الفهرس | Only 14 pages are availabe for public view |
Abstract The current study was carried out in three stages: The first stage: Recording both total and dissolved concentrations of Zn, Pb, Ni and Cd for Industrial Region and Suez Canal University Wastewaters in Ismailia govemorate, from 11112004 to 31/12/2004. The second stage: (Bench scale study): This experiment was carried out in four tests as follows: Test 1 (preliminary experiment). Removal of studied heavy metals by some adsorbents like: I kaolin, hematite, iron ore, Maghara coal, shale 1, shale 11, Gaser EI- Suez shale, clayey soil, limestone and activated sludge) using synthetic wastewaters. Test 2 (removal process of studied heavy metals), by using the more effective adsorbents in the test I to investigate the effect of initial dose and temperature effects, retention time and then, studying the kinetics modules to meaningful the fitness models under these conditions and initial concentrations of studied metals and then, studying the mode ling of adsorption isotherm (Freundlich, Langmuir and D- R modules). Test 3 (effect of pH factor in removal process), via achievement the optimum conditions in precipitation process for all metals in synthetic wastewater. The treatments of this test divided into two treatments (slaked lime treatments and slaked lime + elemental sulfur treatments). Test 4 (the precipitation process), effect of pH values on removal efficiency of studied heavy metals in actual wastewater (SCUW). The Third Stage: The pilot scale study was carried out on SCUW Treatment Plant. The treatments in which were selected according to the results of previous bench scale study which are precipitation process by using slaked lime and agricultural sulfur, sorption process by using limestone and sorption process by using the two kinds of shale. The data showed: -The concentrations of studied heavy metals (Industrial wastewater and SCUW) exceed over the permissible limits of these metals in irrigation water and the discharge on the sewers system. - Test 1 showed the best adsorbents are shale 1, shale 11, clayey soil, limestone, activated sludge, -The second order and Freundlich isotherm are fit for all treatments under these conditions. -The addition of slaked lime to wastewaters able to achieve extremely degrees of the removal, but addition of sulfur improves the characteristics of precipitates. - The optimum pH for achievement the highly degrees of metals removal was 9 for two kinds of waste waters. -For the pilot scale study for each treatment with limestone and the two kinds of shale achieved the highly degrees of removal for all metals under the study. -XRD and SEM with EDX analyses were carried out for the best raw adsorbents and the some resides of its after accomplishment of selected treatments. Key words: wastewaters, heavy metals, adsorption, precipitation, clays, limestone, slaked. |