Removal of Selected Organic Micropollutants from WWTP Effluent with Powdered Activated Carbon and Retention by Nanofiltration

Abstract

The increasing demand of potable water as well as process water is leading to scarcity of readily available water resources in many regions of the world. In order to preserve fresh water resources waste water reclamation can serve as a promising but technically challenging alternative to conventional water sources. Besides pathogens, organic trace pollutants cause major concerns in reclamation schemes. In this project, the removal of four micropollutants, more specifically bisphenol A, 17α-ethinylestradiol, 5-fluorouracil and cytarabine, from municipal wastewater treatment plant (WWTP) effluent was studied in laboratory scale experiments and in spiking experiments in a pilot plant combining sorption to powdered activated carbon (PAC) and retention by capillary nanofiltration (NF). Laboratory scale experiments evaluating adsorption isotherms and kinetics showed decreased adsorption capacities but increased affinities in the presence of natural organic matter. Spiking experiments showed that the combination of adsorption to PAC and NF retains micropollutants significantly better than direct NF. Retention of lipophilic micropollutants was increased up to 99.9%. Therefore, the PAC/NF process can be considered as an effective way to treat WWTP effluent for reuse.