Date on Master's Thesis/Doctoral Dissertation

5-2019

Document Type

Master's Thesis

Degree Name

M. Eng.

Department

Chemical Engineering

Committee Chair

Gupta, Gautam

Committee Co-Chair (if applicable)

Keynton, Robert

Committee Member

Keynton, Robert

Committee Member

Gerstle, Jim

Committee Member

Ghorbanian, Mahyar

Author's Keywords

Stabilization/Solidification; Sol-Gel; Wastewater; Tetramethyl Orthosilicate; Zero-liquid Discharge

Abstract

To meet the demands of new regulations on coal-fired power plants, many treatment scenarios require a zero-liquid discharge (ZLD) approach. Two revisions to regulations in 2015, the Effluent Limitations Guidelines (ELG) and Coal Combustion Residuals (CCRs) rule, drastically changed the treatment approach for managing effluents at coal-fired plants. In some scenarios, coal-fired plants retired early deeming the capital cost for maintaining compliance too expensive. Traditionally, stabilization/solidification (S/S) ZLD technologies have fallen in two categories: cementitious and vitrification. However, neither approach offers the ideal solution for coal-fired power plants needing ZLD by S/S methods. In what follows, a novel sol-gel encapsulation method with Silane precursors is evaluated as an alternative S/S effluent treatment. It will be shown that sol-gel encapsulation can be used to solidify various wastewater effluents from an LG&E-KU power plant. The encapsulated solids successfully retained positively-charged contaminants during leaching analyses, while struggling to retain negatively-charged contaminants. Based on the results shown, it is proposed that the negatively-charged Silicon Dioxide network chemically fixates positively-charged contaminants, leading to the retention of those contaminants. These results demonstrate that sol-gel encapsulation can be developed as an alternative S/S technique to meet the challenges of ZLD regulations. It is anticipated that the work presented will be a starting point for further development of S/S treatment by sol-gel encapsulation.

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