Environmental fate of triasulfuron in soils amended with municipal waste compost

This work was partially supported by the Leonardo da Vinci 2001. Degradation of imazosulfuron in soil. Pest Manage. Sci. program of the European Commission as part of the project 57:360–365. Pichon, V., C. Cau Dit Coumes, L. Chen, S. Guenu, and M.-C. Hen- ISDEPS 2002.The amendment of soil with compost may significantly influence the mobility and persistence of pesticides and thus affect their environmental fate. Factors like adsorption, kinetics, and rate of degradation of pesticides could be altered in amended soils. The aim of this study was to determine the effects of the addition of compost made from source-separated municipal waste and green waste, on the fate of triasulfuron [(2-(2-chloroethoxy)-N-[[4-methoxy-6-methyl- 1,3,5-triazin-2-yl)amino] carbonyl]benzenesulfonamide], a sulfonylurea herbicide used in postemergence treatment of cereals. Two native soils with low organic matter content were used. A series of analyses was performed to evaluate the adsorption and degradation of the herbicide in soil and in solution after the addition of compost and compost-extracted organic fractions, namely humic acids (HA), fulvic acids (FA), and hydrophobic dissolved organic matter (HoDOM). Results have shown that the adsorption of triasulfuron to soil increases in the presence of compost, and that the HA and HoDOM fractions are mainly responsible for this increase. Hydrophobic dissolved organic matter applied to the soils underwent sorption reactions with the soils, and in the sorbed state, served to increase the adsorption capacity of the soil for triasulfuron. The rate of hydrolysis of triasulfuron in solution was significantly higher at acidic pH and the presence of organic matter fractions extracted from compost also slightly increased the rate of hydrolysis. The rate of degradation in amended and nonamended soils is explained by a two-stage degradation kinetics. During the initial phase, although triasulfuron degradation was rapid with a half-life of approximately 30 d, the presence of compost and HoDOM was found to slightly reduce the rate of degradation with respect to that in nonamended soil.peer-reviewe

Gas Hydrates Formation for High – Efficiency Waste Water Treatment: Experimental Removal of NH4+ from Water via CO2 Hydrates Formation

Waste water treatment is an essential and mandatory step for most of the industrial processes involving water. It has been widely proved that the overconsumption of this source, together with the exponential growth of anthropogenic damaging processed, lowered the quality of groundwater and, more in general, water resources, at an alarming pace. The removal of salts, ions dissolved in water and other effluents, can be carried out through several methods. Membrane separation, evaporation and crystallization are the most applied for water recovery, while membrane, chemical precipitation, adsorption, ion exchange and freezing/thawing are the most effective techniques for heavy metal ion solutions. When applying these procedures, some critical aspects must be considered, mainly associated to removal efficiency, costs, availability and non-toxicity of the raw materials, environmental concerning and other. In this context, gas hydrates can be considered an alternative solution for water treatment, capable to overcome all the critical issues related to the traditional strategies. In particular, the formation of gas hydrates for ion removal from waste water, was proved to reach extremely high efficiencies; moreover, the removal efficiency was found to be proportional to the size of ions and to decrease with their charge. Based on these experimental considerations, this study deals with preliminary research on the removal of NH4+ from water. This species consists of one of the most affecting pollutants in bio – refineries and its removal is often energy intensive, with consequent high costs. Experiments were carried out in a lab – scale apparatus, where water was initially threated with ammonium chloride at specific concentration. Carbon dioxide was finally chosen for the formation of hydrates

Assessing the agricultural reuse of the digestate from microalgae anaerobic digestion and co-digestion with sewage sludge

Microalgae anaerobic digestion produces biogas along with a digestate that may be reused in agriculture. However, the properties of this digestate for agricultural reuse have yet to be determined. The aim of this study was to characterise digestates from different microalgae anaerobic digestion processes (i.e. digestion of untreated microalgae, thermally pretreated microalgae and thermally pretreated microalgae in co-digestion with primary sludge). The main parameters evaluated were organic matter, macronutrients and heavy metals content, hygenisation, potential phytotoxicity and organic matter stabilisation. According to the results, all microalgae digestates presented suitable organic matter and macronutrients, especially organic and ammonium nitrogen, for agricultural soils amendment. However, the thermally pretreated microalgae digestate was the least stabilised digestate in comparison with untreated microalgae and co-digestion digestates. In vivo bioassays demonstrated that the digestates did not show residual phytotoxicity when properly diluted, being the co-digestion digestate the one which presented less phytotoxicity. Heavy metals contents resulted far below the threshold established by the European legislation on sludge spreading. Moreover, low presence of E. coli was observed in all digestates. Therefore, agricultural reuse of thermally pretreated microalgae and primary sludge co-digestate through irrigation emerges a suitable strategy to recycle nutrients from wastewater

Covid-19 And Rheumatic Autoimmune Systemic Diseases: Role of Pre-Existing Lung Involvement and Ongoing Treatments

The Covid-19 pandemic may have a deleterious impact on patients with autoimmune systemic diseases (ASD) due to their deep immune-system alterations

Production of CH₄/C₃H₈ (85/15 vol%) Hydrate in a Lab-Scale Unstirred Reactor: Quantification of the Promoting Effect Due to the Addition of Propane to the Gas Mixture

By itself, propane is capable to form hydrates at extremely contained pressures, if compared with the values typical of “guests” such as methane and carbon dioxide. Therefore, its addition in mixtures with gases such as those previously mentioned is expected to reduce the pressure required for hydrate formation. When propane is mixed with carbon dioxide, the promoting effect cannot be observed since, due to their molecular size, these two molecules cannot fit in the same unit cell of hydrates. Therefore, each species produces hydrates independently from the other, and the beneficial effect is almost completely prevented. Conversely, if propane is mixed with methane, the marked difference in size, together with the capability of methane molecules to fit in the smaller cages of both sI and sII structures, will allow to form hydrates in thermodynamic conditions lower than those required for pure methane hydrates. This study aims to experimentally characterize such a synergistic and promoting effect, and to quantity it from a thermodynamic point of view. Hydrates were formed and dissociated within a silica porous sediment and the results were compared with the phase boundary equilibrium conditions for pure methane hydrates, defined according to experimental values available elsewhere in the literature. The obtained results were finally explained in terms of cage occupancy

A long-term chemical and infrared spectroscopy study on a soil amended with municipal sewage sludge

A long-term field experiment was carried out to evaluate the effect of a seven-year soil amendment with municipal sewage sludge on chemical fertility, soil enzyme activities and the changes in the composition of humic substances. The amended soil showed an increase in total and NaOH soluble organic C, available P and K. The heavy metals contained in the sludge did not affect soil phosphatases (alkaline phosphomonoesterase and phosphodiesterase), arylsulphatase or L-asparaginase activity, even if the concentration of total and available Cu, Ni and Zn increased in the arable layer of soil. The fulvic acids FT-IR spectra showed that amended soil contains a higher concentration of carboxylic and aliphatic groups and polysaccharides compared to unamended soil. The polysaccharide increase in the seven-year amended soil is attributable to the humification process since only a small amount of polysaccharides were present in the sludge. The humic acids FT-IR spectra showed that amended soil contained a higher concentration of aliphatic and N-containing groups and a lower concentration of polysaccharides than unamended soil. The humification parameters (i.e. humification ratio, humification index and degree of humification) highlighted the differences in the humification status between sludge humic-like substances and humus from soil, but were unable to show the differences between unamended and amended soils.Étude chimique et spectroscopique à long terme sur un sol amendé par épandage des eaux de l'égout municipal. On a effectué une étude de terrain sur sept ans pour évaluer l'effet, sur la fertilité chimique, sur les activités enzymatiques du sol et sur les variations dans la composition de substances humiques, d'un sol amendé pendant sept ans avec des eaux d'égout. On a relevé, dans le sol ainsi soumis à épandage, une augmentation de C organique total et humifié et de P et K disponibles. La présence de métaux lourds dans les eaux d'égout n'affectent pas l'activité de phosphatase du sol (phospho-monoestérase et phospho-diestérase), aryl-sulfatase ou L-asparaginase, même si l'on a pu relever une augmentation de la teneur en Cu, Ni et Zn totaux et disponibles dans la couche arable du sol. Le spectre FT-IR de l'acide fulvique a montré que les sols amendés contiennent une concentration plus élevée de groupes carboxyliques et aliphatiques et de polysaccharides que le sol non amendé. On peut attribuer au processus d'humification l'augmentation en polysaccharides du sol amendé pendant sept ans, car les eaux d'égout ne contenaient qu'une quantité réduite de polysaccharides. Le spectre FT-IR de l'acide humique a montré que, comparé au sol non amendé, le sol amendé présente une teneur plus élevée en groupes aliphatiques et en groupes azotés et une concentration plus basse de polysaccharides. Les données provenant du paramètre d'humification (c'est-à-dire rapport d'humification, grade d'humification et indice d'humification) ont mis en évidence les différences de condition d'humification entre les substances humicoles contenues dans les eaux d'égout et l'humus contenu dans le sol, mais non les différences entre sol amendé et sol non amendé

Mechanisms of Pb (II) sorption and desorption at some clays and goethite-water interfaces

The aim of this research is to corroborate the results obtained with Pb (II) sorption and desorption macroscopic equilibrium studies on some soil minerals (montmorillonite, illite, kaolinite and goethite) using microscopic techniques. The sorption isotherms demonstrate that the adsorption capability of the substrates varies in the following sequence: illite $>$ montmorillonite $>$ kaolinite $>$ goethite, and the desorption isotherms demonstrate the irreversibility of the bonds formed. pH adsorption edges on montmorillonite show that at a pH lower than the hydrolysis point the sorption edge is primarily due to ion exchange, while at a pH higher than the hydrolysis point, it is a combination of both ion exchange and precipitation. The EDS semi-quantitative analysis performed by SEM demonstrates that in the clays Pb replaced almost exclusively Ca ions. In the montmorillonite this replacement may also include the Ca ions in the interlayer space, and in the illite also, the replacement of protonated OH groups and the K ions situated at the edge of interlattice sites. Goethite shows an adsorption capability of the same magnitude as kaolinite.Mécanismes d'absorption et de désorption du Pb (II) à l'interface entre solution aqueuse et certaines argiles et la goethite. L'objectif de cette recherche est d'étayer, au moyen de techniques microscopiques, les résultats obtenus par le biais d'études macroscopiques d'équilibre sur l'absorption et la désorption du Pb (II) sur certains composants minéraux du sol (montmorillonite, illite, kaolinite et goethite). Les isothermes d'absorption ont montré que la capacité d'adsorption des substrats variait de la façon suivante : illite $>$ montmorillonite $>$ kaolinite $>$ goethite, et les isothermes de désorption ont démontré l'irréversibilité des liens formés. La variation du pourcentage de Pb adsorbé par la montmorillonite en fonction du pH montrait que, lorsque l'on a une valeur de pH inférieure au point d'hydrolyse, l'absorption est principalement due à une réaction d'échange ionique alors que, lorsque l'on a une valeur de pH supérieure au point d'hydrolyse, l'absorption est due à une combinaison de réactions d'échange ionique et précipitation. Les analyses semi-quantitatives effectuées au microscope électronique à balayage (MEB) couplé à la micro-analyse aux rayons X par dispersion d'énergie (EDS) ont démontré que, dans les argiles, le Pb remplaçait exclusivement les ions Ca. Dans la montmorillonite, cette substitution pourrait intéresser aussi les ions Ca de l'espace interlamellaire et, dans l'illite, il pourrait également y avoir substitution de groupes OH protonés et d'ions K situés au bord des sites interstrates. La goethite a montré une capacité d'adsorption équivalente à celle de la kaolinite

Experimental Study of Cavitation Unsteadiness and Erosion on a Plane Convex Hydrofoil.

International audienceCavitation is a major issue in hydraulic machinery, it causes performance drop, vibrations increase, and damage due to erosion. This research is dedicated to the identification of different cavitation erosion mechanisms and proposes tools to quantify the erosive potential of a cavitating flow close to a moving boundary. Experiments were conducted on a plano-convex hydrofoil placed in the center of a cavitation tunnel where the fluid velocity, the overall pressure, and the angle of attack of the hydrofoil can be varied. Fast imaging recording and stereo particle image velocimetry were used to identify the characteristics of the flow. Previously, it has been shown that in steadyconditions, cavitation exhibits three different regimes depending on the cavitation number and the angle of attack. In this work, we recreated the conditions for each cavitating regime and added a rapid motion to the hydrofoil, which starts from a steady position at a given angle of attack and goes rapidly to a null inclination where it stops. The three mentioned regimes are characterized by the size and shedding behavior of the cavitation cloud, and these characteristics change when the hydrofoil is moving. Three modes of cavitation collapse were identified depending on the acceleration of the hydrofoil. For relatively small angular accelerations a soft collapse of the cavity is observed (mode I). The cavity remains attached to the hydrofoil leading edge and collapses by the upstream movement of its closure region towards the leading edge. For larger accelerations, the leading-edge cavity turns into a cloud that is entrained by the flow and collapses in a symmetrical way (mode II). Mode III is the post-motion collapse mode that is observed for the largest values of the angular acceleration and take place when the foil has reached the null inclination. The collapses in these three modes were compared to the cloud shedding in thestationary regime, and a relation between the stationary shedding and the hydrofoil motion collapse was established. We have compared the velocity profiles around the hydrofoil for the non-cavitating case, and the cavitating cases with stationary and moving hydrofoil. Results show that the cavitation collapse has a significantimpact on the fluid velocity field