Document Detail


Polychlorinated dibenzo-p-dioxins/dibenzofurans distributions in ash from different units in a municipal solid waste incinerator.
MedLine Citation:
PMID:  18068298     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study determined the polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) contents in ash in the super heater (SH), economizer (EC), semi-dryer absorber (SDA), fabric filter (FF), fly ash pit (FAP) and bottom residue (BR) in a municipal solid waste incinerator (MSWI). A high-resolution gas chromatograph/high-resolution mass spectrometer (HRGC/HRMS) was utilized for analyzing 17 PCDD/F species. Experimental results showed that average PCDD/F contents in ash samples from the SH, EC, SDA, FF, FAP and BR were 0.102, 0.788, 0.210, 1.95, 2.04 and 0.0218 ng I-TEQ g(-1), respectively. PCDD/F content was very low in the SH and BR due to high temperatures (around 461 degrees C in the SH and 914 degrees C in combustion chamber). Conversely, total PCDD/F content was significantly high in ash samples from the EC (around 340 degrees C), mainly because the temperature is within the favorable range of 250-400 degrees C for PCDD/F formation due to de nova reformation mechanisms. Although the SDA operated at 245 degrees C, the PCDD/F content decreased very significantly, mainly because the temperature was relatively low and because calcium carbonate was introduced into flue gases to dechlorinate and dilute chlorine-containing species. PCDD/Fs were captured by the active carbon in the FF. Furthermore, the duration that fly ash remained in the FF was longer than that for other incinerator units, and thus causing an increasing trend of PCDD/Fs level downstream (except the SDA). Total PCDD/Fs emission factors (microg tonnes-waste(-1); microg I-TEQ tonnes-waste(-1)) in ash samples from different units were: SH (42.3; 0.846), EC (326; 6.12), SDA (58.1; 1.10), FF (1540; 61.3), FAP (2950; 107) and BR (537; 4.31). Most PCDD/Fs in ash were contributed by the FF (about 56%), and the generation of PCDD/Fs in ash was significant (about 35%) during the transfer process from different units to the FAP. A strong and positive correlation in a logarithmic form existed between PCDD/Fs and chlorine (Cl(-1)) contents in ash. In Taiwan, the government policy for incineration residues advocates their reuse as road sub-bases or secondary building materials provided that total PCDD/Fs content is below the legal limit (1 ng I-TEQ g(-1)). Thus, ash with total PCDD/Fs content below the legal limit, such as that from the SH, EC, SDA and BR, can be collected and transferred to the FAP and reused. Ash with total PCDD/Fs content exceeding the legal limit, such as that from the FF, should be collected separately and be treated properly before being disposal in a landfill.
Authors:
Yu-Sheng Lin; Kang-Shin Chen; Yuan-Chung Lin; Chung-Hsien Hung; Guo-Ping Chang-Chien
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Publication Detail:
Type:  Journal Article     Date:  2007-11-07
Journal Detail:
Title:  Journal of hazardous materials     Volume:  154     ISSN:  0304-3894     ISO Abbreviation:  J. Hazard. Mater.     Publication Date:  2008 Jun 
Date Detail:
Created Date:  2008-04-25     Completed Date:  2008-07-29     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9422688     Medline TA:  J Hazard Mater     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  954-62     Citation Subset:  IM    
Affiliation:
Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
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MeSH Terms
Descriptor/Qualifier:
Benzofurans / analysis*
Carbon / analysis*
Construction Materials
Environmental Monitoring
Environmental Pollutants / analysis*
Incineration*
Industrial Waste / analysis*
Particulate Matter / analysis*
Taiwan
Tetrachlorodibenzodioxin / analogs & derivatives*,  analysis
Chemical
Reg. No./Substance:
0/Benzofurans; 0/Environmental Pollutants; 0/Industrial Waste; 0/Particulate Matter; 0/chlorinated dibenzofurans; 0/polychlorodibenzo-4-dioxin; 1746-01-6/Tetrachlorodibenzodioxin; 68131-74-8/fly ash; 7440-44-0/Carbon

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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