Arsenic (As) is among one of the most toxic naturally occurring metallic elements. Its occurrence in water resources causes severe health hazards. The viable solution to address this health hazard, is to treat As contaminated water. This study presents an overview of naturally occurring As in water resources and various As removal techniques adapted to treat As contaminated water. The study specifically focuses on low cost indigenous technologies which can be easily adopted to treat As from drinking water resources, especially in remote areas. The review reports that various low cost materials have been scrutinized for As removal from water, however, challenges such as a simpler process for development at local levels are still prevailing. These challenges have to be resolved in order to offer competent As removal technologies for underdeveloped regions of developing countries.

The economic/ecological contexts and the CO₂ regulation lead the automotive industry to improve the spark ignited engines. A way of improvement is the admission of a lean mixture or of a diluted mixture by recirculation of exhaust gases in the combustion chamber. The main difficulty in these conditions is to start the combustion. To overcome this problem, ignition systems are studied and more particularly the spark one. This discharge leads to the apparition of plasma and the understanding of the energy transfer mechanisms between this plasma and the reactive mixture is essential. This work is focus on the modeling of a spark during its electrical arc phase in order to predict the hydrodynamic behavior of the arc and the shock wave propagation. The difficulty on the choice of initial conditions for the model is highlighted. A two dimensional model based on ANSYS Fluent software is developed. This model allows us to show the role of each initial parameter as well as their impacts on the plasma flow. One calculation case presents the shock wave propagation and the plasma kernel. Finally a parametric study is presented. Without a complete model describing all the phases of the spark the choice of initial conditions is essential, nevertheless experimental measurements are difficult to perform.  The interdependence of the initial parameters is demonstrated and care is needed in case of incomplete set of initial conditions which should be completed.

An experimental setup is developed to study the bubble dynamic created by a wire explosion in a liquid. This arrangement can be encountered in many configurations and processes and differs by the level and frequency of the applied energy and of the liquid nature. In our study the wire explosion is due to a current intensity around one thousand amps during 10ms in a water medium and a distance between the electrodes of few millimeters. By fast imaging the bubble radius is determined versus time depending on the applied energy. The results indicate that the maximum radius of the bubble versus the applied energy leads to a linear variation of 2.3 cm/kJ roughly. A modification of the Rayleigh model is proposed to consider not an empty bubble but pressure variation inside. The experimental results coupled with the Rayleigh model allow determining the maximum bubble radius, the bubble dynamic and to evaluate its mean temperature. For electrical arc energy of 846 J and an inter-electrode distance of 1 mm, the bubble presents an expansion and a collapse. A maximal radius is reached near 4 cm before 1.5 ms the end of the half current period, due to the leak of energy to feed the bubble.