Ammonia and iron removal from drinking water with clinoptilolite tuff

Abstract

Field experiments were carried out for removal of ammonium and iron ions from drinking water containing high amounts of humic acids and dissolved gases. Three ion exchange columns filled with sodium form clinoptilolite (particle size: 0.5–1.0 mm), were connected in series. The ammonia content of the influent drinking water was ∼10 mg dm −3 and the 0.5 mg NH 3-N/dm 3 breakthrough concentration was kept. The iron content ranged between 0.70–0.90 mg dm −3 and 0.05 mg Fe/dm 3 was chosen as a limit for good quality drinking water. In a 90 h continuous experiment about 3.24 m 3 drinking water was purified by three 4 dm 3 bed volume, 9.5 cm ID × 92 cm ion exchange columns. The ammonia ion exchange capacity was about 3 mg NH 3-N/g zeolite. The natural zeolite contained only 46% clinoptilolite. For regeneration, 50 dm 3 (12.5 BV) regenerant was used. After backwashing with 10 BV ammonia-free water, the freshly regenerated column was placed to the end of the series in service. Design and construction of a pilot-plant unit, including a 50 m 3/day capacity ion-exchange system, is suggested.