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Many water and wastewater treatment plants (WWTPs) are fitted with a UV system that provides post treatment disinfection before the water is released to receiving water. This paper presents a study on expected removal for the pharmaceutical venlafaxine (VEN) in a typical UV unit at a municipal WWTP with analysis of removal rates of an advanced oxidation process using UV irradiation with injection of H2O2. The study is supported by bench scale degradation experiments on VEN. Results demonstrated that UV can completely degrade VEN, but the addition of H2O2 increased pseudo first order rate constant by up to 2.5 times. Extrapolations of the lab data indicated that removal rates of VEN at the UV disinfection unit of a typical municipal WWTP are approximately 0.4% at standard operating conditions. With the addition of 10 mg/L of H2O2, degradation of VEN can be increased by ten times over existing UV treatment. By studying the impact of adjusting parameters such as UV intensity, UV dosage, and H2O2 dosage, a framework is set to allow researchers and engineers to move forward with developing UV/H2O2 systems that meet their future design needs for pharmaceutical removal. [ABSTRACT FROM AUTHOR]

This study evaluates the influence of UV dose on degradation of carbamazepine (CBZ) in wastewater under UV-C (λ = 254 nm) photolysis with and without H2O2. The rate of degradation of CBZ exhibited a direct dependence on the intensity of incident UV irradiation as the rate of degradation was observed to increase linearly (R2 = 0.98) with UV intensity between 1.67 and 8.95 × 1017 photons/s. More than 95% of the CBZ that spiked in wastewater rapidly degraded within 4 min with a first-order rate constant of 1.2 min−1 for an optimum H2O2 dose of 100 mg/L. Bench-scale continuous flow reactor experiments also showed that CBZ degraded with first-order kinetics at a rate constant of 1.02 min−1. The kinetic parameters obtained for a continuous bench-scale reactor were in good agreement with the relationships developed through batch experiments with only a marginal deviation of ± 6.5%. The relationship between UV intensity and CBZ degradation rate obtained in this study was extrapolated to the UV disinfection unit of a wastewater treatment plant to predict possible degradation of CBZ during UV disinfection. The addition of 100 mg/L of H2O2 to the secondary-treated effluent entering the UV disinfection unit is predicted to achieve over 60% degradation of CBZ. Abbreviations: CBZ carbamazepine; AOPs advanced oxidation processes; UV ultraviolet radiation; UV-C ultraviolet C (λ = 254 nm) radiation; NZVI non-zerovalent iron; WWTP wastewater treatment plant; HPLC high-performance liquid chromatography [ABSTRACT FROM AUTHOR]

This article presents the results of an investigation into the function of UV in a photo-assisted ozonation process for treatment of carbamazepine (CBZ) in treated domestic wastewaters. Experiments were conducted on synthetic spiked water and secondary treated municipal wastewater. Degradation of CBZ was studied for various combination of O3 dosage ranging from 4.8 to 14.4 mg/h and UV intensities with varying intensity and wavelength (UVC: λ = 254 nm and UVA: 352 nm). In synthetic spiked water, CBZ was degraded to below detectable limits within 0.5 min for ozone dose of 14.4 mg/h. The rate of degradation of CBZ increased exponentially with increase in ozone dose following a zero-order rate at each dose level. The degradation rate of CBZ in wastewater was slower compared to deionized water (DI) water by 40-75% for various doses of ozone, presumably due to the presence of organic matter remaining in treated wastewater. Optimal UV intensities for UVA and UVC were obtained as 0.62 and 0.82 mW/cm2 for all doses of ozone in synthetic spiked water samples and UV intensities beyond this resulted in lower rates of degradation of CBZ. For photo-assisted ozonation with ozone doses of 9.6 and 14.4 mg/L, rate constants were two times higher for UVA irradiations as compared to UVC irradiation. Contrary to observations in DI water, experiments in wastewater showed increase in rate of degradation with higher UV intensities. Overall, photo-assisted ozonation was found to be appropriate for both water and wastewater treatment by exploiting the benefit of direct attack of ozone and of produced .OH radicals to yield a greater extent of mineralization of CBZ. [ABSTRACT FROM AUTHOR]

Selenomethionine (SeMet) and selenocysteine (SeCys) are the most common forms of organic selenium, which is often found in the effluent of industrial wastewater. These organic selenium compounds are toxic, bioavailable and most likely to bioaccumulate in aquatic organisms. This study investigated the use of two adsorbent candidates (granular activated carbon (GAC) and nano zerovalent iron (nZVI)) as treatment technologies for SeMet and SeCys removal. Batch experiments were performed and inductively coupled plasma optical emission spectrometer (ICP-OES) was used for sample analysis. Experimental data showed GAC demonstrated a higher affinity towards the removal of SeMet and SeCys compared to nZVI. The removal efficiency of SeCys and SeMet by GAC was 96.1% and 86.7%, respectively. NZVI adsorption capacity for SeCys was 39.4% and SeMet < 1.1%. Irrespective of the adsorbent, SeMet is more refractory to be adsorbed compared to SeCys. Kinetics data of GAC and nZVI agreed well with the pseudo-second-order model (R2 > 0.990). The experimental data of SeCys was characterized by Langmuir model, indicating monolayer adsorption. The adsorption capacity of nZVI for SeCys increased significantly by about 35%, with a decrease in pH from 9.0 to 4.0, indicating that SeCy removal by nZVI is pH dependent. While electrostatic attraction is considered the driving mechanism for nZVI adsorption, GAC uptake capacity is controlled by weak van der Waal forces. The adsorption of binary adsorbates (SeMet and SeCys) exhibited an inhibitory effect due to the competitive interaction between contaminant molecules. [ABSTRACT FROM AUTHOR]

Catchments located in cold weather regions are highly influenced by the natural seasonality that dictates all hydrological processes. This represents a challenge in the development of river flow forecasting models, which often require complex software that use multiple explanatory variables and a large amount of data to forecast such seasonality. The Athabasca River Basin (ARB) in Alberta, Canada, receives no or very little rainfall and snowmelt during the winter and an abundant rainfall–runoff and snowmelt during the spring/summer. Using the ARB as a case study, this paper proposes a novel simplistic method for short-term (i.e., 6 days) river flow forecasting in cold regions and compares existing hydrological modelling techniques to demonstrate that it is possible to achieve a good level of accuracy using simple modelling. In particular, the performance of a regression model (RM), base difference model (BDM), and the newly developed flow difference model (FDM) were evaluated and compared. The results showed that the FDM could accurately forecast river flow (ENS = 0.95) using limited data inputs and calibration parameters. Moreover, the newly proposed FDM had similar performance to artificial intelligence (AI) techniques, demonstrating the capability of simplistic methods to forecast river flow while bypassing the fundamental processes that govern the natural annual river cycle. [ABSTRACT FROM AUTHOR]

Many water and wastewater treatment plants (WWTPs) are fitted with a UV system that provides post treatment disinfection before the water is released to receiving water. This paper presents a study on expected removal for the pharmaceutical venlafaxine (VEN) in a typical UV unit at a municipal WWTP with analysis of removal rates of an advanced oxidation process using UV irradiation with injection of H 2 O 2 . The study is supported by bench scale degradation experiments on VEN. Results demonstrated that UV can completely degrade VEN, but the addition of H 2 O 2 increased pseudo first order rate constant by up to 2.5 times. Extrapolations of the lab data indicated that removal rates of VEN at the UV disinfection unit of a typical municipal WWTP are approximately 0.4% at standard operating conditions. With the addition of 10 mg/L of H 2 O 2 , degradation of VEN can be increased by ten times over existing UV treatment. By studying the impact of adjusting parameters such as UV intensity, UV dosage, and H 2 O 2 dosage, a framework is set to allow researchers and engineers to move forward with developing UV/H 2 O 2 systems that meet their future design needs for pharmaceutical removal.

This study evaluates the influence of UV dose on degradation of carbamazepine (CBZ) in wastewater under UV-C (λ = 254 nm) photolysis with and without H 2 O 2 . The rate of degradation of CBZ exhibited a direct dependence on the intensity of incident UV irradiation as the rate of degradation was observed to increase linearly ( R 2  = 0.98) with UV intensity between 1.67 and 8.95 × 10 17 photons/s. More than 95% of the CBZ that spiked in wastewater rapidly degraded within 4 min with a first-order rate constant of 1.2 min -1 for an optimum H 2 O 2 dose of 100 mg/L. Bench-scale continuous flow reactor experiments also showed that CBZ degraded with first-order kinetics at a rate constant of 1.02 min -1 . The kinetic parameters obtained for a continuous bench-scale reactor were in good agreement with the relationships developed through batch experiments with only a marginal deviation of ± 6.5%. The relationship between UV intensity and CBZ degradation rate obtained in this study was extrapolated to the UV disinfection unit of a wastewater treatment plant to predict possible degradation of CBZ during UV disinfection. The addition of 100 mg/L of H 2 O 2 to the secondary-treated effluent entering the UV disinfection unit is predicted to achieve over 60% degradation of CBZ. Abbreviations: CBZ carbamazepine; AOPs advanced oxidation processes; UV ultraviolet radiation; UV-C ultraviolet C ( λ  = 254 nm) radiation; NZVI non-zerovalent iron; WWTP wastewater treatment plant; HPLC high-performance liquid chromatography.