Date of Award

2005

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Dr. Farid BeoYahia

Second Advisor

Tom Stephenson

Third Advisor

Dr. Ali Hassan AI-Marzouqi

Abstract

Ahmed S. Embaby

Removal of ammonia from wastewater is one of the problematic issues in wastewater treatment because nitrifies are very slow growing and can be washed out from activated sludge processes. There is a need to use higher advanced techniques to retain biomass. Among these techniques is cell immobilization in appropriate reactor environments. Cell immobilization technology can be approached by various methods, including cell entrapment or biofilms. However, these immobilization techniques are often accompanied by challenges in terms of biomass activity preservation and recovery following the immobilization treatment, reduction of nutrients mass transfer rates, adequate performance under shock situations and preservation of structural and mechanical integrity of the support material.

Our literature review revealed that important issues like, the effect of support matrix

Composition on nitrification performance was not addressed adequately, and the effect of pH

shock and load shock to immobilized systems were not quantitatively investigated. Hence, it

was decided to make these issues prime objectives of this investigation. In addition, the effect of initial ammonia concentration on nitrification performance was studied.

In this investigation, immobilization of Nitrosamines cells was carried out using various methods that include entrapment in support matrices and surface biofilms, in order to evaluate the potential of this technology in large-scale wastewater treatment applications. Support material considered for entrapment in this work included alginate gels and Polyvinyl alcohol (PVA). Materials considered for biofilm growth included available natural and synthetic particles.

The results from the biofilm growth experiments suggested that the particles considered in this

work were not suitable for Nitrosamines cells. On the other hand, the results of entrapment experiments suggested that out of the three PVA compositions considered in this work (10%, 15% and 20%), the 10% PYA gave the best overall results. This was ascertained by nitrite liberation rates and SEM imagery. In addition, the initial ammonia concentration of 100 ppm that is used in bacterial reactivation gave the best overall nitrification results.

This investigation has clearly shown the positive potential of immobilized Nitrosamines

cell for nitrification in wastewater treatment applications. In addition to biomass retention,

which is a prime objective of immobilization, additional benefits were attained. These

Included a resistance to pH and load shock and the ability to sustain nitrification even at high ammonia concentrations.

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