Date of Award

5-2014

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemical and Petroleum Engineering

First Advisor

Prof. Muftah El-Naas

Second Advisor

Dr. Sulaiman Al-Zuhair

Third Advisor

Dr. Munjed Maraqa

Abstract

Chlorinated phenolic compounds represent a major class of hazardous pollutants commonly encountered in wastewater generated by the petroleum and petrochemical industries. In this regard, biological treatment, as an economical and green technology, has been shown to be one of the most promising approaches for the removal of many organic water pollutants such as chlorophenols. Under aerobic conditions, bacteria utilize chlorophenols as a source of carbon and energy. This study aimed at developing an integrated system for biodegradation of 2, 4 dichlorophenol (DCP) in a specially designed spouted bed bioreactor (SBBR), characterized by systematic intense mixing, resulting in enhanced biodegradation rates. The system utilizes microbial immobilization of an effective commercial bacterial consortium, consisting mainly of Pseudomonas putida, in order to retain the biomass within the reactor. The bacteria were immobilized in polyvinyl alcohol (PVA) gel particles and used in the SBBR to remove DCP from the wastewater.

The role of glucose, which has often been included as a carbon source during initial biomass acclimatization, was investigated and found not to be significant enough to justify its inclusion in the acclimatization process. In addition, the effects of several operating parameters were investigated in the batch mode operation, then modeled and optimized for maximum degradation rate by response surface methodology. The process was further tested in a continuous mode in order to evaluate the SBBR hydrodynamics in terms of stability and sustainability to shock loads. Total removal of the contaminant was achieved in the batch process at every initial concentration up to 200 mg/l, whereas a combined 80% removal at a throughput of 1400 g/m3day was obtained during

Continuous operation. Additionally, the process was mathematically modeled using a dynamic modeling approach in order to assess reaction and mass transfer limitations. The results supported the use of the PVA immobilization technique as the most effective decontamination process. Finally, the process was evaluated for the treatment of refinery wastewater and was proven to be very effective.

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