Evaluation of Tertiary Processes to Remove Trace Pharmaceuticals from Treated Sewage Effluent

Abstract

In countries with limited water resources such as Qatar, reusing treated sewage effluent (TSE) is necessary to overcome the water scarcity. The quality of the TSE to be reused should be adequate to avoid adverse effects on the environment and its creatures. Pharmaceuticals are among the persistent contaminants to the conventional wastewater treatment process being regularly discharged into sewage effluents from various human activities. In this study, the removal of two widely used pharmaceuticals, ibuprofen (a painkiller) and gemfibrozil (a lipid regulator), from TSE has been investigated using five different processes: chlorination, ozonation, ozone/hydrogen peroxide (O3/H2O2), adsorption, and catalytic ozonation. For the last two processes, activated carbon was produced from local date pits treated by phosphoric acid at 550°C with high surface area of 726 m2/g to serve as adsorbent and/or catalysts. The removals were evaluated as single components and in binary systems at different dosages for the relevant methods along with the effect of initial pH and temperature. Chlorination showed insignificant removal for both compounds, whereas by ozone and O3/H2O2, complete removal of gemfibrozil and 80% ibuprofen removal were achieved. For the adsorption process study, different kinetics and isotherm models were investigated in addition to the adsorption from TSE, where the process was found to be efficient but very slow. On the other hand, very fast and complete removals of both compounds were obtained by the catalytic ozonation process, and the activated carbon reusability showed almost no effect on the removal efficiencies after 10 cycles with almost unchanged phosphate and nitrate concentrations. The cost analysis showed reductions of 19.4% and 18.8% of the capital cost and the annual operation and maintenance costs when compared with ozone alone. The aim of this work was to produce high quality TSE for possible use in agriculture with high nutrients and low contaminants at relatively low cost.

Date of Award	2022
Original language	American English
Awarding Institution	HBKU College of Science and Engineering