Date of this Version
Bausk A.S. (2015) Methodology for Selecting the Column Configuration with Lowest Media Replacement Cost for Small Adsorption Systems. M.S. Thesis, University of Nebraska – Lincoln.
The relative performance of three column configurations often used for adsorption systems serving small communities was evaluated in terms of which results in the lowest overall replacement cost. Replacement cost is the cost of fresh media and the transportation, labor, and material costs to replace the media. Both the adsorption capacity and the media replacement costs were modeled. The pore and surface diffusion model was utilized to simulate the fixed-bed adsorption and obtain the breakthrough curves, which were then normalized using the target effluent to influent concentration ratio (C/Co) and the mass transfer zone fraction (%MTZBT). Normalization methods for replacement cost were developed in part based on cost data from the US EPA Arsenic Treatment Technology Demonstration Program. Two factors were found to be most important for the relative replacement cost of each configuration – the frequency which at least one column needed replacement of media, and the cycle replacement cost (CRCost) as a combination of the fresh media cost and the replacement service cost. The lead-lag configuration has the lowest annual replacement cost at low target C/Co, high %MTZBT, and high CRCost ratios. The parallel configuration performs better at high target C/Co, high %MTZBT, and high CRCost ratios. Although the single configuration (two columns operated operated in tandem and replaced at the same time) has a higher media consumption compared to lead-lag and parallel, it can result in the lowest replacement cost at short %MTZBT and a very low CRCost ratios due to less frequent media replacements.
Advisor: Bruce I. Dvorak