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Development of Biological Coal Gasification (MicGAS Process). Topical report, July 1991--February 1993

Description: Laboratory and bench scale reactor research carried out during the report period confirms the feasibility of biomethanation of Texas lignite (TxL) and some other low-rank coals to methane by specifically developed unique anaerobic microbial consortia. The data obtained demonstrates specificity of a particular microbial consortium to a given lignite. Development of a suitable microbial consortium is the key to the success of the process. The Mic-1 consortium was developed to tolerate higher coal loadings of 1 and 5% TxL in comparison to initial loadings of 0.01% and 0.1% TxL. Moreover, the reaction period was reduced from 60 days to 14 to 21 days. The cost of the culture medium for bioconversion was reduced by studying the effect of different growth factors on the biomethanation capability of Mic-1 consortium. Four different bench scale bioreactor configurations, namely Rotating Biological Contactor (RBC), Upflow Fluidized Bed Reactor (UFBR), Trickle Bed Reactor (TBR), and Continuously Stirred Tank Reactor (CSTR) were evaluated for scale up studies. Preliminary results indicated highest biomethanation of TxL by the Mic-1 consortium in the CSTR, and lowest in the trickle bed reactor. However, highest methane production and process efficiency were obtained in the RBC.
Date: June 1, 1993
Creator: Srivastava, K. C.
Partner: UNT Libraries Government Documents Department

Development of biological coal gasification (MicGAS Process). Fifteenth quarterly report, [January 1, 1994--March 31, 1994]

Description: Maximum methane production was obtained in the experimental vials that contained 0.2% SNTM supplemented with 10 mM sodium citrate and 1% TxL (144 cc), while in the control vials CH{sub 4} production was only 58 cc. The conversion efficiency was 24%. This clearly shows citrate to be an important mediator for the formation of acetate (main precursor for CH{sub 4} formation) in the glyoxylate cycle, on the one hand, and as a sequestering agent, on the other. These results further indicate that citrate can, be successfully used as co-substrate for enhancement of the TxL biogasification process. The results obtained reconfirmed our hypothesis that the metals (such as Fe{sup 3+}, Mn{sup 2+}, Mg{sup 2+}, CO{sup 2+}, Zr{sup 2+}, etc., present in the coal structure) are chelated/sequestered by the addition of citrate. Mass balance calculations show that this increase in CH{sup 4} production is due to the biomethanation of TxL and not because of the chemical conversion of co-substrate(s) to CH{sub 4} (Table 1). The effect of sodium citrate on biomethanation of TXL from the first experiment ``Effect of co-substrate addition No. 1`` was reconfirmed in this experiment. The peak in acetate concentration (1317 ppm) on day 7 was followed by a rapid conversion of this precursor to CH{sub 4} (Figure 16). The VFA data obtained from both experiments (``Effect of co-substrate addition No. 1 and No. 2``) confirms the hypothesis that citrate and methanol can significantly enhance the biomethanation of TxL (Figure 17).
Date: April 26, 1994
Creator: Srivastava, K. C.
Partner: UNT Libraries Government Documents Department

Development of HUMASORB{trademark}, a lignite derived humic acid for removal of metals and organic contaminants from groundwater

Description: Heavy metal and organic contamination of surface and groundwater systems is a major environmental concern. The contamination is primarily due to improperly disposed industrial wastes. The presence of toxic heavy metal ions, volatile organic compounds (VOCs) and pesticides in water is of great concern and could affect the safety of drinking water. Decontamination of surface and groundwater can be achieved using a broad spectrum of treatment options such as precipitation, ion-exchange, microbial digestion, membrane separation, activated carbon adsorption, etc. The state of the art technologies for treatment of contaminated water however, can in one pass remediate only one class of contaminants, i.e., either VOCs (activated carbon) or heavy metals (ion exchange). This would require the use of at a minimum, two different stepwise processes to remediate a site. The groundwater contamination at different Department of Energy (DOE) sites (e.g., Hanford) is due to the presence of both VOCs and heavy metals. The two-step approach increases the cost of remediation. To overcome the sequential treatment of contaminated streams to remove both organics and metals, a novel material having properties to remove both classes of contaminants in one step is being developed as part of this project.
Date: December 31, 1995
Creator: Sanjay, H.G.; Srivastava, K.C. & Walia, D.S.
Partner: UNT Libraries Government Documents Department

Development of biological coal gasification (MicGAS) process

Description: Biomethanation of coal is a phenomenon carried out in concert by a mixed population (consortium) of at least three different groups of anaerobic bacteria and can be considered analogous to that of anaerobic digestion of municipal waste. The exception, however, is that unlike municipal waste; coal is a much complex and difficult substrate to degrade. This project was focused on studying the types of microorganisms involved in coal degradation, rates of methane production, developing a cost-effective synthetic culture medium for these microbial consortia and determining the rate of methane production in bench scale bioreactors.
Date: January 1, 1992
Creator: Walia, D.S.; Srivastava, K.C. & Barik, S.
Partner: UNT Libraries Government Documents Department

Development of biological coal gasification (MicGAS) process

Description: Biomethanation of coal is a phenomenon carried out in concert by a mixed population (consortium) of at least three different groups of anaerobic bacteria and can be considered analogous to that of anaerobic digestion of municipal waste. The exception, however, is that unlike municipal waste; coal is a much complex and difficult substrate to degrade. This project was focused on studying the types of microorganisms involved in coal degradation, rates of methane production, developing a cost-effective synthetic culture medium for these microbial consortia and determining the rate of methane production in bench scale bioreactors.
Date: November 1, 1992
Creator: Walia, D. S.; Srivastava, K. C. & Barik, S.
Partner: UNT Libraries Government Documents Department

BIODESULF(TM), A Novel Biological Technology for the Removal of H2S From Sour Natural Gas

Description: The state-of-the-art technologies for the removal of sulfur compounds from Sour Natural Gas (SNG) are not cost-effective when scaled down to approximately 2-5 MMSCFD. At the same time, the SNG Production is increasing at 3-6 TCF/Yr and -78 TCF potential reserves are also sour. Assuming only 3% treatment of this potential SNG market is for small volume processing, the potential U.S. Market is worth $0.14 to $0.28 billion. Therefore, the Gas Processing Industry is seeking novel, cost-effective, environmentally compatible and operator friendly technologies applicable to the small volume producers in the range of less than 1 MMSCFD to - 5 MMSCFD. A novel biological process, BIODESTJLFTM (patent pending), developed at ARCTECH removes H{sub 2}S and other sulfur contaminants that make the Natural Gas Sour. The removal is accomplished by utilizing an adapted mixed microbial culture (consortium). A variety of anaerobic microbial consortia from ARCTECH`s Microbial Culture Collection were grown and tested for removal of H{sub 2}S. One of these consortia, termed SS-11 was found to be particularly effective. Utilizing the SS-11 consortium, a process has been developed on a laboratory-scale to remove sulfur species from Sour Natural Gas at well head production pressures and temperatures. The process has been independently evaluated and found to be promising in effectively removing H{sub 2}S and other sulfur species cost effectively.
Date: October 1, 1997
Creator: Srivastava, K.C.; Stashick, J.J.; Johnson, P.E. & Kaushik, N.K.
Partner: UNT Libraries Government Documents Department

Development of HUMASORB{trademark}, a lignite derived humic acid for removal of metals and organic contaminants from groundwater

Description: Heavy metal and organic contamination of surface and groundwater is a major environmental concern. The contamination is primarily due to improperly disposed industrial wastes. Decontamination of surface and groundwater can be achieved using a broad spectrum of treatment options such as precipitation, ion-exchange, microbial digestion, membrane separation, activated carbon adsorption, etc. The state-of-the-art technologies for treatment of contaminated water, however, can in one pass remediate only one class of contaminants, i.e., either VOCs (activated carbon) or heavy metals( ion-exchange). The groundwater contamination at different Department of Energy (DOE) sites (e.g. Hanford) is due to the presence of both VOCs and heavy metals. Therefore, two different stepwise processes are needed to remediate a site. The two-step approach increases the cost of remediation. A novel material having properties to remove both classes of contaminants in one step is being developed as part of this project. The objective of this project is to develop a lignite derived adsorbent, HUMASORB{sup TM}, to remove heavy metal and organic contaminants from groundwater and surface water streams in one processing step. As part of this project, HUMASORB{sup TM} is being characterized and evaluated for its ion-exchange and adsorption capabilities.
Date: December 31, 1996
Creator: Sanjay, H.G.; Tiedje, M.; Stashick, J.J.; Srivastava, K.C.; Johnson, H.R. & Walia, D.S.
Partner: UNT Libraries Government Documents Department