ABSTRACT
Direct capillary nanofiltration also in combination with an upstream powdered activated carbon treatment was tested for high quality water reuse of tertiary effluent from a municipal wastewater treatment plant. Two endocrine disruptors (BPA and EE2) and two cytostatics (CytR and 5-FU) were spiked in concentrations of 1 to 2 microg/L to evaluate the process performance. In direct NF the real total removal of the micropollutants was between 5 and 40%. Adsorption to the membrane played a major role leading to a seemingly total removal between 35 and 70%. Addition of powdered activated carbon and lignite coke dust largely reduced the influence from adsorption to the membrane and increased the total removal to >95 to 99.9% depending on the PAC type and dose. The cytostatics showed already in direct NF a very high removal due to unspecified losses. Further investigations are ongoing to understand the underlying mechanism. The PAC/NF process provided a consistently high permeate quality with respect to bulk and trace organics.
