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BIOLOGICAL TREATABILITY OF UNDERGROUND COAL GASIFICATION WASTEWATER Timothy P. Caire, Graduate Student Desmond F. Lawler, Assistant Professor Department of Civil Engineering University of Texas, Austin Austin, Texas 78712 Michael J. Humenick, Jr., Professor Department of Civil and Architectural Engineering University of Wyoming Laramie, Wyoming 82071 INTRODUCTION Coal gasification is of interest in the United States because it is a promising method of utilizing one of the country's largest natural energy resources, coal, as a substitute for a more limited resource, natural gas. Coal gasification processes convert coal into a methane-rich gaseous product. There are several coal gasification processes, with most currently at the pilot stage. They differ with respect to operating conditions, coal types accepted, and consequently, with respect to the characteristics of the wastewater produced. Many coal gasification processes produce wastewater effluents which contain large amounts of both organic and inorganic pollutants. Biological treatment of these wastewaters is favored because they contain high concentrations of phenolic compounds, which are removed efficiently by an acclimated biomass. Unfortunately, these wastewaters typically contain compounds which can be toxic to microorganisms and thereby impair the biological treatment process. The wastewater investigated in this study was generated by an undergound gasification process in Hanna, Wyoming. No other studies of the treatability of wastewaters from underground coal gasification are known to these investigators. Above-ground gasification effluents previously studied for biological treatability include Hygas [1], GFETC [2], Synthane [3,4], and MERC [5] process effluents. Also, Singer et al [6] have reported on the treatment of synthetic coal gasification wastewater. These wastes have been successfully treated by the activated sludge process. Raw product gas quench condensates from these gasification processes are quite similar with respect to the nature of the contaminants present; accordingly, they can be considered as a family of related industrial wastewaters. However, because of differences in relative proportion and concentration of various contaminants among the wastewaters, they may require different pretreatments and exhibit different treatability characteristics. Investigators have found that treatment of these wastewaters generates a low cell yield in comparison to that observed with domestic waste. As a result, these effluents must be treated within a range of high sludge ages (and correspondingly low specific substrate utilization rates). Underground coal gasification (UCG) generates a heavily contaminated condensate which forms on cooling the product gas and yields an aqueous phase and an organic phase. The wastewater treated during this project was a composite sample of the aqueous fraction generated from the Hanna IVB field test in Hanna, Wyoming. Measurements performed as part of this research indicated that the wastewater had a very high COD and high concentrations of phenolics and ammonia, as shown in Table I. The measured inorganic carbon and pH correspond to an alkalinity of 8200 mg/1 as CaC03. 519
Object Description
Purdue Identification Number | ETRIWC198354 |
Title | Biological treatability of underground coal gasification wastewater |
Author |
Caire, Timothy P. Lawler, Desmond F. Humenick, Michael J. |
Date of Original | 1983 |
Conference Title | Proceedings of the 38th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,34749 |
Extent of Original | p. 519-528 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Date Digitized | 2009-07-28 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 519 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | BIOLOGICAL TREATABILITY OF UNDERGROUND COAL GASIFICATION WASTEWATER Timothy P. Caire, Graduate Student Desmond F. Lawler, Assistant Professor Department of Civil Engineering University of Texas, Austin Austin, Texas 78712 Michael J. Humenick, Jr., Professor Department of Civil and Architectural Engineering University of Wyoming Laramie, Wyoming 82071 INTRODUCTION Coal gasification is of interest in the United States because it is a promising method of utilizing one of the country's largest natural energy resources, coal, as a substitute for a more limited resource, natural gas. Coal gasification processes convert coal into a methane-rich gaseous product. There are several coal gasification processes, with most currently at the pilot stage. They differ with respect to operating conditions, coal types accepted, and consequently, with respect to the characteristics of the wastewater produced. Many coal gasification processes produce wastewater effluents which contain large amounts of both organic and inorganic pollutants. Biological treatment of these wastewaters is favored because they contain high concentrations of phenolic compounds, which are removed efficiently by an acclimated biomass. Unfortunately, these wastewaters typically contain compounds which can be toxic to microorganisms and thereby impair the biological treatment process. The wastewater investigated in this study was generated by an undergound gasification process in Hanna, Wyoming. No other studies of the treatability of wastewaters from underground coal gasification are known to these investigators. Above-ground gasification effluents previously studied for biological treatability include Hygas [1], GFETC [2], Synthane [3,4], and MERC [5] process effluents. Also, Singer et al [6] have reported on the treatment of synthetic coal gasification wastewater. These wastes have been successfully treated by the activated sludge process. Raw product gas quench condensates from these gasification processes are quite similar with respect to the nature of the contaminants present; accordingly, they can be considered as a family of related industrial wastewaters. However, because of differences in relative proportion and concentration of various contaminants among the wastewaters, they may require different pretreatments and exhibit different treatability characteristics. Investigators have found that treatment of these wastewaters generates a low cell yield in comparison to that observed with domestic waste. As a result, these effluents must be treated within a range of high sludge ages (and correspondingly low specific substrate utilization rates). Underground coal gasification (UCG) generates a heavily contaminated condensate which forms on cooling the product gas and yields an aqueous phase and an organic phase. The wastewater treated during this project was a composite sample of the aqueous fraction generated from the Hanna IVB field test in Hanna, Wyoming. Measurements performed as part of this research indicated that the wastewater had a very high COD and high concentrations of phenolics and ammonia, as shown in Table I. The measured inorganic carbon and pH correspond to an alkalinity of 8200 mg/1 as CaC03. 519 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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