Total Phosphorus and Reactive Phosphate Removal from Aquaculture Wastewater using Calcined Eggshell

Abstract

Phosphorus is the key nutrient in fish feed, and it has been one of the major soluble nutrients found in aquaculture wastewater (AW). This work aims to evaluate the removal of Total Phosphorus (TP) and Reactive Phosphate (PO4 3-) via adsorption in batch studies using thermally calcined eggshell as adsorbent. The effect of calcination temperature (700 – 1000°C), particle size and holding time were investigated. The screening phase showed that calcined eggshell at 800 °C for 30 minutes was the most suitable condition. Characterization of adsorbents revealed that crystalline structure and functional groups were responsible for the TP and PO4 3- removal using calcined eggshell from AW. Adsorption equilibrium was attained after 15 min with the dosage of 0.2 g of the optimized adsorbent, capable of removing more than 97 % of TP and PO4 3- from AW. This finding has proven the ability of calcined eggshell waste as a potential phosphorus adsorbent from liquid effluents.