According to the most abundant microorganisms in soils are bacteria. In order to withstand adverse environmental conditions, some bacteria make spores. They have a cell diameter ranging from 0.5 mm to 3 mm and shape of nearly round, rod like or spiral.revealed that bacteria can survive in an environment of low to high acidity and/or salinity. They can also survive at very low to high temperatures ranging from below freezing to above boiling points and withstand very high pressures. Majority of bacterial cells have a negative surface charge for groundwater pH values between 5 and 7, which is typical for near surface soils; and the negative surface charge decreases with increasing concentration and valence of ions in the pore fluid