Interference of the Real Water Matrix with Micropollutant Removal via Advanced Filtration: Insights from the Goreangab Reservoir in Namibia

The Goreangab Reservoir was built in 1958 as part of the water reclamation plant to support the water supply in the Windhoek area, Namibia. It has not been used since 2002 due to deteriorated water quality. This work describes the occurrence of micropollutants in Goreangab Reservoir water and assesses the removal of a target steroid hormone micropollutant, 17β-estradiol (E2), with various emerging membrane processes. Results show that a variety of micropollutants exist in water, and many of them exceed the European guideline concentration values for surface water. While nanofiltration provides only moderate E2 removal (50 ± 9% for loose and 81 ± 4% for dense NF) from an initial concentration of 100 ng L^-1, reactive photocatalytic membranes and a combination of ultrafiltration (UF) and adsorption by polymer-based spherical activated carbon (PBSAC) can remove 85-98% of E2, bringing the water quality closer to the target guideline (0.4 ng L^-1). Water components such as organic matter, ions, and other micropollutants interfered with E2 removal to varying degrees, highlighting the requirement for pretreatment and process validation with real water. UF-PBSAC achieves good E2 removal at a comparatively low pressure, resulting in low energy consumption. The amount of energy required to apply light irradiation and voltage in photo- and electrocatalytic membrane systems is significant based on theoretical estimation.