Ergogenic L-citrulline and malate are amino acids used in specific combination to effect muscular endurance during athletic performances. Purpose: The study aimed to investigate the ergogenic properties of citrulline-malate (CM) during a resistance training protocol. Methods: Utilizing a randomized, counterbalanced, double blind study, fifteen trained males completed a resistance training protocol once using placebo (PL) and once with CM (8.0g). Results: CM supplementation increased repetitions in chin-ups, reverse chin-ups, push-ups, and total trial repetitions. Blood lactate was significantly increased post-exercise compared to pre-exercise, but was not significantly different between CM and placebo. Further, a significant interaction effect was revealed for systolic blood pressure, a significant condition effect for diastolic blood pressure, and a significant time effect for HR. Post-hoc analysis revealed that SBP responses were more elevated in the placebo condition during recovery. Conclusion: Collectively, these novel findings suggest CM increases muscular endurance during upper body resistance exercise.

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Section I: Facultative and obligatory anaerobic bacteria were isolated from the ground water of a sanitary landfill characterized by sandy soil and a periodically high water table. Isolates were examined for 63 characteristics and subject to numerical analysis. Eight clusters were established and correlations with conventional taxonomy were made. The Bacteriodaceae were found to be the dominant group of organisms by the methods employed. The anaerobic population was observed to decrease as the period of seasonal rainfall ended. At the same time, gram positive anaerobes were largely replaced with gram negative ones. Leaching between sampling sites (wells) made correlations between metabolic end products (observed by gas-liquid chromatography) and metabolites produced by the organisms in vitro, impossible. Attempts were made to modify the original test battery to create a smaller battery which would yield approximately the same groupings as the original battery. Clusters became less discreet with these modifications and probably unacceptable for detailed taxonomic work. Section II: An index is described which measure the "goodness of fit" of an organism within a phenon as established by numerical taxonomy. A hypothetical mean organism was established for each phenon. Similarity and relevance coefficients were generated between this hypothetical organism and each member of the phenon. The product of these two coefficients has been termed the Index of Relevance and Similarity (IRS). This index ranges from zero to unity and can be generated with two-state and/or multistate data.

Sludge management is the highest operating cost in municipal wastewater treatment. Anaerobic digestion (AD) is used to stabilize the sludge and reduce biosolids generation. Hydrolysis kinetics limit the rate of anaerobic digestion and must be improved to increase the overall process rate. In this study a new sludge characterization analysis was used to evaluate hydrolysis in a lab-scale pretreatment process operated at 55℃, 65℃, and 75℃. The experimental results were used to develop a new AD mathematical model, the hydrolysis digestion model (HDM). The model developed is easier to use, as the number of processes and variables were reduced by half, in comparison to existing models. The model variables can be measured using standard sludge characterization analysis, and the hydrolysis reactions included the fermenting microorganism to more accurately model the two-phase hydrolysis model. Model simulations were found to be a good fit of the experimental results, accurately predicting the rate and extent of hydrolysis in the pretreatment digester. / Thesis / Master of Applied Science (MASc)

Thesis (PhD (Food Science))--University of Stellenbosch, 2009. / In the absence of anaerobic granules, anaerobically digested sewage sludge is frequently used to seed industrial upflow anaerobic sludge blanket (UASB) reactors. Because of its flocculent nature, start-up with digested sludge instead of granular sludge proceeds much slower and presents various operational problems. Any manner in which the granulation of digested sludge can be enhanced would benefit UASB reactor start-up and application in developing countries such as South Africa. The main objective of this dissertation was to improve granulation and reduce UASB reactor start-up by using pre-treated digested sludge as seed. The sludge was pre-treated based on the batch granulation-enhancement model of Britz et al. (2002). The main aim of the model was to improve extracellular polymer (ECP) production of lactate-utilising populations by applying short-term controlled organic overloading in a mechanically agitated environment. The batch granulation-enhancement (pre-treatment) process was applied to an ECP-producing digester strain, Propionibacterium jensenii S1. Non-methanogenic aggregates were formed when batch units were incubated on a roller-table instead of a linear-shake platform. Larger, more stable aggregates were obtained in the presence of apricot effluent medium. Preliminary batch granulation-enhancement studies confirmed that using the roller-table as mixing system had a positive influence on batch granulation-enhancement. The roller-table showed the most potential for handling larger volumes in comparison to a linear-shake waterbath and linear-shake platform. The addition of 450 mg.L-1 Fe2+ at the start of the study also influenced aggregate numbers positively. These studies revealed that pre-treatment results varied depending on the seed sludge source. A denaturing gradient gel electrophoresis (DGGE) method was applied for the detection of Archaea in digested sludges and UASB granules. In addition, a methanogenic marker containing methanogens important to the granulation process was constructed to aid identification. The positive influence of DMSO and “touchdown” PCR on the elimination of artifactual double bands in DGGE fingerprints were also demonstrated. Results revealed that only one of the four digested sludges tested contained Methanosaeta concilii (critical to granular nuclei formation) while it was present in all the UASB granules regardless of substrate type. Four digested sludges were obtained from stable secondary digesters. DGGE indicated the presence of M. concilii in all sludges. The Athlone 4Sb-sludge was the only sludge which exhibited measurable methanogenic activity during substrate dependent activity testing. The ST-sludge showed the highest increase in volatile suspended solids (VSS) particles ≥0.25 mm2. Laboratory-scale UASB reactor start-up was done with both sludges and start-up proceeded better in the Athlone 4Sb-reactor. Athlone 4Sb-sludge batches were pre-treated in a rolling-batch reactor in the presence of either lactate or sucrose and used to seed lab-scale UASB reactors B (sucrose seed) and C (lactate seed). Start-up efficiencies were compared to a control (Reactor A). Overall Reactor B was more efficient that the control. At the end of the study the Reactor B sludge had a higher methanogenic activity than the control reactor. It also had the highest increase in VSS ≥1.0 mm2. Pre-treatment of digested sludge in the presence of sucrose, therefore, aided granulation and reduced UASB reactor start-up time.

Organosilicon compounds, which are heavily utilized in personal care products, are typically present, sometimes in high concentrations in the influent of wastewater treatment facilities. During anaerobic sludge digestion, these compounds volatilize and enter the methane gas recovery stream. As the methane is combusted for energy cogeneration, these compounds become oxidized to microcrystalline silicon dioxide and cause damage and potential failure of expensive infrastructure. Adsorption and other catchment methods are typically utilized for removal of these volatilized compounds in order to mitigate their entrance into methane combustion systems. This research investigated the effect of phased anaerobic digestion, specifically acid-gas digestion, on the behavior of the volatilization of these organosilicon compounds, particularly octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) as these are the most abundant volatile silicone compounds present in sludge. A bench scale acid reactor anaerobic digester was operated at varying solids retention times and temperatures in order to quantify biogas effects generated in the downstream gas reactor, which was operated at a constant mesophilic conditions. Results of the research indicated that the addition of an acid reactor did not cause a change in behavior of the D4 and D5 siloxane volatilization in the downstream gas reactor. However, it was observed that hydrogen sulfide gas was decreased in the gas reactor when an acid reactor was utilized, which could permit decreased corrosivity of biogas recovery. Cumulative volatile solids reduction and gas reactor methane yield data did not indicate an enhancement due to utilization of acid-gas digestion. / Master of Science

Energy shortfall and air pollution are some of the challenges the human kind is facing today. Fossil fuel is still the most widely used fuel, which is a non-renewable resource, increasing excess carbon dioxide into the air. To overcome these issues, and reduce the carbon footprint, a greater development of renewable energy from green and natural resources is required. Compared to fossil energy, renewable energy has the benefit to reduce greenhouse gas emissions. There are different solutions available for green and renewable energy. Biomass is all biologically produced matter. Through the biological breakdown of biomass, biogas can be produced through the process called anaerobic digestion. This work was focused on the production of biogas, using algal biomass, sewage sludge and coffee grounds in an anaerobic co-digestion system. The main goal of this study was to investigate the feasibility of combining these three substrates. Two different types of algae were employed; Chlorella vulgaris and Scenedesmus sp. and the investigations included even the cultivation and harvesting of algal biomass. The production of biogas was examined under anaerobic conditions using 5 batch reactors in duplicate under constant temperature of 37 °C in 30 days. The result showed that co-digestion of algal biomass with sewage sludge led to an enhanced biogas production by 75 % compared to that of just sewage sludge. This indicates the synergistic effects of co-digestion. However, the addition of coffee ground to the mixture lowered the biogas production. All mixtures except the two with coffee grounds were in neutral pH. Methanogens, involved in the last step in biogas production are very sensitive to pH, and pH around 7 is the optimal for their activity. Furthermore, the presence of caffeine in the coffee ground could also inhibit the biogas production.

Innovative pre-treatment methods applied to anaerobic digestion (AD) have developed to enhance the methane yields of food waste. This study investigates hydrodynamic cavitation, which induce disintegration of biomass through microbubble formations, impact on food waste solubilisation and methane production during following AD. Two different sub-streams of food waste (before and after the digestion) pre-treated by hydrodynamic cavitation were evaluated in lab scale for its potential for implementation in a full scale practise. First, the optimum condition for the hydrodynamic cavitation device was determined based on the solids and chemical changes in the food waste. The exposure time was referred to as the number of cycles that the sample was recirculated through the cavitation inducer’s region. The optimal cycles were later tested as a pre-treatment step in a BMP test and semi-CSTR lab scale operation. The tests showed that sufficient impact from the hydrodynamic cavitation was achieved by 20 cavitation cycles. Due to the pre-treatment, food waste solubilisation increased, up to 400% and 48% in terms of turbidity and sCOD measurements, respectively. In the BMP test, the treated samples improved the methane yield by 9-13%, where the digested food waste increased its kinetic constant by 60%. Fresh food waste was then processed in the semi-CSTR operation and the methane yield was increased by up to 17% with hydrodynamic cavitation for two reference periods. These promising results suggest that the hydrodynamic cavitation can be implemented for full scale production with food waste.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

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