Microfiber emission from a municipal wastewater treatment plant in Hungary.

Since the ingestion of both natural and anthropogenic microfibers produces a deleterious effect on aquatic organisms, it is crucial to explore the emission of these pollutants by WWTPs into the receiving water bodies, such as rivers. Cellulose- and petroleum-based microfibers, as well as microplastic particles, were collected from the effluent of a municipal WWTP operating with activated sludge technology in Budapest, Hungary. During two sampling campaigns organized in February and April of 2023 on different working days and at different times of the day, 123-145 L of effluent was sieved and filtered. The organic matter was removed by hydrogen-peroxide treatment. All fibers and particles larger than 10 µm were counted, and using a fluorescence microscope, the fibers were geometrically characterized in terms of length and diameter. Each fiber was individually identified by transflection-FT-IR method. The fiber concentration varied in the range of 1.88-2.84 and 4.25-6.79 items/L during the 7th and the 16th week of 2023, respectively. In February and April, the proportion of microfibers in the solid particles was 78.3 and 94.7%, respectively. In the effluent the cellulose-based microfibers were dominant (53-91%), while among the petroleum-based microfibers, polyester occurred most often. The median length of cellulose-based fibers was considerably higher in April than in February (650 vs. 1250 µm), and simultaneously the median diameter also increased from 21 to 29 µm. This behaviour was also seen, albeit to a lesser extent, in connection to microfibers derived from petroleum. The treated wastewater's daily microfiber transport to the Danube River varied between 0.44 - 0.69 and 0.94-1.53 billion in February and April 2023, respectively.

Lithium concentration in tap water, bottled mineral water, and Danube River water in Hungary.

Due to increased manufacture and recycling of lithium batteries across the world, we may anticipate a rise in lithium pollution in the aquatic environment and drinking water reservoirs. In order to investigate the current status regarding the lithium content in Hungarian tap waters, samples were collected from the public drinking water supply systems of 19 county seats in Hungary during seasonally selected times. Depending on the water sources, such as bank-filtrated river water, surface water from open reservoirs, and groundwater, the lithium concentrations varied between 0.90-4.23, 2.12-11.7 and 1.11-31.4 µg/L, respectively, while the median values were 3.52, 5.02 and 8.55 µg/L, respectively. The lithium concentration in the bottled Hungarian mineral waters was also determined since the daily intake of lithium can be influenced by the consumption of mineral waters. The concentrations ranged from 4.2 to 209 µg/L, while the median value was only 17.8 µg/L. Additionally, a correlation was only found between lithium and potassium concentrations. The lithium concentration was also assessed at ten sampling locations in the Hungarian segment of the Danube River since the Danube water is also a water source for additional drinking water utilities using bank filtration technology. The mean and median lithium concentrations were 2.78 and 2.64 µg/L, respectively.

UV and (V)UV irradiation of sitagliptin in ultrapure water and WWTP effluent: Kinetics, transformation products and degradation pathway.

Sitagliptin (SITA) is an antidiabetic drug consumed worldwide in high quantities. Because of the low removal rate of this compound in conventional wastewater treatment plants (WWTPs), it enters receiving surface waters with the discharged WWTP effluents. SITA can be detected up to µg/L concentration in rivers. In this study, UV (254 nm) and (V)UV (185 nm + 254 nm) irradiation was applied in laboratory scale to degrade SITA. The effect of three parameters was evaluated on the degradation rate, namely i) the efficiency in UV and (V)UV irradiation, ii) the presence or absence of dissolved oxygen, iii) the matrix effect of WWTP effluent. Degradation rate of SITA was largely increased by (V)UV irradiation, and decreased in WWTP effluent as expected. The presence of dissolved oxygen increased the degradation rate only in UV experiments and did not have a considerable effect in (V)UV experiments. In total, 14 transformation products (TPs) were identified (twelve new); their structures were proposed based on high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy analyses. The most characteristic reaction steps of the degradation of SITA involved nucleophilic aromatic photosubstitution whereas hydroxide ions acted as attacking nucleophiles and replaced F atoms of the phenyl moiety by hydroxide groups, in agreement with the increase in photolysis rate with increasing pH. The photochemical degradation pathway of SITA was also interpreted. Kinetic profiles revealed TP 421, TP 208 and TP 192 to be the most recalcitrant TPs.

Application of (V)UV/O3 technology for post-treatment of biologically treated wastewater: A pilot-scale study.

For the first time, high energy VUV photons and generation of O3 by (V)UV lamps were applied together for removal of active pharmaceutical ingredients (APIs) from biologically treated wastewater (BTWW) in pilot-scale. The core of the pilot container unit was a photoreactor assembly consisting of six photoreactors, each containing a low-pressure Hg lamp (UV dose of 1.2 J/cm2 and 6.6 J/cm2 at 185 nm and 254 nm, respectively). BTWW was irradiated (4.75 min residence time) by (V)UV light in presence of in situ photochemically generated O3 from coolant air of the lamps. Experiments were conducted at the site of two wastewater treatment plants. Out of seven target APIs (namely carbamazepine, ciprofloxacin, clarithromycin, diclofenac, metoprolol, sitagliptin, and sulfamethoxazole), 80-100% removal was accomplished for five and 40-80% for two compounds. Two degradation products of carbamazepine were detected. Degradation products of other target compounds were not found. The applied O3 dose was 30-45 µg O3/mg dissolved organic carbon. Inactivation of up to log-4.8, log-4.5 and log-3.8 could be achieved for total coliform, Escherichia coli and Enterococcus faecalis, respectively. SOS Chromotest indicated no genotoxicity nor acute toxicity. Generation of neither NH4+, NO2- nor NO3- was observed during post-treatment. Electric energy per order values were calculated for the first time for (V)UV/O3 treatment in BTWW with a median value of 1.5 kWh/m3. This technology can be proposed for post-treatment of BTWWs of small settlements or livestock farms to degrade micropollutants before water discharge or for production of irrigation water. Further studies are essential in pilot-scale for other applications.

Experimental and Theoretical Study on the OH-Reaction Kinetics and Photochemistry of Acetyl Fluoride (CH3C(O)F), an Atmospheric Degradation Intermediate of HFC-161 (C2H5F).

The direct reaction kinetic method of low pressure fast discharge flow (DF) with resonance fluorescence monitoring of OH (RF) has been applied to determine rate coefficients for the overall reactions OH + C2H5F (EtF) (1) and OH + CH3C(O)F (AcF) (2). Acetyl fluoride reacts slowly with the hydroxyl radical, the rate coefficient at laboratory temperature is k2(300 K) = (0.74 ± 0.05) × 10(-14) cm(3) molecule(-1) s(-1) (given with 2σ statistical uncertainty). The temperature dependence of the reaction does not obey the Arrhenius law and it is described well by the two-exponential rate expression of k2(300-410 K) = 3.60 × 10(-3) exp(-10500/T) + 1.56 × 10(-13) exp(-910/T) cm(3) molecule(-1) s(-1). The rate coefficient of k1 = (1.90 ± 0.19) × 10(-13) cm(3) molecule(-1) s(-1) has been determined for the EtF-reaction at room temperature (T = 298 K). Microscopic mechanisms for the OH + CH3C(O)F reaction have also been studied theoretically using the ab initio CBS-QB3 and G4 methods. Variational transition state theory was employed to obtain rate coefficients for the OH + CH3C(O)F reaction as a function of temperature on the basis of the ab initio data. The calculated rate coefficients are in good agreement with the experimental data. It is revealed that the reaction takes place predominantly via the indirect H-abstraction mechanism involving H-bonded prereactive complexes and forming the nascent products of H2O and the CH2CFO radical. The non-Arrhenius behavior of the rate coefficient at temperatures below 500 K is ascribed to the significant tunneling effect of the in-the-plane H-abstraction dynamic bottleneck. The production of FC(O)OH + CH3 via the addition/elimination mechanism is hardly competitive due to the significant barriers along the reaction routes. Photochemical experiments of AcF were performed at 248 nm by using exciplex lasers. The total photodissociation quantum yield for CH3C(O)F has been found significantly less than unity; among the primary photochemical processes, C-C bond cleavage is by far dominating compared with CO-elimination. The absorption spectrum of AcF has also been determined by displaying a strong blue shift compared with the spectra of aliphatic carbonyls. Consequences of the results on atmospheric chemistry have been discussed.