Effects of water washing on removing organic residues in bottom ashes of municipal solid waste incinerators.
Due to their potential toxicity and odourous nature, the residual organics in municipal solid waste incinerators are recently gaining attention as an important issue of resources recovery apart from their complex mixture of organic counterpart. Studies of the organic fractions in municipal solid waste incinerator residues have been limited. In this study, extended solid-phase extraction of the water-washed bottom ash and liquid-phase extraction of the washing water were carried out with regard to bottom ash samples from three mass-burning incinerators in Taipei County (Taiwan) during four consecutive seasons of year 2008-2009. Supercritical fluid extraction and Soxtec extraction techniques along with GC-MS were successfully used to characterize the residual organics in weathered and washed bottom ashes. Supercritical fluid extraction provided the quantification of aliphatics and aromatic compounds such as hexanoic acid and benzaldehyde, respectively. Soxtec extraction was useful for qualitative analysis of aromatic and aliphatic groups in the ashes and many of which were odourous and toxic compounds. By mixing one unit weight (g) bottom ash with two unit volume (mL) water for 15 min, total organic carbon in the bottom ash was greatly reduced (e.g., from 4.1 to 1.8 wt.%). Among the removed were foul odour-causing compounds such as pyridine and quinoline derivatives, while some aromatic compounds such as 4-hydroxybenzaldehyde and low-molecular-weight aliphatics such as hexanoic acid remained. The results here suggest that washing with water can be an effective pre-treatment step for removing odour-causing and environmental concerned organics.
Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, Taiwan, ROC.
Yen-Ching
YC
Lin
Sri Chandana
SC
Panchangam
Chung-Hsin
CH
Wu
Pui-Kwan Andy
PK
Hong
Cheng-Fang
CF
Lin
D002244:Carbon / Q000032:analysis / Q000737:chemistry; D025924:Chromatography, Supercritical Fluid; D008401:Gas Chromatography-Mass Spectrometry; D017745:Incineration / Q000379:methods*; D009930:Organic Chemicals / Q000737:chemistry*; D052616:Solid Phase Extraction; D014866:Waste Products / Q000032:analysis; D014867:Water / Q000737:chemistry*
D009930:Organic Chemicals; D014866:Waste Products; D014867:Water; D002244:Carbon