In this study, high surface area porous carbons were synthesized by chemical activation using petroleum coke as the precursor and KOH as the activation agent. The pore structure of the as-synthesized activated carbons was characterized by nitrogen adsorption, and their CO₂ sorption capacities were measured by a magnetic suspension balance at 1 and 10 bar, respectively. The effects of activated carbon preparation parameters (preheating temperature, preheating time, activation time, heating rate during the pyrolysis, and particle size of the precursor) on porous texture, CO₂ adsorption capacity, and CO₂/N₂ selectivity of the activated products were investigated. It has been found that at 1 bar, the CO₂ adsorption capacity is determined by the micropore contribution, i.e., the ratio between micropore surface area and Brunauer–Emmett–Teller (BET) surface area of the sorbents, while at 10 bar, CO₂ adsorption capacity is related to the BET surface area of the activated products. The maximum CO₂ adsorption uptake of 15.1 wt% together with CO₂/N₂ selectivity of 9.4 at 1 bar were obtained for a sample activated at 700 °C indicating its high potential in the capture of CO₂.

Pollution by heavy metals (Co, Cu, Ni, Pb, Sb and Zn), Ra-226 and U was studied in eight profiles (1.0-1.8 m deep) in the floodplain sediments of the Ploucnice River, the Czech Republic. The element concentrations were processed by establishing local geochemical background functions from non-polluted overbank fines yet not affected by reductimorphic processes and a subsequent calculation of enrichment factors in the polluted strata. In the case of Cu and Ni, the geogenic variability of the watershed (Cretaceous marine sediments and Cenozoic volcanics and their weathering products) was successfully handled using different background functions in two parts of the studied area, which allowed us to decipher the anthropogenic and natural portions of the heavy metals and hence evaluate the history of pollution. The upper course of the river drains an extensive area of so-called chemical mining (underground acid leaching of low-grade U-bearing sediments) and hydrometallurgical processing in Straz pod Ralskem that started in the late 1960s and operated without waste-processing plants up to 1989. The river system has consequently been impacted by U and gamma-emitting Ra-226 and obviously also by divalent heavy metals (Co, Ni, Zn). In the entire study area, that pollution was preceded by increasing levels of Cu, Pb and Sb and by the Pb-206/Pb-207 ratio decreasing from 1.20 towards 1.17, which had started earlier in the twentieth century before the U mining. That pre-mining pollution can be attributed to diffuse anthropogenic activities of regional or continental importance. The most recent Pb-206/Pb-207 ratio in the Ploucnice alluvium coincides with that of peatbog profiles on the borders of the Czech Republic, showing the usefulness of floodplains as pollution archives of widespread regional to continental pollution signals.

Vapor phase mass transfer is an important interphase transport process that dominates the overall transport phenomena in liquid–gas system in porous media. Volatilization of nonaqueous phase liquids (NAPLs) in porous media is such system that takes place during the remediation of volatile organic compound-contaminated soil using soil vapor extraction. Usually, interphase mass transfer coefficient is lumped together with the air–liquid interfacial area because of the inaccessibility to quantify this parameter due to the heterogeneous nature of the pore structure of the media and the morphology of the fluid distribution. In this paper, the air–liquid interfacial area is quantified using a simple method derived from pressure–saturation relationship in three glass bead media. A series of one-dimensional NAPL volatilization experiments were carried out in a horizontal column for the same porous media by using toluene as the single contaminant. Experiments were conducted for NAPL saturation range of 13.8 ~ 71 % and pore gas velocities of 0.1 ~ 2 cm/s, and lumped mass transfer coefficients were evaluated. Actual vapor phase mass transfer coefficients were calculated using corresponding air–liquid interfacial area for a specific NAPL saturation and characterized in dimensionless form for all porous media. Results revealed that the vapor phase mass transfer increases with pore gas velocities and grain sizes but decreases with NAPL saturation.

The use of Cu-based fungicide can pose a risk to nearby surface water bodies due to the run-off of accumulated Cu from agricultural soils. In 2008, we conducted a reconnaissance survey of the presence and concentration of copper in sediments at 18 sites within the Yarra River Catchment, an important horticultural production system in south-eastern Australia. Observed Cu concentrations in sediment samples from the study sites (mean (95 % confidence interval) 12.0 (10.6-13.6) mg/kg dry weight) were similar to the concentrations present in the samples from the reference sites (mean (95 % confidence interval) 12.0 (6.7-16.8) mg/kg dry weight). The data on Cu and other metals in the sediments suggest that that there is unlikely to have been wide spread, diffuse, off-site transport of Cu from the soils of horticultural properties to nearby surface waterways in the Yarra River Catchment and that that observed sediment metal concentrations are unlikely to pose an ecological risk to sediment-dwelling organisms at the study sites. © 2013 Springer Science+Business Media Dordrecht.

Robust and cheap, biofiltration is one of the most used methods for the biological treatment of industrial gaseous odours and VOCs emissions. The chemical, physical and microbial properties, as well as the economical impact of 11 organic and inorganic packing materials potentially suitable for biofiltration, have been investigated in order to select the most relevant for the treatment of rendering gaseous emissions. Fibrous materials such as peat and coconut fibres are predisposed to compaction. Moreover, according to their low expected running period, their implementation remains expensive, such as activated carbon which induce overweening costs (>100,000€ an -1 for the treatment of 40,000 m3 h-1 with a 60-s empty bed gas residence time). Considering economical aspects, physico-chemical and biological properties, pines barks, composted wood mulch and expanded schist seem fit for this application. The performance of these materials was therefore investigated in a pilot-scale study conducted on a rendering site. According to its appropriate pH (8.62) and water-holding capacity (1.41 g g-1) and its highest nutrients content and colonization at the biofilter start-up (93 g of ATP m-3, 29.10 13 CFU m-3), composted would mulch show the best odour removal efficiency during the 134 days of operation. Performances ranged between 75 and 93 % for the treatment of odourous inlet load between 1.16 and 10.10·106 ouE m-3 h-1 with an empty bed gas residence time of 47 s. However, the pressure drop of the compost bed decreased, suggesting structural changes which may impact the performances in the long term. © 2013 Springer Science+Business Media Dordrecht.

Biowastes and inorganic additives are acknowledged efficient but site-dependent alternatives for in situ metal immobilization. The present study evaluates food waste-based compost, a particularly abundant type of biowaste in South Korea, and zeolite as amendments for increasing pH and reducing metal leaching potential in weathered tailings from an abandoned mine site. Two types of biowaste were used: food waste compost (60 % food waste and 40 % sawdust) and market compost (50 % food waste, 10 % agricultural waste, 10 % manure, and 30 % lime). Materials were thoroughly characterized. Leaching tests were then performed in reactors filled with various mixtures of organic–inorganic amended tailings, over a 4-week period. The in situ metal immobilization efficiency of compost was evaluated based on collected leachate quality. Results indicated that both organic and inorganic materials were successful for increasing pH (from 3.0 to up to 8.1) and metal immobilization, except for Pb and As, with which leaching potential increased in most amended reactors relative to un-amended tailings (up to 43 and 158 %, respectively). Over the duration of the experiment, the cumulative reduction of metal leaching potential ranked as follows: Zn (44–91 %) > Mn (4–76 %) > Cr (20–53 %) > Fe (34–44 %) > Cd (17–43 %) > Al (0.5–24 %). Among mixtures, combined biowaste and zeolite-amended tailings showed the best performance for increasing pH (7.5–8.1) and for metal immobilization. Chemical and biological processes, such as sorption and precipitation processes, were predominant. Overall, the study provides useful data on the efficient use of food waste compost for acid mine drainage prevention in South Korea.

Soils polluted by metals and organic compounds are a major challenge in soil remediation and environmental recovery; however, the technology to efficiently decontaminate soils polluted by both metal and organic pollutants does not yet exist. Most of these soils are disposed of in landfills. This study first evaluates chemical reagents (hydrochloric, nitric, sulfuric and lactic acids and ethanol) for leaching metals from soil. Assays were then conducted to evaluate non-ionic, ionic and amphoteric surfactants for pentachlorophenol (PCP) removal by flotation. Finally, a laboratory-scale leaching/flotation process was applied to treat four soil samples polluted with both organic ([PCP]ᵢ = 2.5–30 mg kg⁻¹) and metals ([As]ᵢ = 50–250 mg kg⁻¹, [Cr]ᵢ = 35–220 mg kg⁻¹, [Cu]ᵢ = 80–350 mg kg⁻¹) compounds. The organic compounds and metals are concentrated in the froth and liquid fractions, respectively. Removal yields of 82–93 %, 30–80 %, 79–90 % and 36–78 % were obtained from As, Cr, Cu and PCP, respectively, under optimized process conditions (H₂SO₄ = 1 N, [cocamidopropyl betaine]ᵢ = 1 % (w w⁻¹), t = 60 min, T = 60 °C, PD = 10 % (w v⁻¹)). The treatment of the produced leachate was also tested by chemical precipitation using different reagents.

Previous research demonstrated that nutrient treatment in conventionally drained bioretention cells is dependent upon temperature and varying wetting and drying regimes in the media. This study examines the influence that previous events have on outflow concentrations by analyzing flow-weighted composite samples from four to six consecutive events during three different seasons for two sets of field-monitored bioretention cells in Nashville, NC. The bioretention cells had different media depths (0.6-m versus 0.9-m). As a means to analyze performance from consecutive events, the evolution of cumulative pollutant loads was presented by plotting cumulative load versus cumulative volume. This method of presenting water quality data allows for the direct analysis of event mean concentrations, load reduction, and volume reduction with one graph, as well as describing the seasonal impacts and impacts from consecutive events. Runoff and outflow concentrations were also correlated to media temperature and rainfall characteristics. The overall results of this study showed that conventionally drained bioretention cells mainly convert organic nitrogen, the predominant source of nitrogen in runoff, into nitrate in the aerobic environment present in the media. Nitrate is then exported from the media during subsequent events. The greatest export occurred during the warmer months because higher media temperatures increased microbial activity. Pollen and leaf litter were identified as organic nitrogen and total phosphorus sources because of elevated runoff concentrations that occurred in the spring and autumn. Based on these results, future bioretention studies should strongly consider monitoring consecutive events and this method of data analysis, as they reveal internal processes and allow researchers to draw conclusions that independent event monitoring could not.

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.

High mercury concentrations in freshwater fish from the Nordic region have been of concern for a long time. Ongoing monitoring of key ecological species occurs in these countries to follow the situation. Here, we investigated spatial and temporal trends in mercury concentrations in European perch (Perca fluviatilis) within the Swedish and Finnish aquatic environments, collated from national monitoring programmes collected between 1974 and 2005 (n = 5,172). Data were length and weight adjusted to remove perch size as a confounding factor. Temporal trend analyses and t tests comparing pre- and post-1996 mercury concentrations for each country (1974-1995; 1996-2005; perch adjusted to 200 g/25 cm), showed a significant decrease in mercury concentration in perch from Sweden (p < 0.001) and a possible increase in mercury concentration in perch from Finland (p < 0.001). No statistically significant geographical trends were seen. Average mercury concentrations exceeded both the current environmental quality standard (EQS) of 20 ng/g wet weight (ww) and a discussed EQS for the Nordic region of 200-250 ng/g ww. Despite large reductions in mercury use and production in these countries, concentrations in perch continue to be higher here than in other European areas, posing a continued environmental risk. © 2013 Springer Science+Business Media Dordrecht.