REMOVAL OF TOTAL CHROMIUM FROM WASTE WATER BY SAND

Abstract

This thesis is concerned with a low cost approach of treating priority pollutants such as Chromium, a heavy metal, by Slow Sand Filters. These filters are probably the most effective, simplest and least expensive wastewater treatment options available in developing countries. The performance of sand filers in terms of total Chromium removal efficiency was studied. For this purpose a filter column 1.2 meters in depth with a diameter of 50 mm was fabricated. The column was filled with ordinary sand and sampling ports were fitted at the depth of 0.4, 0.8 and 1.2 meters. In order to minimize interferences, standard solutions of Chromium Chloride were prepared in the distilled water. Solutions of different concentrations ranging from 50 to 250 ppm were adjusted at pH ranging from 4 to 9 and at various flow rates of 0.1,0.2,0.3 and 0.4 m 3/m 2-hr. A series of laboratory and pilotscale experiments was performed to evaluate the potential effect of the removal of Chromium through an ordinary sand filter. The removal efficiency of these sand filters was found between 89 to 100 percent.