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, 1997

Bioregeneration is a special feature of Biological Activated Carbon (BAC) process. The bioregeneration lengthens the service period of Granular Activated Carbon (GAC) and provides significant cost savings in operation because of reduction in energy consumption for GAC regeneration. This study has focused on the batch bioregeneration of GAC loaded with phenols with a view to investigate kinetics of bioregeneration and bioregeneration mechanism. The extent of bioregeneration was quantitatively determined using a simple equation based on adsorption capacity of GAC. Two types of model compounds namely phenol and 2,4- dicholorophenol (2,4-DCP) were used in batch bioregeneration experiments. The batch bioregeneration efficiency of GAC loaded with phenols was found to be modest. The results obtained revealed that about 31 % capacity of GAC loaded with phenol and 14-22% capacity of2,4-DCP loaded with 2,4-DCP was regenerated over a period of 7-10 days. Desorption studies coupled with batch bioregeneration experiments showed that desorption by exoenzyme reaction can be one of the possible factors for regeneration of active sites on GAC. The kinetics studies demonstrated that a first order kinetics may explain the pattern of bioregeneration in the batch bioregeneration.