Aquaculture water treatment by ion exchange: Continuous ammonium ion removal with clinoptilolite

The performance of Hector Clinoptilolite as an ion exchange medium during uptake and regeneration in small continuous fixed bed columns is examined. The model system used was the multi ion system Na⁺ NH₄⁺K⁺Mg²⁺Ca²⁺ in the presence of Cl^- as the co-ion. The objective of the work was to examine the suitability of clinoptilolite as an exchange medium for fish farm water treatment in fresh water recycle systems. Ammonia uptake, the most important criterion used to assess performance, was strongly influenced by ammonium ion concentration in the feed and in the concentration range studied (1-5 mg NH₄N litre^-1) the exchange capacity for ammonium varied linearly with feed concentration. The presence of calcium ion appeared to depress the capacity of the clinoptilolite after the first uptake/regeneration cycle. The multi cycle use of clinoptilolite may be inhibited by this loss of capacity and the relatively inefficient rinsing characteristics which were exhibited. © 1989.