Fate of antibiotics and hormones during hydrothermal carbonization of poultry litter: degradation kinetics and toxicity assessment of filtrates and hydrochars.

This study investigated degradation kinetics of five selected organic micropollutants (OMPs) present in poultry litter (namely: sulfadiazine, tetracycline, and doxycycline hyclate (antibiotics); estrone and 17-ß-estradiol (hormones)) during hydrothermal carbonization (HTC) treatment as the temperature stepwise increased to 250 °C. All five pure OMPs were completely degraded before 250 °C was reached during the HTC process. Nevertheless, presence of poultry litter slowed down the degradation of OMPs. Through elemental mass balance calculation, it is noted that after 15 min (temperature less than 137 °C), 69-82% of organic carbon and 50-66% of organic nitrogen initially consisting part of the target antibiotics were fully mineralized. Both HTC filtrates and hydrochars obtained from poultry litter inhibited Escherichia coli and Bacillus subtilis growth. A combination of high salinity, high nutrients, dissolved organic carbon, and other ions in the filtrate as well as the adsorption of OMPs on hydrochars were probably the reason for the high toxicity.

A combined approach of electrodialysis pretreatment and vacuum UV for removing micropollutants from natural waters.

Advanced oxidation processes (AOPs) augment traditional water treatment methods, enhancing the removal of persistent contaminants. Efficiency of AOPs that utilize UV radiation for oxidants generation (e.g., ·OH) is reduced in water matrices that contain substants that may act as inner UV filters and/or scavengers for the generated radicals. Among such interfering compounds are major inorganic ions and dissolved organic matter that are naturally present in realistic waters. Thus, to improve AOPs efficiency it is desirable to separate the target pollutants from these natural species before treatment. Here the potential of electrodialysis as such pretreatment was investigated. The impact of this pretreatment on photo-oxidation of the pharmaceutical carbamazepine (CBZ) under VUV (λ<200 nm) irradiation, which yields ·OH generation via water homolysis, was tested in different water matrices. The obtained results indicate that in all tested solutions: Deionized water, groundwater, surface water, and treated wastewater, the addition of electrodialysis pretreatment successfully separated the target micropollutant CBZ from the major natural ions and to some extend the NOM, resulting faster degradation rates of CBZ and its transformation products in the following VUV-based AOP. Energy cost calculations indicated that addition of this pretreatment step reduces the overall energy demand of the system (i.e., energy consumption for the electrodialysis step was smaller than the energy gained by reducing the required VUV irradiation dose).

A novel approach for accurate quantification of lake residence time - Lake Kinneret as a case study.

Water residence time, which is affected by increasing water demands and climate change, plays a crucial role in lakes and reservoirs since it influences many natural physical and ecological processes that eventually impact the water quality of the waterbody. Thus, accurate quantification of the water residence time and its distribution is an important tool in lake management. In this study we present a novel approach for assessing the residence time in lakes and reservoirs. The approach is based on the Leslie matrix model that was originally developed for the analysis of age-structured biological population dynamics. In this approach the water in the lake is divided into different age classes each representing the time since the "parcel" of water entered the lake and provides an overall picture of the water age structure. The traditional approach for calculating residence times, which relies only on the lake volume and annual inflow or outflow volumes thereby disregarding any previous information, is very sensitive to large interannual variation. While the proposed approach produces the fraction and volume distribution curves of all age classes within the lake for each simulated timestep. Thus, in addition to mean residence time, the fraction of young water (FYW), quantifying the "young" fraction of water in the lake can be analyzed. The same is true for any other age class of water. The approach was applied to Lake Kinneret (Sea of Galilee) historical data collected over 32 years (1987-2018) and for prediction of long-term time series based on several future scenarios (inflows and outflows). It offers a more accurate quantification of the mean residence time of water in a lake and can easily be adapted to other waterbodies. Comparison of simulation results may serve as basis for determining the lake's management policy, by controlling the inflows and outflows, that will affect both the mean residence time and the fraction of "young/old" age classes of water.

City-level SARS-CoV-2 sewage surveillance.

The COVID-19 pandemic created a global crisis impacting not only healthcare systems, but also economics and society. Therefore, it is important to find novel methods for monitoring disease activity. Recent data have indicated that fecal shedding of SARS-CoV-2 is common, and that viral RNA can be detected in wastewater. This suggests that wastewater monitoring is a potentially efficient tool for both epidemiological surveillance, and early warning for SARS-CoV-2 circulation at the population level. In this study we sampled an urban wastewater infrastructure in the city of Ashkelon (Ì´ 150,000 population), Israel, during the end of the first COVID-19 wave in May 2020 when the number of infections seemed to be waning. We were able to show varying presence of SARS-CoV-2 RNA in wastewater from several locations in the city during two sampling periods, before the resurgence was clinically apparent. This was expressed with a new index, Normalized Viral Load (NVL) which can be used in different area scales to define levels of virus activity such as red (high) or green (no), and to follow morbidity in the population at the tested area. The rise in viral load between the two sampling periods (one week apart) indicated an increase in morbidity that was evident two weeks to a month later in the population. Thus, this methodology may provide an early indication for SARS-CoV-2 infection outbreak in a population before an outbreak is clinically apparent.

H2S Removal from Groundwater by Chemical Free Advanced Oxidation Process Using UV-C/VUV Radiation.

Sulfide species may be present in groundwater due to natural processes or due to anthropogenic activity. H2S contamination poses odor nuisance and may also lead to adverse health effects. Advanced oxidation processes (AOPs) are considered promising treatments for hydrogen-sulfide removal from water, but conventional AOPs usually require continuous chemical dosing, as well as post-treatment, when solid catalysts are applied. Vacuum-UV (VUV) radiation can generate ·OH in situ via water photolysis, initiating chemical-free AOP. The present study investigated the applicability of VUV-based AOP for removal of H2S both in synthetic solutions and in real groundwater, comparing combined UV-C/VUV and UV-C only radiation in a continuous-flow reactor. In deionized water, H2S degradation was much faster under the combined radiation, dominated by indirect photolysis, and indicated the formation of sulfite intermediates that convert to sulfate at high radiation doses. Sulfide was efficiently removed from natural groundwater by the two examined lamps, with no clear preference between them. However, in anoxic conditions, common in sulfide-containing groundwater, a small advantage for the combined lamp was observed. These results demonstrate the potential of utilizing VUV-based AOP for treating H2S contamination in groundwater as a chemical-free treatment, which can be especially attractive to remote small treatment facilities.

Removal of organic micropollutants from biologically treated greywater using continuous-flow vacuum-UV/UVC photo-reactor.

Despite growing apprehension regarding the fate of organic micropollutants (MPs) of emerging concern, little attention has been paid to their presence in domestic greywater, where they mainly originate from personal care products. Many MPs are not fully removed in conventional greywater treatments and require additional treatment. Vacuum-UV radiation (VUV) can generate ·OH in situ, via water photolysis, initiating advanced oxidation process (AOP) without any chemical addition. Despite growing interest in VUV-based AOP, its performance in real-life grey- or wastewater matrices has hardly been investigated. The present study investigates the removal of triclosan (TCS) and oxybenzone (BP3), common antibacterial and UV-filter MPs, in deionized water (DIW) and in treated greywater (TGW) using combined UVC/VUV or UVC only radiation in a continuous-flow reactor. Degradation kinetics of these MPs and their transformation products (TPs) were addressed, as well as bacterial growth inhibition of the resulting reactor's effluent. In DIW, MP degradation was much faster under the combined UVC/VUV irradiation. In TGW, the combined radiation successfully removed both MPs but at lower efficiency than in DIW, as particles and dissolved organic matter (DOM) acted as radical scavengers. Filtration and partial DOM removal prior to irradiation improved the process efficiency and reduced energy requirements under the combined radiation (from 1.6 and 167 to 1.1 and 6.0 kWh m-3·Ö¼order-1 for TCS and BP3, respectively). VUV radiation also reduced TP concentrations in the effluent. As a result, bacterial growth inhibition of triclosan solution irradiated by VUC/VUV was lower than that irradiated by UVC light alone, for UV dose > 120 mJ cm-2.

Disinfection of greywater effluent and regrowth potential of selected bacteria.

Chlorination and UV irradiation of RBC (rotating biological contactor)-treated light GW (greywater) was investigated. The ability of chlorine and UV to inactivate indictor bacteria (FC - Faecal Coliforms, HPC - Heterotrophic Plate Count) and specific pathogens (P.a. - Pseudomonas aeruginosa sp., S.a. - Staphylococcus aureus sp.), was assessed and their regrowth potential was examined. The RBC removed 88.5-99.9% of all four bacteria groups. Nevertheless, the treated GW had to be disinfected. Most of the chlorine was consumed during the first 0.5 h, while later its decay rate decreased significantly, leaving enough residual after 6 h to prevent regrowth and to further inactivate bacteria in the stored GW effluent. Under exposure to low UV doses (≤69 mJ/cm(2)) FC was the most resistant bacteria group, followed by HPC, P.a. and S.a. Exposure to higher doses (≤439 mJs/cm(2)) completely inactivated FC, P.a. and S.a., while no further HPC inactivation was observed. FC, P.a. and S.a. did not exhibit regrowth after exposure to all the UV doses applied (up to 6 h storage). HPC did not exhibit regrowth after exposure to low UV doses (19-69 mJ/cm2), while it presented statistically significant regrowth in un-disinfected effluent and after exposure to higher UV doses (147-439 mJ/cm(2)).

Performance of UV disinfection and the microbial quality of greywater effluent along a reuse system for toilet flushing.

This paper examines the microbial quality of treated RBC (Rotating Biological Contactor) and MBR (Membrane Bioreactor) light greywater along a continuous pilot-scale reuse system for toilet flushing, quantifies the efficiency of UV disinfection unit, and evaluates the regrowth potential of selected microorganisms along the system. The UV disinfection unit was found to be very efficient in reducing faecal coliforms and Staphylococcus aureus. On the other hand, its efficiency of inactivation of HPC (Heterotrophic Plate Count) and Pseudomonas aeruginosa was lower. Some regrowth occurred in the reuse system as a result of HPC regrowth which included opportunistic pathogens such as P. aeruginosa. Although the membrane (UF) of the MBR system removed all bacteria from the greywater, bacteria were observed in the reuse system due to "hopping phenomenon." The microbial quality of the disinfected greywater was found to be equal or even better than the microbial quality of "clean" water in toilet bowls flushed with potable water (and used for excretion). Thus, the added health risk associated with reusing the UV-disinfected greywater for toilet flushing (regarding P. aeruginosa and S. aureus), was found to be insignificant. The UV disinfection unit totally removed (100%) the viral indicator (F-RNA phage, host: E. coli F(amp)(+)) injected to the treatment systems simulating transient viral contamination. To conclude, this work contributes to better design of UV disinfection reactors and provides an insight into the long-term behavior of selected microorganisms along on-site greywater reuse systems for toilet flushing.

UV disinfection of RBC-treated light greywater effluent: kinetics, survival and regrowth of selected microorganisms.

The microbial quality of raw greywater was found to be much better than that of municipal wastewater, with 1.6 x 10(7)cfu ml(-1) heterotrophic plate count (HPC), and 3.8 x 10(4), 9.9 x 10(3), 3.3 x 10(3) and 4.6 x 10(0)cfu 100 ml(-1) faecal coliforms (FC), Staphylococcus aureus sp., Pseudomonas aeruginosa sp. and Clostridium perfringes sp., respectively. Further, three viral indicators monitored (somatic phage, host: Escherichia coli CN(13) and F-RNA phages, hosts: E. coli F+(amp), E. coli K12) were not present in raw greywater. The greywater was treated by an RBC followed by sedimentation. The treatment removed two orders of magnitude of all bacteria. UV disinfection kinetics, survival and regrowth of HPC, FC, P. aeruginosa sp. and S. aureus sp. were examined. At doses up to 69 mW s cm(-2) FC were found to be the most resistant bacteria, followed by HPC, P. aeruginosa sp. and S. aureus sp. (inactivation rate coefficients: 0.0687, 0.113, 0.129 and 0.201 cm2 mW(-1)s(-1), respectively). At higher doses (69-439 mW s cm(-2)) all but HPC (which exhibited a tailing curve) were completely eliminated. Microscopic examination showed that FC self-aggregate in the greywater effluent. This provides FC an advantage at low doses, since the concentration of suspended matter (that can provide shelter from UV radiation) in the effluent was very low. FC, P. aeruginosa sp. and S. aureus sp. did not exhibit regrowth up to 6h after exposure to increasing UV doses (19-439 mW s cm(-2)). HPC regrowth was proven to be statistically significant in un-disinfected effluent and after irradiation with high UV doses (147 and 439 mW s cm(-2)). At these doses regrowth resulted from growth of UV-resistant bacteria due to decreased competition with other bacteria eliminated by the irradiation.