טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentAbadi Yaron
SubjectApplication of Batch Data to Continuous Flow Reactor by
Using Segregation Model
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Emeritus Yerachmiel Argaman (Deceased)


Abstract

Although activated sludge process has been used for few decades and a large amount of knowledge has been collected, there are still dispute and uncertainty about the way kinetic data should be measured and analyzed. A problem, which is also of a great practical importance, is the use of kinetic data from batch experiments for the design of a continuous activated sludge process.

The purpose of this work was to develop a model, which enables the use of batch experiment kinetic data for the formulation of a rate equation for the continuous activated sludge process. The model is based on the chemical reaction engineering theory and combines concepts from the biological wastewater treatment research, such as the “multiple zero order” and "specialist biomass". It deals with the removal of a simple substrate but offer the theoretical basis for its application for any other removal process. All the batch tests were conducted under a low initial substrate to initial biomass ratio, which is essential to minimize cell multiplication and shifts in the properties of the biomass.  The data collected in the experiment was used to determine the time dependent substrate concentration or substrate removal rate.

Two differences between batch and continuous reactors have been demonstrated and quantified. 1) The effect of segregation - the continuous activated sludge reactor is affected by segregation. Therefore, this effect should be introduced into the rate equation describing removal of substrate in the continuous reactor.  2) The interaction between substrates in a multi-substrate removal process - four substrate interaction types were observed: shift of biomass from utilization of one substrate to another, inhibition by one substrate, mutual inhibition of two substrates, and higher mutual removal rate. In case of interactions, the kinetic parameters may be modified to include their influence.

The formulation of the rate equation for the continuous process requires the following data collection procedure: the determination of the kinetics of the system, kinetics of each component, substrate interaction types, and required kinetic parameter modifications.