Effect of Diatomite and Seashell on Ammonium Nitrogen in Aquarium Wastewater

Abstract

In aquarium systems, nitrogenous compounds such as ammonium/ammonia are produced through the decomposition of fish metabolic wastes, feces, and uneaten feed, thereby adversely affecting water quality. In this study, the effects of powdered and gravel-sized diatomite and seashell, which can be used as natural substrate materials, on ammonium removal from aquarium wastewater were investigated. The study was conducted in five groups—control, powdered diatomite, gravel-sized diatomite, seashell, and powdered seashell—with three replicates per group. Each experimental container was filled with 600 mL of aquarium wastewater, and 6 g/L of natural material was added to all groups except the control. Water temperature, pH, NH₃, NH₄⁺-N, and TAN values were monitored for 53 hours. At the end of the experiment, no significant differences were observed among the groups in terms of water temperature and pH (p > 0.05). However, NH₃ values in the powdered and gravel-sized diatomite groups were significantly lower than those in the control group (p < 0.05). NH₄⁺-N values decreased in all treatment groups compared with the control. Diatomite and seashell contributed to the reduction of ammonium levels in aquarium wastewater. In conclusion, diatomite and seashell can be used in aquaria as low-cost, natural, and decorative substrate materials; however, diatomite was found to be more effective, particularly in ammonia control.