Ground Water Treatment Using Slow Sand Filtration or Conventional System (Dept.C)

Abstract

Iron and manganese represent a serious problem in ground water, therefore this research study two alternatives for water treatment contains these metals through two pilot plants constructed within a groundwater plant in Walga village, Mnia El Kamh Markaz, Sharqia governorate, Egypt. The main objective of this research is to compare the two alternative systems for iron and manganese removal, the first method mainly depends on biological treatment of slow sand filtration (SSF) with pre-aeration (multiple trays), while, the other method is conventional system (pressure filters) with pre-aeration (aeration tank) and using the additional chemicals. Filtration rates used for slow sand filters ranged from 3 to 6 m/d and Fc influent concentration ranged from 0.6 to 1.3 mg/l and Mn influent concentration ranged from 2 to4.4 mg/l. Total Fe and Mo removal efficiencies obtained by slow sand filtration system, which functions under natural conditions and without using any chemical agents, are in the range between 97% to 99 % and the effluent concentrations of Mn and Fe for all the runs were less than the Egyptian allowable limits. The conventional system used aeration with influent iron and manganese concentrations of 1.3 and 4.4 mg/l respectively, potassium permanganate doses were in the ranges of 2 to 6 mg/l and the rate of filtration was 150 m3/m2lday. The removal of manganese increased by increasing KMnO4 dose but iron removal efficiency was the same for all runs. The effluent concentration of Mn was higher that the allowable limits for all the runs of the conventional system. The aeration step has an important effect on removal efficiency of iron and manganese by slow sand filter and conventional system. Finally, it concluded that the use of slow sand filtration (SSF) plants in Egypt is better than using conventional plants due to the simplicity of operation and maintenance and without using chemicals, further more the high efficiency of iron and manganese removal with accep table limits for potable water.