Biofumigation is considered a good alternative to chemical fumigation because it can control crop pathogens and diseases with lower health and environmental risks than chemical fumigants. Glucosinolates are volatile compounds found in most Brassica species, and when hydrolysed, it forms a range of natural toxins including isothiocyanates that act as biofumigants. However, the effect of glucosinolates and their breakdown products on non-target and beneficial soil organisms is not well documented. Three biofumigants, broccoli, mustard and oilseed radish, were evaluated for their effect on earthworms (Eisenia andrei) and the soil microbial community. Sub-lethal endpoints, including growth and reproductive success of the earthworms, were monitored. Genotoxicity of the biofumigants towards earthworms was evaluated by means of the comet assay. Broccoli reduced earthworm reproduction while mustard induced more DNA strand breaks in earthworm cells compared to the control. Soil microbial community function and structure were evaluated by means of community level physiological profiling and phospholipid fatty acid analyses. The effects exerted by the biofumigants on the microbial community were the most pronounced within the first 14 days after application. Carbon substrate utilisation was most affected by the oilseed radish treatment and microbial community structure by the mustard treatment.

Fe₂O₃ and CeO₂ modified activated coke (AC) synthesized by the equivalent-volume impregnation were employed to remove elemental mercury (Hg⁰) from simulated flue gas at a low temperature. Effects of the mass ratio of Fe₂O₃ and CeO₂, reaction temperature, and individual flue gas components including O₂, NO, SO₂, and H₂O (g) on Hg⁰ removal efficiency of impregnated AC were investigated. The samples were characterized by Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Results showed that with optimal mass percentage of 3 % Fe₂O₃ and 3 % CeO₂ on Fe3Ce3/AC, the Hg⁰ removal efficiency could reach an average of 88.29 % at 110 °C. Besides, it was observed that O₂ and NO exhibited a promotional effect on Hg⁰ removal, H₂O (g) exerted a suppressive effect, and SO₂ showed an insignificant inhibition without O₂ to some extent. The analysis of XPS indicated that the main species of mercury on used Fe3Ce3/AC was HgO, which implied that adsorption and catalytic oxidation were both included in Hg⁰ removal. Furthermore, the lattice oxygen, chemisorbed oxygen, and/or weakly bonded oxygen species made a contribution to Hg⁰ oxidation.

Denitrification coupled to anaerobic methane oxidation is a recently discovered process performed by bacteria affiliated to the NC10 phylum. These microorganisms could play important roles in the energy-efficient way of anaerobic wastewater treatment where residual dissolved methane might be removed at the expense of nitrate or nitrite. The difficulty to enrich these microorganisms due to a slow growth rate, especially at low temperatures, limited its application in engineering field. In this study, an NC10 bacteria community was enriched from Taihu sediments by a membrane biofilm bioreactor at ambient temperature of 10–25 °C. After 13 months enrichment, the maximum denitrification rate of the enriched culture reached 0.54 mM day⁻¹ for nitrate and 1.06 mM day⁻¹ for nitrite. Anaerobic methane oxidation coupled denitrification was estimated from the ¹³C-labeled CO₂ (¹³CO₂) production during batch incubations with ¹³CH₄. Furthermore, analysis of 16S rRNA genes clone library confirmed the presence of NC10 phylum bacteria and fluorescence in situ hybridization showed that NC10 bacteria dominated the reactor. All of the results indicated the NC10 bacteria community was competitive in terms of treating nitrate-contaminated water or wastewater under natural conditions.

In this paper, Zn(0)-catalyzed ozonation degradation of acid orange 7 (AO7) and its impact factors including solution pH, Zn loading, and AO7 initial concentration were investigated through a series of bath experiments. The results demonstrated that Zn could markedly accelerate the degradation of AO7 by ozone (O₃) and the degradation efficiency of AO7 increased by 77 and 71 % within 30 min as compared with those in the systems of O₃ alone and Zn/air, respectively. The reuse of Zn resulted in a slight decline in AO7 degradation, suggesting that a coating of ZnO on the surface of Zn particles weakened Zn catalytic activity. The optimal removal of AO7 was achieved in a wide pH range of 4 to 10, and a lower or higher pH was not conducive to the degradation of AO7. In addition, the degradation efficiency of AO7 increased with Zn loading but decreased with AO7 initial concentration. The introduction of free radical scavengers into the system of AO7/Zn/O₃ confirmed that O₂ •⁻, rather than •OH, was the main free radicals responsible for the rapid removal of AO7. The degradation of AO7 by O₃ assisted with Zn could be well expressed with pseudo-first-order kinetic model.

The occurrence of n-alkanes and biomarkers (hopane and sterane) in surface sediments from Southwestern coasts of Caspian Sea and 28 rivers arriving to this lake, determined with a gas chromatography–mass spectrometry method, was used to assess the impacts of anthropogenic activities in the studied area. The concentrations of total n-alkanes (Σ21 n-alkane) in costal and riverine sediments varied from 249.2 to 3899.5 and 56 to 1622.4 μg g⁻¹, respectively. An evaluation of the source diagnostic indices indicated that petroleum related sources (petrogenic) were mainly contributed to n-alkanes in costal and most riverine sediments. Only the hydrocarbons in sediment of 3 rivers were found to be mainly of biogenic origin. Principal component analysis using hopane diagnostic ratios in costal and riverine sediments, and Anzali, Turkmenistan, and Azerbaijan oils were used to identify the sources of hydrocarbons in sediments. It was indicated that the anthropogenic contributions in most of the costal sediment samples are dominated with inputs of oil spills from Turkmenistan and Azerbaijan countries.

dithiocarbamate-graphene oxide (GO) was prepared by simple method through reactions between poly3-aminopropyltriethoxysilane functionalized GO (PAS-GO) and CS₂. DTC-GO can capture Cu²⁺ and Cd²⁺ effectively to generate stable structures and then remove them from aqueous solutions. The properties of the DTC-GO are characterized by Fourier transform infrared spectroscopy (FTIR). The adsorption capacity for heavy metal ions of DTC-GO was evaluated by the removal of Cu²⁺ and Cd²⁺ from aqueous solution. The effect of several factors, including the pH, contact time, and temperature, was investigated by batch experiment. The results show that the DTC-GO exhibits excellent adsorption capacity for Cu²⁺ and Cd²⁺. The adsorption kinetics study indicates that the adsorption kinetics of Cu²⁺and Cd²⁺ all could be well described by pseudo-second-order kinetic model. The adsorption isotherm was investigated by Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models, and the adsorption process was well described by the Langmuir model. The effect of temperature shows that the process of DTC-GO for Cu²⁺ and Cd²⁺ is an endothermic process. The results indicated that the DTC-GO can be used as one of the promising candidate adsorbents with enhanced removal capacity for the adsorption of Cu²⁺ and Cd²⁺.

In this study, column leaching experiments were used to evaluate the leachability, distribution and bioavailability of phenanthrene and pyrene by root exudates from contaminated mangrove sediments. We observed that root exudates significantly promoted the release and enhanced the bioavailability of phenanthrene and pyrene from sediment columns. The concentration of phenanthrene and pyrene and cumulative content released from the analyzed sediment samples following root exudate rinsing decreased in the following order: citric acid > oxalic acid > malic acid. After elution, the total concentrations of phenanthrene and pyrene in sediment layers followed a descending order of bottom (9–12 cm) > middle (5–7 cm) > top (0–3 cm). Furthermore, a positive correlation between leachate pH values and PAH concentrations of the leachate was found. Consequently, the addition of root exudates can increase the leachability and bioavailability of phenanthrene and pyrene.

Geothermal waters exploited in the southeastern region of Hungary are alkali-hydrogen-carbonate type, and beside the high amount of dissolved salt, they contain a variety of aromatic, heteroaromatic, and polyaromatic hydrocarbons. The majority of these geothermal waters used for heating are directed into surface waters following a temporary storage in reservoir lakes. The aim of this study was to gain information about the temporal and spatial changes of the water quality as well as the bacterial community composition of an alkaline and saline oxbow lake operated as reservoir of used geothermal water. On the basis of the water physical and chemical measurements as well as the denaturing gradient gel electrophoresis (DGGE) patterns of the bacterial communities, temporal changes were more pronounced than spatial differences. During the storage periods, the inflow, reservoir water, and sediment samples were characterized with different bacterial community structures in both studied years. The 16S ribosomal RNA (rRNA) gene sequences of the bacterial strains and molecular clones confirmed the differences among the studied habitats. Thermophilic bacteria were most abundant in the geothermal inflow, whereas the water of the reservoir was dominated by cyanobacteria and various anoxygenic phototrophic prokaryotes. In addition, members of several facultative anaerobic denitrifying, obligate anaerobic sulfate-reducing and syntrophic bacterial species capable of decomposition of different organic compounds including phenols were revealed from the water and sediment of the reservoir. Most of these alkaliphilic and/or halophilic species may participate in the local nitrogen and sulfur cycles and contribute to the bloom of phototrophs manifesting in a characteristic pink-reddish discoloration of the water of the reservoir.

Nitrogen pollution in ground and surface water significantly affects the environment and its organisms, thereby leading to an increasingly serious environmental problem. Such pollution is difficult to degrade because of the lack of carbon sources. Therefore, an electrochemical and biological coupling process (EBCP) was developed with a composite catalytic biological carrier (CCBC) and applied in a pilot-scale cylindrical reactor to treat wastewater with a carbon-to-nitrogen (C/N) ratio of 2. The startup process, coupling principle, and dynamic feature of the EBCP were examined along with the effects of hydraulic retention time (HRT), dissolved oxygen (DO), and initial pH on nitrogen removal. A stable coupling system was obtained after 51 days when plenty of biofilms were cultivated on the CCBC without inoculation sludge. Autotrophic denitrification, with [Fe²⁺] and [H] produced by iron–carbon galvanic cells in CCBC as electron donors, was confirmed by equity calculation of CODCᵣ and nitrogen removal. Nitrogen removal efficiency was significantly influenced by HRT, DO, and initial pH with optimal values of 3.5 h, 3.5 ± 0.1 mg L⁻¹, and 7.5 ± 0.1, respectively. The ammonia, nitrate, and total nitrogen (TN) removal efficiencies of 90.1 to 95.3 %, 90.5 to 99.0 %, and 90.3 to 96.5 % were maintained with corresponding initial concentrations of 40 ± 2 mg L⁻¹ (NH₃–N load of 0.27 ± 0.01 kg NH₃–N m⁻³ d⁻¹), 20 ± 1 mg L⁻¹, and 60 ± 2 mg L⁻¹ (TN load of 0.41 ± 0.02 kg TN m⁻³ d⁻¹). Based on the Eckenfelder model, the kinetics equation of the nitrogen transformation along the reactor was N ₑ = N ₀ exp (−0.04368 h/L¹.⁸⁴³⁸). Hence, EBCP is a viable method for advanced low C/N ratio wastewater treatment.

Surfactants always play a special role in wastewater processes due to their amphiphilic properties. The performance of ultrafiltration was investigated for the treatment of wastewater containing low-level anionic surfactant and trace-level nuclides. Results showed that sodium dodecyl benzene sulfonate (SDBS) below the critical micelle concentration (CMC) caused significant effects on membrane fouling and rejection of nuclides. The membrane flux decreased at SDBS concentrations below the CMC but increased at the concentrations near the CMC. The phenomenon was caused by two distinct effects of SDBS, pore blocking by the monomers and enhancement of nuclide scaling caused a decrease in flux, while hydrophilic modification of the membrane surface by micelles caused an increase in flux. The nuclides alone had no significant effect on membrane fouling, but the flux decreased upon an increase in nuclide concentration when coexisting with SDBS. After the addition of low-level SDBS, the rejections of nuclides increased sharply from 20–30 to 60–98 %. The rejections of Sr(II) and Co(II) were higher than those of Ag(I) and Cs(I) due to stronger complexation of SDBS with divalent cations compared with monovalent cations. Deposition of nuclides increased with the addition of SDBS and with increasing of nuclide concentration, resulting in more radioactive solid waste production and more frequent replacement of membrane module.