Treatment of toluene contaminated soils using aerobic bioremediation processes

• Main Author: 李依穎
• Other Authors: 李志源
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/25570917034686739342

碩士 === 國立海洋大學 === 河海工程學系 === 91 === Batch tests were conducted to evaluate the degradation of toluene in soil-water slurries. Samples of soil were collected from KeeLung to represent solids with high organic content (denoted as Soil KL). In addition, samples collected from TauYuan represent soils with low pH, and low bacteria content (Soil TY). Three bioremediation processes, including (1) acclimation of indigenous microorganisms (I.M.), (2) bioaugmentation by supplementing toluene oxidizing bacteria (B.A.), and (3) bioaugmentation for preequilibrated soil-water slurry (B.P.) were tested for soil water ratios over 0.01, 0.04, 0.3及0.6 Kg/L for Soil KL and 0.01, 0.05, 0.4, and 0.9 Kg/L for Soil TY. Results show that the rate and extent of biodegradation of toluene decreases with increasing soil/water ratio. Among the three processes, Process B. A. exhibited the highest degradation rate and extent, but I.M. process was also competent in remediation of soils contaminated with toluene. The toluene degradation rate and extent in Soil TY is higher than that in Soil KL, since sorption coefficient (Kd) of toluene for Soil TY, 6.1 L/kg, is much lower than that of Soil KL, 53.6 L/kg. It is suggested that using acclimated indigenous microorganisms for bioremediation of soils contaminated with toluene is favorable. This requires the contaminated site be immediately supplied with nutrients of nitrogen, phosphate, electron acceptor, and prepared with proper soil water ratio. Bioaugmentation by adding toluene oxidizing bacteria seems bring little advantages as operating costs is considered.