الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
 |  | from | 32 |  |  |
| | | from | 32 | | |
Abstract
Ground water is a vital water resource and is used for many purposes, including public and domestic water supply system, irrigation, livestock watering, and for industrial purposes. And it serves as the only reliable source of drinking and irrigation water in many areas. Ground water use is still facing some problems; such as the contamination by iron and manganese. Although iron and manganese are not considered a health risk, their increased content in the water substantially affects human health , also their presence create several problems for the consumers such color, bad taste, staining and deposition in the water distribution system leading to high Turbidity. The secondary maximum contamination levels for Iron and Manganese are 0.3 mg/L and 0.4 mg/L respectively according to Egyptian drinking water standards.The removal of Iron and Manganese from ground water is still the main objective for many studies and projects, and there are many methods of removal Iron and Manganese from ground water such as oxidation, Ion exchange, lime softening and biological treatment by slow sand filter. But the majority of Iron and Manganese treatment systems employ the processes of oxidation followed by filtration, which is considered a relatively simple process. During the past 50 years, a number of new synthetic filter-media such as foam plastic media have been developed and are now available for the filtration of water and waste water.Floating media filters differ from the conventional sand filters in many ways. First, because of the density of the synthetic filter media is (0.015-0.10 gm/cm3) less than water density a retaining grate is placed at the top of the filter in order to maintain the media inside the filter in submerged state. Second, under the action of Archimedes floating force, the grains (beads) of filter media are sorted downward for size, with the large grain size at the top of the filter and the small grain size at the bottom. So, the direction of downward filtration simply coincides with the direction of a uniform decrease in pore size through the filter depth. Third, floating media filters are washed with down-flow water, therefore the media expands downward and the gravitational force direction of the deposited solids coincides with the direction of wash water, so that the required volume of water for washing is less than for sand filters.The pilot plant was installed in the laboratory of sanitary engineering, faculty of engineering-El-Mansoura University and the experimental work was planned to be in two phases, the first phase was by using synthetic water (have Iron and Manganese salts) and the second phase was by using synthetic water (have only Manganese salts) in both phases.In phase one, filtration rates used ranged from 2.5 to 7m/hr and Fe influent concentration ranged from 1 to 3 mg/L and Mn influent concentration ranged from 1 to 3mg/L. The oxidation of Fe and Mn were made by adding of Sodium hypochlorite (NaOCL) with dose more than 3mg/L for both phases.Total Fe and Mn removal efficiencies obtained were in the range between 90 to 98% and the effluent concentrations of Fe and Mn for all runs were less than the Egyptian allowable limits.Some of the effluent turbidities were more than 1NTU.For phase two, filtration rates used in the range 3 to 5 m/hr and Mn influent concentration ranged from 0.5 to 3mg/L. The Mn removal efficiencies obtained in the range from 70 to 95.5 % and less than 0.4mg/L. But effluent turbidities exceeded 1NTU. The Presence of Fe with Mn salts helps the process of Mn removal and reduces the turbidity which means that Fe works as coagulant.