Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 99 for “"Digesters"”.
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The structural performance of egg-shaped sludge digesters
Includes bibliographical references.
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Dairy Manure Flushwater Treatment by Packed-Bed Anaerobic Digesters
… of three pilot-scale packed-bed anaerobic digesters with walnut shell medium was researched for treating dairy freestall barn flushwater. Reciprocation mixing was evaluated as a means to lessen channelization in the media bed and to improve biogas production and organic matter removal at …
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Optimisation of biogas production from percolating packed bed anaerobic digesters
Percolating packed bed digesters were operated successfully in a batch mode using a wheat straw - dairy manure substrate of between 21 and 27% total solids. The vessels used had a nominal 10 1 volume and were constructed of perspex. Temperatures of 25-35°C were used, recirculation rates of 0-15 …
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Design and performance studies of pilot scale inclined tubular digesters operating on cattle slurry
Two pilot scale (1 and 2m3) inclined tubular digesters were designed and constructed adjacent to a large dairy unit. The digesters were instrumented to monitor automatically gas production, temperatures and the electrical energy used for heating. Operation of the digesters was reliable. Aspect …
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Stresses in egg-shaped sludge digesters in the form of ellipsoidal shells of revolution
Anaerobic sludge digesters of the squat cylindrical shape have inherent flaws which drive up maintenance costs, limits its ability to maintain optimum environmental conditions and is not shaped for efficient mixing. The egg-shaped sludge digester is an effective solution to these flaws. However, …
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Comparison of Dairy Manure Anaerobic Digestion Performance in Gas-lift and Bubble Column Digesters
… type of gas-circualtion based anaerobic digesters, with the aim to understand the effects of hydrodynamic behavior of the digesting liquid on the anaerobic digestion performance, so a better mixing strategy can be provided. We used two 20-L gas circulation based anaerobic digesters with …
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An investigation into increased productivity of small scale anaerobic digesters by means of temperature management
… biogas is traditionally used for heating of the digesters in order to increase process performance. Smaller scale anaerobic digesters using food waste as a primary energy source for biogas production could be implemented for residences and restaurants. The biogas produced could be used for …
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The effect of biomass acclimation on the co-digestion of toxic organic effluents in anaerobic digesters
Dissertation submitted in fulfilment of academic requirements for the Degree of Master of Technology: Chemical Engineering, Durban University of Technology, Durban, South Africa, 2008.
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Kinetics of the release and precipitation of phosphorus in anaerobic digesters sequencing biological phosphorus removal systems
… granules of microorganisms present in anaerobic digesters sequencing a biological phosphorus removal (BPR) activated sludge system was examined. The research was conducted at the York River Wastewaster Treatment plant which was converted from a conventional system to a A/O process for biological …
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Opportunities for Nutrient Recovery from Post-Digestion Sludge Handling: Analysis and Feasibility Study Using Municipal Scale Aerobic and Anaerobic Digesters
The wastewater treatment process has developed with the primary goals of protecting receiving water ecosystems and human health. Over time, there have been continuous innovations in process efficiencies, energy recovery, and nutrient removal. Wastewater offers opportunity for recovery of resources …
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Establishing the environmental and economic benefits of applying advanced thermal hydrolysis to existing anaerobic digesters in the Western Cape, South Africa
… sludge could be processed using the existing digesters' volume i.e. without building any additional digesters. This results in sludge treatment throughput increasing from 60 dry tonnes of solids per day for conventional digestion to 153 dry tonnes per through advanced THP digestion. Modelling …
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Operation of a Tubular Anaerobic Digested on Piggery Waste
Three inclined tubular digesters of 13-15.3L volume were operated successfully at 20-35 C with hydraulic retention times (HRT) of 10-50 days on pig slurry of 10,,5,.2.5 and 1% Total Solids content. Tube inclination of 16-20 overcame the scumming problems encountered with horizontal tubular …
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Barriers to Adoption of Methane Digester Technology on California Dairies
… to analyze the barriers to adoption of methane digesters on California dairies. Methane digesters have long existed as a technology in the dairy industry, both in the United States and abroad. Much research has been done to attest to the viability and economic sustainability of methane …
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A Comparative Study of Anaerobic Digestion Processes for Sewage Sludge
… D.C. is in the process of updating its anaerobic digesters, with a completion date set for 2008. This research was undertaken to aid designers at Blue Plains by evaluating alternative digestion approaches. The technologies applicable to the plant included thermophilic anaerobic digestion, acid/gas …
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Insights into Adaptations of Biogas-Producing Microbial Communities from Taxonomic Profiling, Metagenomically Assembled Genomes and Analysis of the Methanogenic Isolate Methanothermobacter wolfeii SIV6
… in differently operated large-scale agricultural digesters. For this purpose, three different approaches were applied to unravel certain types of adaptations of the microbial communities within biogas plants. <br />Firstly, a 16S rRNA gene-based taxonomic profiling of 67 differently operated …
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Development of a mathematical model for predicting bio-slurry temperature and subsequent gas production rate for underground brick-built biogas digester using ambient air temperature forecast
… brick, and mortar built fixed dome type digesters are the most deployed small-scale biogas technology in sub-Saharan Africa (SSA) countries such as Rwanda, Ethiopia, Tanzania, Kenya, Uganda, Burkino Faso, Cameroon, Benin, Senegal, and South Africa despite their relatively high initial …
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Upflow anaerobic sludge blanket reactors for treatment of wastewater from the brewery industry
… this project was to set up lab-scale anaerobic digesters to collect data that will be used to develop and validate a predictive monitoring and controls solution to improve digester performance. The research project involved the design, construction, and instrumentation of lab-scale anaerobic …
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Weed seed survival in an agriculturally-based anaerobic digester
… fermentation processes in laboratory-scale digesters. The effect of influent solids concentration (4% and 6%) and retention time (15 days and 20 days) on seed viability was observed. The experiments were carried out in the mesophilic temperature range [35°C±1ºC]. Fall Panicum seeds were …
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Methane Production by a Packed-Bed Anaerobic Digester Fed Dairy Barn Flush Water
<p>Packed-bed digesters are an alternative to covered lagoon digesters for methane production and anaerobic treatment of dilute wastewaters such as dairy barn flush water. The physical media of packed-beds retain biofilms, often allowing increased treatment rates. Previous studies have evaluated …
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Anaerobic Co-digestion of Wastewater Treatment Pond Algae with Wastewater Sludge
… content of algae can lead to ammonia toxicity in digesters. Co-digestion of algae with substrates containing higher C:N ratios (e.g., waste paper) can be used to maintain non-inhibitory ammonia concentrations and increase methane production. However, high carbon waste co-substrates have become …
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