Evaluation of the Use of Fly Ash as a Low Cost Technology for Phosphorus Removal in Wastewater Treatment

Abstract

“Pozzolan” is a slag from the burning of coal in power plants which has the potential to assist as a low-cost adsorbent for wastewater treatment. The excess of Phosphorus (P) in the environment can promote chemical pollution and harm ecosystems, especially water. It is therefore necessary to implement inexpensive techniques and processes for the efficient treatment of water and wastewater. In this context, this study evaluated the use of the pozzolanic fly ash material for P removal from wastewater for the development of low-cost treatment technologies for environmental restoration and remediation of water resources. The treatment systems were developed in batch configuration. The removal tests from a synthetic sample with a known concentration of P reached a maximum of 30% removal in concentration, even varying the pH and performing different treatments of the pozzolanic material. This low removal efficiency of Phosphorus led to a comparative test between different lots of pozzolan in order to verify if the results obtained were characteristic of the material itself or of the lot obtained. Also the P adsorption isotherms were constructed with the two lots achieving adsorption capacities from 0.87 mg g-1 to 74 mg g-1. This difference indicates that the low P removal efficiency in the preliminary tests is due to the characteristics of the substrate of the first lot. Tests on a real effluent using the pozzolan from the second sample lot indicated a 99% efficiency of P removal, with an initial concentration of Phosphorus in the effluent of 5.5 mg L-1.