Dechlorination and destruction of PCDDs/PCDFs in fly ashes from municipal solid waste incinerators by low temperature thermal treatment.
Dechlorination and destruction characteristics of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) in fly ashes from commercial-scale municipal solid waste incinerators by low temperature thermal treatment using a laboratory-scale heating system were investigated. Experiments were carried out in reducing atmosphere at temperatures of 300 degrees C, 450 degrees C and 600 degrees C respectively, for the treatment time of 1h and 3h. Concentrations of PCDDs/PCDFs in raw fly ashes ranged from 35.5 to 107.3 microg kg(-1) (1.5-3.4 microg TEQ kg(-1)) and treated fly ashes ranged from 0.34 to 45.3 microg kg(-1) (0.012-1.63 microg TEQ kg(-1)). Concentrations of PCDDs/PCDFs in fly ashes treated at the different temperatures and times were observed to decrease with increase of treatment temperature and time by dechlorination or destruction. The distribution of octa- and hepta-chlorinated congeners were decreased and tetra-, penta- and hexa-chlorinated congeners were increased at 300 degrees C and 450 degrees C, but the distribution of octa- and hepta-chlorinated congeners were increased and tetra-, penta- and hexa-chlorinated congeners were again decreased at 600 degrees C. Total destruction efficiencies of PCDDs/PCDFs in fly ashes showed above 95% at the treatment temperature of 450 degrees C for 3h. However, removal efficiency of each congener in fly ashes varied, especially, 2,3,7,8-TeCDD and 1,2,3,7,8-PeCDD in fly ash A increased. And the dechlorination and destruction characteristics of PCDDs/PCDFs in fly ash A and B was different due to difference in contents of Ca-compounds and metal oxides such as CuO and PbO in fly ashes.
Song
Geum-Ju
GJ
Institute of Environmental and Energy Technology, Pohang University of Science and Technology, San-31 Hyoja-Dong, Nam-Gu, Pohang, Gyeongbuk, Republic of Korea.
Kim
Seong Heon
SH
Seo
Yong-Chil
YC
Kim
Sam-Cwan
SC
D000393:Air Pollutants / Q000737:chemistry / Q000302:isolation & purification; D001572:Benzofurans / Q000737:chemistry / Q000302:isolation & purification; D002118:Calcium / Q000737:chemistry; D002244:Carbon; D002713:Chlorine / Q000737:chemistry*; D002947:Cities; D060729:Coal Ash; D000072338:Dibenzofurans, Polychlorinated; D004784:Environmental Monitoring; D017745:Incineration; D010087:Oxides / Q000737:chemistry; D052638:Particulate Matter; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification; D013696:Temperature; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*
D000393:Air Pollutants; D001572:Benzofurans; D060729:Coal Ash; D000072338:Dibenzofurans, Polychlorinated; D010087:Oxides; D052638:Particulate Matter; D000072317:Polychlorinated Dibenzodioxins; D002713:Chlorine; D002244:Carbon; D002118:Calcium