining in the form of algal biomass. Previous studies in the Eastern Cape Province have shown that few small wastewater treatment works produce effluent that meets the microbial count specification. Therefore, in addition to the collation of IAPS data from the entire nine year monitoring period, this study also investigated the use of the HRAP as an independent unit operation for disinfection of effluent from small sewage plants. It was demonstrated that the independent high rate algal pond (IHRAP) as a free standing unit operation could consistently produce water with Escherichia coli counts of 0cfu.100ml-1. The observed effect was related to a number of possible conditions prevailing in the system, including elevated pH, sunlight and dissolved oxygen. It was also found that the IHRAP greatly enhanced the nutrient removal capabilities of the conventional IAPS, making it possible to reliably and consistently maintain phosphate and ammonium levels in the final effluent to below 5mg.l-1 and 2mg.l-1 respectively (South African discharge standards are 10mg.l-1 and 3mg.l-1 in each case). The quality of the final effluent produced by the optimisation of the IAPS would allow it to be used for irrigation, thereby providing an alternative water source in water stressed areas. The system also proved to be exceptionally robust and data collected during periods of intensive and low management regimes were broadly comparable. Results of the 9 year study have demonstrated reliable performance of the IAPS and its use an appropriate, sustainable wastewater treatment option for small communities.

Anaerobic digestion (AD) of corn thin stillage (CTS) offers the potential to reduce corn grain ethanol production energy consumption. This thesis focuses on results collected from AD of CTS at mesophilic temperatures in batch and by down-flow fixed film reactor. Experiments conducted include a series of biochemical methane potential (BMP) assays that investigated the digestion of CTS as the sole carbon source at a variety of food-to- microorganism ratios with and without acclimated biomass, under co-digestion conditions and also with the addition of supplemental nutrients. Additional BMP assays were conducted which investigated the potential to reduce fresh water consumption by using of digested effluent for substrate dilution. Continuous studies employed two 28L down-flow stationary fixed film reactors to examine. Chemical oxygen demand and volatile solids removal efficiencies greater than 85% were achieved up to an organic loading rate of 7.4 g TCOD/L/d and hydraulic retention time of 5 days.

The rapid accumulation of municipal solid waste is a significant environmental concern in our rapidly growing world. Due to its low cost, high energy recovery and limited environmental impact anaerobic digestion (AD) is a promising solution for stabilizing the organic fraction of municipal solid waste (OFMSW). Hydrolysis is often the rate-limiting step during AD of wastes with high solid content; this step can be accelerated by pretreatment of waste prior to AD. This thesis presents the results of alkaline pretreatment of OFMSW using NaOH and KOH. Four different pH levels 10, 11, 12 and 13 at two temperatures 23±1°C and 80±1°C were examined to study the effects of the pretreatment on (i) enhancing the solubility of the organic fraction of the waste, and (ii) enhancing the AD process and the biogas production. The effects on solubility were investigated by measuring changes in the soluble COD (SCOD) concentrations of pretreated wastes and the enhanced AD was investigated by measuring volatile solids (VS) destruction, total COD (TCOD) and SCOD removal in addition to biogas and methane production using biochemical methane potential (BMP) assay and semi-continuous laboratory reactor experiments. Pretreatment at pH 13 at 80±1°C demonstrated the maximum solubility for both NaOH and KOH pretreated samples; however the BMP analysis demonstrated that pretreatment at pH 12 at 23±1°C showed the greatest biogas yield relative to the removed VS for both chemicals. Thus pretreatment at pH 12 at 23±1°C using NaOH and KOH were examined using semi-continuous reactors at three different HRTs: 10, 15 and 20 days. Pretreatment demonstrated a significant improvement in the AD performance at SRTs of 10 and 15 days.

O objetivo deste estudo foi a validação da medida de limiar anaeróbio com o teste escalonado intermitente de 20 m de ida-e-volta em quadra, comparando-o com teste escalonado em esteira e com o máximo “steady state” de lactato (MLSS) em teste retangular simulado, em jogadores de Futsal. Para isso, nove jogadores de Futsal (16,8 ± 1,27 anos) realizaram um teste incremental em esteira (protocolo de HECK, 1985) para determinação da velocidade de 3,5 mmol.l-1 de lactato (V3,5Heck). Também para determinação da V3,5 (V3,5leger), os atletas realizaram teste progressivo de 20 m de ida-e-volta, com velocidade inicial de 8,5 km.h-1, com incremento de 1 km.h-1 a cada três minutos. Após a determinação da V3,5leger, os atletas retornaram à quadra e realizaram (pelo menos) três testes para a determinação do MLSS. O MLSS foi determinado através de corrida intermitente (20 m de ida-e-volta) e definido como a maior velocidade em que o lactato sanguíneo não aumentou mais que 1 mmol.l-1 de lactato entre o 10 e 30 minutos com velocidade constante. As velocidades correspondentes à V3,5leger e MLSS tiveram correlação de r = 0,86. O teste de comparações múltiplas TURKEY TEST detectou que existe diferença (p<0,05) entre as médias de intensidade de MLSS e V3,5Heck e entre V3,5Heck e V3,5leger. Já entre V3,5leger e MLSS, o teste não detectou diferença. A correlação entre a F.C. no V3,5leger e o MLSS foi de r = 0,70. O teste de comparações múltiplas TURKEY TEST detectou que existe diferença (p<0,05) entre as médias de F.C. entre V3,5leger e MLSS e entre V3,5Heck e MLSS. Já entre V3,5leger e V3,5Heck, o teste não detectou diferença. Portanto, nós concluímos que a V3,5leger é um instrumento válido para se estimar o MLSS em jogadores de Futsal. / The objective of this study was to investigate the validity of the anaerobic threshold in the 20 m shuttle run test in the determination of the maximal lactate steady state (MLSS) in Futsal players. Nine male futsal players (16,8 ± 1.27 years) performed an incremental treadmill test for the determination of the velocity corresponding of 3.5 mmol.l-1 of lactate (HECK et alii, 1985) (V3.5Heck). Also for the determination of the V3.5 (V3.5leger), the Futsal players performed the 20 m shuttle run test, with the initial running speed of 8.5 km.h-1 and increment of 1 km.h-1 each three minutes. After the determination of the V3.5 the athletes performed at least three tests to determine the MLSS. The MLSS was determined through intermittent running (20 m shuttle run) and defined as the highest velocity at which blood lactate did not increase by more than 1 mmol.l-1 between the minutes 10 and 30 of the constant velocity runs. There was a significant correlation between the velocities of V3.5leger and MLSS (r = 0.86). Analysis of variance revealed significant difference (p<0.05) between the intensities of the MLSS and V3.5Heck and between V3.5Heck e V3.5leger, but the analysis did not reveal difference between V3.5leger and the MLSS. The correlation between the heart frequency (F.C.) in the V3.5 Leger and MLSS was r=0.70. The analysis of variance revealed significant differences (p<0.05) between F.C. in V3.5leger and MLSS and between V3.5Heck and MLSS. The analysis did not revealed differences between V3.5leger and V3.5Heck. We conclude that OBLA can be utilized in Futsal players to estimate the MLSS.

Clostridium difficile is a strictly anaerobic, spore-forming bacterium that is linked to over 250,000 infections annually in the United States. One of the greatest challenges facing C. difficile research has been the lack of genetic tools. This limited repertoire is due, in part, to the anaerobic nature of C. difficile. For example, most fluorescent protein reporters require O2 for chromophore maturation. Here, we demonstrate that O2-dependent fluorescent proteins produced anaerobically can acquire fluorescence after cells are fixed with cross-linkers to preserve native patterns of protein localization. This was shown using the blue and the red codon-optimized fluorescent proteins, CFPopt and mCherryOpt, respectively. Little is known about cell division in C. difficile. Here we identify and characterize a three-gene operon encoding cell division proteins found only in C. difficile and a small number of closely related bacteria. These proteins were named MldA, MldB, and MldC, for midcell localizing division proteins. MldA is predicted to be a membrane protein with coiled-coil domains and a peptidoglycan-binding SPOR domain. MldB and MldC are predicted to be cytoplasmic proteins; MldB has two predicted coiled-coil domains, while MldC lacks obvious conserved domains or sequence motifs. Mutants of mldA or mldB had morphological defects, including loss of rod shape (a curved cell phenotype) and inefficient separation of daughter cells (a chaining phenotype). Fusions of CFPopt to MldA, MldB, and MldC revealed that all three proteins localize sharply to the division site. Mutants lacking the Mld proteins are severely attenuated for pathogenesis in a hamster model of C. difficile infection. Because all three Mld proteins are essentially unique to C. difficile, they could be exploited as targets for antibiotics that combat C. difficile without disrupting the intestinal microbiome. C. difficile pathogenesis is mediated primarily by two large exotoxins called Toxin A (TcdA) and Toxin B (TcdB). Transcription of tcdA and tcdB depends on TcdR, an alternative sigma factor for RNA polymerase. Previous studies have shown both toxins are produced upon entry into stationary phase, and that this response is mediated in part by the CodY repressor, which senses GTP and branched chain amino acids. Here we used mCherryOpt as a reporter of gene expression to visualize toxin expression at the level of individual cells. This approach led to the unexpected discovery that only a subset of cells in the population induces expression of tcdA (and tcdB under specific conditions). In other words, toxin production is a “bistable” phenotype. Further experiments indicated TcdR plays a central role in mediating bistability, while CodY makes a minor but still significant contribution to bistability. Why it is advantageous for only a subset of C. difficile cells to produce toxin is not known, but one interesting possibility is related to conflicting requirements for transmission to a new host. Some cells produce toxin to provoke diarrhea while other cells differentiate into spores that can survive exposure to air.

No description available.

Anaerobic digestion can be used to decrease the mass of organic wastes to be disposed of while producing useful biogas (CH4 and CO2) for heat or power production, but in air basins with strict emissions limits, biogas combustion is difficult to implement due to the high costs of controlling NOx emissions. NOx production can be minimized by blending H2 gas with CH4 at a volume ratio of 15:85 H2:CH4, which allows burning at ultra-lean air-to-fuel ratios. For biogas systems, a potential low-cost NOx control strategy is to produce H2-CH4 mixtures through two-phase anaerobic digestion, where two digester tanks are operated in series, with the first one producing a majority H2 and the second CH4. The resulting mixture of H2, CH4, and CO2 should combust with low NOx emissions. Furthermore, in theory, if the biogas from the second-phase is sparged through the first-phase, H2 would be stripped from the first-phase liquid medium, and H2 production would be more thermodynamically favored, possibly increasing H2 production. Laboratory experiments were used to determine the optimal conditions to generate biogas with a 15:85 H2:CH4 ratio using two phase digestion with glucose as the substrate. Specifically, the objectives of this thesis were to (1) determine the optimal conditions for operating the first-phase to produce H2, (2) determine the sparging rate required to achieve 15:85 H2:CH4 in the biogas, and (3) operate the first and second-phases together with second-phase biogas being sparged through first-phase medium to achieve 15:85 H2:CH4. The results from each of these objectives are described below. (1) The optimal conditions for H2 production in the first-phase were an organic loading rate of 22.9 g COD/L-day (chemical oxygen demand) and a hydraulic residence time of 12 hours. The resulting pH in the first-phase was 6.11 when operated under these conditions. Optimized hydrogen production in the first phase resulted in the generation of 1.02 ± 0.13 L H2/Ldigester-day, which can also be expressed as 0.61 ± 0.10 mol H2/mol glucoseconsumed, 0.42 ± 0.06 mol H2/mol glucoseintroduced, 1.06 ± 0.16 mol H2/mol CODdestroyed, and 0.06 ± 0.01 mol H2/mol CODintroduced. (2) Initial sparging experiments were conducted using nitrogen (N2) to represent second-phase biogas. The rates tested ranged from 1- 30 L N2/Lfirst-phase digester-hr. A 1.1 L gas/L-hr sparging rate was projected to result in a 15:85 H2:CH4 ratio. The projection was made using a power regression model (R2 = 0.99) of sparging rate vs. hydrogen content results, assuming the sparged N2 was replaced with typical biogas (60% CH4 and 40% CO2). (3) When both phases were integrated, the second-phase produced enough gas to sparge at only 0.28 L gas/Lfirst-phase digester-hr, which was far less than the optimal 1.1 L gas/Lfirst-phase digester-hr sparging rate. A non-optimal H2:CH4 ratio of 15:12 was obtained at the 0.28 L gas/L-hr sparging rate. Insufficient CH4 was generated due to the low organic loading provided to the second-phase. Although the 1.1 L gas/L-hr sparging rate was not tested in an integrated system, the results obtained from the 0.28 L gas/L-hr sparging rate differed from what was predicted by the nitrogen sparging model by only 14%. Therefore, the model was fairly accurate (at least at a low flow rate of 0.28 L gas/L-hr) and could still be valid for the predicted optimal flow rate of 1.1 L gas/L-hr. For future two-phase digestion studies, biogas production from the second-phase can be increased by adding more substrate to the second-phase or by using fixed-film digesters to possibly increase the number density of methanogens. It is also recommended to digest practical waste feedstocks, and possibly digest different feedstocks in the first and second-phases. Also, the effects of carbon dioxide on the combustion characteristics and NOx emissions of hydrogen-methane mixtures in biogas need to be researched.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23184号 / 工博第4828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 田中 宏明, 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

Biogas is an environmentally friendly energy source with great importance for sustainable development. The purpose of this study is to determine the feasibility of setting up a biogas plant at the student housing area planned at Albano in Stockholm. The possibility of attaining self-sustainability in Albano is also investigated. After compiling the processes for converting household waste into biogas through a literature study, a quantitative feasibility study of setting up a biogas plant is carried out. The usable amount of household waste is determined through an empirical study. Investment costs of comparable biogas production facilities are obtained from companies working in the biogas field. The producible biogas amount and rates of conversion from biogas to heat/electricity are derived from existing data in similar studies. The energy demand is calculated based on existing data from housing companies and authorities. Four possible scenarios are created to study all the possible outcomes of establishing a biogas plant. The maximum producible biogas is determined to be 12.199 m3/year. The total energy demand in Albano is determined to be 2.931MWh/year, of which 2,4 TWh/year is heat and 531 MWh/year is electricity. This amount is not sufficient to meet the specific requirements. Recommendations for Albano were made accordingly. / Biogas betraktas som ett en miljövänlig energikälla med stor betydelse för det kommande arbetet mot en mer hållbar utveckling. Denna rapport avser behandla möjligheten till ett upprättande av en biogasanläggning vid ett planerat studentboende vid Albano, Stockholm. Vidare kommer även möjligheterna till ett mer självständigt hållbart arbete i området behandlas. Som en del i rapporten kommer en analys av omvandlingen från hushållsavfall till biogas utföras i form av en kvantitativ studie med fokus på en förstudie för upprättande av biogasanläggning. Mängden hushållsavfall fås genom en empirisk studie av författaren. Den andel energi som beräknas kunna produceras fås genom befintlig data från utförda studier på Albano. Utifrån detta fastställs energibehovet utifrån givna rekommendationer och uppskattningar utförda av företag och myndigheter. Fyra möjliga utfall är definierade i syfte att kartlägga de möjliga utfallen för biogasanläggningen. Den maximala andel producerad biogas uppgår till 12.199 m3/år. Den totala energibehov i Albano bestämdes till 2.931 MWh/år, varav värmebehovet är 2,4 TWh/år och elbehovet är 531 MWh/år. Den maximala andel producerad biogas kan användas för att tillverka 48,8 MWh/år värme och 24,4 MWh/år elektricitet. Denna mängd är inte tillräcklig för att tillgodose de bestämda kraven. Utifrån detta har olika förslag utformats.

Trends in pairs figure skating have shown that increasingly difficult jumps have become an essential aspect of high-level performance, especially in the latter part of a competitive program. We compared a repeated jump power index in a 60 s repeated jump test to determine the relationship of repeated jump test to competitive rank and to measure 2D hip, knee, and ankle angles and angular velocities at 0, 20, 40, and 60 s. Eighteen National Team Pairs Figure Skaters performed a 60 s repeated jump test on a large switch-mat with timing of flight and ground durations and digital video recording. Each 60-s period was divided into 6, 10-s intervals, with power indexes (W/kg) calculated for each 10-s interval. Power index by 10-s interval repeated measures ANOVAs (RMANOVA) showed that males exceeded females at all intervals, and the highest power index interval was during 10 to 20 s for both sexes. RMANOVAs of angles and angular velocities showed main effects for time only. Power index and jumping techniques among figure skaters showed rapid and steady declines over the test duration. Power index can predict approximately 50% of competitive rank variance, and sex differences in jumping technique were rare.