Mohsen Azizi; Abbas Khashei; Mehdi Dastorani
Abstract
Background & objective: Today, the pollution caused by landfills is considered as one the serious environmental threats, including groundwater resources. The purpose of this research, the use of mathematical models and numerical with high precision in determining and explaining the current situation ...
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Background & objective: Today, the pollution caused by landfills is considered as one the serious environmental threats, including groundwater resources. The purpose of this research, the use of mathematical models and numerical with high precision in determining and explaining the current situation and relatively accurate predictions, to examine the groundwater pollution caused by leakage of leachate centers around landfill. Materials & Methods: In this research, The MODFLOW, MODPATH and MT3DMS models was used to estimate the speed of movement of pollution, tracing path and simulate the process of transfer of leachate producedat San Angelo landfill site in the United States to the downstream drinking water well. Also Three scenarios of a) improved bedding of landfill bottom and reduced leachate penetration to 25%; b) Reducing the amount of extraction downstream drinking water well to 20%; c) landfill Movement as much as 100m to upstream were evaluated. Results: The results of the modeling showed that in the current situation, the leachate produced landfill reaches the downstream well going through a distance of 608 meters in 2158 days. By applying three scenarios in the numerical model was seen that the leachate reaches to the downstream well by passing a distance of 613, 618, and 667 m in 4000, 3250 and 4000 days, respectively. Conclusion: Therefore, in the field of locating the landfill and leakage of leachateto groundwater, numerical models can be used to predict the direction and speed of pollution movement and to make management decisions for reducing the time and distance of arriving the pollution at the groundwater.
Fahimeh Sharifan; Ali Shahidi; Abbas Khashei
Abstract
Background& objective: The hexavalent chromium is a toxic and water-soluble heavy metal that is absorbed and stored through the digestive system and through the skin in the human body. That amount is exceeded in drinking water in Birjand. So the purpose of this studies, Process about remove the hexavalent ...
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Background& objective: The hexavalent chromium is a toxic and water-soluble heavy metal that is absorbed and stored through the digestive system and through the skin in the human body. That amount is exceeded in drinking water in Birjand. So the purpose of this studies, Process about remove the hexavalent chromium by using from pine fruit powder, carbon and compare to each other. Methods: In this research, for Calculate removal efficiency (Re), Parameters of contact time, pH, adsorbent dose, initial Cr (VI) concentration and Temperature was studied. Experiments were intermittently performed in batch reactor on Shaker. Results: The results showed that the absorption of chromium significantly depends on the pH of the solution and the absorption rate in the range of 3 for powder and 1 for carbon was achieved when the pH of the solution. The maximum removal of Cr (VI) for pine fruit powder is 96/5 % and for activated Carbon Pine Cones is 93/958%. The results indicate that the soluble chromium ions through the absorbent used in this study, as well as follow the Langmuir isotherm model. Conclusion: The most remove of the hexavalent chromium happened by pine fruit powder and Pine cones can be used as an effective and inexpensive method to remove of the hexavalent chromium from contaminated wastewater.