Treatment of landfill leachate by fenton process with nano sized zero valent iron particles

Leachate treatment from municipal landfills has been always a major anxiety in waste management due to its high level of various contaminations. In this paper the effect of Nanosized Zero Valent Iron particles [NZVI] in Fenton process for the treatment of high COD strength landfill leachate was scrutinized. The results corroborated this procedure was fast and efficient. In fact, about 87% of initial COD [38 g/L] was reduced in an hour. The various operation conditions such as pH, initial H[2]O[2] concentration, H[2]O[2]/Fe molar ratio and temperature in a batch reactor were investigated. The optimum condition was obtained at pH value of 2, temperature of 40°C and H[2]O[2] to Fe molar ratio equal to 39 by using only 0.07 M of NZVI. In such conditions, 0.08 M H[2]O[2] for the removal of 1 g/L of COD was needed. Furthermore, hydrogen peroxide consumption after Fenton process was evaluated and it was found that it had a direct relationship with COD removal efficiency

Response surface methodology approach to the optimization of oil hydrocarbon polluted soil remediation using enhanced soil washing

One of the environmental concerns in recent decades is the prevalence of different pollutants in soil. Hence, the importance of remediation has led to the development of various methods to remediate polluted soil. Among these methods, soil washing has gained significant attention to treat polluted soils. In this paper, the response surface methodology was applied in order to determine the optimal conditions for total petroleum hydrocarbon remediation using nonionic surfactant Brij35 in soil environment. The effect of different factors in soil washing process including surfactant solution concentration and volume, washing time, age of pollution and frequency of washing are evaluated. The predicted values for total petroleum hydrocarbon remediation efficiency by the response functions are in a very close agreement with experimental data [R[-2] = 98.75%]. The second order model was developed as experimented response and optimal conditions were obtained by analyzing the contour and surface plots and also by solving the regression equation using LINGO 9.0 software. The optimal concentrations [8 g/L], volume of surfactant solution [500 mL], washing time [75 min], age of pollution [29 days] and frequency of washing [three times] are determined. In this optimal condition, the removal efficiency has been observed to be 93.54% which conforms to the results of process optimization using response surface methodology. Based on the results, it can be concluded that the response surface methodology is a suitable approach to determine the optimal conditions of soil washing to remediate organic hydrophobic pollutants using the nonionic surfactant Brij35 from the soil

[Review on new techniques in tropane alkaloids production]

Increasing from day to day tendency of human societies to plant based drug usage increased demand of secondary metabolite application. Although artificial production of these compounds greatly progressed, but the only way to achieve these fine medicinal compounds has been to extract them from plant resources. Alkaloid field, although very old, is still in its infancy with regard to being fully understood, and biotechnologically exploited. Up to now, approximately 5000 different alkaloids, in 15% of plants that belong to 150 families, have been recognized, that tropane alkaloids such as hyosyamine, scopolamine, atropine and cocaine, with a broad medical usage are a class of them. Industrial tropane alkaloid production by modern techniques such as cell and tissue culture, somatic hybridization, metabolic engineering and commercial large scale culture, is highly concerned nowadays and in this review, the authors have tried to point out some of the results obtained by application of these techniques

beast available technology for small electroplating plants applying analytical hierarchy process

In this study analytical hierarchy process approach which uses expert's knowledge, was applied for selection of the best wastewater treatment alternative for electroplating workshops, located in Tehran province, Iran. This method can be applied for complicated multi-criteria decision making to obtain scientific and reasonable results. Four wastewater treatment alternatives including reverse osmosis, nano filtration, ion exchange, and chemical precipitation were evaluated and ranked based on economical, technical, environmental/ social aspects. Each criterion includes different indices such as land area, capital cost, sludge disposal issues, operating and maintenance, local suppliers and warranty, system flexibility, required skilled and non skilled man power safety, and etc. The results showed that reverse osmosis achieved the maximum general profits and can be the best choice. Sensitivity analysis can shows the effect of inputs parameters change on the results. Sensitivity analysis was applied for each criterion. The results illustrated that for economic and technical criterion, chemical precipitation and for environment criterion, reverse osmosis were qualified

Discretization of flow contain nitrate in porous media by finite volume technique

One of the most important pollutants of groudwaters is nitrate. Different human activities including the application of chemical fertilizers in agriculture, causes the emission of nitrate into groudwaters. In this paper, the dynamic effect of soil moisture on carbon and nitrogen cycles has been analyzed by presenting a connection between soil moisture sample and nonlinear differential equations. At present, wide researches are carried out on modeling soil moisture control in solution flows contain nitrate. In order to do so, separation of energy conservation law equations is carried out by a particular method. The mathematical model governing the nitrate containing current in non-isotropic environment has been presented in the form of combined equations. Equation for distribution in multiple environments and Darcy rule has been considered in this model. Then, using finite volume method, separation of flows contain nitrate in porous media is carried out. The current flux is obtained from central difference approximations or upwind approximation. Mashad plain has been considered for case study at this research. Carrying out calibration operation, the measured results have been contrasted with numerical results of finite volume method. After testing the model, it is possible to foresee the way of nitrate changes in other nodes of calculation network. Using these forecasts, the quality of drinking water for several next years is determined. Carrying out numerical modeling by finite volume method, it is found out that the quality of drinking water of Mashad plain would be suitable for the next ten years