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The main purpose of this study was to improve sand filtration process by using local media and optimizing to obtain the best operating parameters. Sand from the Algerian desert was utilized. The treatment effectiveness on domestic effluent was assessed by monitoring pollution parameters such as turbidity, chemical oxygen demand (COD) and biological oxygen demand (BOD). The results of showed that the sand had a homogenous structure with a large presence of angular and blunted grains and a low percentage in round grains. This characteristic improves the filtration efficiency. The results showed also that the abatement rates of pollution indicators such as turbidity, COD and BOD were high for all experiments, between 60% and 90%. The sand filter designed in this study demonstrated a great performance for the treatment of domestic wastewater. [ABSTRACT FROM AUTHOR]

The main objective of this study was to demonstrate the efficiency and to optimize the operating conditions of photodegradation of paracetamol in the presence of suspended titanium dioxide catalyst in a photoreactor. An experimental design study was carried out using central composite design modelling. Optimization was applied to the tubular reactor under fixed photonic flux with radiation from two 24-watt UV-A lamps. The optimal values of the operating parameters were found to be pH of 7.288, TiO2 concentration of 0.9932 g·L-1 and paracetamol initial concentration of 15 mg·L-1. The paracetamol degradation rate approached 98.46% under optimal conditions. Modelling of the system led to a second-degree polynomial. Regression analysis gave an R² value of 0.977 which meant good agreement between the experimental results and the predicted values. An interaction was demonstrated between the catalyst and the operating parameters (pH, CPara and CTiO2) as well as between the model pollutant concentration and the pH had an insignificant effect on the yield compared to that of the quantity of the catalyst and the initial pollutant concentration. [ABSTRACT FROM AUTHOR]

In sustainable development context, solar energy may be adapted to improve the development of green technologies in wastewater treatment. In this paper, the photocatalytic elimination of Methylene Blue (MB) as a reference dye is performed in a fixed bed photoreactor. A commercial TiO2 catalyst is immobilized on a cement support irradiated by solar light. The effects of some parameters such as the light source, pH of the solution as well as the pollutant initial concentration were investigated. The results show that the quantity of catalyst affects positively the MB degradation rate unlike the pollutant initial concentration which decreases the degradation efficiency. The degradation efficiency was found higher at around basic pH values (93%-97%). In addition, the degradation rate of pollutant was higher with solar light irradiation (97%) rather than with artificial irradiation (16%). This solar photocatalytic device is a potential application for organic dyes elimination. [ABSTRACT FROM AUTHOR]

The methodology of experimental research was carried out using the MODDE 6.0 software to study the acetamiprid photodegradation depending on the operating parameters, such as the initial concentration of acetamiprid, concentration and type of the used catalyst and the initial pH of the medium. The results showed the importance of the pollutant concentration effect on the acetamiprid degradation rate. On the other hand, the amount and type of the used catalyst have a considerable influence on the elimination kinetics of this pollutant. The degradation of acetamiprid as an environmental pesticide pollutant via UV irradiation in the presence of titanium dioxide was assessed and optimized using response surface methodology with a D-optimal design. The acetamiprid degradation ratio was found to be sensitive to the different studied factors. The maximum value of discoloration under the optimum operating conditions was determined to be 99% after 300 min of UV irradiation. [ABSTRACT FROM AUTHOR]