Pandey, Janardan Raj creator Chongrak Polprasert Chairperson Vigneswaran, Saravanamuthu Examination Committee Yamamoto, Kazuo Examination Committee Suphat Vongvisessomjai Examination Committee Yang, P. Y. Examination Committee Government of Japan Scholarship Donor text series technical report th Bangkok Asian Institute of Technology 1990 continuing eng 155 p. The increasing dependence on biological treatment to treat toxic and hazardous wastes emphasize the need for continuing improvement of treatment methods. Phenol is presently the most widely used model compound for the study of toxic and inhibitory organics. In this research , aerobic treatment of phenolic wastewater by immobilized mixed microbial cells is proposed. Microbial cell immobilization is defined as the physical confinement or localization of intact cells to a certain defined region of space with the preservation of some desired catalytic activities and offers several advantages for the treatment of wastewater. These include extremely high cell concentrations, the protection of cells from the effects of inhibitory substrates and the possibility of continuous operation and higher stability. Experiments on immobilized mixed microbial eel 1 ( IMMC) reactors were conducted to investigate their efficiencies on phenol removal. Four laboratory - scale IMMC reactors each with a volume of 1 L, were fed with a synthetic phenolic wastewater under aerobic condition at the phenol loading rates of 1 - 16 g/(L.d) , based on the initial phenol concentration of 250 mg/L. The IMMC reactors could reach the steady state, based on phenol removal , in about 10 days and could remove phenol about 90 % when the phenol loading rates were equal to or below 8 g/ (L.d) . The IMMC reactors could maintain high biomass in the reactor (about 13000 - 54000 mg VSS/L), and were able to tolerate organic and hydraulic shock loadings under the experimental conditions employed in this study. (iii) Data from the laboratory - scale experiments indicate that at the low phenol loading rates of about 4 g/(L.d), the contribution from the biofilms adsorbed on the outer surface of the carrier for phenol treatment was significant and could be higher than that of the immobilized cells. However, at the phenol loading rates higher than 4 g/ (L.d), the beneficial effects of the immobilized cells on phenol removal could be distinctly observed. Th e food to microorganisms (F/M) ratios for the IMMC reactors at the phenol loading rates of 1- 8 g/(L .d ) were 0 . 08 - 0 . 15 mg phenol/(mg VSS.d) in which the observed growth yield for substrate was found to be in the range of 0.26 - 0.31 mg VSS/mg COD. These rather low values of growth yield was probably due to the single step conversion of phenol directly into low energy by products such as C02 a nd H20. A mathematical mode l was proposed to predict the effluent substrate concentrations in the IMMC reactor . The substrate utilization rates due to immobilized microorganisms in the carrier and due to the suspended microorganisms in the reactor were also predicted from the mod el. It was found that the contribution from the suspended growth microorganisms for the phenol removal in IMMC reactor was negligible when compared to with those from the immobilized microorganisms in the carrier. A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering, School of Environment, Resources and Development Thesis (Ph.D.) - Asian Institute of Technology, 1990 Sewage Purification Activated sludge process Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B18148 http://203.159.5.9/ait-thesis/detail.php?q=B18148 181197 20260817161802.0