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BIOLOGICAL SULFATE REDUCTION IN SULFATE-RICH INDUSTRIAL
WASTEWATERS BY ANAEROBIC FLUIDIZED-BED REACTORS: EFFECT
OF ELECTRON DONORS
by
Atosa Vahdati Nikzad
A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(ENGINEERING)
December 2007
Copyright 2007 Atosa Vahdati Nikzad
Object Description
| Title | Biological sulfate reduction in sulfate rich industrial wastewaters by anaerobic fluidized-bed reactors: effect of electron donors |
| Author | Vahdati Nikzad, Atosa |
| Author email | vahdati@usc.edu |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Civil Engineering (Environmental Engineering) |
| School | Viterbi School of Engineering |
| Date defended/completed | 2007-06-29 |
| Date submitted | 2007 |
| Restricted until | Restricted until 8 Oct. 2009. |
| Date published | 2009-10-08 |
| Advisor (committee chair) | Pirbazari, Massoud |
| Advisor (committee member) |
Yen, Teh Fu Shing, Katherine S. |
| Abstract | High-sulfate wastewaters are a major problem in industry because they increase the total dissolved solid content and interfere with methanogenesis, resulting in a decrease in the production of methane, which is a valuable fuel. A large variety of industries, including pulp and paper production, molasses fermentation, seafood processing, potato-starch factories, and tanneries, that produce wastewaters with a high sulfate concentration, have major problems in discharging their wastewaters. The reason for this is that the discharge of industrial wastes into water bodies is governed by National Pollutant Discharge Elimination System (NPDES) program, which limits the amount of pollutants, especially chemical oxygen demand (COD), received by the surface waters. Unfortunately, high sulfate content in the wastewater limits the usage of anaerobic methanogenesis for COD reduction.; Biological sulfate reduction is an effective means of removing sulfate from wastewater. Sulfate-reducing bacteria can adjust effectively to different environments, and the production of biofilm protects the bacteria from the toxic environment. The ability of the bacteria to acclimate to different pH levels, along with the possibility of toxic metal precipitation by hydrogen sulfide, have made this method a very attractive treatment alternative for wastewaters containing heavy metals.; This research has investigated the effectiveness of biological reduction in the removal of high concentrations of sulfate from wastewater. An anaerobic fluidized bed reactor (FBR) with recycle was chosen, and thermodynamic and kinetic parameters were used to evaluate best electron donors. Completely mixed batch reactor (CMBR) studies with different electron donors were conducted to investigate the feasibility of biological reduction with each electron donor. In addition, the effects of pH, temperature and carbon to sulfur ratio on sulfate reduction have been evaluated in several CMBRs. The results of the batch biokinetic studies rationalized directly to the fluidized bed bioreactor studies to perform the biological sulfate reduction from wastewater with a high level (2000 mg/L) of sulfate.; High sulfate removal efficiencies, as high as 96%, were observed, without any inhibition by produced H2S. Production of hydrogen fuel from the by-products of the experiment is proposed as a promising technology. Anaerobic biofilters have been introduced for effective removal of H2S as well as an effective alternative for producing elemental sulfur from the produced H2S. Finally, the FBR systems not only mange to remove sulfate with very high efficiencies, but this method can have a significant financial return from production of valuable products including methane, hydrogen fuel, and elemental sulfur from the by-products of the system. |
| Keyword | sulfate reduction; industrial wastewaters; biological treatment; fluidized bed reactors; electron donor; energy production; hydrogen sulfide control |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Type | texts |
| Legacy record ID | usctheses-m850 |
| Contributing entity | University of Southern California |
| Rights | Vahdati Nikzad, Atosa |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | http://www.usc.edu/isd/libraries/services/ask_a_librarian/email/ |
| Filename | etd-VahdatiNikzad-20071008 |
| Archival file | uscthesesreloadpub_Volume26/etd-VahdatiNikzad-20071008.pdf |
Description
| Title | Page 1 |
| Contributing entity | University of Southern California |
| Full text | BIOLOGICAL SULFATE REDUCTION IN SULFATE-RICH INDUSTRIAL WASTEWATERS BY ANAEROBIC FLUIDIZED-BED REACTORS: EFFECT OF ELECTRON DONORS by Atosa Vahdati Nikzad A Dissertation Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (ENGINEERING) December 2007 Copyright 2007 Atosa Vahdati Nikzad |
