Distribution of PAHs in Phragmites australis in Sludge Drying Reed Bed
Cui Yubo,Sun Hongjie and Ran Chunqiu
DOI:10.11835/j.issn.1674-4764.2013.05.003
Received ,Revised , Accepted , Available online July 01, 2015
Volume ,2013,Pages 13-18
- Abstract
The transfer of polycyclic aromatic hydrocarbons (PAHs) from sewage sludge to Phragmites australis and the distribution of PAHs in Phragmites australis were investigated in a field experiment. Tested phragmites australis were planted in a sludge drying reed bed (SDRB) with the size of 3 m×1 m×1.3 m (0.65 m media layer and 0.65 m extra height). The experiment lasted three years including two years' sludge loading and one year's resting period. Totally 8.4 meters surplus activatied sludge with 99.14% of moisture content was feed into the SDRB during loading time, and raw sludge contained 5.69 mg/kg (DW) of total PAHs. Native Phragmites australis contain higher PAHs in the stems and leaves, averaged 2.198 and 2.583 mg/kg (DW) which are 2.44 and 2.87 times of that in the roots, respectively. The results showed that Phragmites australis accumulated PAHs from sludge obviously. Lower molecular weight PAHs are the dominant contents in which of Phragmites australis. According to the experimental results in September, October and November of the second year, the PAHs contents in the roots, stems and leaves of tested Phragmites australis have the trend of increasing with plant growing time; the total PAHs in the roots, stems and leaves are averaged 7.642, 7.713 and 7.946 mg/kg (DW) in November of the third year, which are 8.5, 3.52 and 3.08 times of that in native ones, and also lower molecular weight PAHs are dominant with the percentages of 55.14%, 56.96% and 44.59%, respectively. PAHs contents in Phragmites australis are observed to be significant positive relations with their coarse fat contents and have no relationship with lipid percentages.