No abstract

The presence of micropollutants that include endocrine-disrupting compounds (EDC) in aquatic environments is currently one of the most relevant aspects of water quality due to their adverse effects on aquatic organisms and human health. From the several categories of EDC, 17β-estradiol (E2) is a natural hormone, which is prevalent in vertebrates, associated with the female reproductive system and maintenance of the sexual characters. 17α-Ethinylestradiol (EE2) is a synthetic hormone produced from the natural hormone E2 and is an essential component of oral contraceptives. These compounds are susceptible to bioconcentration and have high potential to bioaccumulation. Wastewater treatment plants are the main point source of E2 and EE2 into aquatic environments, but conventional wastewater treatment systems are not specifically designed for steroid removal. To overcome this problem, biological tertiary treatment may be a solution for the removal of emergent pollutants such as E2 and EE2. The main purpose of the present study is to provide a solution based on the optimization of a rotating biological contactor system to remove estrogens, specifically E2 and EE2, and to quantify their removal efficiency on different matrices, namely real wastewater and different synthetic wastewaters. All assays presented viable removal efficiencies for compound E2 with values always above 50%; real wastewater yielded the highest removal efficiencies. EE2 removal had better removal efficiencies with synthetic wastewater as feed solution, with removals above 15%, whereas the removal efficiency with real wastewater was inexistent.

Perovskite-type CaTiO3 material was synthesized by the polymeric precursor method and characterized. The powder was applied as a promising alternative to TiO2 photocatalyst. Photocatalytic reaction parameters were optimized by surface analysis methodology on the degradation of methylene blue under UV radiation. After optimization, complex textile- and tannery wastewaters were treated and the COD reduction was evaluated. At optimized conditions (pH=11.2 and 1 g L-1 of catalyst concentration), the results obtained for the photodegradation of the real wastewater after 240 min of irradiation were 45% COD reduction for both effluents. The reactions were adjusted to the pseudo first order kinetic and the rate constants were 2.07 x 10-3 (min-1) and 2.23 x 10- 3 (min-1) for COD reduction for textile- and tannery wastewaters, respectively.

Fotocatálise aplicada ao tratamento de efluentes de lavanderia de jeans: comparação entre TiO2 e ZnO na eficiência de remoção de cor Photocatalysis applied tolaundry wastewater treatment: comparison between TiO2 and ZnO on the efficiency of color removal