Impact of acute and chronic exposure to sulfamethoxazole on the kinetics and microbial structure of an activated sludge community

The aim of this study was to reveal the microbial and kinetic impacts of acute and chronic exposure to one of the frequently administered antibiotics, i.e., sulfamethoxazole, on an activated sludge biomass. Respirometric analysis and model evaluation of the oxygen utilization rate profiles were the backbone of this study. The results showed that continuous exposure to sulfamethoxazole resulted in the inhibition of substrate storage and an increase in the endogenous decay rates by twofold, which was supported by analysis of the resistance genes. A mild inhibition on the growth and hydrolysis kinetics was also observed. Moreover, sulfamethoxazole had a binding impact with available organic carbon, resulting in a slightly less oxygen consumption. DNA sequencing and antibiotic resistance gene analyses showed that continuous exposure to sulfamethoxazole caused a change in the community structure at the species level. Resistant bacteria including Arthrobacter sp. and members of the Chitinophagaceae and Intrasporangiaceae families were found to have dominated the bacterial community. The impact of intermittent exposure was also investigated, and the results indicated a drop in the severity of the impact after 20 days of intermittence

Treatment of Commercial Surfactants With Chemical and Photochemical Advanced Oxidation Processes

© 2012 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. Surfactants are among the most abundant, man-made organic pollutants with a high potential to enter the environment through the discharge of domestic and industrial wastewater as well as sewage sludge. Due to their amphiphilic structure, they not only are present in natural waters at concentrations varying between nondetectable to several μg/L’s, but also tend to significantly sorb onto sewage sludge, ultimately bioaccumulating in soil sediments of receiving water bodies. According to extensive biodegradability and ecotoxicological studies, most surfactants are readily biodegradable regarding the parent compound; however complete oxidation is usually achieved neither in engineered treatment systems nor in the natural environment. In addition, acute toxicity data reveal that most surfactants are fairly toxic toward aquatic as well as terrestrial organisms. Considering these facts, treatment with alternative, advanced oxidation processes (AOPs) could be a promising option to alleviate the problem of uncontrolled bioaccumulation and biodegradation of surfactants in the environment. The present work reviews the application of chemical and photochemical AOPs for the detoxification and mineralization of commercial surfactant formulations. Special emphasis has been given to the main limitations of advanced oxidative treatment applications, namely toxicity of advanced oxidation intermediates/end products

Treatment of textile dye bath wastewater with ozone, persulfate and peroxymonosulphate oxidation

In this study, the treatment of wastewater of two different reactive dye bath wastewater (WW1, WW2) belonging to a yarn dyeing textile industry was evaluated by ozone, heat-activated persulfate (PS) and heat-activated peroxymonosulfate (PMS) oxidation methods. WW1 and WW2 contains azo group dyes and BOD5 values are 245 and 105 mg/L, Total Organic Carbon (TOC) values are 793 and 3016 mg/L respectively. TOC and color removal and BOD5/TOC ratio were investigated in samples taken at specific time intervals (15, 30, 45, 60, 90 and 120 min). For WW1, the TOC and color removal rates for heat-activated PS oxidation were 19% and 100%, respectively, and these removal rates were higher than the oxidation results for ozonation (15% and 76%) and heat-activated PMS (16% and 99%). Although the ozone dose applied to WW1 was about 3 times that of the ozone dose applied to WW2, the color removal rate in WW2 (94%) was higher than WW1 (76%) and the TOC removal rates were almost the same. In the result of oxidation studies, no significant increase in BOD value was observed for both wastewater. However, an increase in BOD5/TOC was achieved by decreasing the TOC value in heat-activated PS oxidation for WW1

Iprodione Removal by UV-Light-, Zero-Valent Iron- and Zero-Valent Aluminium-Activated Persulfate Oxidation Processes in Pure Water and Simulated Tertiary Treated Urban Wastewater

The degradation of iprodione (IPR), a once frequently used but recently banned dicarboximide fungicide, by UV-C light-, zero-valent iron- (ZVI), and zero-valent aluminium (ZVA)-activated persulfate (PS) oxidation processes was comparatively studied in distilled (pure) water (DW) and simulated, tertiary treated urban wastewater (SWW). The performance of PS-activated oxidation processes was examined by following IPR (2–10 mg/L) removal, PS (0.01–1.00 mM) consumption, metal ion release (for the two heterogeneous catalytic oxidation processes), dissolved organic carbon (DOC) removal as well as hydroxylated aromatic and low molecular weight aliphatic degradation products. The effect of pH and PS concentrations on IPR removal was examined in DW. While the experiments in DW highlighted the superior performance of UV-C/PS treatment (with 78% DOC removal after 120 min at pH = 6.2), the performance of UV-C/PS treatment decreased sharply (to 24% DOC removal after 120 min at pH = 6.8) in the complex wastewater matrix (in SWW). Complete IPR (in 20 min) and 40% DOC (in 120 min) removals were obtained with ZVI/PS treatment (1 g/L ZVI, 1.5 mM PS, pH = 3.0), which was the most effective oxidation process in SWW. The treatment performance was strongly influenced by the SWW constituents, and UV-C/PS treatment appeared to be the most sensitive to it

S2O8(2-)/UV-C and H2O2/UV-C treatment of Bisphenol A: Assessment of toxicity, estrogenic activity, degradation products and results in real water

The performance of S2O8 2/UV-C and H2O2/UV-C treatments was investigated for the degradation and detoxification of Bisphenol A (BPA). The acute toxicity of BPA and its degradation products was examined with the Vibrio fischeri bioassay, whereas changes in estrogenic activity were followed with the Yeast Estrogen Screen (YES) assay. LC and LC–MS/MS analyses were conducted to determine degradation products evolving during photochemical treatment. In addition, BPA-spiked real freshwater samples were also subjected to S2O82/UV-C and H2O2/UV-C treatment to study the effect of a real water matrix on BPA removal and detoxification rates. BPA removal in pure water was very fast (67 min) and complete via both H2O2/UV-C and S2O82/UV-C treatment, accompanied with rapid and significant mineralization rates ranging between 70% and 85%. V. fischeri bioassay results indicated that degradation products being more toxic than BPA were formed at the initial stages of H2O2/UV-C whereas a rapid and steady reduction in toxicity was observed during S2O82/UV-C treatment in pure water. UV-C treatment products exhibited a higher estrogenic activity than the original BPA solution while the estrogenicity of BPA was completely removed during H2O2/UV-C and S2O82/UV-C treatments parallel to its degradation. 3-methylbenzoic and 4-sulfobenzoic acids, as well as the ring opening products fumaric, succinic and oxalic acids could be identified as degradation products. BPA degradation required extended treatment periods (>20 min) and TOC removals were considerably retarded (by 40%) in the raw freshwater matrix most probably due to its natural organic matter content (TOC = 5.1 mg L1). H2O2/UV-C and S2O82/UV-C treatment in raw freshwater did not result in toxic degradation products

S2O82-/UV-C and H2O2/UV-C treatment of Bisphenol A: Assessment of toxicity, estrogenic activity, degradation products and results in real water

The performance of S2O82-/UV-C and H2O2/UV-C treatments was investigated for the degradation and detoxification of Bisphenol A (BPA). The acute toxicity of BPA and its degradation products was examined with the Vibrio fischeri bioassay, whereas changes in estrogenic activity were followed with the Yeast Estrogen Screen (YES) assay. LC and LC-MS/MS analyses were conducted to determine degradation products evolving during photochemical treatment. In addition, BPA-spiked real freshwater samples were also subjected to S2O82-/UV-C and H2O2/UV-C treatment to study the effect of a real water matrix on BPA removal and detoxification rates. BPA removal in pure water was very fast (20 min) and TOC removals were considerably retarded (by 40%) in the raw freshwater matrix most probably due to its natural organic matter content (TOC = 5.1 mg L-1). H2O2/UV-C and S2O82-/UV-C treatment in raw freshwater did not result in toxic degradation products. (C) 2014 Elsevier Ltd. All rights reserved

S2O8 2/UV-C and H2O2/UV-C treatment of Bisphenol A: Assessment of toxicity, estrogenic activity, degradation products and results in real water

The performance of S2O8 2/UV-C and H2O2/UV-C treatments was investigated for the degradation and detoxification of Bisphenol A (BPA). The acute toxicity of BPA and its degradation products was examined with the Vibrio fischeri bioassay, whereas changes in estrogenic activity were followed with the Yeast Estrogen Screen (YES) assay. LC and LC???MS/MS analyses were conducted to determine degradation products evolving during photochemical treatment. In addition, BPA-spiked real freshwater samples were also subjected to S2O82/UV-C and H2O2/UV-C treatment to study the effect of a real water matrix on BPA removal and detoxification rates. BPA removal in pure water was very fast (67 min) and complete via both H2O2/UV-C and S2O82/UV-C treatment, accompanied with rapid and significant mineralization rates ranging between 70% and 85%. V. fischeri bioassay results indicated that degradation products being more toxic than BPA were formed at the initial stages of H2O2/UV-C whereas a rapid and steady reduction in toxicity was observed during S2O82/UV-C treatment in pure water. UV-C treatment products exhibited a higher estrogenic activity than the original BPA solution while the estrogenicity of BPA was completely removed during H2O2/UV-C and S2O82/UV-C treatments parallel to its degradation. 3-methylbenzoic and 4-sulfobenzoic acids, as well as the ring opening products fumaric, succinic and oxalic acids could be identified as degradation products. BPA degradation required extended treatment periods (>20 min) and TOC removals were considerably retarded (by 40%) in the raw freshwater matrix most probably due to its natural organic matter content (TOC = 5.1 mg L1). H2O2/UV-C and S2O82/UV-C treatment in raw freshwater did not result in toxic degradation products