A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development

Thesis (M.Sc.) - Asian Institute of Technology, 1990

The potential of a toxic organic , phenol, removal in an immobilized ceil sequencing batch reactor was studied with three laboratory scale reactors using synthetic wastewater. Three different operating aeration times with varying aerobic/anaerobic phases were applied in order to find the potential of the immobilized cells to degrade phenol. The results obtained in this research revealed that an average of 57% phenol and 35% COD removal efficiency was obtained at an organic loading of 15.31 kg/m3-day. For t he second organic loading rate of 5.076 kg/m3-day tested, more than 95% phenol and COD removals were obtained within four hours of aeration out of 8 hours of operation time. Batch studies conducted along t h e study revealed that maximum degradation of organics took place during the initial stages of aeration and under saturated conditions of dissolved oxygen. High levels of organic degradation was not observed during the anaerobic stages and the aeration times used in this research were not sufficient for nitrification. A kinetic study of immobilized cells indicated that very high levels of dissolved oxygen can inhibit the immobilized cells leading to low oxygen uptake r ate and consequently less activity (less degradation).