Water and Wastewater.
Large-scale cation-exchange processes using natural zeolites for extracting NH4 from municipal and agricultural waste streams. Hundreds of papers have dealt with wastewater treatment by natural zeolites. Adding powdered clinoptilolite to sewage before aeration increased O2-consumption and sedimentation, resulting in a sludge that can be more easily dewatered and, hence, used as a fertilizer.
Clinoptilolite cation exchange columns went on stream in Denver, CO, and brought the NH4 content of sewage effl uent down to potable standards (0,1 ppm). By adding a layer of crushed zeolite, the water fi ltration rate tripled, with no deleterious effects. Clinoptilolite beds are used regularly to upgrade river water to potable standards. The selectivity of several natural zeolites for lead (Pb) suggests an inexpensive means of removing lead and other metals from drinking water.