Urban wastewater treatment plants (UWTPs) are among the main sources of antibiotics' release into various compartments of the environment worldwide. The aim of the present paper is to critically ...review the fate and removal of various antibiotics in wastewater treatment, focusing on different processes (i.e. biological processes, advanced treatment technologies and disinfection) in view of the current concerns related to the induction of toxic effects in aquatic and terrestrial organisms, and the occurrence of antibiotics that may promote the selection of antibiotic resistance genes and bacteria, as reported in the literature. Where available, estimations of the removal of antibiotics are provided along with the main treatment steps. The removal efficiency during wastewater treatment processes varies and is mainly dependent on a combination of antibiotics' physicochemical properties and the operating conditions of the treatment systems. As a result, the application of alternative techniques including membrane processes, activated carbon adsorption, advanced oxidation processes (AOPs), and combinations of them, which may lead to higher removals, may be necessary before the final disposal of the effluents or their reuse for irrigation or groundwater recharge.
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► Urban wastewaters are the main sources of antibiotics' release in the environment. ► The removal efficiency of treatment processes toward antibiotics is presented. ► Treatments discussed include biological and chemical processes. ► The removal efficiency is dependent on antibiotics’ physicochemical properties. ► The removal efficiency is dependent on the treatment process operating conditions.
Urban wastewater treatment plants (UWTPs) are among the main sources of antibiotics' release into the environment. The occurrence of antibiotics may promote the selection of antibiotic resistance ...genes (ARGs) and antibiotic resistant bacteria (ARB), which shade health risks to humans and animals. In this paper the fate of ARB and ARGs in UWTPs, focusing on different processes/technologies (i.e., biological processes, advanced treatment technologies and disinfection), was critically reviewed. The mechanisms by which biological processes influence the development/selection of ARB and ARGs transfer are still poorly understood. Advanced treatment technologies and disinfection process are regarded as a major tool to control the spread of ARB into the environment. In spite of intense efforts made over the last years to bring solutions to control antibiotic resistance spread in the environment, there are still important gaps to fill in. In particular, it is important to: (i) improve risk assessment studies in order to allow accurate estimates about the maximal abundance of ARB in UWTPs effluents that would not pose risks for human and environmental health; (ii) understand the factors and mechanisms that drive antibiotic resistance maintenance and selection in wastewater habitats. The final objective is to implement wastewater treatment technologies capable of assuring the production of UWTPs effluents with an acceptable level of ARB.
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► UWTPs may positively affect ARB spread and selection as well as ARG transfer. ► Resistance integrons may be used to characterize ARG transfer. ► High trough technologies are a useful complementation of PCR technologies. ► Biological process effect on ARB and ARG transfer should be further investigated. ► Advanced treatments/disinfection effect should be further investigated too.
In 2011–2012, Santorini was characterized by seismic‐geodetic‐geochemical unrest, which was unprecedented since the most‐recent eruption occurred in 1950 and led to fear an eruption was imminent. ...This unrest offered a chance for investigating the processes leading to volcanic reactivation and the compositional characteristics of involved magma. We have thus analyzed the He‐Ne‐Ar‐isotope composition of fluid inclusions in olivines and clinopyroxenes from cumulate mafic enclaves hosted in cogenetic dacitic lavas of the 1570–1573 and 1925–1928 eruptions of Nea Kameni. These unique data on Aegean volcanism were compared with those of gases collected in quiescent periods and during the unrest. The 3He/4He ratios (3.1–4.0 Ra) are significantly lower than the typical arc‐volcano values (R/Ra ∼ 7–8), suggesting the occurrence of magma contamination in Santorini plumbing system, which would further modify the 3He/4He ratio of parental magmas generated in the local metasomatized mantle. The 3He/4He values of enclaves (3.1–3.6 Ra) are comparable to those measured in gases during quiescent periods, confirming that enclaves reflect the He‐isotope signature of magma residing at shallow depths and feeding passive degassing. A significant increase in soil CO2 flux from Nea Kameni and anomalous compositional variations in the fumaroles were identified during the unrest, accordingly with previous studies. Simultaneously, 3He/4He ratios up to 4.0 Ra were also measured, demonstrating that the unrest was due to the intrusion into the shallow plumbing system of a more‐primitive 3He‐rich magma, which is even volatile richer and less contaminated than mafic magma erupted as enclaves. This new intrusion did not however trigger an eruption.
Key Points:
We studied the He‐Ne‐Ar isotopes in mafic enclaves and in gases from Santorini
The 3He/4He ratios of gases and enclaves is in the range 3.0–4.0 Ra
The 2011–2012 unrest at Santorini was due to the intrusion of a new mafic magma
Th17, Th22, and Th1 cells are detected in psoriatic skin lesions and implicated in psoriasis pathogenesis, but inflammatory T cell numbers in blood, as well as the relative importance of each cell ...type, is unclear. Using 7-color flow cytometry, circulating Th17, Th22, and Th1 cells were quantified in 21 untreated psoriatics and 17 healthy individuals. CCR6 was the best cell surface marker for IL-17A+ cells when compared with IL-23R or CD161. CCR6+, IL-17A+, IL-22+, CCR6+IL-17A+, CCR6+IL-22+, CCR6+tumor necrosis factor-α+, IL-17A+IFN-γ-, IL-17A+IL-22+IFN-γ-, and IL-17A+IL-22-IFN-γ- cells were increased in psoriatics (all values P<0.001), indicating elevations in circulating Th17 cells, using multiple criteria to define these cells. Th22 (IL-17A-IL-22+IFN-γ-, P<0.05) and Th1 (IL-17A-IFN-γ+, P<0.05) cells were also increased in psoriatics, but to a lesser extent. Inhibition of either NF-κB or STAT3 in vitro blocked cytokine production by both Th17 and Th1 cells. Circulating levels of Th17 and Th1 cells decreased in a subset of five psoriasis patients serially evaluated following induction therapy with infliximab. In summary, elevated numbers of circulating inflammatory T cells may contribute to cutaneous inflammation and systemic inflammatory disease that occurs in individuals with psoriasis.
Contaminants of emerging concern (including pharmaceuticals) are not effectively removed by municipal wastewater treatment plants (WWTPs), so particular concern is related to agricultural wastewater ...reuse due to their possible uptake in crops irrigated with WWTPs effluents. Advanced oxidation processes (AOPs) and solar AOPs have been demonstrated to effectively remove pharmaceuticals from different aqueous matrices. In this study, an heterogeneous photocatalytic process using powdered nitrogen-doped TiO2 immobilized on polystyrene spheres (sunlight/N–TiO2) was compared to the benchmark homogenous AOP sunlight/H2O2 in a compound triangular collector reactor, to evaluate the degradation of three pharmaceuticals (carbamazepine (CBZ), diclofenac (DCF), trimethoprim (TMP)) in water. The degradation of the contaminants by sunlight and sunlight-AOPs well fit the pseudo-first order kinetic model (but for TMP under sunlight). High removal efficiency by solar photolysis was observed for DCF (up to 100%, half-life sunlight cumulative energy QS,1/2 = 2 kJ L−1, half-life time t1/2 = 32 min), while CBZ (32%, QS,1/2 = 28 kJ L−1, t1/2 = 385 min) and TMP (5% removal after 300 min) removal was poor. The degradation rate of CBZ, TMP and DCF was found to be slower during sunlight/H2O2 (QS,1/2 = 5 kJ L−1, t1/2 = 77 min; QS,1/2 = 20 kJ L−1, t1/2 = 128 min; QS,1/2 = 4 kJ L−1, t1/2 = 27 min, respectively) compared to sunlight/N–TiO2 (QS,1/2 = 4 kJ L−1, t1/2 = 55 min; QS,1/2 = 3 kJ L−1, t1/2 = 42 min; QS,1/2 = 2 kJ L−1, t1/2 = 25 min, respectively). These results are promising in terms of solar technology upscale because the faster degradation kinetics observed for sunlight/N–TiO2 process would result in smaller treatment volume, thus possibly perspective compensating the cost of the photocatalyst.
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•Comparison between homogeneous and heterogeneous solar driven AOPs.•The degradation of the contaminants well fit pseudo-first order kinetic model.•Diclofenac effectively degraded even by solar photolysis.•Faster degradation of pharmaceuticals by sunlight/N–TiO2 compared to sunlight/H2O2.•Sunlight/N–TiO2 process would result in a smaller treatment volume than sunlight/H2O2.
The effect of TiO2 photocatalysis on the inactivation of an antibiotic resistant Escherichia coli strain selected from an urban wastewater treatment plant (UWWTP) effluent was investigated. Different ...light sources including a 250 W wide spectrum lamp, a 125 W UV-A lamp and solar radiation, as well as, photocatalysts loadings (TiO2 Degussa P25) in the range from 0.05 to 2.00 g TiO2 L−1 were evaluated. The higher efficiency (total bacterial inactivation after 10 min of irradiation) was observed in the absence of TiO2 when the wastewater was irradiated using the 250 W lamp. In the presence of TiO2 a decreasing inactivation trend was observed (99.76% and 72.22% inactivation after 10 min irradiation at 0.10 and 2.00 g TiO2 L−1 respectively). Under solar simulated conditions the highest inactivation efficiency (93.17%) after 10 min of irradiation was achieved at the lower photocatalyst loading (0.05 g TiO2 L−1). The concept of “reactor optical thickness” was introduced to explain the rates of disinfection observed. The optimum photocatalyst loading estimated by radiation absorption-scattering modeling was found to be 0.1 g TiO2 L−1 for all lamps. The difference between experimental tests and modeling may be due to TiO2 particles aggregation. Comparative kinetic tests between solar and solar simulated photocatalytic (SSP) processes using 0.05 g TiO2 L−1 in suspension showed a quite similar inactivation behavior up to 30 min of irradiation, but only the SSP process resulted in a total inactivation of bacteria after 60 min of exposure. Antibiotic resistant test (Kirby–Bauer) on survived colonies showed that the SSP and SP processes affected in different ways the resistance of E. coli strain to the target antibiotics.
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•Photocatalytic inactivation of an indigenous antibiotic resistant Escherichia coli strain.•Optimum catalyst loading estimated by radiation absorption-scattering modeling.•Total inactivation was achieved in 60 min under simulated solar radiation.•Photocatalysis affected antibiotic resistance (AR) of the selected E. coli strain.•AR of the E. coli strain changed according to light source and target antibiotic.
Energy distance is a statistical distance between the distributions of random vectors, which characterizes equality of distributions. The name energy derives from Newton's gravitational potential ...energy, and there is an elegant relation to the notion of potential energy between statistical observations. Energy statistics are functions of distances between statistical observations in metric spaces. Thus even if the observations are complex objects, like functions, one can use their real valued nonnegative distances for inference. Theory and application of energy statistics are discussed and illustrated. Finally, we explore the notion of potential and kinetic energy of goodness-of-fit.
The climate impact of deforestation depends on the relative strength of several biogeochemical and biogeophysical effects. In addition to affecting the exchange of carbon dioxide (CO
) and moisture ...with the atmosphere and surface albedo, vegetation emits biogenic volatile organic compounds (BVOCs) that alter the formation of short-lived climate forcers (SLCFs), which include aerosol, ozone and methane. Here we show that a scenario of complete global deforestation results in a net positive radiative forcing (RF; 0.12 W m
) from SLCFs, with the negative RF from decreases in ozone and methane concentrations partially offsetting the positive aerosol RF. Combining RFs due to CO
, surface albedo and SLCFs suggests that global deforestation could cause 0.8 K warming after 100 years, with SLCFs contributing 8% of the effect. However, deforestation as projected by the RCP8.5 scenario leads to zero net RF from SLCF, primarily due to nonlinearities in the aerosol indirect effect.
•Increased photocatalytic disinfection (PCD) time is required to inactivate antibiotic resistant E. coli.•Sub-lethal stress induced by PCD increased antibiotic resistance gene (ARG) transfer among E. ...coli.•The components of waste water effluent reduced PCD efficacy and decreased ARG transfer.
The widespread use and abuse of antibiotics in human and animal medicine has produced a reservoir of antibiotic resistant bacteria (ARB) which persist and spread within many environments including natural and wastewater systems. This paper reports the first investigation into the effect of advanced oxidation technologies, photocatalysis, on the potential to induce antibiotic resistant gene transfer within sub-lethally injured ARB. The impact of photocatalytic disinfection (PCD) treatments on three strains of Escherichia coli, an antibiotic sensitive strain (K12) and two antibiotic resistant strains (J-53R (rifampicin resistant) and HT-99 (chloramphenicol resistant), within an immobilised titanium dioxide stirred tank reactor. When suspended in distilled water, viable cell numbers (CFUmL−1) of both ARB declined from 3log10 to 0.5log10 with 180min PCD treatment. However, subsequent recovery to 3log10 of both ARB was observed during post treatment incubation at 37°C for 24h. No E. coli K12 were recovered immediately after 150min treatment, or after post treatment incubation. These observations suggest that the ARB are less sensitive to the oxidative stresses involved in PCD treatment than the antibiotic sensitive strain.
Gene pair conjugant numbers in PCD treated mixtures of J-53R and HT-99 cells (a 9:1 ratio) were calculated to be four-fold greater than in the (no treatment) control experiments. Both surviving bacterial cell numbers and conjugant pair numbers were lower when ARB were PCD treated in final effluent from an urban wastewater treatment plant.
In conclusion, the results of this study confirm the efficacy of PCD, but also highlight the importance of applying PCD treatment “long enough” to avoid post treatment recovery from sub-lethal injury and the highly undesirable transfer of antibiotic resistant genes amongst bacteria during wastewater treatment.
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