The natural zeolite - clinoptilolite specifically - as well as the synthetic zeolite is an excellent filtration media because it is a natural cation exchanger. It retains large percentages of certain salts, as well as ammonia nitrogen and particles even tinier than 3 microns, becoming an ideal choice to replace sand and sand/anthracite filtration for pools and other surface water bodies. Once conditioned, a zeolite can raise its adsorption capacity for other pollutants such as heavy metals.
Moreover, thanks to its porous structure zeolites encourage the development of aerobic bacteria - for the specific case of industrial and wastewater treatment by oxidation ponds. It also significantly reduces odors by adsorbing ammonia nitrogen.