Micropollutants are defined as contaminants found in trace concentrations in water bodies that are persistent and bioactive, meaning they are not completely biodegradable and cannot be removed by conventional water treatment methods. Because of these aspects, their detection and removal pose a challenge to the scientific community. Among them are endocrine disruptors, drugs, agricultural chemicals, personal grooming products, industrial additives and others. These micropollutants are the cause for global concern, because their presence in water supply systems is suspected of causing health problems in humans and animals. To develop efficient techniques to remove them, it is fundamental to understand their physico-chemical properties and the available treatment types and conditions. Membrane separation processes (MSPs) and advanced oxidation processes (AOPs) are the focus of this literature review, as potential treatment methods to remove micropollutants. The former process stands out for high rejection rates (above 90%) of various micropollutants, but it generates a concentrated secondary waste stream. In turn, the latter process can remove micropollutants without generating secondary wastes, and can also be applied and combined with other treatment methods.

The presence of micropollutants in sewage is already widely known, as well as the effects caused by natural and synthetic hormones. Thus, it is necessary to apply treatments to remove them from water systems, such as advanced oxidation processes (AOPs) and membrane separation processes, which can oxidize and remove high concentrations of organic compounds. This work investigated the removal of 17β-estradiol (E2), 17α-ethinylestradiol (EE2), and estriol (E3) from biotreated sewage. Reverse osmosis processes were conducted at three recoveries (50, 60, and 70 %). For E2 and EE2, the removals were affected by the recovery. The best results for RO were as follows: the E2 compound removal was 89 % for 60 % recovery and the EE2 compound removal was 57 % for 50 % recovery. The RO recovery did not impact the E3 removal. It was concluded that the interaction between the evaluated estrogens, and the membrane was the major factor for the hormone separation. The AOP treatment using HO/UV was carried out in two sampling campaigns. First, we evaluated the variation of UV doses (24.48, 73.44, 122.4, and 244.8 kJ m) with 18.8 mg L of HO in the reaction. EE2 showed considerable removals (around 70 %). In order to optimize the results, an experimental design was applied. The best result was obtained with higher UV dose (122.4 kJ m) and lower HO concentration (4 mg L), achieving removal of 91 % for E3 and 100 % for E2 and EE2.

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