The sorption-desorption behavior and bioavailability of BTEX in marine sediments

• Main Authors: KaiWenChen, 陳愷文
• Other Authors: 李志源
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/81498864805700137995

碩士 === 國立海洋大學 === 河海工程學系 === 91 === The soil-water distribution coefficients, Kd, of benzene, toluene, ethylbenzene, and xylene (B, T, E, X) for two marine sediments were investigated by batch sorption-desorption tests. The marine sediments used were collected from harbors of Badaozr and Shenao, both located in Keelung, Taiwan. Biodegradations of single compound of BTX in seawater were tested for determining Monod biokinetic parameters. The bioavailiability factor developed by Zhang (1998) was modified through coupling the Kd’s with Monod constants, which can be used for evaluating the biodegradations of BTX in the sediment. Results of sorption tests show that the BTEX for both sediments had Kd values in the order of xylene> ethylbenzene> toluene > benzene. In addition, the Kd values for Shenao sediment are higher than that for Badaozr sediment. The higher values of Kd of BTEX for Shenao sediment may results from higher organic content in Shenao sediment. Results of desorption test show that BTEX for Shenao sediment had Kd values in the order of ethylbenzene> toluene> xylene> benzene, and xylene> toluene> ethylbenzene> benzene for Badaozr sediment. In the biodegradation tests of BTX in seawater, the initial concentrations were 20 mg/L of B, T, and X, respectively, and 45 mg/L of biomass. Results indicate that toluene was depleted completely in 15 hours, while complete biodegradation for xylene and benzene took 28 and 40 hours, respectively. The retardation effect of sorption and desorption on biodegradation in sediment was successfully evaluated by the modified bioavaialibility factor. For example, the complete biodegradation of benzene in sediment, soil/water ratio of 0.07 kg/L, will be delayed for 25 hours at least by the presence of sediment solids.