Removal of microorganism an suspended material by coagulation and filtration

Abstract

The quality of water is of vital concern for mankind since it is directly linked with human welfare. But majority of people are still not aware of it. People use surface water for various domestic purposes. Surface water is often physically and bacteriologically contaminated due to unhygienic practices. During floods the water quality deteriorates and treatment is required to make water potable. The study was devoted to acquire a better understanding of the effectiveness of alum for removal of faecal coliform as well as kaolin particles. Different parameters affecting removal of faecal coliform and kaolin particles were investigated in this study such as alum dosage, pH. sedimentation time and mixing. Filtration with filter paper was performed after coagulation. Removal of faecal coliform was observed at different pH and sedimentation time. Alum dosage was found effective for reduction of faecal coliform and kaolin particles. With increasing alum dosage faecal coliform and turbidity removal rate were found increasing. pH and sedimentation time also significantly affected the removal of faecal coliform and turbidity. Most of the experiments were performed at pH 4.5 and 6.0. It was observed that the removal efficiency at pH 6.0 was higher than that of pH 4.5. At any alum .dosage. removal of faecal coliform was found to increase with increasing sedimentation time. Moreover for the same removal of microorganism less sedimentation time was required for increased alum dosage. With increasing sedimentation time settlement rate was found to decrease. It was found that with increasing alum dosage potable water could be obtained within a short period of sedimentation.