Energy generating performance of domestic wastewater fed sandwich dual-chamber microbial fuel cells
- Authors: Adeniran, Joshua Adeniyi
- Date: 2015-06-26
- Subjects: Waste products as fuel , Water - Purification - Membrane filtration , Water - Purification - Biological treatment , Sewage - Purification - Anaerobic treatment , Microbial fuel cells , Waste heat , Bioreactors
- Type: Thesis
- Identifier: uj:13627 , http://hdl.handle.net/10210/13808
- Description: M.Tech. (Civil Engineering) , This study presents work on the design and construction of three dual-chamber microbial fuel cells (MFCs) using a sandwich separator electrode assembly (SSEA) and membrane cathode assembly (MCA) for the dual purposes of energy generation from domestic wastewater and wastewater treatment. MFC1 was designed using an improvised SSEA technique (i.e. a separator electrode membrane electrode configuration, SEMEC) by gluing a sandwich of anode, membrane and a mesh current collector cathode to an anode chamber made from a polyethylene wide-mouth bottle. The reactor was filled with 1500 mL of domestic wastewater and operated on a long fed-batch mode with a residence time of 3 weeks. The reactor was inoculated with a mixed culture of bacteria present in the wastewater stream. The aim was to study the impact of wastewater COD concentration on power generation and wastewater treatment efficiency. For MFC2 and MFC 3, cathodes were constructed using the MCA technique consisting of a membrane and a mesh current collector cathode, with the anode electrode at the opposite side of stacked Perspex sections used for the anode chamber. The impact of electrode material on current production was examined in this study. For MFC2 a mesh current collector treated with polytetrafluoroethylene (PTFE) and activated carbon (AC) functioned as the cathode, while the MFC3 cathode was an uncatalyzed mesh current collector. The two reactors were both filled with 350 mL of domestic wastewater...
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Synthesis and characterization of choline based ionic liquids and their utilization in the recovery of base metals from BCL slag assisted by gold 1 mine bacterial isolates
- Authors: Moyaha, Letlhabile Thapelo
- Date: 2017
- Subjects: Ionic solutions , Bacterial leaching , Choline , Bioreactors
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/243976 , uj:25225
- Description: M.Tech. (Biotechnology) , Abstract: Due to the depletion of rich ore bodies, the fact that conventional extractions become obsolete and uneconomical and additional stringency on environment related regulations, there is a call for cheaper and greener metal extraction methods. Through research and innovation, new developments and improvements of processes and products are required in both metallurgical and biological areas. As a result, research interests in the use of microbes in the optimization of metal recovery from low grade sulphide ores have grown increasingly popular. The involvement of microbes in the recovery process is thus dependent on the growth of the microbes, which is influenced by their physicochemical parameters. The availability of nutrient salts is thus essential for maintaining optimal growth, furthermore is the dependence of metal dissolution with nutrient quantities on substrate accessibility. Considering the “green chemistry” of some ionic liquids the important “technological”, “toxicological ” and “eco-toxicological” assessment of the risks related with ionic liquid design; choline based ionic liquids were selected by virtue of their low toxicity, low environmental persistence and readily biodegradable nature. As a result of the selective solubility strength of metal oxides in ionic liquids, choline based ionic liquids were considered novel media for obtaining target metals and improving bioleaching kinetics. The study thus sought to develop an economic and eco-friendly alternative technology, employing choline based ionic liquids as biocompatible substrates for the optimal recovery of base metals, improving bioleaching kinetics. Biological and molecular characterization of ultra-deep mine isolates (Gold 1 Mine East Rand, Springs Johannesburg, South Africa) revealed a halophilic community of gram positive and negative bacteria namely Raoultella ornithinolytica, Bacillus sp., Bacillus thuringiensis and Pseudomonas moraviensis. The halophilic bacterial strains indicated high biocompatibility in choline lactate, choline chlorite, choline dihydrogen phosphate, choline citrate and choline levulinate with poor biocompatibility noted in choline citrate and choline tartarate. According to literature, the biocompatibility of the leading choline based ionic liquids (ILs) was accredited to the quaternary- ammonium cation integrating a polar hydroxyl and the limited branching of the side chain. Prominent logarithmic growth in choline lactate was indicative of the metabolic advantage of choline lactate over conventional glucose sources. Furthermore, the bioleaching of BCL slag by Bacillus species and Bacillus...
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Volatile organic compounds abatement : a critical discussion of destruction techniques
- Authors: Muzenda, Edison , Belaid, Mohamed
- Date: 2013
- Subjects: Volatile organic compounds , Bioreactors
- Type: Article
- Identifier: uj:4968 , http://hdl.handle.net/10210/13069
- Description: This paper critically discusses volatile organic compounds destruction techniques. The methods discussed are thermal and recuperative oxidation, catalytic oxidation, regenerative oxidation, flares and bioreactors. Examples of bioreactors discussed are bio-filters, bio-trickling filters and bio-scrubbing filters. The principle of operation as well as the strength and weaknesses of each methods are given.
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