Phosphate removal from water using low-cost dolomite filters

Abstract

The extensive usage of phosphate in different industries, such as detergents and fertilizers, remarkably increased its concentration in water bodies. Moreover, the weathering of phosphate-containing geochemical deposits represents another source of water pollution with phosphate. This pollutant has significant impacts on water quality, aquatic life, and the cost of the water treatment process. Therefore, the current project investigates the applicability of calcium-rich dolomite as a filtration media to remove phosphate from water. Firstly, the chemical and physical properties of dolomite samples were examined to check the suitability of these samples for phosphate removal. Then, several batch flow experiments were carried out at a water/solid ratio of 1.77, taking into accounts the influence of some key operating parameters such as treatment time, and the initial concentration of phosphate. The obtained results showed that the longer the treatment time was, the higher the removal of phosphate was. It was found that the calcium-rich dolomite removes about 30 percent of initial phosphate concentration (10 mg/L) within 120 min. Additionally, the results obtained from the application of the Langmuir isothermal model, and the separation factor indicate a good affinity between dolomite and phosphate atoms.