LABORATORY STUDIES ON THE TRAVEL OF GROUNDWATER POLLUTANTS

Abstract

Many people building wells do not realise the importance of well sanitation. There is nothing more dangerous to the health of a community than a polluted well. In India, most of the rural population depend on underground sources like dug wells, bore wells, and tube.wells for water supply. Reason of its being used so widely is because of excellent bacterial quality, clarity and potability. But it has not to be taken for granted that underground water is safe for drink.. ing purposes. The sources of contamination of ground water are many and complex. It is essential, however, to take heed of the fact that if the purifying capacity of ground is overtaxedAndesirable phenomena occur. An attempt has been made in the present study to investigate the efficiency of bacterial removal and distance travelled by the bacteria through sand and Roorkee soil as porous media. Two different porous media were tried. Sand of effective size 0,165 mm. and uniformity coefficient 8.41. Roorkee soil of effec. time size 0.07 mm. and uniformity coefficient 2.93. Domestic sewage was used as pollutant. The results obtained show that pollution travels vertically till it intereepts the water table and then horizontally as well as vertically►. There was almost no retention of bacteria when the pollutant passed through the sand bed, but the bacterial reduction was quite significant in case of Roorkee soil. Most of the bacter. ial reduction took place in the soil above the water table. There was 90/ removal of bacteria in a depth of travel of 5 inches and 99/ removal in a depth of 11 inches, and length 15 inches. The points farther, show a reduc.. tion of more than 99.99/. Bacterial and conductivity reduction was found to be inversly proportional to length and depth of travel