Alum is a mineral substance that is obtained from nature in pure and impure forms. It is derived from aluminum ore, which is a mineral salt. It is found in many pharmaceutical, cosmetic, and food products. In this study, the three different types of alum were synthesized and evaluated by physical and chemical characteristics. The groundwater from different areas of Chennai was collected and evaluated by semi-quantitative and quantitative methods via Limit Test, Assay by Mohr’s Method, Flame Photometry, and Total Hardness Test. All three different alums were treated with groundwater by the coagulation method for the purification of water. The alum-treated water was post-evaluated by semi-quantitative and quantitative methods. In the Limit test, alum-treated water produces less opalescence or turbidity, or colour when compared with untreated water. In the Estimation of chloride by Mohr’s method in some water samples, alum reduces the amount of chloride ion concentration. In the Flame photometry analysis, the alum reduces the sodium ion concentration in all areas’ groundwater. When compared with all alum, Soda alum is more efficient. In the total hardness test, the hardness of alum-treated water increases due to its interaction with water and the excess production of metal ions. In vitro antimicrobial activity of alum proved that potash alum produces high antimicrobial activity ammonium and soda alum showed significant anti-microbial activity. We summarized that soda alum is highly efficient in the water purification process and produces higher antimicrobial activity than the other two alums.
