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Die rol van metaboliese beheermeganismes in Acinetobacter spp met betrekking tot fosfaatverwydering deur die geaktiveerdeslykproses

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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Parametric study and economic evaluation of a simulated biogas upgrading plant

  • Authors: Masebinu, Samson Oluwasegun
  • Date: 2015-06-25
  • Subjects: Sewage disposal plants - Biodegradation , Sewage disposal plants - Energy conservation , Sewage - Purification - Anaerobic treatment , Water - Purification - Biological treatment , Water - Purification - Membrane filtration , Sewage - Purification - Filtration
  • Type: Thesis
  • Identifier: uj:13616 , http://hdl.handle.net/10210/13799
  • Description: M. Tech. (Chemical Engineering) , The usual target of an upgrading process using membrane is to produce a retentate stream, the product, with high CH4 concentration. This work presents a simulation of two possible membrane configurations, single stage without recycle (SSWR) and double stage with permeate recycle (DSPR), of an existing operational biogas upgrading plant. The simulation was conducted using ChemCAD and AlmeeSoft gas permeation software to investigate the performance of the configurations on product purity, recovery and required compressor power with a view to determine the optimal operational conditions for maximising the concentration of CH4 and its recovery. Thereafter, an economic assessment on the optimal configuration was conducted to determine the gas processing cost (GPC), the profitability of producing biomethane and cost-benefit of utilising biomethane as a vehicular fuel. The simulation was validated against plant data with a maximum percentage error of 2.64%. Increasing CO2 in feed reduced product recovery and purity. Increasing feed pressure and selectivity increased product recovery and purity up to the pressure limit of the membrane module. Increasing feed flow rate increased product recovery but reduces purity. In both configurations, increasing CO2 in the feed and increasing feed pressure increased the GPC. However, increasing feed flow rate reduced the GPC. The overall performance of DSPR configuration was much higher due to increased trans-membrane area available for separation. At optimal conditions, a product purity of 91% and 96% CH4 recovery was achieved from the initial plant result of 87.2% product purity and 91.16% CH4 recovery. The total compression duty was 141 kW. The GPC was $0.46/m3 of biomethane. The cumulative discounted NPV, IRR and BCR for producing biomethane was R15,240,343, 22.41% and 2.05 respectively, with a break-even in the 5th year after plant start-up considering a prime lending rate at 9%. Using CBG instead of gasoline saves 34% of annual fuel cost with a payback period of one year and three months for the cost of retrofitting the vehicle.
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