Removal of active pharmaceutical ingredients from wastewater by application of nanobubble technology and ultraviolet light
Authors
Hansen, Vibeke Kirstine ; Wanstrup, Klara
Term
4. term
Publication year
2023
Submitted on
2023-06-07
Pages
87
Abstract
Active pharmaceutical ingredients in wastewater effluents are a growing concern. This thesis evaluates nanobubble technology combined with ultraviolet light as a potentially more environmentally friendly alternative to ozonation and activated carbon. Nanobubbles were generated in water and documented in clean samples by dynamic light scattering (size distributions 256 to 484 nm, zeta potential -13 to -20 mV); a combination of O2 and demineralised water with added salts to increase ionic strength yielded the most consistent results. In environmental samples, a modified Winkler titration was used, where lowering pH collapsed nanobubbles and increased dissolved oxygen over time (e.g., from 8.45 to 10 mg/L after two days and to 11.6 mg/L after seven days). Oxidative capacity was probed using methylene blue as an indicator, but no consistent degradation was observed. Degradation of diclofenac and venlafaxine under UV with and without nanobubbles was assessed; diclofenac was mainly removed by UV (about 84.7% with nanobubbles and UV and 81.8% with UV alone over one hour), while venlafaxine was removed to a limited extent (6.35% vs. 4.82%). Overall, the results suggest nanobubbles provided only a modest additional effect under the tested conditions, while the approaches for documenting nanobubbles were applicable.
Aktive lægemiddelstoffer i udløb fra renseanlæg er en voksende bekymring. Denne afhandling undersøger nanobubble-teknologi kombineret med UV-lys som et mulig mere miljøvenligt alternativ til ozonering og aktivt kul. Nanobobler blev genereret i vand og dokumenteret i rene prøver med dynamisk lysspredning (størrelsesfordeling 256 til 484 nm, zeta-potentiale -13 til -20 mV); en kombination af O2 og demineraliseret vand med tilsatte salte for øget ionstyrke gav de mest konsistente resultater. I miljøprøver blev en modificeret Winkler-titrering anvendt, hvor sænkning af pH fik nanobobler til at kollapse og øgede opløst ilt over tid (fx fra 8,45 til 10 mg/L efter to dage og til 11,6 mg/L efter syv dage). Den oxidative kapacitet blev vurderet med methylenblåt som indikator, men uden konsekvent nedbrydning. Nedbrydning af diclofenac og venlafaxin under UV med og uden nanobobler blev undersøgt; diclofenac blev primært fjernet af UV (ca. 84,7% med nanobobler og UV og 81,8% med UV alene over en time), mens venlafaxin kun blev fjernet i begrænset omfang (6,35% vs. 4,82%). Resultaterne tyder på, at nanobobler under de undersøgte betingelser kun gav en beskeden ekstra effekt, mens metoderne til dokumentation af nanobobler var anvendelige.
[This apstract has been generated with the help of AI directly from the project full text]
Keywords