Fluid catalytic cracking of heavy ends to high-value liquid fuels is a common unit operation in oil refineries. In this process, the heavy feedstock that contains sulfur is cracked to light products. Sulphur content is hence redistributed in the liquid and gaseous products and coke of the catalyst used in this process. The coke is later burnt in the regenerator releasing sulfur into the discharged flue gas as SO₂. In the present work, comprehensive emission inventories for a fluid catalytic cracking unit in a typical oil refinery are prepared. These inventories are based on calculations that assume complete combustion of catalyst coke in the regenerator. Yearly, material balances for both SO₂ and particulate matters emissions are carried out taking into account seasonal variations in the operation of the process unit. The results presented in this article reflect the variation of sulfur in feedstock originating from various units in the refinery. The refinery operations are not dependant on seasons but controlled by market-driven conditions to maximize the profit. The seasonal impact on refinery emissions is minimal due to its operation at optimum capacity fulfilling the international market demand. The data presented and analyzed here can be used to assess the hazardous impact of SO₂ and particulate matter emissions on surrounding areas of the refinery.

Osmium tetroxide (OsO4) is one of the most toxic air contaminants but its environmental effects are poorly understood. Here, for the first time, we present evidence of osmium uptake in a common herbivore (bank vole, Myodes glareolus) in boreal forests of northern Sweden. Voles (n = 22) and fruticose arboreal pendular lichens, the potential main winter food source of the vole, were collected along a spatial gradient to the west of a steelwork in Tornio, Finland at the Finnish–Swedish border. 187Os/188Os isotope ratios increased and osmium concentrations decreased in lichens and voles along the gradient. Osmium concentrations in lichens were 10,000-fold higher than those in voles. Closest to the steelwork, concentrations were highest in kidneys rather than skin/fur that are directly exposed to airborne OsO4. The kidney-to-body weight ratio was higher at the two localities close to the steelwork. Even though based on a small sample size, our results for the first time demonstrate that osmium is taken up, partitioned, and accumulated in mammal tissue, and indicate that high kidney-to-body weight ratios might be induced by anthropogenic osmium.

Typical controlled drainage structures in drainage ditches provide drainage management strategies for isolated temporal periods. Innovative, low-grade weirs are anticipated to provide hydraulic control on an annual basis, as well as be installed at multiple sites within the drainage ditch for improved spatial biogeochemical transformations. This study provides evidence toward the capacity of low-grade weirs for nutrient reductions, when compared to the typical controlled drainage structure of a slotted riser treatment. Three ditches with weirs were compared against three ditches with slotted risers, and two control ditches for hydraulic residence time (HRT) and nutrient reductions. There were no differences in water volume or HRT between weired and riser systems. Nutrient concentrations significantly decreased from inflow to outflow in both controlled drainage strategies, but there were few statistical differences in N and P concentration reductions between controlled drainage treatments. Similarly, there were significant declines in N and P loads, but no statistical differences in median N and P outflow loads between weir (W) and riser (R) ditches for dissolved inorganic phosphate (W, 92%; R, 94%), total inorganic phosphate (W, 86%; R, 88%), nitrate-N (W, 98%; R, 96%), and ammonium (W, 67%; R, 85%) when nutrients were introduced as runoff events. These results indicate the importance of HRT in improving nutrient reductions. Low-grade weirs should operate as important drainage control structures in reducing nutrient loads to downstream receiving systems if the hydraulic residence time of the system is significantly increased with multiple weirs, as a result of ditch length and slope.

This study examined a comparative degradation of various chlorinated phenolic compounds including phenol, 4-chlorophenol (4-CP), 2,6-dichlorophenol (2,6-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP), and pentachlorophenol (PCP) using 28, 580, and 1,000 kHz ultrasonic reactors. The concentration of hydrogen peroxide was also determined in order to investigate the efficacy of different sonochemical reactors for hydroxyl radical production. Clearly, it was observed that the 580 kHz sonochemical reactor had maximum efficacy for hydroxyl radical production. The degradation of all the compounds followed the order; 580 kHz (91–93%) > 1,000 kHz (84–86%) > 28 kHz (17–34%) with an initial concentration of 2.5 mg L−1 at a reaction time of 40 min with ultrasonic power of 200 ± 3 W and aqueous temperature of 20 ± 1°C in each experiment. Overall, the degradation of those phenolic compounds followed the order, PCP > 2,3,4,6-TeCP > 2,4,6-TCP > 2,6-DCP > 4-CP > phenol at various frequencies in the presence/absence of a radical scavenger (tert-butyl alcohol). It was revealed that the correlations between the compound degradation rates and the physicochemical parameters, R 2 = 0.99 for octanol–water partition coefficient, R 2 = 0.95 for water solubility, R 2 = 0.94 for vapor pressure, and R 2 = 0.88 for Henry’s law constant, excluding PCP, were very good in the entire range of each parameter.

Methane fluxes in alpine ecosystems remain insufficiently studied, especially in terms of the magnitude, temporal, and spatial patterns. To quantify the mean methane emission of alpine ecosystems, methane fluxes were measured among six ecosystems and microsites within each ecosystem at Zoige National Wetland Reserve. The average methane emission from Zoige Plateau was 2.25 mg CH4 m−2 h−1, which fell into the range of methane emission rate reported by a number of studies in other alpine wetlands. Prevailing ecosystem types had important impacts on the methane flux on the landscape scale. In the wet ecosystems, the microsites had different methane emissions resulting from the differences in the depth of water table and associated vegetation characteristics. The identification of the microsites based on their vegetation characteristics thus allows upscaling of methane emissions in these ecosystems. However, in the dry ecosystems showing even methane uptake, the spatial variation in the methane fluxes was low and the vegetation has a poor predicative value for the methane fluxes. There, the soil porosity linked to the gas diffusion rate in soil would be the key factor explaining methane fluxes.

Different substrates were evaluated to investigate their effect on nitrate removal and denitrifying bacterial community in soils obtained from wetland. Serial batch kinetic tests were conducted on soils obtained from wetland mixed with glucose and sawdust using KNO3 solution. Column tests were also conducted on soils obtained from wetland mixed with three different substrates (glucose, sawdust, and scoria coated with zero-valent iron) using KNO3 solution. For the batch tests, the nitrate removal efficiency for soil mixed with glucose was comparable to that for soil mixed with sawdust, but the nitrate removal rate for soil mixed with glucose (23.3 NO3 −-N mg/L-d) was approximately eight times higher than that for soil mixed with sawdust (2.8 NO3 −-N mg/L-d). For column tests among soil samples, nitrate removal efficiency was highest in soil mixed with glucose, which is an easily biodegradable carbon source. Removal efficiency increased with increasing incubation time for both soil samples with glucose and sawdust. A phylogenetic analysis based on nitrate reductase gene demonstrated that the different carbon sources affected both the diversity and compositions of the denitrifying bacterial in soil samples.

Methylibium petroleiphilum PM1, which is capable of degrading of methyl tert-butyl ether (MTBE), was immobilized in calcium alginate gel beads. Various applications were explored to increase the mechanical strength of these gel beads. The introduction of 0.3 mol/L calcium chloride into the crosslinking solution, 0.002 mol/L calcium chloride into the growth medium, and 0.2% polyethyleneimine (PEI) as chemical crosslinking agent increased the stability of the Ca-alginate gel beads under the operation conditions of the bioreactor. The degradation rates of MTBE by the immobilized cells in the bioreactor system operated in batch and continuous mode , respectively, were compared. A MTBE biodegradation rate of 5.79 mg/L·h was reached for over 400 h (50 batches), and the immobilized cells in the bioreactor removed >96% MTBE during 50 days of operation. Molecular analysis of the PM1 cells revealed that microbial growth occurred predominantly as microcolonies in the outer area of the beads during the first 20 days of operation. The results of this study show that a continuous-mode, fixed-bed bioreactor reactor coupled with PM1-immobilized cells is a promising technology for remediating MTBE-contaminated groundwater.

Photocatalytic degradation of bisphenol A (2,2-bis(4-hydroxyphenyl)propane, BPA), a representative endocrine-disrupting compound, was carried out in the presence of the Ti-MCM-41 mesoporous molecular sieve in this investigation. The degradation rate was strongly dependent on those factors such as the catalyst, catalyst amount, radiation time, and pH value. The photolysis reaction was found to follow the Langmuir-Hinshelwood model. After the photocatalytic treatment, decomposition of BPA rendered five intermediates as follows: 2-methyl-2,3-dihydrobenzofuran, 4-hydroxyacetophenone, 1,1-diethoxyethane, isobutanol, and 3-methylbutanal, which could be the direct evidence supporting our proposal for the degradation mechanism.

The efficiency of UV- and VUV-based processes (UV, VUV, UV/H2O2, and VUV/H2O2) for removal of sulfamethoxazole (SMX) in Milli-Q water and sewage treatment plant (STP) effluent was investigated at 20°C. The investigated factors included initial pH, variety of inorganic anions (NO3 − and HCO3 −), and humic acid (HA). The results showed that the degradation of SMX in Milli-Q water at both two pH (5.5 and 7.0) followed the order of VUV/H2O2 > VUV > UV/H2O2 > UV. All the experimental data well fitted the pseudo-first order kinetic model and the rate constant (k) and half-life time (t 1/2) were determined accordingly. Indirect oxidation of SMX by generated .OH was the main degradation mechanism in UV/H2O2 and VUV/H2O2, while direct photolysis predominated in UV processes. The quenching tests showed that some other reactive species along with .OH radicals were responsible to the SMX degradation under VUV process. The addition of 20 mg L−1 HA significantly inhibited SMX degradation, whereas, the inhibitive effects of NO3 − and HCO3 − (0.1 mol L−1) were observed as well in all processes except in UV irradiation for NO3 −. The removal rate decreased 1.7–3.6 times when applying these processes to STP effluent due to the complex constituents, suggesting that from the application point of view the constituents of these complexes in real STP effluent should be considered carefully prior to the use of UV-based processes for SMX degradation.

Artemisia vulgaris (mugwort) is a tall (1.0–2.0 m) high biomass perennial herb which accumulates considerable amounts of metals on contaminated sites. An outdoor pot experiment was conducted on a sandy, slightly alkaline soil of moderate fertility to study the uptake of cadmium and the distribution of Cd in plant tissues of A. vulgaris. Cadmium was applied as CdCl2 (a total of 1 l solution of 0, 10, 50 and 100 mg Cd l−1) to 12-l pots with a height of 25 cm. HNO3- and water-extractable concentrations of Cd were correlated with the applied Cd at 2-cm soil depth, but were not correlated at 20-cm soil depth, suggesting that Cd was either not mobile in the soil or completely taken up by mugwort roots. The Cd concentrations in different organs of A. vulgaris and litter increased with increasing soil contamination. Leaf/soil concentration ratios (BCFs) up to 65.93 ± 32.26 were observed. Translocation of Cd to the aboveground organs was very high. The leaf/root Cd concentration ratio (translocation factor) ranged from 2.07 ± 0.56 to 2.37 ± 1.31; however, there was no correlation of translocation factors to Cd enrichment, indicating similar translocation upon different soil contamination levels. In summary, A. vulgaris is tolerant to the metal concentrations accumulated, has a high metal accumulating biomass and accumulates Cd up to about 70% in the aboveground parts. Both a high phytoextraction potential and a high value for phytostabilisation would recommend mugwort for phytoremediation.