الفهرس 
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Abstract
In this thesis, there was much concern about the Technically Enhanced Naturally Occurring Radioactive Materials (TENORM) associated with oil and gas productions facilities from different areas in Egypt. These TENORM were collected as sludge and scale wastes, with various activity concentrations much higher than exist in normal case (background). The work carried out in this thesis, was classified into three main chapters, as the following:
Chapter 1, Introduction
This chapter includes some information about the different sources of the natural radioactive materials (TENORM), especially TENORM associated with oil and gas production. This chapter included some definitions of radioactivity, exposure, radiation dose and annual effective dose as well as other radiations indices. It contained some aspects on the chemistry and radiochemistry of radium and radon as well as the last trials efforts treatments for the natural radioactive materials. The end of this chapter included the aim of the present work.
Chapter 2, Experimental
This chapter included preparation of all test samples for analysis, chemicals and reagents, as well as the references materials used for energy and efficiency calibration of gamma spectroscopic systems used in the experimental work. It also included description of the different spectroscopic instruments that were used such as gamma spectroscopic techniques with Hyper Pure Germanium detector HPGe and NaI γ-ray spectroscopy, X-ray diffraction (XRD), X-ray fluorescence (XRF), and FTIR-spectrometry. The energy and efficiency calibrations of γ-spectrometry were also presented.
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Chapter 3, Results and Discussion
This chapter was divided to two main parts as the following:
Part one (General characterization of TENORM waste samples)
This part covered the characterization of the different samples of petroleum sludge and scale TENORM waste samples through, physical, chemical, mineralogical and radiological analysis. The results showed that, the samples of the TENORM wastes were mixture contained silicates, carbonates and sulfates of alkaline earth metals, organics compounds with different percent. The radiological analysis of all test samples showed that, these samples contain the natural radionuclides of 226Ra, 232Th and their decay series as well as 40K. The radioactivity concentration of the different TENORM samples were determined by γ-ray spectrometer with HPGe-detector. The radioactivity of 226Ra, 232Th and 40K were found to exceed the permissible levels by the international regulations.
Different radiation hazards indices ( Raeq, Dabs, Dann, Raeq, Hex, Hin…..etc) were calculated in sludge and scale TENORM waste samples based on their activity concentrations of 226Ra, 232Th and 40K. The results obtained showed that all calculated values were found higher than the permissible and/or recommended safe levels. So, the TENORM waste which contains high activity concentration of 226Ra represent radiation hazard to the environmental impacts to the surrounding by TENORM wastes.
Part two (Trials of treatment of TENORM wastes)
This part contained the results related to leaching and treatments of some radionuclides in sludge and scale TENORM waste samples under study, using several leaching surfactant reagent. It included sub-section as follows:
Section one (Surfactants leaching reagent)
Surfactants or surface active agents are chemical substances that adsorb on or concentrate at a surface when present at low concentration in a system. They alter the interfacial properties
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significantly; in particular, they decrease the surface tension. Different types of surfactants were used as non-ionic, ionic, zwitter ionic and commercial surfactants.
Section two (Treatment trials of the sludge TENORM waste samples)
Among of various types of surfactant, anionic surfactants were found to be more effective for leaching of Ra than non-ionic, zwitter-ionic and commercial surfactants in scale TENORM waste samples. It was found that the maximum leaching percent of Ra was 58% and 65% using benzethonium chloride 4% and sodium larouyl sarcosiate 4% solution, respectively and under the optimum condition.
Section three (Treatment trials of the scale TENORM waste samples)
Leaching removal percent and the activity concentrations of TENORM waste samples can differ from one place to another depending on some factors, e.g., location of sampling, age of the producing oil and gas type of production process and geological formation conditions.
The successive leaching results showed that, the removal of Ra in scale TENORM waste was found to be more than 90% through four successive cycles using new solutions of benzethonium chloride and for both scale samples (from weasern desert area and Ras Shukeir area).
Section four (Leaching Kinetics)
The results were analyzed by SCM and Arrhenius model to explore the leaching kinetics and mechanism. Since the activation energies were below 20 kJ/mole, the leaching process for dissolution of Ra-isotopes is a diffusion-controlled process as described by shrinking core model C.