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Organic Pollutants Removal from Olive Mill Wastewater using a new Ecosystem Treatment Texto completo
2023
Bougassa, Rim | Tahri, Latifa | Nassri, Ilham | Fekhaoui, Mohammed
Olive mill wastewater is the main by-product derived from olive mills using the three-phase extraction process,displaying a serious environmental risk due to its notable content in organics and phenolics Olive oil production, an agro-industrial of vital economic particularly in Mediterranean countries, is unfortunately associated with the generation of large quantities of OMW (Olive Mill Wastewater) and solid wastes. The OMW is considered a major environmental problem, it is a powerful pollutant rejected in nature without any prior treatment. This research work aims to study the treatment of OMW by a new ecological and economic system, which consists of the use of the following components: gravel, sawdust, soil, activated carbon, bamboo, and the valorization of the solid residues. HPLC analysis showed that hydroxytyrosol is the most abundant biophenol. Many other biophenols were identified (Tyrosol, gallic acid, and eleonic acid). The comparison between before and after filtration by the new system showed an essential degradation of phenolic compounds after treatment and found a new compound resulting from their degradation.
Mostrar más [+] Menos [-]A Review of Air Pollution and Solutions Way Management Related to Ribbed Smoked Sheets (RSS) Production of Community-Level Rubber Cooperatives in Thailand: Smoke, Soot and PAHs particles Texto completo
2020
Kalasee, W. | Teekapakvisit, C.
In Thailand, RSS chamber of community-level rubber cooperatives can be classified into two models: old and new model, named after the years of their establishment. Hot gas as a heat supply from Para-rubber (PR) wood (Hevea brasiliensis) combustion is used for removing moisture from the natural rubber (NR) sheets. Smoke and soot particles from PR wood burning has effected to the quality of the NR sheet and the pollution in the workplace area and lead to health problems of the worker. Cascade impactors are equipment for measuring the smoke and soot particles size distribution from PR wood combustion. PAHs compounds from PR wood combustion were found 15 different PAHs components (Tekasakul et al., 2005; Furuuchi et al., 2006). Important methods in decreasing smoke and soot particles from combustion of PR wood for rubber smoking chamber are separation equipment and ventilation designed by computational fluid dynamics (CFD) technique. In this article, the separation method is focused on smoke and soot particle collection to maintain the quality of the NR sheet. This equipment is reviewed both indoor and outdoor, for example, an impaction wall, electrostatic precipitator, stainless-wire, etc. This review indicates that the ESP installing between the furnace and the smoking chamber is suitable to eliminate aerosol particles at the rubber smoking industry. In addition, CFD technique reports is aimed at collecting aerosol particles for decreasing smoke and soot particles emission from rubber smoking chamber is presented.
Mostrar más [+] Menos [-]Evaluation of methods to determine adsorption of polycyclic aromatic hydrocarbons to dispersed carbon nanotubes Texto completo
2017
Glomstad, Berit | Sørensen, Lisbet | Liu, Jingfu | Shen, Mohai | Zindler, Florian | Jenssen, Bjørn Munro | Booth, Andy
A number of methods have been reported for determining hydrophobic organic compound adsorption to dispersed carbon nanotubes (CNTs), but their accuracy and reliability remain uncertain. We have evaluated three methods to investigate the adsorption of phenanthrene (a model polycyclic aromatic hydrocarbon; PAH) to CNTs with different physicochemical properties; dialysis tube (DT) protected negligible depletion solid phase microextraction (DT-nd-SPME), ultracentrifugation and filtration using various types of filters. Dispersed CNTs adhered to the unprotected PDMS-coated fibers used in nd-SPME. Protection of the fibers from CNT adherence was investigated with hydrophilic DT, but high PAH sorption to the DT was observed. The efficiency of ultracentrifugation and filtration to separate CNTs from the water phase depended on CNT physicochemical properties. While non-functionalized CNTs were efficiently separated from the water phase using ultracentrifugation, incomplete separation of carboxyl functionalized CNTs was observed. Filtration efficiency varied with different filter types (composition and pore size), and non-functionalized CNTs were more easily separated from the water phase than functionalized CNTs. Sorption of phenanthrene was high (<70%) for three of the filters tested, making them unsuitable for the assessment of phenanthrene adsorption to CNTs. Filtration using a hydrophilic polytetrafluoroethylene (PTFE) filter membrane (0.1 µm) was found to be a simple and precise technique for the determination of phenanthrene adsorption to a range of CNTs, efficiently separating all types of CNTs and exhibiting a good and highly reproducible recovery of phenanthrene (82%) over the concentration range tested (70-735 µg/L). | acceptedVersion
Mostrar más [+] Menos [-]Co-transport and co-release of Eu(III) with bentonite colloids in saturated porous sand columns: Controlling factors and governing mechanisms Texto completo
2022
Accurate prediction of the colloid-driven transport of radionuclides in porous media is critical for the long-term safety assessment of radioactive waste disposal repository. However, the co-transport and corelease process of radionuclides with colloids have not been well documented, the intrinsic mechanisms for colloids-driven retention/transport of radionuclides are still pending for further discussion. Thus the controlling factors and governing mechanisms of co-transport and co-release behavior of Eu(III) with bentonite colloids (BC) were discussed and quantified by combining laboratory-scale column experiments, colloid filtration theory and advection dispersion equation model. The results showed that the role of colloids in facilitating or retarding the Eu(III) transport in porous media varied with cations concentration, pH, and humic acid (HA). The transport of Eu(III) was facilitated by the dispersed colloids under the low ionic strength and high pH conditions, while was impeded by the aggregated colloids cluster. The enhancement of Eu(III) transport was not monotonically risen with the increase of colloids concentration, the most optimized colloids concentration in facilitating Eu(III) transport was approximately 150 mg L⁻¹. HA showed significant promotion on both Eu(III) and colloid transport because of not only its strong Eu(III) complexion ability but also the increased dispersion of HA-coated colloid particles. The HA and BC displayed a synergistic effect on Eu(III) transport, the co-transport occurred by forming the ternary BC-HA-Eu(III) hybrid. The transport patterns could be simulated well with a two-site model that used the advection dispersion equation by reflecting the blocking effect. The retarded Eu(III) on the stationary phase was released and remobilized by the introduction of colloids, or by a transient reduction in cation concentration. The findings are essential for predicting the geological fate and the migration risk of radionuclides in the repository environment.
Mostrar más [+] Menos [-]Efficiency of the bank filtration technique for diclofenac removal: A review Texto completo
2022
de Carvalho Filho, José Adson Andrade | da Cruz, Hedmun Matias | Fernandes, Bruna Soares | Motteran, Fabrício | de Paiva, Anderson Luiz Ribeiro | Cabral, Jaime J. P. (Jaime Joaquim Pereira)
Bank filtration (BF) has been employed for more than a century for the production of water with a better quality, and it has been showing satisfactory results in diclofenac attenuation. Considered the most administered analgesic in the world, diclofenac has been frequently detected in water bodies. Besides being persistent in the environment, this compound is not completely removed by the conventional water treatments, drinking water treatment plants (DWTPs) and wastewater treatment plant (WWTPs). BF has a high complexity, whose efficiency depends on the characteristics of the observed pollutant and on the environment where the system in installed, which is why this is a topic that has been constantly studied. Nevertheless, studies present the behavior of diclofenac during the BF process. In this context, this research performed the evaluation of the factors and the biogeochemical processes that influence the efficiency of the BF technique in diclofenac removal. The aerobic conditions, higher temperatures, microbial biomass density, hydrogen potential close to neutrality and sediments with heterogeneous fractions are considered the ideal conditions in the aquifer for diclofenac removal. Nonetheless, there is no consensus on which of these factors has the greatest contribution on the mechanism of attenuation during BF. Studies with columns in laboratory and modeling affirm that the highest degradation rates occur in the first centimeters (5–50 cm) of the passage of water through the porous medium, in the environment known as hyporheic zone, where intense biogeochemical activities occur. Research has shown 100% removal efficiency for diclofenac persistent to compounds not removed during the BF process. However, half of the studies had removal efficiency that ranged between 80 and 100%. Therefore, the performance of more in-depth studies on the degradation and mobility of this compound becomes necessary for a better understanding of the conditions and biogeochemical processes which act in its attenuation.
Mostrar más [+] Menos [-]Responses of Asian clams (Corbicula fluminea) to low concentration cadmium stress: Whether the depuration phase restores physiological characteristics Texto completo
2021
Wang, Zhen | Kong, Fanlong | Fu, Lingtao | Li, Yue | Li, Minghui | Yu, Zhengda
The effect of low concentration Cd stress on bivalves is unclear. In this study, Asian clams (Corbicula fluminea) were continuously exposed to 0, 0.05, 0.10, and 0.20 mg/L Cd for 14 d (exposure phase) and to artificial freshwater for 7 d (depuration phase). A total of 16 variables were measured to explore the toxic effects on C. fluminea. All physiological characteristics were significantly inhibited in the treatments (p < 0.05), and the negative effects of Cd did not return to normal levels in the short term. Tissue damage was found in the feet and gills of C. fluminea in all the treatments. On the 7th day (D7), enzyme activity in all the treatments was significantly higher (p < 0.05) than in the control group. Acetylcholinesterase, superoxide dismutase, and catalase activities were enhanced on D14 in all the treatments. However, only glutathione S-transferase activity was significantly higher in all the treatments (p < 0.05) than in the control group on D21. The instability of the enzymes indicated that the adaptability of C. fluminea became stronger throughout the experiment. In each group, the maximum bioaccumulation of Cd followed the order: 0.20 mg/L > 0.05 mg/L > 0.10 mg/L, which might be caused by the filtration capacity of C. fluminea in the 0.05-mg/L group, which was higher than that of the 0.10-mg/L group. Thus, low Cd concentrations effect the physiological characteristics, tissue health, and antioxidant system of C. fluminea and may require a long recovery time to be restored to normal levels.
Mostrar más [+] Menos [-]De facto reuse at the watershed scale: Seasonal changes, population contributions, instream flows and water quality hazards of human pharmaceuticals Texto completo
2021
Švecová, Helena | Grabic, Roman | Grabicová, Kateřina | Vojs Staňová, Andrea | Fedorova, Ganna | Cerveny, Daniel | Turek, Jan | Randák, Tomáš | Brooks, Bryan W.
With increasing population growth and climate change, de facto reuse practices are predicted to increase globally. We investigated a longitudinal gradient within the Uhlava River, a representative watershed, where de facto reuse is actively occurring, during Fall and Spring seasons when instream flows vary. We observed human pharmaceutical levels in the river to continuously increase from the mountainous areas upstream to downstream locations and a potable intake location, with the highest concentrations found in small tributaries. Significant relationship was identified between mass flow of pharmaceuticals and the size of human populations contributing to wastewater treatment plant discharges. Advanced ozonation and granular activated carbon filtration effectively removed pharmaceuticals from potable source waters. We observed a higher probability of encountering a number of targeted pharmaceuticals during colder Spring months when stream flows were elevated compared to warmer conditions with lower flows in the Fall despite a dilution paradigm routinely applied for surface water quality assessment and management efforts. Such observations translated to greater water quality hazards during these higher Spring flows. Future water monitoring efforts should account for periods when higher chemical uses occur, particularly in the face of climate change for regions experiencing population growth and de facto reuse.
Mostrar más [+] Menos [-]Acute cardiovascular effects of traffic-related air pollution (TRAP) exposure in healthy adults: A randomized, blinded, crossover intervention study Texto completo
2021
Han, Bin | Zhao, Ruojie | Zhang, Nan | Xu, Jia | Zhang, Liwen | Yang, Wen | Geng, Chunmei | Wang, Xinhua | Bai, Zhipeng | Vedal, Sverre
Exposure to traffic-related air pollution (TRAP) may enhance the risk of cardiovascular disease. However, the short-term effects of TRAP components on the cardiovascular system are not well understood. We conducted a randomized, double-blinded, crossover intervention study in which 39 healthy university students spent 2 h next to a busy road. Participants wore a powered air-purifying respirator (PAPR) or an N95 mask. PAPRs were equipped with a filter for particulate matter (PM), a PM and volatile organic compounds (VOCs) filter or a sham filter. Participants were blinded to PAPR filter type and underwent randomized exposures four times, once for each intervention mode. Blood pressure (BP), heart rate (HR) and heart rate variability (HRV) were measured before, during and for 6 h after the roadside exposure. Linear mixed-effect models were used to evaluate the effects of the interventions relative to baseline controlling for other covariates. All HRV measures increased during and following exposure for all intervention modes. Some HRV measures (SDNN and rMSSD during exposure and SDNN after exposure) were marginally affected by PM filtration. Wearing the N95 mask affected VLF power and rMSSD responses to traffic exposure differently than the PAPR interventions. Both systolic and diastolic BP increased slightly during exposure, but then were generally lower than baseline after exposure for the sham and filter interventions. HR, which fell during exposure and mostly remained lower than baseline after exposure, was lower yet with all filter interventions compared to the sham mode following exposure. Therefore, short-term exposure to traffic acutely affects HRV, BP and HR, but N95 mask and PAPR interventions generally show little efficacy in reducing these effects. Removing the PM component of TRAP has some limited effects on HRV responses to exposure but exaggerates the traffic-related decrease in HR. HRV findings from N95 mask interventions need to be interpreted cautiously.
Mostrar más [+] Menos [-]Separation and identification of microplastics in marine organisms by TGA-FTIR-GC/MS: A case study of mussels from coastal China Texto completo
2021
Liu, Yi | Li, Ruojia | Yu, Jianping | Ni, Fengli | Sheng, Yingfei | Scircle, Austin | Cizdziel, James V. | Zhou, Ying
Microplastics are ubiquitous in the marine environment but characterizing them in marine organisms is challenging. Herein we describe a method to detect, identify, and quantify microplastics in marine mussels (Mytilus edulis) using thermal gravimetric analysis – Fourier Transform infrared spectroscopy – gas chromatography mass spectrometry (TGA-FTIR-GC/MS) after extracting and isolating the microplastics using chemical digestion, density separation, and filtration. Combining the three instrumental techniques adds discriminatory power as temperature profiles, chromatograms, and vibrational and mass spectra differ among common plastics. First, we tested several digestion schemes after spiking the mussels with plastics commonly found in the marine environment, including polyethylene (PE), polystyrene (PS), polypropylene (PP) and polyvinyl chloride (PVC). KOH (10%, w/v) was the most suitable reagent, providing good recoveries (>97%) without degrading the microplastics. We show that the technique TGA-FTIR-GC/MS can be optimized to readily determine both the type (polymer) and amount (mass) of microplastics in the sample. Applied to 100 mussels from each of six locations along the coast of China, we found an average of 0.58 mg of plastic per kg of tissue (range 0.16–1.71 mg/kg), with PE being the most abundant type of plastic measured. Among the coastal cities, mussels from Dalian had the highest microplastic content. Overall, we demonstrate that the method is a powerful technique to quantify masses of microplastics in marine mussels, a species commonly used as a bioindicator of pollution, and may be applied to other biota as well.
Mostrar más [+] Menos [-]Urinary metabolites of polycyclic aromatic hydrocarbons after short-term fine particulate matter exposure: A randomized crossover trial of air filtration Texto completo
2021
Shi, Jiazhang | Zhao, Yan | Xue, Lijun | Li, Guoxing | Wu, Ziyuan | Guo, Xinbiao | Wang, Bin | Huang, Jing
Research on the relationship between short-term exposure to fine particulate matter (PM₂.₅) and urinary metabolites of polycyclic aromatic hydrocarbons (PAHs) is sparse in the nonoccupationally exposed populations. A quasi-experimental observation of haze events nested within a randomized crossover trial of alternative 1-week real or sham indoor air filtration was conducted to evaluate the associations of urinary monohydroxy-PAHs (OH-PAHs) with short-term exposure to PM₂.₅ and PM₂.₅-bound PAHs. The study was conducted among 57 healthy college students in Beijing, China. PM₂.₅-bound PAHs and urinary OH-PAHs were quantified using gas chromatography coupled with a triple-quadrupole tandem mass spectrometer. Linear mixed-effect models were applied to evaluate the association of urinary OH-PAHs with time-weighted personal PM₂.₅ and PM₂.₅-bound PAHs, controlling for potentially confounding variables. The results demonstrated that air filtration could markedly reduce external exposure to PM₂.₅ and PM₂.₅-bound parent, nitrated, and oxygenated PAHs. In the intervention trial, the urinary concentrations of 2-hydroxyfluorene (2-OH-FLU) and 9-hydroxyphenanthrene (9-OH-PHE) were elevated significantly by 16.5% (95% CI, 2.1%, 33.1%) and 37.9% (95% CI, 8.4%, 75.4%), respectively, in association with a doubling increase in personal PM₂.₅ exposure. Urinary 9-OH-PHE was also significantly positively associated with the increase in the sum of PM₂.₅-bound parent PAHs. Furthermore, the levels of urinary OH-PAHs such as 2-OH-FLU and 9-OH-PHE in the haze events were elevated by 31.1% (95% CI, 8.7%, 53.4%) and 73.5% (95% CI, 16.0%, 131.0%), respectively, in association with a doubling increase in personal PM₂.₅ exposure. The findings indicated that urinary 2-OH-FLU and 9-OH-PHE could serve as potential internal exposure biomarkers for assessing short-term PM₂.₅ exposure in nonoccupational populations.
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