Experimental and modeling investigations of wastewater filtration

Abstract

In an effort to make wastewater recycling risk-free, this research investigated the feasibility of using a waste material as filter for the removal of humic substances (HS), and ultimately the toxic hydrophobic organic compounds (HOC) attached to them. Based on the results of earlier studies, laboratory experiments were conducted in a large-scale set up to investigate with synthetic and real (municipal) wastewater, the effects of the flow rate, column diameter, and column height on the efficiency of the filtration process. Furthermore, with the experimental data, a mathematical model was calibrated and used to predict the performance of the filtration process under various conditions. The results of the investigation with the synthetic samples showed that all concentration-time profiles had a reversed ‘S’ shape, and at any given flow rate, the efficiency of the filtration increased when the height and/or diameter of the PPL column increased. However, it decreased when the flow rate increased. Under similar conditions, the filtration efficiency with municipal wastewater samples was much higher. The mathematical model predicted with more or less success the experimental data. Overall, this research confirmed that PPL can be used to remove HS. It also suggested that PPL may be able to remove HOC attached to HS. Nevertheless, further investigations are necessary to eliminate the release of background organics by PPL, and improve the model by taking into account the dual adsorption–filtration capability of its granules.