Concentrations and sources of Dechlorane Plus in sewage sludge

Sewage sludge from 31 urban Spanish wastewater treatment plants (WWTP) was analyzed for the emerging halogenated flame retardant Dechlorane Plus (DP). Concentrations of the two major isomers in the technical mixture, syn and anti, ranged between 0.903-19.2 and 1.55-75.1 ng g⁻¹ dry weight, respectively. Overall, concentrations of DP were lower than those of polybrominated diphenyl ethers (PBDEs) (9.10-995 ng g⁻¹ dry weight) and this is likely related to the higher usage of brominated flame retardants. The average ratio of the syn isomer to total DP (f_syn) was 0.28 ± 0.05, which is similar to that of the commercial mixture. Comparing different wastewater treatment methods, we found lower concentrations in those using biological nitrogen and phosphorous elimination, suggesting that DP is susceptible to microbial degradation and that anti-DP is more so, given the enrichment of syn-DP in the sewage sludge. Principal components analysis revealed significant positive correlation (r = 0.619, p < 0.05) between total DP concentrations with the contribution of industrial input to waste streams. This implies release of DP is related to industrial activity, likely stemming from the use of the technical product during manufacture of consumer goods. However, use and disposal of products containing DP could not be dismissed. According to our knowledge, this is the first report on DP in WWTP sludge.     

Influence of RFID tags on recyclability of plastic packaging

The use of Radio Frequency IDentification Technology (RFID) in the packaging sector is an important logistical improvement regarding the advantages offered by this technology in comparison with barcodes. Nevertheless, the presence of these devices in plastic packaging, and consequently in plastic waste, can cause several problems in the recycling plants due to the materials included in these devices.In this study, the mentioned recycling constraints have been experimentally identified in a pilot scale recycling study consisting in three recycling tests with an increasing presence of RFID tags. Differences in each test were evaluated. Furthermore, the quality of the recycled material of each test was studied through the injection and testing of tests probes.The results of the pilot scale recycling tests did not show a decrease in the quality of the recycled plastic due to the presence of RFID tags. Nevertheless, several operational problems during the recycling process were observed such as the obstruction of the screens, which lessened the process yield and created process interruptions, as well as the loss of extruded plastic during the process.These recycling constraints cannot be directly extrapolated to the industrial plants due to the different working scales. Nevertheless, technological solutions are proposed in order to avoid these recycling constraints if they appear.     

Kinetics of simazine advanced oxidation in water

Abstract

Comparison of the effects and kinetics of UV photolysis and four advanced oxidation systems (ozone, ozone/hydrogen peroxide, ozone/UV radiation and UV radiation/hydrogen peroxide) for the removal of simazine from water has been investigated. At the conditions applied, the order of reactivity was ozone < ozone/hydrogen peroxide < UV radiation < ozone/UV radiation and UV radiation/hydrogen peroxide. Rate constants of the reactions between ozone and simazine and hydroxyl radical and simazine were found to be 8.7 M^‐1s^‐1 and 2.1x10⁹ M^‐1s^‐1, respectively. Also, a quantum yield of 0.06 mol.photon^‐1 was found for simazine at 254 nm UV radiation. The high value of the quantum yield corroborated the importance of the direct photolysis process. Percentage contributions of direct reaction with ozone, reaction with hydroxyl radicals and direct photolysis were also quantified.     

Fuel from waste tyres and particulate matter emitted from the process

The interest in obtaining alternative fuels from waste sources and at the same time diminishing the impact of waste disposal has drawn attention to scrap tyres' carbon recovery. In order to thermally degrade used tyre rubber, a laboratory pyrolysis system was developed in this work. The installation devised focused on the production of liquid pyrolysates, where shredded rubber was supplied as the feedstock and nitrogen used as the carrier gas to provide an oxygen-free atmosphere. The variables affecting the performance of the process were investigated, including target temperature, heating rate and total residence time. Characterization of the volatile matter released was conducted by means of mass spectrometry to determine the composition of products, and particulate matter analysis to ascertain the aerosol content in the gas stream. The reproducibility of experiments, the influence of the temperature and time, and differences between the vapours before condensation and the exhaust gases are discussed. This work identified that the larger hydrocarbon fragments condense to constitute the oils, whereas the lighter molecules remain as non-condensable gases. This work also identified that the total number of nano-scale particles carried by the exhaust stream varies with temperature; significant changes in the composition of products and particle content were reported at approximately 400°C. The high number of nano-scale solid particulate matter present in the exhaust gases suggests that a thorough treatment for that stream would be required to avoid human health hazards.     

Phytomanagement of strongly acidic,saline eutrophic wetlands polluted by mine wastes: The influence of liming and Sarcocornia fruticosa on metals mobility

The aim of this study was to assess the effectiveness of combining liming and vegetation for the phytomanagement of strongly acidic, saline eutrophic wetlands polluted by mine wastes. Simulated soil profiles were constructed and four treatments were assayed: without liming + without plant, without liming + with plant, with liming + without plant and with liming + with plant. The plant species was the halophyte Sarcocornia fruticosa. Three horizons were differentiated: A (never under water), C1 (alternating flooding–drying conditions) and C2 (always under water). The soluble Cd, Cu, Mn, Pb and Zn concentrations were measured regularly for 18 weeks and a sequential extraction procedure was applied at the end of the experiment. Liming was effective (between ～70% and ～100%) in reducing the soluble Zn, Cu and Pb. In contrast, soluble Mn and Cd increased with liming, especially in the treatment with liming + with plant, where the concentrations were 2-fold higher than in the non-limed treatments. The amendment increased the contents of Zn, Mn and Cd bound to potentially-mobilisable soil fractions at the expense of the most-environmentally-inert fractions. Hence, the combined use of liming and vegetation may increase the long-term environmental risk of metals solubilisation.     

Evaluation of the urban/rural particle-bound PAH and PCB levels in the northern Spain (Cantabria region)

The aim of the present study was to evaluate the polycyclic aromatic hydrocarbon (PAH) and polychlorinated biphenyl (PCB) levels in PM(10) and PM(2.5), at one rural and three urban sites in the Cantabria region (northern Spain). From all of these pollutants, benzo(a)pyrene is regulated by the EU air quality directives; its target value (1?ng/m(3)) was not exceeded. The concentration values of the studied organic pollutants at the studied sites are in the range of those obtained at other European sites. A comparison between the rural-urban stations was developed: (a) PAH concentration values were lower in the rural site (except for fluorene). Therefore, the contribution of local sources to the urban levels of PAHs seems relevant. Results from the coefficient of divergence show that the urban PAH levels are influenced by different local emission sources. (b) PCB rural concentration values were higher than those found at urban sites. Because no local sources of PCBs were identified in the rural site, the contribution of more distant emission sources (about 40?km) to the PCB levels is considered to be the most important; the long-range transport of PCBs does not seem to be significant. Additionally, local PAH tracers were identified by a triangular diagram: higher molecular weight PAHs in Reinosa, naphthalene in Santander and anthracene/pyrene in Castro Urdiales. A preliminary PAH source apportionment study in the urban sites was conducted by means of diagnostic ratios. The ratios are similar to those reported in areas affected by traffic emissions; they also suggest an industrial emission source at Reinosa.     

An empirically tested overlap between indigenous and scientific knowledge of a changing climate in Bolivian Amazonia

Regional Environmental Change - Existing climate data for Bolivian Amazonia rely on observations from a few sparse weather stations, interpolated on coarse-resolution grids. At the same time, the...     

Daily and seasonal variations of optimum quantum yield and phenolic compounds in Cystoseira tamariscifolia (Phaeophyta)

Effects of solar radiation on phenolic compound concentrations and photosynthetic activity, estimated as in vivo chlorophyll fluorescence, in the brown alga Cystoseira tamariscifolia (Hudson) Papenfuss were analyzed in southern Spain from June 1988 to July 2000. Annual and diurnal variations of optimum quantum yield were negatively correlated with incident irradiance. Optimum quantum yield decreased as irradiance increased at noon, and yield values recovered in the afternoon suggesting a dynamic photoinhibition. The annual and daily fluctuations of phenolic compound concentration in the tissue of C. tamariscifolia showed contrasting patterns. There was an annual cycle of phenolic compound concentration in the apical thallus, which was positively correlated with incident irradiance. The increase in phenolic compounds, however, was twofold greater in the first half of the year than the decrease during the second half of the year. In contrast to the annual cycle, there appeared to be a negative correlation between phenolic compound concentration and irradiance in the summer months while no specific relationship was observed in the fall–winter months. Loss of phenolic compounds from the tissue to the surrounding water was increased as irradiation dosage increased. This suggests that the decrease of phenolic compounds during the diurnal cycle might be regulated by the exudation of these compounds at high irradiances in the field. Collectively, our results suggest that, like dynamic photoinhibition, the rapid synthesis and turnover time of phenolic compounds in the tissue of C. tamariscifolia might serve as photoprotective mechanisms against high irradiances.