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THE ACCUMULATION OF MUTAGENIC POLYCYCLIC AROMATIC HYDROCARBONS IN BIOLOGICAL SLUDGE Charles J. Moretti, Acting Manager Waste Management Division University of North Dakota Energy Research Center Grand Forks, North Dakota 58202 Ronald D. Neufeld, Professor Department of Civil Engineering University of Pittsburgh Pittsburgh, Pennsylvania 15261 INTRODUCTION Mutagenic polycyclic aromatic hydrocarbons (PAH) are produced during fixed-bed coal gasification as a result of coal devolatilization. When the raw syngas from the gasification process is quenched, a highly-polluted quench condensate wastewater is generated. Previous research [1,2] has shown that trace amounts of mutagenic PAH are present in the condensate wastewater. Other studies [3] have shown that treatment of this wastewater with an activated-sludge operation reduces the PAH content. Activated sludge treatment of coal gasification wastewater, however, creates a separate waste disposal problem since it produces a biological sludge which accumulates the lipophilic PAH. The disposal of biological sludge produced from fixed-bed coal gasification wastewater treatment must be carefully controlled to protect the public health. To aid in this control effort, a research project was performed both to study the accumulation of mutagenic PAH in biological sludge and to evaluate the relationship between sludge PAH content and sludge mutagenicity. A general equation was developed as a result of this work to predict the mutagenic potential of the sludge from wastewater PAH concentrations in the activated-sludge system. The equation can be used as a rapid means of estimating the degree of hazard associated with the biological sludge directly from wastewater PAH analyses. WASTEWATER COMPOSITION The diversity of chemical species present in fixed-bed coal gasification quench condensate is directly attributable to the complex organic nature of the coal itself. Table I is a compilation of selected trace organics that were detected in condensate wastewater from two different fixed-bed coal gasification processes [1,4]. The two processes were the Grand Forks slagging gasifier and the experimental gasifier located at Research Triangle. The chemicals listed in Table I were selected from hundreds of different trace organics found in the wastewater and were included in the table because of their significant adverse health effects. Most of these compounds are known or suspected carcinogens, mutagens (as defined by the Salmonella reverse mutation bioassay) and priority pollutants, as well as being highly bioaccumulative. The coal gasification wastewater used for this research was obtained from an experimental slagging fixed-bed gasifier located at the University of North Dakota Energy Research Center (UNDERC). The wastewater was steam stripped and solvent extracted to remove phenol and ammonia respectively before being treated by an activated sludge system. The principal constituents in this wastewater which serve as substrates for microbial growth are phenol and methanol and to a lesser extent ammonia and thiocyanate. 937
Object Description
Purdue Identification Number | ETRIWC198592 |
Title | Accumulation of mutagenic polycyclic aromatic hydrocarbons in biological sludge |
Author |
Moretti, Charles J. Neufeld, Ronald D. |
Date of Original | 1985 |
Conference Title | Proceedings of the 40th Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,36131 |
Extent of Original | p. 937-948 |
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 | 2009-07-15 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 937 |
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 | THE ACCUMULATION OF MUTAGENIC POLYCYCLIC AROMATIC HYDROCARBONS IN BIOLOGICAL SLUDGE Charles J. Moretti, Acting Manager Waste Management Division University of North Dakota Energy Research Center Grand Forks, North Dakota 58202 Ronald D. Neufeld, Professor Department of Civil Engineering University of Pittsburgh Pittsburgh, Pennsylvania 15261 INTRODUCTION Mutagenic polycyclic aromatic hydrocarbons (PAH) are produced during fixed-bed coal gasification as a result of coal devolatilization. When the raw syngas from the gasification process is quenched, a highly-polluted quench condensate wastewater is generated. Previous research [1,2] has shown that trace amounts of mutagenic PAH are present in the condensate wastewater. Other studies [3] have shown that treatment of this wastewater with an activated-sludge operation reduces the PAH content. Activated sludge treatment of coal gasification wastewater, however, creates a separate waste disposal problem since it produces a biological sludge which accumulates the lipophilic PAH. The disposal of biological sludge produced from fixed-bed coal gasification wastewater treatment must be carefully controlled to protect the public health. To aid in this control effort, a research project was performed both to study the accumulation of mutagenic PAH in biological sludge and to evaluate the relationship between sludge PAH content and sludge mutagenicity. A general equation was developed as a result of this work to predict the mutagenic potential of the sludge from wastewater PAH concentrations in the activated-sludge system. The equation can be used as a rapid means of estimating the degree of hazard associated with the biological sludge directly from wastewater PAH analyses. WASTEWATER COMPOSITION The diversity of chemical species present in fixed-bed coal gasification quench condensate is directly attributable to the complex organic nature of the coal itself. Table I is a compilation of selected trace organics that were detected in condensate wastewater from two different fixed-bed coal gasification processes [1,4]. The two processes were the Grand Forks slagging gasifier and the experimental gasifier located at Research Triangle. The chemicals listed in Table I were selected from hundreds of different trace organics found in the wastewater and were included in the table because of their significant adverse health effects. Most of these compounds are known or suspected carcinogens, mutagens (as defined by the Salmonella reverse mutation bioassay) and priority pollutants, as well as being highly bioaccumulative. The coal gasification wastewater used for this research was obtained from an experimental slagging fixed-bed gasifier located at the University of North Dakota Energy Research Center (UNDERC). The wastewater was steam stripped and solvent extracted to remove phenol and ammonia respectively before being treated by an activated sludge system. The principal constituents in this wastewater which serve as substrates for microbial growth are phenol and methanol and to a lesser extent ammonia and thiocyanate. 937 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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