Comparison between absorption and biological activity on the efficiency of the biotrickling filtration of gaseous streams containing ammonia

Polluted air streams can be purified using biological treatments such as biotrickling filtration, which is one of the most widely accepted techniques successfully tuned to treat a wide variety of exhausted gaseous streams coming from a series of industrial sectors such as food processing, flavor manufacturers, rendering, and composting. Since the degradation of a pollutant occurs at standard pressure and temperature, biotrickling filtration, whether compared with other more energy-demanding chemical-physical processes of abatement (such as scrubbing, catalytic oxidation, regenerative adsorption, incineration, advanced oxidation processes, etc.), represents a very high energy-efficient technology. Moreover, as an additional advantage, biodegradation offers the possibility of a complete mineralization of the polluting agents. In this work, biotrickling filtration has been considered in order to explore its efficiency with respect to the abatement of ammonia (which is a highly water-soluble compound). Moreover, a complete mathematical model has been developed in order to describe the dynamics of both absorption and biological activities which are the two dominant phenomena occurring into these systems. The results obtained in this work have shown that the absorption phenomenon is very important in order to define the global removal efficiency of ammonia from the gaseous stream (particularly, 44% of the ammonia is abated by water absorption). Moreover, it has been demonstrated (through the comparison between experimental results and theoretical simulations) that the action of bacteria, which enhance the rate of ammonia transfer to the liquid phase, can be modeled through a simple Michaelis-Menten relationship.

     

Contribution of vehicular traffic and industrial facilities to PM10 concentrations in a suburban area of Caserta (Italy)

PM10 levels have been recorded in the suburban area of Caserta (Italy) from February to October 2012. The daily limit was exceeded in 13 % of the determinations, with no significant difference between weekdays and weekends. Benzo[a]pyrene concentrations were in the range 0.01–0.46 ng/m³, thus, never exceeding the National Standard. The B(a)P-eq was 0.20 ng/m³. PM10 peaks were associated with wind from east–northeast. The same was observed for Ca concentrations, whereas no relation with wind direction was observed for organic pollutants. The results point to a local limestone quarry and cement factory as the likely major source of PM10 pollution in the area investigated.     

Degradation of Post-consumer PLA: Hydrolysis of Polymeric Matrix and Oligomers Stabilization in Aqueous Phase

Degradation of post-consumer PLA to lactic acid was analysed in order to assess the economic feasibility of the PLA chemical recycling process. Hydrolysis of PLA, in batch reactor, was analysed in the temperature range of 443–473 K, under autogenous pressure and a constant PLA to water ratio (equal to approximately 0.11 by weight), without the use of a catalyst. The experimental results suggest that the complete degradation of PLA can be obtained using relatively low reaction-times with the production of a mixture containing the monomer and traces of the dimer of lactic acid. The overall process was modelled using a two-step process: bulk degradation of PLA (in the solid or molten phase) with the solubilisation of low molecular weight oligomers, and their subsequent hydrolysis in water (stabilization). The model describes the trend of oligomer concentrations in the aqueous phase and PLA conversion as a function of time with both high accuracy and agreement with experimental results.     

Lignin/Poly(ε-Caprolactone) Blends with Tuneable Mechanical Properties Prepared by High Energy Ball-Milling

Polymer blends between lignin, a natural, widely available, no-cost material, and Poly(ε-caprolactone) (PCL), a biodegradable polymer, have been prepared using the ‘clean’, friendly to the environment, technique of the High Energy Ball Milling (HEBM). Two kinds of lignin have been used, Straw lignin, obtained through the Steam Explosion process (SE lignin), and/or Lignosulphonated one (LS lignin). The tensile mechanical tests have shown that, at certain specific compositions, the blends, in particular those with both SE and LS lignin, have good mechanical properties. In particular, by varying the blend composition it is possible to obtain materials with tuneable properties, therefore useful for different applications. Dynamic-Mechanical-Thermal Analysis (DMTA) reveals substantial immiscibility of the blends. Experiments of UV irradiation show that lignin acts as an UV stabilizer for PCL. The effect is higher with SE lignin, likely due to its low molecular weight, which allows the short lignin chains to diffuse more easily within the amorphous regions of PCL.     

Modelling the biphasic sorption of simazine,imidacloprid, and boscalid in water/soil systems

The sorption kinetics of simazine (6-chloro-N,N′-diethyl-1,3,5-triazine-2,4-diamine), imidacloprid (1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine), and boscalid (2-chloro-N-(4′-chlorobiphenyl-2-yl)nicotinamide), three pesticides of wide use in agriculture, was determined in five different water/soil systems over a time interval from the initial few seconds to about 1 month. In all the experiments, sorption kinetics showed a biphasic pattern characterized by an initial, relatively short phase with a high sorption rate and a later phase with much a lower sorption rate. Initial sorption capacity increased with soil organic carbon content and with sorbate hydrophobicity. We postulate that the first phase of the process involves a fast second-order sorption reaction on superficial sites of soil particles, whereas the second phase depends on diffusion-controlled migration to internal binding sites. A kinetic equation based on this hybrid model accurately fitted all data sets. Less satisfactory results were obtained employing the pseudo-first order, pseudo-second order, Elovich, two site non-equilibrium, or Weber-Morris equation. The superior performance of the hybrid model for describing boscalid sorption probably reflects the high hydrophobic character and consequent low diffusion rates of this compound. The accuracy of modelling was in any case strongly dependent on the time interval considered.     

Toxic effects of four sulphonylureas herbicides on soil microbial biomass

The effect of four triazinyl-sulfonylurea herbicides (cinosulfuron, prosulfuron, thifensulfuron methyl, triasulfuron) on soil microbial biomass, soil respiration, metabolic activity, metabolic quotient, and some enzymatic activities (acid and alkaline phosphatase, β-glucosidase, arylsulphatase, and fluorescein diacetate hydrolysis) were monitored under controlled conditions over 30 days. The herbicides were applied at the normal field dose (FD) and at ten-fold (10 FD) the field dose, in order to mimic a long term toxic effect. The measured soil microbial parameters showed that the FD had slight effects on soil microflora, while at 10 FD the tested herbicides exerted a stronger detrimental effect on soil microbial biomass and its biochemical activities.     

Assessment of susceptibility of olive cultivars to the Bactrocera oleae (Gmelin, 1790) and Camarosporium dalmaticum (Thüm.) Zachos & Tzav.-Klon. attacks in Calabria (Southern Italy)

Within the framework of research concerning the application of techniques alternative to chemical pesticides for control of parasites, the C.R.A. Experimental Institute for Olive Growing for many years has been performing a large investigation in order to detect sources of genetic resistance in olive germplasm. In the present study we observed the behavior related to the olive fly (Bactrocera oleae) infestation and Camarosporium dalmaticum infection of ten olive cultivars farmed under the same agronomic and climatic conditions in Calabria, Southern Italy. The sampling and the data collecting were carried out in three different ripening times.The drupe amount of oleuropein and cyanidine was detected by laboratory analyses in order to verify a possible correlation between these molecules and the level of infestation/infection of the above-mentioned parasites. The obtained data were submitted to analysis of variance. In relation to the fungal infection the results displayed that cvs Tonda nera dolce showed the lowest susceptibility, while the cv Giarraffa turned out to be the most susceptible. The less susceptible cultivars to the phytophagous were Tonda nera dolce and Bhardi Tirana. Since the less susceptible cultivar to olive fly attacks are the same observed in relation to the susceptibility to olive fruit rot, it is suggested a relation between the olive fly infestation and the fungal infection. It suggests the utility to achieve these results both to transfer directly to the farmers' world and to emphasize ecosystem health and biodiversity conservation.