Formation and reverse osmosis removal of bromate ions during ozonation of groundwater in coastal areas

Summarization: The generation of bromate ions during ozonation of groundwater samples affected by seawater intrusion was investigated. The ozone‐water contact times studied were 2.5, 5, 10, 15, and 30 min, while the applied ozone rate was 4.5 mg/min. Generation of bromate ions started right after the application of ozone. The level of bromates increased with time as more ozone was added to the reactor. Even after 30 min of ozonation, the concentration of bromates kept rising without reaching a plateau. The higher the initial concentration of bromide ions, the higher the level of bromate ions in the ozonated water sample. The experimental results obtained during ozonation of the specific groundwater samples (low TOC and low ammonia concentrations) were used in order to develop a mathematical model capable of forecasting the generation of bromate ions. The empirical model containing two independent variables, conductivity and contact time, was:his model allows the prediction of bromate ion generation, when the groundwater conductivity and the contact time are known, for an ozone application rate around 4.5 mg/min. Finally, the ozonated water was treated by reverse osmosis. The removal of bromate ions reached 96.1%. Equivalent reduction in the conductivity of the water was also achieved.Presented on: Separation Science and Technolog

Study on the Occurrence of Artificial Sweeteners, Parabens, and Other Emerging Contaminants in Hospital Wastewater Using LC-QToF-MS Target Screening Approach

The presence of 220 emerging contaminants belonging to different classes (artificial sweeteners, personal care products, coffee and tobacco-related compounds, and industrial chemicals) was investigated in hospital wastewater for the first time. Twenty samples were collected within two sampling periods from two points of a Greek General Hospital. Target compounds were analyzed using a solid-phase extraction protocol followed by UHPLC-ESI-QToF-MS analysis. Analytical results showed that 23 micropollutants were detected at least once in hospital wastewater samples in Period 1, while 27 compounds were detected at least once in Period 2. The coffee and tobacco-related compounds were the most frequently detected substances, followed by artificial sweeteners, parabens, and industrial chemicals. The highest mean concentrations were recorded for the artificial sweeteners cyclamic acid (377 μg/L) and saccharine (295 μg/L), followed by caffeine (193 μg/L), nicotine (162 μg/L), and the industrial chemical lauryl diethanolamide (153 μg/L). The group of artificial sweeteners contributed up to 55.1% (Point A/Period 1) to the total concentration of studied chemicals. The detection of high concentrations of artificial sweeteners in hospital effluents reveals that hospitals should be considered as important point-sources of these contaminants. © 2023 by the authors