preparation-of-free-surface-hyperbolic-water-vortices

Preparation of Free-Surface Hyperbolic Water Vortices

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implementation-hyperbolic-vortex-plasma-reactor-for-removal

Implementation of a Hyperbolic Vortex Plasma Reactor for the Removal of Micropollutants in Water

The presence of micropollutants in water is an increasingly pressing environmental concern. While some micropollutants are readily biodegradable, others, ...

Eindhoven University of Technology

There is a growing concern about pharmaceuticals entering the aquatic environment. Many of these compounds cannot be removed completely in sewage treatment plants. To remove these unwanted medicines from water, oxidative degradation techniques may complement the current purification steps. In this paper we studied the effect of advanced oxidation on the cytostatic drug cyclophosphamide (CP) by comparing thermal plasma activation with UV/HO treatment. Plasma activated water (PAW) contains highly reactive oxygen and nitrogen species (RONS) as a result of electric gas discharges in air over water. CP solutions in tap water were oxidized over a period of 120 min and subsequently analyzed by LC-MS/MS to measure the compound degradation. Plasma activation was applied at 50, 100, or 150 W electric power input and UV/HO treatment was carried out by the addition of HO and placing an UV-C source above the test solution for immediate irradiation. The oxidative degradation of CP in PAW resulted in a complete degradation within 80 min at 150 W. CP was also completely degraded within 60 min applying UV/HO oxidation. Both treatment techniques do induce different structural changes, demonstrating that CP is completely degraded in tap water.

Oxidative degradation of cyclophosphamide using thermal plasma activation and UV/HO treatment in tap water.

The aquatic environment becomes increasingly contaminated by anthropogenic pollutants such as pharmaceutical residues. Due to poor biodegradation and continuous discharge of persistent compounds in sewage water samples, pharmaceutical residues might end up in surface waters when not removed. To minimize this pollution, onsite wastewater treatment techniques might complement conventional waste water treatment plants (WWTPs). Advanced oxidation processes are useful techniques, since reactive oxygen species (ROS) are used for the degradation of unwanted medicine residues. In this paper we have studied the advanced oxidation in a controlled laboratory setting using thermal plasma and UV/HO treatment. Five different matrices, Milli-Q water, tap water, synthetic urine, diluted urine and synthetic sewage water were spiked with 14 pharmaceuticals with a concentration of 5 μg/L. All compounds were reduced or completely decomposed by both 150 W thermal plasma and UV/HO treatment. Additionally, also hospital sewage water was tested. First the concentrations of 10 pharmaceutical residues were determined by liquid chromatography mass spectrometry (LC-MS/MS). The pharmaceutical concentration ranged from 0.08 up to 2400 μg/L. With the application of 150 W thermal plasma or UV/HO, it was found that overall pharmaceutical degradation in hospital sewage water were nearly equivalent to the results obtained in the synthetic sewage water. However, based on the chemical abatement kinetics it was demonstrated that the degree of degradation decreases with increasing matrix complexity. Since reactive oxygen and nitrogen species (RONS) are continuously produced, thermal plasma treatment has the advantage over UV/HO treatment.

Thermal plasma activation and UV/HO oxidative degradation of pharmaceutical residues.

Pharmaceutical residues are released in the aquatic environment due to incomplete removal from wastewater. With the presence of multiple chemicals in sewage waters, contaminants may adversely affect the effectiveness of a wastewater treatment plant (WWTP). In certain cases, discharged metabolites are transformed back into their pristine structure and become bioactive again. Other compounds are persistent and can withstand conventional wastewater treatment. When WWTP effluents are released in surface waters, pristine and persistent chemicals can affect the aquatic environment. To complement WWTPs and circumvent incomplete removal of unwanted chemicals or pharmaceuticals, on-site wastewater treatment can contribute to their removal. Advanced oxidation processes (AOPs) are very powerful techniques for the abatement of pharmaceuticals, however, under certain circumstances reactive toxic by-products can be produced. We studied the application of on-site AOPs in a laboratory setting. It is expected that treatment at the contamination source can eliminate the worst polluters. Thermal plasma and UV/HO oxidation were applied on simulation matrices, Milli-Q and synthetic sewage water spiked with 10 different pharmaceuticals in a range of 0.1 up to 2400 μg/L. In addition, untreated end-of-pipe hospital effluent was also subjected to oxidative treatment. The matrices were activated for 180 min and added to cultured HeLa cells. The cells were 24 h and 48 h exposed at 37 °C and subsequently markers for oxidative stress and viability were measured. During the UV/HO treatment periods no toxicity was observed. After thermal plasma activation of Milli-Q water (150 and 180 min) toxicity was observed. Direct application of thermal plasma treatment in hospital sewage water caused elimination of toxic substances. The low cytotoxicity of treated pharmaceutical residues is likely to become negligible if plasma pre-treated on-site wastewater is further diluted with other sewage water streams, before reaching the WWTP. Our study suggests that AOPs may be promising technologies to remove a substantial portion of pharmaceutical components by degradation at the source. Further studies will have to be performed to verify the feasibility of upscaling this technology from the benchtop to practice.

Determination of cytotoxicity following oxidative treatment of pharmaceutical residues in wastewater.

Advanced oxidation processes such as thermal plasma activation and UV-C/HO treatment are considered as applications for the degradation of pharmaceutical residues in wastewater complementary to conventional wastewater treatment. It is supposed that direct oxidative treatment can lower the toxicity of hospital sewage water (HSW). The aim of this study was to predict the ecotoxicity for three aquatic species before and after oxidative treatment of 10 quantified pharmaceuticals in hospital sewage water. With the application of oxidative chemistry, pharmaceuticals are degraded into transformation products before reaching complete mineralization. To estimate the potential ecotoxicity for fish, Daphnia and green algae ECOSAR quantitative structure-activity relationship software was used. Structure information from pristine pharmaceuticals and their oxidative transformation products were calculated separately and in a mixture computed to determine the risk quotient (RQ). Calculated mixture toxicities for 10 compounds found in untreated HSW resulted in moderate-high RQ predictions for all three aquatic species. Compared to untreated HSW, 30-min treatment with thermal plasma activation or UV-C/HO resulted in lowered RQs. For the expected transformation products originating from fluoxetine, cyclophosphamide and acetaminophen increased RQs were predicted. Prolongation of thermal plasma oxidation up to 120 min predicted low-moderate toxicity in all target species. It is anticipated that further degradation of oxidative transformation products will end in less toxic aliphatic and carboxylic acid products. Predicted RQs after UV-C/HO treatment turned out to be still moderate-high. In conclusion, in silico extrapolation of experimental findings can provide useful predicted estimates of mixture toxicity. However due to the complex composition of wastewater this in silico approach is a first step to screen for ecotoxicity. It is recommendable to confirm these predictions with ecotoxic bioassays.

ArticleTotal : 2	Year
Publication title Cited by 6	2023
Publication title	2025

Article	Year
Oxidative degradation of cyclophosphamide using thermal plasma activation and UV/HO treatment in tap water. Environmental research\| PubMed ID: 31884193	2020
Thermal plasma activation and UV/HO oxidative degradation of pharmaceutical residues. Environmental research\| PubMed ID: 33631140	2021
Determination of cytotoxicity following oxidative treatment of pharmaceutical residues in wastewater. Chemosphere\| PubMed ID: 35618071	2022
In silico ecotoxicity assessment of pharmaceutical residues in wastewater following oxidative treatment. Environmental research\| PubMed ID: 38056612	2024

Wilfred F. L. M. Hoeben

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