Date of Award


Document Type


Degree Name

Master of Science (MS)


Environmental Science

First Advisor

Dr. Walid EI Shorbagy,

Second Advisor

Ronald Droste,

Third Advisor

Samir I. Abu-Eishah,


In the field of wastewater treatment, there is an increasing demand to improve the effluent

quality especially if it is going to be discharged to surface water. Effluent discharged

to surface water should have minimum nutrients level (nitrogen and phosphorus) in order

to avoid eutrophication and the resulting algal blooms which deplete the water from the oxygen

needed by other plant and animal species. Moreover, there is a demand to reduce the chemical

consumption in the treatment processes and to depend as much as we can on the biological

Treatment methods in achieving the required effluent quality in terms of BOD and nutrients

Concentration. This thesis implements an extended and more comprehensive analysis in order to accomplish an optimal sizing that achieve minimum capital and operation costs for the

Biological nutrients removal (BNR) activated sludge processes using ASM kinetic models. An

Existing model that optimally sizes the activated sludge processes will be further

Developed and refined to incorporate and consider new components; mainly denitrification and

Phosphorus removal. The study has revealed the strengths and practicality of using ASM

Kinetic models in a more sophisticated activated sludge system. It has been found that

The internal recirculation ratio (ir) is an important design parameter that can contribute

Significantly in achieving an economical BNR design, thus, imposing a maximum upper limit for the internal recirculation ratio (like what have been suggested by Metcalf & Eddy 1991) could form a real

Obstacle against the optimal economical design. The study has proposed a new design philosophy

That considers the life cycle cost analysis of the BNR system (CAPEX &OPEX). The model results have shown that more economical design for the BNR system might be achieved if the highest influent temperature is considered rather than the lowest temperature. The higher organisms’ growth rate at higher temperatures will generate higher amounts of sludge and therefore a considerable increase in the disposal cost. The study illustrates that the BNR system design can be more economical in terms of life

Cycle cost if consideration is given to minimize the amount of the sludge generated from the