Performance of clinoptilolite alone and in combination with sand filters for the removal of ammonia peaks from domestic wastewater

Ion exchange using clinoptilolite for the removal of peak concentrations of ammonia from domestic wastewater as a second stage, by itself and in combination with sand filters, is evaluated. It is observed that there is no significant loss of capacity of clinoptilolite when placed in sand filters. All three configurations studied are successful in the removal of peak concentrations of ammonia, and hence can be used as a polishing unit, to comply with the demands of stringent standards, Among those investigated, the combined scheme, with clinoptilolite and aerated sand filters where biological activity is enhanced, is found to be the most effective provided that sufficient time for the development of nitrifiers are allowed. The performance loss of the clinoptilolite was observed to be 10% after 10 cycles of regular operation and regeneration. (C) 1997 IAWQ. Published by Elsevier Science Ltd.