The photooxidation degradation of tri (2-chloroethyl) phosphate (TCEP) by combining UV with hydrogen peroxide as oxidant was primarily studied in the present study by evaluating various treatment parameters. The results suggested that light intensity, initial pH and concentration of TCEP and H₂O₂, and reaction time affected the degradation efficiency of TCEP. The total organic carbon (TOC) removal rates, and the yield rates of Cl⁻and PO₄ ³⁻reached up to 86 %, 94 % and 97 %, respectively, under the optimized conditions in the present study. The degradation process obeyed the pseudo-first-order kinetic reaction expressed as ln (C ₜ/C ₀) =−0.0275 t with a R ² of 0.9962. The addition of t-butanol indicated that hydroxyl radicals played an important role in the degradation of TCEP. The primary investigation of the degradation mechanism of TCEP suggested that TCEP molecules were attacked by hydroxyl radicals produced from H₂O₂ with the irradiation of UV light, PO₄ ³⁻, Cl⁻and chlorinated alcohol/aldehyde, and/or non-chlorinated aldehyde with small molecular weight were produced, these produced small organic molecules were furthered oxidized to acids, most of them were finally mineralized to CO₂ and H₂O. The present technology was successfully applied for degrading TCEP in simulated real wastewater, which shows a promising potential for treating similar contaminants using corresponding advanced oxidation technology.

We investigated the influence of immobilization of bacterial cells and photocatalytic material TiO2 on the degradation of phenol by conducting batch microcosm studies consisting of suspended, immobilized cells and immobilized TiO2 at various initial phenol concentrations (50-1,000 mg L-1). Results showed that both suspended and immobilized cells were concentration-dependent, exhibiting the increasing degradation rate with the concentration of up to 500 mg L-1 above which it declined. The degradation rate of 0.39-3.47 mg L-1 h-1 by suspended cells was comparable with those of the literature. Comparison of the degradation rates between suspended, immobilized cells and immobilized TiO2 revealed that immobilized cells achieved the highest degradation rate followed by immobilized TiO2 and suspended cells due to the toxicity of phenol at the high concentration of 1,000 mg L-1. This indicates that immobilization of bacterial cells or photocatalytic materials can serve a better alternative to offer the higher degradation efficiency at high phenol concentrations. © 2013 Springer Science+Business Media Dordrecht.

The current study estimates premature mortality caused by long-term exposure to elevated concentrations of PM₂.₅ (particulate matter with aerodynamic diameter equal to or less than 2.5 μm) in Japan from 2006 to 2009. The premature mortality is calculated based on a relative risk of 1.04 (95 % CI, 1.01–1.08) per 10 μg m⁻³ increase above the annual mean limit of 10 μg m⁻³ taken from the World Health Organization Air Quality Guidelines. The spatiotemporal variations of PM₂.₅ are estimated based on the measurements of suspended particulate matter (SPM) (with aerodynamic diameter approximately less than 7.0 μm) at 1,843 monitors. The improvements of air quality in Japan by reducing the emissions of SPM from 2006 to 2009 could save 3,602 lives based on a reduction target of 10 μg m⁻³ annual mean concentration. This finding could be a tangible benefit gained by reducing the emissions of particulate matter in Japan.

Unreclaimed mine tailings sites are a worldwide problem. This study evaluates the potential of Salvia verbenaca for phytoremediation of copper mine tailings treated with technosol and compost. Ecophysiological results reveal the species ability to thrive in the assessed range of conditions, while the hydrogen peroxide assays exhibit the plant’s capacity to successfully respond to metal toxicity, supporting literature reports about its antioxidant capabilities. Furthermore, the results suggest a selective antioxidant response of S. verbenaca towards Cd, indicative of a protection mechanism against high concentrations of this element. Moderate concentrations of Cu in the roots, adequate translocation and bioconcentration factors, tolerance to metal toxicity, and ecophysiological characteristics classify S. verbenaca as a promising candidate for phytostabilization of mine tailings. The importance of the amendments in order to improve the overall phytostabilization performance is highlighted by the elevated correlations between the treatment properties and the extractable concentrations of trace metals.

The compositional changes of saturates, aromatics, resins and asphaltenes (SARA) fractions in aqueous clay/oil microcosm experiments with a hydrocarbon-degrading microorganism community were analysed using Iatroscan. The clay mineral samples used in this study were organomontmorillonite, acid-activated montmorillonite and K, Ca, Zn and Cr montmorillonites produced by modifying the original montmorillonite sample. The evaluation and quantification of biodegradation and adsorption were carried out using a combination of the Iatroscan and gravimetric analysis. The SARA compositions in the presence of organomontmorillonite and acid-activated montmorillonite after incubation follow the same pattern in which the aromatic fraction is higher than the other fractions unlike in the presence of unmodified, K, Ca and Zn montmorillonites, where the saturates fraction is higher than the other fractions. Changes in SARA fractions due to biodegradation seemed to occur most in the presence of unmodified and calcium montmorillonites; hence, the removal of SARA fractions due to biodegradation was significant and enhanced in the presence of these two clay samples. However, biodegradation in the presence of organomontmorillonite and acid-activated and Cr montmorillonites was hindered. The study indicated that Cr montmorillonite adsorbed resins most, whereas Zn and K montmorillonites adsorbed aromatics most after incubation.

Several studies related to zero-valent iron (ZVI), which is employed for water remediation, have been made during the last years. It was found in the literature that the tests made with ZVI in situ, especially for groundwater remediation, were performed using ZVI and nano zero-valent iron (nZVI) as well. Particles usually are used like a “trench-and-fill” installation. In this arrangement, ZVI or nZVI is disposed in the contaminated areas, applied alone or mixed with other materials. The aim of the current work is to evaluate the use of nZVI, which is synthesized in laboratory, for copper ion removal in aqueous solution. The present study will serve like a base focusing, in a future stage, on the use of nZVI on groundwater remediation. For this purpose, commercial ZVI particles were also tested in order to compare the removal behavior. During this study, a relation between the solution characteristic (pH, ion concentration) and the surface purity of the iron particles was found. This relation generally is not reported in the literature. Finally, the copper removal was satisfactory with ZVI and nZVI.

A novel dye degrading bacterium capable of decolorizing and mineralizing four different dyes (Methyl red, Orange II, Direct red 80, and Direct blue 71) was isolated from textile industrial wastewater using the selective enrichment technique. The bacterium was identified as Pseudomonas aeruginosa. More than 80 % decolorization of Direct red 80 was obtained under microaerophilic conditions in 48 h, whereas only 10 % color removal was obtained under oxic conditions at the same time. Subsequent aeration of the decolorized medium resulted in the mineralization of the metabolic intermediates generated after azo bond cleavage by P. aeruginosa as confirmed by total organic carbon content and high-performance liquid chromatography analyses. The degradation products were characterized by Fourier transform infrared spectrometer and nuclear magnetic resonance techniques whereas the biotoxicity profile of the samples were evaluated using the brine shrimp lethality test assay. Data from this study provide evidence of dye mineralization and detoxification by a monoculture of P. aeruginosa in successive microaerophilic/oxic stages. © 2013 Springer Science+Business Media Dordrecht.

Textile dye Victoria Blue-B (VB-B) was approached in two different ways: one to get rid of the color for its easy disposal to the environment, and the other is to reuse the decolorized water for coloring the same dye. Shewanella decolorationis (MBTD16) isolated from Dona Paula Bay, identified by 16S rRNA gene and its action over decolorization was monitored by Fourier transform infrared spectroscopy, UV–Vis spectrum, and a color scanner. Dye removal index increased L*, a*, and b* to 91.585, −2.856, and −0.132 against 62.29, −4.93, and −20.75 within 42 h as a first report. A maximum extent of decolorization (94.83 %) could be achieved with minimum dye concentration of 50 mg L⁻¹. The colored water treated by free and immobilized bacterial cells tested to reuse (VB-B dye) could give 35–50 % more color than the original. Process parameters optimized to achieve maximum decolorization indicated pH 7, temperature 32 ± 2 °C, inoculum size 8 % with co-substrates of glucose and yeast extract 5 g L⁻¹ for its supremacy. Synthesis of lignin peroxidase and tyrosinase augmented in strain S. decolorationis only after being exposed into the dye signifies the enzymes in decolorization, and it was confirmed through one-way ANOVA. Results obtain by this work could suggest that S. decolorationis can be used very well to decolorize the textile dye, and the same water could be recycled to get back its original color by adding around half the quantity of dye. Thus, by the use of water, dye and pollution levels could be minimized.

Low-grade weirs are innovative management strategies that control surface drainage, slow water velocities, and encourage sedimentation in agricultural drainage ditches. There is little information on how low-grade weirs perform in terms of short-term (0–12 months) sediment retention and associated phosphorus (P) dynamics. This study documents initial results of sediment and P dynamics of low-grade weirs in a drainage system that was built in a two-stage ditch design. Average sediment deposition did not differ significantly among sites (χ ² = 2.42; P = 0.49); however, average water depths behind weir sites were significantly greater (28 ± 10 cm) than the comparison inflow site (6 ± 8 cm; χ ² = 7.67; P = 0.05). Total P concentrations were not significantly different through time, or between sites, but there was a general trend of progressively higher total P retention moving downstream. Bioavailability ratios of P (i.e., the ratio of potentially bioavailable to non-bioavailable P fractions) were similar between all sites through time (χ ² = 2.09; P = 0.55). The only variables correlated significantly with time were found at the inflow site, where water depth significantly decreased with corresponding increases in sediment/water column pH and bioavailability ratios. From best management practice installation to 12 months after construction, there was a lack of significant correlations with any measured variables behind weirs. However, the lack of correlation between variables suggests increasing the hydroperiod, reducing the ephemeral nature of the drainage ditch system, and prolonging inundation, improves conditions for P retention.

Domestic water is abstracted from its sources in raw form with a high content of dissolved and suspended material. Polydiallyldimethylammonium chloride (polyDADMAC) is a cationic polyelectrolyte used in the initial water clarification process. However, its residues in treated water pose a health risk as they react with chlorine to produce a carcinogenic compound. There is a need to determine the concentration of the polyelectrolyte cations that pass through the flocculation stage before the chlorine disinfection process in water treatment plants to ascertain the safety of water to consumers. The cationic polymer is UV inactive, and previously available methods for determining the concentrations of polyelectrolytes are unsatisfactory due to poor detection limits. This paper describes a UV-Visible (UV-vis) spectrophotometry method for the determination of residual polyDADMAC as an epoxide. The novelty method lies on the epoxidation of polyDADMAC using 20 % sodium hydroxide dissolved in 30 % hydrogen peroxide to produce a UV-Vis active compound. The epoxidation was confirmed by UV-Vis, FTIR and 1H NMR techniques. Dilute solutions of varying concentrations of polyDADMAC (0.2-1.0 mg L-1) were treated with a basic solution of hydrogen peroxide then analysed by UV-Vis spectrophotometry. The wavelength at maximum absorption (λmax) was found to be 313 nm, and a linear calibration curve with a correlation coefficient (R 2) of 0.993 was used for quantification purposes. The detection limit measured as three times the signal of the blank and was found to be 2.1 × 10-4 mg L-1. The method was applied to determine the concentration of polyDADMAC spiked in water samples collected from a pool as a model for environmental matrix. The results obtained agreed with the quantities spiked in the solution, thus qualified the method to be suitable for the determination of polyDADMAC in treated waters at trace levels. The method was also used to investigate the adsorption capacity of polyDADMAC on sand filters. The adsorption method was found to be in accordance with Langmuir with an adsorption capacity of 2.068 mg g-1. © 2013 The Author(s).