Poly Aluminium Chloride (PAC) is a widely used inorganic polymer coagulant with high performance in water and wastewater treatment. It is effective in removing suspended solids, colloids, and organic matter due to its strong coagulating and flocculating abilities. PAC offers advantages such as high efficiency, low sludge production, wide pH range, and easy handling compared to traditional coagulants like alum or ferric chloride. It is commonly used in drinking water treatment, industrial effluent treatment, and paper manufacturing.