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BIOLOGICAL SULFATE REDUCTION OF REVERSE OSMOSIS BRINE
CONCENTRATE: PROCESS MODELING AND DESIGN
by
Masoud Samee
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
(ENVIRONMENTAL ENGINEERING)
May 2007
Copyright 2007 Masoud Samee
Object Description
| Title | Biological sulfate reduction of reverse osmosis brine concentrate: process modeling and design |
| Author | Samee, Masoud |
| Author email | samee@usc.edu |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Civil Engineering (Environmental Engineering) |
| School | Viterbi School of Engineering |
| Date defended/completed | 2007-01-16 |
| Date submitted | 2007 |
| Restricted until | Restricted until 21 Feb. 2009. |
| Date published | 2009-02-21 |
| Advisor (committee chair) | Pirbazari, Massoud |
| Advisor (committee member) |
Yen, Teh Fu Shing, Katherine S. |
| Abstract | The Colorado River is the most important source of water in southern California which typically contains high total dissolved solids (TDS) of more than 700 mg/L. Reverse osmosis is one of the best available technologies for desalination of the water for reducing the TDS level. One of the major problems associated with reverse osmosis process under a high-recovery of over 95%, is the precipitation of sparingly soluble inorganic salts present in the brine concentrate. These salts include barium sulfate, calcium sulfate, strontium sulfate, and calcium carbonate, and they have the potential to cause precipitation fouling of reverse osmosis membranes resulting in lowering of membrane permeate fluxes. Sulfate removal from the brine concentrate is the only solution to overcome the problem of membrane scaling. This research evaluated a biological process to recover reverse osmosis concentrate produced from desalting high-sulfate waters. The process employed biological sulfate reduction (BSR) using fluidized bed bioadsorber reactor (FBBR) and to concomitantly reduce the saturation levels of sparingly soluble salts. This research also focused on evaluating biological kinetics and pertinent operating variables in the BSR reactor and modeling of the process.; In the first phase of the study, a series of completely mixed batch reactor (CMBR) studies were conducted to determine the effect of various environmental parameters including pH, temperature, and carbon-to-sulfur (C/S) on the desulfurization process. Subsequently, a series of chemostat experiments were carried out to determine the biokinetic parameters. These parameters further used as input for the mathematical model developed for the desulfurization process. Furthermore, fluidized bed bioadsorber reactor studies were conducted to evaluate the process performance as a function of several variables including the influent sulfate concentration, C/S ratio, and pH. The process performance was evaluated at different influent sulfate concentrations of 600, 700, 800, 900, 1000, and 1100 mg/L, different pHs of 6.5, 7.0,and 7.5, and different C/S ratios of 0.8, 1.0, and 1.2. Sulfate reduction and removal efficiencies as high as 86-91% were achieved at an influent sulfate concentration of 1100 mg/L. Later, the FBBR-sand process performance was investigated and compared with those using granular activated carbon (GAC). The general observation was that GAC performed significantly better than sand. Nonetheless, the superiority of GAC would even be more apparent, should the brine concentrate contain heavy metals and organic constituents that would potentially inhibitmicrobial activity.; The next phase of the research included the simulation of the chemostat process dynamics and performance of model sensitivity analyses to identify the various key parameters that have a significant influence on the system operation and subsequently on the FBBR process, and to evaluate the biokinetic parameters that would eventually be employed as input parameters in the FBBR model. The chemostat simulation studies demonstrated good agreement between the experimental data and the chemostat model predictions. Sensitivity analyses of the chemostat model indicated that maximum specific growth rate, micron and half-velocity constant, Ks had the geartest influence on chemostat dynamics with reference to sulfate reduction and carbon source (ethanol) utilization.; The next phase involved the development of a mathematical model for predicting the FBBR process dynamics. Model calibration was based on biological and transport parameters determined from independent laboratory experiments and/or correlation techniques. The model was verified and validated for different process variables.; In the last phase of this study, process design and upscaling strategies were developed, and the significance of the relevant non-dimensional groups identified besides their relative contribution to the overall process dynamics. Model simulation studies were performed to predict the FBBR dynamics under different process and operating conditions, and to determine the sensitivity of process dynamics to various biokinetic parameters. Sensitivity analyses demonstrated that the maximum specific growth rate, micron and half-velocity constant, Ks had the most profound influence on the process dynamics with reference to sulfate reduction and ethanol utilization.; The results of this study demonstrated that the FBBR system represents a reliable, efficient, and cost effective technology for removing sulfate from the reverse osmosis brine concentrate. It was found that the FBBR system using GAC was significantly more efficient than the FBBR-sand system. However, the latter process required lower hydraulic retention time, and therefore, entails smaller reactor and lower energy costs. The FBBR model successfully predicted the process dynamics with reference to sulfate removal and carbon source utilization. Furthermore, it was found useful in the performance prediction of laboratory-scale FBBR systems and provided the means for process upscaling using dimensional analysis and similitude. The results of biofiltration of hydrogen sulfide demonstrated that the anaerobic biofiltration would be a preferred treatment method for H2S gas stream. Additionally, the anaerobic biofiltration of H2S and its subsequent conversion to elemental sulfur is important from the economic perspective of sulfate recovery. |
| Keyword | biological sulfate reduction; anaerobic biofiltration; fluidized bed bioadsorber reactor; chemostat biokinetic studies; chemostat simulation |
| 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-m283 |
| Rights | Samee, Masoud |
| 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-Samee-20070221 |
| Archival file | uscthesesreloadpub_Volume23/etd-Samee-20070221.pdf |
Description
| Title | Page 1 |
| Full text | BIOLOGICAL SULFATE REDUCTION OF REVERSE OSMOSIS BRINE CONCENTRATE: PROCESS MODELING AND DESIGN by Masoud Samee 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 (ENVIRONMENTAL ENGINEERING) May 2007 Copyright 2007 Masoud Samee |
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