حسین ساسانی

TiO2 nanoparticle is a heterogeneous semiconductor material with a photocatalytic properties in irradiation condition of the light source with a below 387 nm wavelength (equal to the Titanium dioxide bandgap, 3.2 eV). due to the low toxicities (in comparison with other semiconductors), cheap preparation, and strong oxidation abilities, there is a huge demand for wastewater treatment. in this study, the surface of commercial titanium dioxide nanoparticles (TiO2-P25 Degussa) that placed and immobilized on the surface of Expanded perlite (EP) was modified with the help of the Ultrasonic Co-precipitation method with alpha-Iron oxide nanoparticles (α-Fe2O3) and obtained nanocomposite are evaluated for the purification of water contain Methylene blue (M.B) pollution in aqueous solution. experiments are set up in a batch reactor (50-milliliter beaker) contain 35 ml synthetic dye wastewater. for Titanium dioxide nanoparticles to become activated, used 3 Ultraviolet lamps (UV-C) with the wavelength 285/7 nm and power of irradiations equal to the 15 watt. experiments at three pH levels (3, 7 and 11) was performed, the highest decolorization methylene blue from the water was observed at the following condition, pH equal to 11, light irradiation time equal to one hour, initial concentration of methylene blue is 10 mg/L, and 5 g/L of coated perlites, in reactor, that reached 99.7 % decolorization. the surface of Expanded perlite before and after coating with TiO2 and α-Fe2O3 nanoparticles was study and investigated with SEM test, also the disperse of these nanoparticles at surface of expanded perlite was studied with an SEM-MAP analyst.

The quality of water available to humans has been seriously threatened due to population growth and the resulting increase in urban and industrial wastewater. To evaluate changes in the water quality of the Karun River in the urban area of Ahvaz, a simulation model was developed and used to assess the river's water quality based on existing standards. Results show that the quality variables of the river are highly dependent on the season of the year, with the largest changes in dissolved oxygen occurring during the driest and wettest seasons. Comparison of the river's current situation with national and international standards indicates that the water quality does not meet most standards, except during the autumn season when the flow rate is highest. Even if all effluents entering the river comply with existing discharge standards, the quality of the river does not meet desired standards. This highlights the importance of considering specific hydraulic conditions and the effect of time on river quality when updating existing standards.

Background and Waste stabilization pond is one of the conventional wastewater treatment processes especially in warm climate regions. This study investigated the effect of baffle and attached growth on improvement of coliform removal efficiency.
This research was carried out in pilot scale adjacent to wastewater treatment plant in Ahvaz, Iran. The pilot composed of a control system and three other systems. In control system two ponds were serially connected. Dimension and configuration of other three systems were similar to those of the control system. However, the ponds in these systems were equipped with various baffles and fixed bed media. Within four months, the capability of each system in coliform removal was evaluated in various detention times and coliform die-off coefficient (Kb) of each pond was determined.
During sampling with average detention time of 8.7 day, the average of coliform removal was 69% in control system, while it in two, three and four baffles system these values were 80, 84 and 86%, respectively. Also, Kb20 average in the first pond of control system was 0.11 d-1 and in other systems with increasing of baffles and media packages number to two, three and four it increased to 0.16, 0.17 and 0.18 d-1, respectively. Furthermore, Kb20 in second pond was higher than first pond of each system.
Use of baffles and fixed bed media improved coliform removal efficiency. The efficiency of two and three baffles system was more than that of the control system and was found to be better than four baffles system technically and economically