Abstract: A coagulating and flocculating agent based on aluminum pentahydroxychloride for purifying and treating water and/or waste water and/or sludge and/or other contaminated liquids as well as to separate suspended and colloidal particles from liquids in industrial manufacturing processes has its activity enhanced with an inorganic or organic flocculation enhancing additive such as natural or synthetic zeolite and/or cationic, anionic and non-ionic powdered, emulsified or liquid polyacrylamide. Aluminum pentahydroxychloride is formed by treating a natural nepheline, aluminum powder, aluminum oxide or other aluminum providing material with hydrochloric acid after which it is mixed with the flocculation enhancing additive.