Dynamics of Simultaneous Degradation of Phenol and Salicylate Using Freely Suspended and Immobilized Cells

• Main Authors: Shang-Yuan Tsai, 蔡尚原
• Other Authors: Ruey-Shin Juang
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/84465503095545457747

碩士 === 元智大學 === 化學工程學系 === 92 === Phenolic compounds are often encountered in industrial effluents. The discharge of wastewater without proper treatment poses serious environmental problems. A Pseudomonas putida strain capable of degrading phenol and salicylate in wastewater was utilized to investigate the dynamics of phenol and salicylate removal and, hopefully, to meet the standard of discharge. When the total molar concentration of phenol and salicylate was kept constant it took a longer time for biodegradation of the mixture by Pseudomonas putida when the fraction of salicylate was high. The kinetic studies have shown that both phenol and salicylate inhibited the growth of Pseudomonas putida. In addition the biodegradation of phenol was faster than salicylate, and the cells showed a better affinity to salicylate. Salicylate inhibited the culture to a greater extent than phenol. It was concluded that the culture preferred to biodegrade phenol inspite of the cells being pre-cultured with salicylate. The kinetics parameters were nearly the same for the biodegradation of single and mixed substrates. All the correlation coefficient R2 were above 0.92. In hydrophobic hollow fiber modules, the mass transfer of phenol from wastewater tank to cell medium tank was slow and there was no mass transfer for salicylate. After phenol was biodegraded to zero level, the cells were transferred to the wastewater tank and salicylate was then biodegraded. In hydrophilic hollow fiber modules, salicylate could pass through the membrane and the mass transfer of phenol from wastewater tank to cell medium tank was faster than hydrophobic. Hydrophilic fibers are more promising for continuous biodegradation, especially when the substrates were not so toxic and their concentrations were high enough. At last, we combine kinetic results and mass transfer theory for prediction the dynamic of substrate degradation and cell growth in hollow fiber. By comparing modeled line and experimental data at a total substrate concentration below 37.20 mM, the times required for complete biodegradation were nearly the same.